The starting points for building your own MechMate - selecting table size, etc.

[Gerald_D]

The very basic thing to do is to decide for yourself what size of MechMate you want to build. You need to pick your own X,Y table (or board) dimensions that you want to achieve and then my drawings will say "cut the rack to length Y plus 150mm" or something like that. The basic MechMate design will work with a fairly wide range of x-table_lengths and y-gantry_widths, but a narrow range of z-slide_heights, being essentially a machine for processing board materials...

Which brings us to the point that you need to know what size boards you want to process, and indirectly, what board you want to use as the table surface. Then you need to decide if you will have twin routers and how far apart they will be in the y-car. The plans will focus on a single router sitting off-center in the y-car, with a big dust hose using the space that others might eye for a second router. But I will give a priority to those building a MechMate similar in configuration to what we built in 2005/2006.

Back to board sizes....in South Africa, MDF is sold as 2750mm x 1830mm boards [9' x 6']. Masonite, Melamine-face chipboard and lots of other stuff also comes as "nine_by_sixes". Plywoods are not that popular, but they come in smaller sizes in any case (2440mmx1220mm or 8'x4'). Apparently the board sizes in America are narrower and gantries can be limited to 5 foot, but here, and in Europe, a 5 foot gantry is too short for most work.

In the plans, I will give dimensions of rails, racks, gantry beams, etc. as X_plus_1234 or Y_plus_567 where X and Y refer to board size. The MechMate will be capable of moving 50mm [2"] more in all directions. ie. a 100mm [4"] diam cutter will travel just clear of the spoilboard, while a smaller cutter can have up to 50mm [2"] breathing space off the edge of the support/spoilboard. (Only valid for a single router).

Out of curiosity, what board sizes will you guys want to be cutting?

[Mike John]

My board sizes are 2070mm x 2800mm

[Gerald_D]

Mike, how typical is that around Europe? Would you be interested in a gantry that managed to cut across the 2070mm?

[Mike John]

Its very typical for mainland Europe.
I'm not certain for the UK.
To date I have never needed anything larger than my table size (1206mmx2560mm), and feel that lengthening the gantry might introduce an element of 'slop'.
The problem for me deciding size is that, at the moment I put 3 'pallets' up at a time for one common tasks, and have just enough room at 1206mm, so feel 1300mm would be nice. But then, am I going to want 1350mm later on?
At the moment I would stick to 1300mm.
How about the length?
Your trick cutting two side pieces from one 6m [ channel for my table saved a lot of money, making the 2560mm cutting a good choice. Does 'rack' come in certain standard lengths?

I already have my welder/fabricator standing by (my son), and a lazer cutting firm as well.
So I am awaiting the final plans with great anticipation. http://www.mechmate.com/Forum/clipart/happy.gif

.........Mike

[Pete Wood]

I love this forum. Just like Mike, I can't wait to get started.

I am based in the UK, so tomorrow I will see what size boards are most readily available.

[Gerald_D]

I know you guys can't wait, but there is some progress with drawings - while I'm not fiddling with other subjects on the forum http://www.mechmate.com/Forum/clipart/happy.gif

[Gerald_D]

Board sizes in UK (http://www.cncrouting.co.uk/Materials.htm)
Board sizes in Australia (http://www.gunnersens.com.au/products/mdf.htm)
more Australia (http://www.dmkforestproducts.com.au/pages/specialty-products.php)

Valchromat coloured mdf sheet size 2500mm x 1250mm

[David Rosenbleeth]

From Above:

I know you guys can't wait, but there is some progress with drawings - while I'm not fiddling with other subjects on the forum

Reply: Time flies when you're having a good time!!! http://www.mechmate.com/Forum/clipart/biggrin.gifhttp://www.mechmate.com/Forum/clipart/biggrin.gifhttp://www.mechmate.com/Forum/clipart/biggrin.gif

[Bojan Regouc]

2070mm x 2800mm

[Gerald_D]

Bojan, would you want a machine to cut full-size or half-size sheets? In other words, have you got workshop space for the big sheets and can you load the sheets with one or two people?

[Holger Erendi]

Hello Gerald,

Nice job with Mechmate!! You got me to rebuild my PRT, I will try to make mine to cut in Y direction 2100mm.

[Gerald_D]

Hi Holger, good to see you here! The 2100mm in the y-direction should be no problem. The MechMate you see in the photos is 1900mm y-travel for cutting boards up to 1830mm wide. Even with the longer, heavier gantry, we have a similar speed/acceleration to the old PRT 1300mm gantry. You might have to set your "ramps" a little bit slower for that long gantry, but you will still have a good performance.

[Gerald_D]

If the MechMate were restricted to four table lengths (X) and four gantry lengths (Y), it would appear that most of the market could be served by the following capabilities: (max board sizes)....

X dimension equals:
1850mm [6.1 ft]
2500mm [8.2 ft]
2800mm [9.2 ft]
3660mm [12 ft]
....or would a 3050mm [10 ft] be a more popular length?

Y dimension equals:
1250mm [4.1 ft]
1530mm [5 ft]
1850mm [6.1 ft]
2070mm [6.8 ft]

(The design allows for 50mm [2 in] extra travel beyond all edges of the above board sizes)

[Mike John]

Gerald
In manufacturing cost terms, is there a great deal between a 1850mm gantry and a 2070mm gantry?
Or for that matter between a 1250mm and a 2070mm?
It seems to be no more than the cost of the longitudal lengths of steel. All the cross pieces and end pieces, the Y carriage, all the manufacturing, the number of cuts and actual assembly, would all be the same.
And I guess this applies to the x direction.
Doubling the length of the table isn't going to double its cost, apart from maybe material. (I say maybe as you need 3 pairs of legs for a 2.5 m table, only 5 pairs for a 5m table.
I recognise you need twice the length of rack, but everything else remains the same.
So, what is the most economical way to go?
If I had the room, I can imagine loading one end of the table with a full sheet, let it cut, move to a sheet on the other end, then change the first sheet.
..........Mike

[Gerald_D]

In manufacturing cost, you are right, it costs very little to up the size. (steel tubes, racks, cables, cable chain). But, the bigger the table, the more you have to walk to get around it. Getting small parts off the table are also an issue. (our 8x4' table is seldom climbed on - the 9x6' is climbed on often) If the table needs a vacuum system, then size matters a lot. A dust collector hose over a big area is also more difficult to handle.

[Mike John]

Now I have to stop Roxana reading this!
She will want the biggest table possible to make me walk as far as possible. The thing is, if the table is so big that it is too close to the wall on any side, will I even be able to get around the table! http://www.mechmate.com/Forum/clipart/happy.gif

Just how big is your table?

............Mike

[Gerald_D]

2750 x 1830mm [9 x 6 ft] board size - the movement is 50mm [2"] more on all four edges.

[Bill McGuire]

Here in the US, plywood comes in 48" X 96", but Melamine covered particle board is 49" X 97"... don't know why...

[Greg Waggy]

Bill, maybe for the same reason you can't find a 3/4" shhet of plywood any more, they are 15/32nds or something on that order. The 48" x 96" is a standard by which ceiling heights are and use to be stud centers in interior walls. As for the 49" by 97" maybe they have to build in a fudge factor for sloppy construction work or poor building materials. I know a 2" x 4" (3.75" x 1.75") stud has more water in it than a sponge floating in your wife's ketchen sink. Heck they'll spit at you most of the time when you hit them with a hammer.

[Gerald_D]

Aren't those "odd" sizes because of some metric systems creeping up on you? A 2.5 meter board, ripped down the center with a 5mm kerf will give you 2 boards 49.1" wide.....

20mm is slightly thicker than 3/4".....
18mm is popular in some metric countries, slightly thinner than 3/4"........

[vadeem]

The 49x97" sheet as found with MDF, is used so that even with the loss of the saw kerf, one can still get, for instance, two 48x48 pieces.

It indeed comes very square from the factory.

[Gerald_D]

What is the smallest MechMate off the plans? Well, I am very tempted to do a 1200mm [4ft] gantry on a 600mm [2ft] table for making signs at home. In this case I would call the gantry x and the table y.

That gantry would easily transfer to a 2400mm [8ft] table if I want to sell it. I think there comes a point where one considers shortening the table instead of the gantry, since 95% of the MechMate's "engineering" and sweat are in the gantry (and control box) and not in the table. Tables are almost consumable/disposable - unless you are heavily invested in vacuum holddown.

[Greg Waggy]

Gerald, Then what you are saying, build the width you want but the table length can be expanded. The gantry is the moving part(s) that have the milling motor/router attached?

[Gerald_D]

Everything of any complexity sits on the gantry (the moving part). ALL the motors, ALL the switches, ALL the cables/wires (except one ground wire), etc. The static table only carries a pair of rails and racks.

The logic is that you build the gantry in a small corner of the garage, get the x-motors to turn, get the y-car to run, get the z-slide to move. etc. Thats 95% of the sweat. THEN you build the big table and explain to your wife that her car now has to sleep outside.

[fabrica]

Gerald I have started on the base table. In all parts which use 50 mm dia round pipes can I replace them with 2"x1" 3 mm thick box iron . Is their any special reason for you to suggest round pipes.

[Gerald_D]

2"x1"x3mm box section will be perfect. You also need a piece 490mm long for the Z-slide.

I used pipe for two reasons:
1. I had some pipe lying around that wasn't going to be used for anything else.
2. The sawdust doesn't collect on top of round pipe - the machine stays cleaner.

[fabrica]

OK then I will go with the box iron option.

[Sheldon Dingwall]

Gerald, I'm thinking 2' x 4' too. Or possibly smaller, say 20" x 40" with a dual Z.

[Gerald_D]

Sheldon, I would make the gantry long (40-48") and table short (20-24"). It is easier to lengthen the table down the line if you want to go bigger. Also, the access to the job is easier with a long open X. (See this post (http://www.mechmate.com/forums/showpost.php?p=938&postcount=22) above)

Also, I would build such a small table quite high off the ground. And give the table a sturdy vertical front "apron". This is for clamping vertical work where you need to do end work - like drawer sides.

[Gerald_D]

An exchange of mails today (slightly edited):

Received:
Can you advise how I might start out with a simple DIY CNC table?

What budget do I need?

Your forum is so detailled where is a good starting point?

Has anyone applied this to a wood lathe holding a router with only an x and Z axis?

My exposure to CNC is limited but am about to attend a control logics course, we have a few linear motion controlled converted grinders we use Rockwell electronics but the industrial stuff is V expensive I trust you have some home DIY tricks?

Replied:
Unfortunately I avoid getting into protracted 1 on 1 e-mail discussions because I think your questions (as a very good example) are asked by many, and the reply/discussion flowing from it could benefit many. Would you mind if I placed your questions on the open forum, with slight modifications to protect your identity?


And then he said:
No problem, thanks

So, here follows the replies.......

[Gerald_D]

Can you advise how I might start out with a simple DIY CNC table?:
It depends on your motives, skills and weaknesses. The MechMate project is primarily geared to someone wanting to earn income with a CNC router cutting shapes out of boards for clients - this implies someone who has space to build big. The size of a parking pay. Point of saying all this is that Mechmate is not for a hobbyist teenager in his bedroom - there are smaller CNC systems/plans/kits available. The technologies involved in building big or small are no different on the control or software side.

The actual table (the mechanical part) is low-tech stuff (at least to me). The mysteries and lessons are in the control system, up to the point where you get motors to turn on your command. Start by forming an understanding of all the building blocks, what each one does, and how it connects to the others.

If you are itching to build something as you learn, start here (http://www.mechmate.com/forums/showthread.php?t=279). Next thing to build is just a gantry. Leave the big table for very last.

What budget do I need?:
Somewhere near $4000 for building this big board cutting production machine. Maybe only half that for smaller machines that cut with lightweight tools and that you could fit on a desktop. But, you also need a lot of time and access to tools.

Your forum is so detailled where is a good starting point?:
You might have noticed that some forum thread titles now start with ** - these are the one's I consider to be essential reading. I have tried to keep the more informative threads at the top.

Has anyone applied this to a wood lathe holding a router with only an x and Z axis?:
Yes, this is often called an "indexer". The main thread for it is here (http://www.mechmate.com/forums/showthread.php?t=314). Use the Search function to search for indexer. I consider the indexer side to be a diversion from the main MechMate project - something for later....

My exposure to CNC is limited but am about to attend a control logics course, we have a few linear motion controlled converted grinders we use Rockwell electronics but the industrial stuff is V expensive I trust you have some home DIY tricks?:
My home DIY tricks are in the mechanicals, the easy part. The computer/software/control box side is actually fairly standard across thousands of CNC machines. The stuff we recommend that you use at this website is very mainstream, and it actually tends to the conservative, low-risk side. Probably more than enough excitement for a complete beginner, but we try to stick to the proven. There are a couple of other forums on these subjects which spend a lot of time on the exotic and I know they are totally confusing to a newbie - I was there myself about 3 years ago...http://www.mechmate.com/Forum/clipart/happy.gif

[Frank Dixon]

Ok, time for another newbie. I am interested in building a CNC Router for 5052-t3 Aluminum Sheet, Acrylic, Lexan (Plexiglass), and wood. I like the look of your MechMate and was wondering if it could be scaled for a 60" x 60" table. Also, was wondering what kind of price range building such a table would be. These are my basics for now, and I can guarantee there will be many more.

[Marc Shlaes]

Group,

I didn't get any takers on a quick discussion (http://www.mechmate.com/forums/showthread.php?p=3812&postcount=13) so here goes...

As I look at wiring diagrams, I am somewhat handicapped for never having seen a CNC router operate.

The e-stop button's function is obvious. I also read the earlier discussions on the "pause" button. The limit switches are also somewhat obvious - designed to prevent 'over-travel' of movable components. What I really don't understand is how a specific job is actually started. That translates to a non-understanding of the function of the home switches. Are the axes manually jogged until the home switch is triggered and then the router knows where it is at all times? Is that how it works? If and when the router loses its bearings, the process is repeated? Every day? Every job? Only when something goes wrong? How are material edges located? Same way? Manual jogging or is the material typically loaded and clamped to a reference point? I am about to start ordering parts and I am leary of not knowing what I don't know. I am very mechanically inclined and an accomplished woodworker / cabinet maker. Just never seen a CNC system operate.

Gerald, should there be a thread in the General section on Mechmate Operation so that other total newbies can get a clue? I appreciate your thoughts. Feel free to move the content of this note to any thread you feel is appropriate.

(Oh, BTW - I do know that the thread I just posted to was a Power thread not a Control thread. I assume that is why the home/limit switches were not on Greg's drawing. Maybe they were... I'll study his drawing now that it is big enough to read.)

I hope the lightbulb in my head goes to full bright soon. Right this second, it is a little overloaded.

Thanks again!

[Gerald D]

Marc, would it help you if you realise that we havn't ever used a home or limit switch? :)

You seem to have the concern that you won't be able to drive the machine once you have built it. That is a completely back-to-front way of looking at CNC. YOU are the person in control with your computer and you make the machine dance to your tune. You build the machine according to what you want it to do for you. So, the starting point is to decide how you want to do the job.

An example; we mostly cut parts out of sheets. An early decision was that we will ignore the edges of the sheets - ie. all edges of finished components will be re-cut. A result of this approach is that precision homing is very seldom required. Therefore, if we have cut 500 pizza platters, we manually jog the router (with the keyboard cursor keys) until the center of the bit is over bottom left corner of the sheet of plywood, give or take 1/8", then press "Start". The next sheet gets laid at the same corner of the table and Start is pushed again (without any jogging of the router). Cheap labour does this all day. "Homing" within 1/8" was done only once.

Now, do you want to be doing anything more critical than pizza platters? Are your blanks that accurate? Why might you need exact to size blanks? These are the broad issues that need clearing in your head before you get cluttered with the minutae of wiring. (You will only wire for a day or two, but you will be shifting sheets/blanks nearly every day for a long time - which is more important? :))

[Marc Shlaes]

That did help. I thought that the home switch(es) were used all the time to "calibrate" the router. I also cut things out of sheets and the exact size of the sheet isn't important all the time but - once in a while - it is. Like for instance if you are cutting / carving something on the other side of a piece where the first side is finished.

Like I said, I have never even seen one.

Maybe there happens to be another builder within, say, 3 hours drive from Cleveland, OH, US?

Anyone?

[Gerald D]

The trick for lining up front & back is to drill "registration" holes through the center of the workpiece (at the scrap edges) into the spoilboard, flip over and drive dowels through the holes.

Hang around the ShopBot forum for this sort of stuff.

Where a homing position is very useful, is when you have a power failure during a long cut and you need to find the original reference point again.

With Mach3, the limit switch and the home switch can be one and the same switch. If you are doing normal cutting the switch behaves as a limit switch - it trips the movement. However, when you are in Homing mode, then Mach3 finds the switch, zero's itself, and moves away from the switch again.

[Marc Shlaes]

This little bit was a gem. "With Mach3, the limit switch and the home switch can be one and the same switch." I didn't realized that. I was guessing but never asked.

Shows that there are no dumb questions.

[Gerald D]

Realise that all the limit/home switches are wired in series, and therefore Mach3 does not know which specific switch has been hit. However, Mach3 is clever enough to know what it was doing just before hitting a switch and can figure out which switch was hit. If you hear a bang while reversing your car, you know it is at the back.

[paco]

What budget do I need?:
Somewhere near $4000 for building this big board cutting production machine. Maybe only half that for smaller machines that cut with lightweight tools and that you could fit on a desktop. But, you also need a lot of time and access to tools.

I'd like more details on this one; what's included and do I get a Mechmate cap in the package? Seriously, maybe in some sort of logical section like frame, mechanics, electronics, misc...

[Marc Shlaes]

Gerald,

I thought I picked this up on some drawing earlier: "all the limit/home switches are wired in series". I thought I was nuts and just couldn't figure out the drawing. These little tidbits help a lot.

From your earlier post on "a backwards way of looking at things"... I actually am not the slightest bit worried about learning to drive the MM, nor building the mechanical parts correctly. I know I can get it done. I just don't understand any of the control aspects. Therefore, building the control / operational components just don't seem so "step-by-step" as the other aspects.

I know I can get it. Thanks for your patience.

Marc

P.S. I'm more partial to a MechMate travel / shop coffee cup with a spillproof lid! :p

[Gerald D]

Darn, the caps were going to be so easy - my neighbour is a CNC embroiderer and he owes me lots of favours. :)

Paco, I am trying to get a costing together that will make sense to someone outside of Cape Town. This actually means coming up with a shopping list that can be used in America. But I have to figure out if you guys buy screws and springs at the Home Depot, or at MacMaster Carr - that makes a huge difference on costing!

[J.R. Hatcher]

Gerald why not get everyone to contribute (keeps all the work off you). Maybe start a subject named Materials, under that have a thread named bolts. Example: Everyone cas see I'm from NC USA I buy my bolts from Agri Supply in Garner, NC, I pay around $1.70 per pound for any size bolt, nut, washer, in SAE or Metric.
Would something like this work? The first post could be a list of all bolts for a certain size machine, even if it's not the size I'm building it is easy to adjust.

[Marc Shlaes]

J.R.,

That is one reason I created the spreadsheet. I figured that if everyone used it or something similar, we could all just post our updated versions periodically and all the purchasing alternatives are easily illustrated. People could cut and paste parts and suppliers and very quickly create their own "purchase orders". Questions about cost would take care of themselves.

Just my thoughts.

Regards,

Marc

[Greg J]

Gerald,

I thought I picked this up on some drawing earlier: "all the limit/home switches are wired in series". I thought I was nuts and just couldn't figure out the drawing. These little tidbits help a lot.

From your earlier post on "a backwards way of looking at things"... I actually am not the slightest bit worried about learning to drive the MM, nor building the mechanical parts correctly. I know I can get it done. I just don't understand any of the control aspects. Therefore, building the control / operational components just don't seem so "step-by-step" as the other aspects.

I know I can get it. Thanks for your patience.

Marc

P.S. I'm more partial to a MechMate travel / shop coffee cup with a spillproof lid! :p


Marc,

I have never done this kind of controls either. It is do-able, but its not "step-by-step". I also don't think it can be a "step-by-step" process, since every table is different. Everyone has different requirements, cost constraints, capibilities, etc. The help from this forum is exceptional and if there is anything I can do to help, just ask. I think we are around the same point for the control box.

As for my schematics, I update with Gerald's corrections soon. Even with his corrections, I still have a thousand questions.

Good luck and most importantly, have fun.
Greg

P.S. - My vote is for hats and coffee mugs. Not the travel kind, I'm a traditionalist when it comes to coffee, just the good ole ceramic coffee cup.

[extremecanvas]

If the MechMate were restricted to four table lengths (X) and four gantry lengths (Y), it would appear that most of the market could be served by the following capabilities: (max board sizes)....

X dimension equals:
1850mm [6.1 ft]
2500mm [8.2 ft]
2800mm [9.2 ft]
3660mm [12 ft]
....or would a 3050mm [10 ft] be a more popular length?

Y dimension equals:
1250mm [4.1 ft]
1530mm [5 ft]
1850mm [6.1 ft]
2070mm [6.8 ft]

(The design allows for 50mm [2 in] extra travel beyond all edges of the above board sizes)

for the us the 10' ( 3050mm would be more popular. ) Our sheets come in 4x8 and 5x10

[digger]

Hi Gerald,

This is great info.

I am still undecided about the size, should it be "squeezed" or normal size. Regarding my decision, if machine is regular size (4x8), how much of the room around machine you really need? My intention is to build it and use it in my single car garage which doesn't have to much of the width. How much of room around the machine you really need for normal operation and maintaining of Mechmate?

Beside that, I would like to express all compliments to Superior Bearing company. Quality of the product, way of communication really correspond to the their name - superior. This is my experience with them.

Milosh


What is the smallest MechMate off the plans? Well, I am very tempted to do a 1200mm [4ft] gantry on a 600mm [2ft] table for making signs at home. In this case I would call the gantry x and the table y.

That gantry would easily transfer to a 2400mm [8ft] table if I want to sell it. I think there comes a point where one considers shortening the table instead of the gantry, since 95% of the MechMate's "engineering" and sweat are in the gantry (and control box) and not in the table. Tables are almost consumable/disposable - unless you are heavily invested in vacuum holddown.

[Gerald D]

In the Y-direction (your 4'), the back of the y motors are 350 to 400mm [14 to 16"] outside the edges of the 4' wide board. ie across motors with gearboxes that is 48" + 16" + 16" = 80" at the widest points.

In the X-direction you just take the length of the main beams - the gantry does not run beyond that.

Now it depends how much you are willing to suck in your gut to squeeze past the gantry ends....:)

[digger]

In the Y-direction (your 4'), the back of the y motors are 350 to 400mm [14 to 16"] outside the edges of the 4' wide board. ie across motors with gearboxes that is 48" + 16" + 16" = 80" at the widest points.

In the X-direction you just take the length of the main beams - the gantry does not run beyond that.

Now it depends how much you are willing to suck in your gut to squeeze past the gantry ends....:)

Width of 80" is dimension I am looking for.

Milosh

[astarguy]

i just found this site and so far i think that this is the best over all so far. as for a table size i will be using a max of 48 inches and 48 inches the max z height that i would need is 3/4 inches but of course i will be using a bigger z axis just in case i want to do something other than the project i am working on now.

[Gerald D]

Hi All,

I had a post on the forum before which suggested printing out two sets of drawings, but can't find it now. It went something like this:

Print two sets of drawings . . . . .

Set 1: Sorted by drawing number, bound and filed as the reference file. This file collects all the notes, prices, phone numbers, and this set never leaves your office. It is the clean set.

Set 2: Sorted by process code first, and then by number. ie. All the welding drawings will be together in a batch, all the drilling drawings will form a set, etc. You will probably scan the batch of drilling drawings and decide if your drill is big enough, or scan all the W (welding) drawings and decide if you want to get help with that. All the T(turning) drawings would probably go to a machinist. These drawings go to the shop - this is the dirty set. And then, when the parts come back, you refer to Set 1 to see where the parts fit in the bigger scheme of things.

Can anyone remember this post and which thread it was on?

[Blackriver]

Evening Gerald,
Wow, what a labour of love you have going here.
Im not sure if I should be starting a new thread with these questions so am just tacking it on here.
I was doing a bit of research into the 600k-+ machines when out the net you pop and put a new spin on what is possible.
I want to cut aluminium, 3mm to 12mm, on a 6m table, so have been advised that I should be running a 11Hp 4pole spindle. Is it possible to upgrade your Mech Mate to drive a beast of this size,also, with your rack and pinion being straight cut and having seen a helical cut rack on an American made model which to my mind should give you a better opperating system due to the number of teeth in contact with the rack at all times, would you at some time look at this as a modification, or do you see problems in regards to the variations in build quality that could cause uneven tracking due to slight diferences in measurements between the track and rack.
In awe of this site
Nigel
PS is there a GA of the whole layout some where

[Gerald D]

. . . . . .Is it possible to upgrade your Mech Mate to drive a beast of this size, . . . . .
Anything is possible, but I would rather not venture into this territory

. . . . also, with your rack and pinion being straight cut and having seen a helical cut rack on an American made model which to my mind should give you a better opperating system due to the number of teeth in contact with the rack at all times, would you at some time look at this as a modification, . . . .
Have looked at it briefly and discarded it because it isn't necessary for a router in this price class. Helical racks (and the mating helical pinions) are not that freely available, cost a lot more and introduce axial loads on the pinion which our current motors don't like.

. . . .or do you see problems in regards to the variations in build quality that could cause uneven tracking due to slight diferences in measurements between the track and rack. . . . .
Sorry, don't understand this question??

. . . . is there a GA of the whole layout some where
The first page of TableJun07.pdf gives drawing 10 00 000 A - It is dimensionless because each builder determines their own dimenesions.

[CAM Craft]

Board sizes in UK (http://www.cncrouting.co.uk/Materials.htm)
Board sizes in Australia (http://www.gunnersens.com.au/products/mdf.htm)
more Australia (http://www.dmkforestproducts.com.au/pages/specialty-products.php)

Valchromat coloured mdf sheet size 2500mm x 1250mm

Valchromat is 2500mm x 1850mm
MDF in SA varies from 1830 and 1860mm in width and 2750mm in length

[smreish]

...and because I built a 5 x 10 table, I used 275' of cable.

[domino11]

Sean,
When you did your 5x10 how did you do the spoilboard and support board. Did you get stock in one piece or did you have to make it up out of 4x8s? I was wondering this because I cant get anything larger than 4x8s.

Heath.

[smreish]

I am able to find 5x10 and 5x12 MDF easily here in the states.

[Robert M]

Heath,
You MUST search where else than those renovation centers. Call on some woodworking lumber/sheet goods yard/distributor, they have 4x10, 5x10 and 5x12 in MDF, PressWood, Plywood to name a few. I’m not acquainted with distributors and their channels for your Cornwall region? Sorry !!
Maybe try Robert Burry, Commonwealth Plywood, Weyerhaeuser, Goodfellow, Dragon Ply…to name a few of hand. I know they cover Ontario and other many other provinces, just not sure if they cover Cornwall ??

Good luck & let me know if I can be further assistance, I’ll look it up for you if you find nothing!!
Amicalement, Robert ;)

[domino11]

Robert,
Thanks, I have not tried looking outside for larger sheets, but it seems that all the local distributors, yards and stores only stock 4x8 sheets. I might see if they could order in larger sheets. Would have to be a large order though. :)

Heath.

[smreish]

Robert,
Another option is contact a local sign supplier that does sign work. You may find that they order in, and keep in stock for internal use, large oversized sheet goods. Most folks are helpful and will sell you a 1 off sheet for your use. I know this is the case with a few of the sign suppliers in florida. When I get in a bind for MDF, I call in a favor or two! Good luck.
Sean

[jeep534]

Aren't those "odd" sizes because of some metric systems creeping up on you? A 2.5 meter board, ripped down the center with a 5mm kerf will give you 2 boards 49.1" wide.....

20mm is slightly thicker than 3/4".....
18mm is popular in some metric countries, slightly thinner than 3/4"........

Actually 2X4's started out that way before "Milling" so after planing and rounding the edges you get a "nominal" 2X4 and a stud is 3" short of 8' to allow a 2X4 on top and bottom to give you an 8' high wall

archie =) =) =)

[jeep534]

Darn, the caps were going to be so easy - my neighbour is a CNC embroiderer and he owes me lots of favours. :)

Paco, I am trying to get a costing together that will make sense to someone outside of Cape Town. This actually means coming up with a shopping list that can be used in America. But I have to figure out if you guys buy screws and springs at the Home Depot, or at MacMaster Carr - that makes a huge difference on costing!

Fastenall usually www.fastenal.com (http://www.fastenall.com)

Happy Hunting
archie =) =) =)

[tpworks]

http://www.norbord.com/MDF_PS_Thickness.htm
MDF in sizes up to 5' x 18'
pre-cut studs are 92 5/8 with 2 top plates and one bottom for an 8' wall (actually 8' 1-1/8" tall)

[duster]

The very basic thing to do is to decide for yourself what size of MechMate you want to build. You need to pick your own X,Y table (or board) dimensions that you want to achieve and then my drawings will say "cut the rack to length Y plus 150mm" or something like that. The basic MechMate design will work with a fairly wide range of x-table_lengths and y-gantry_widths, but a narrow range of z-slide_heights, being essentially a machine for processing board materials...

Which brings us to the point that you need to know what size boards you want to process, and indirectly, what board you want to use as the table surface. Then you need to decide if you will have twin routers and how far apart they will be in the y-car. The plans will focus on a single router sitting off-center in the y-car, with a big dust hose using the space that others might eye for a second router. But I will give a priority to those building a MechMate similar in configuration to what we built in 2005/2006.

Back to board sizes....in South Africa, MDF is sold as 2750mm x 1830mm boards [9' x 6']. Masonite, Melamine-face chipboard and lots of other stuff also comes as "nine_by_sixes". Plywoods are not that popular, but they come in smaller sizes in any case (2440mmx1220mm or 8'x4'). Apparently the board sizes in America are narrower and gantries can be limited to 5 foot, but here, and in Europe, a 5 foot gantry is too short for most work.

In the plans, I will give dimensions of rails, racks, gantry beams, etc. as X_plus_1234 or Y_plus_567 where X and Y refer to board size. The MechMate will be capable of moving 50mm [2"] more in all directions. ie. a 100mm [4"] diam cutter will travel just clear of the spoilboard, while a smaller cutter can have up to 50mm [2"] breathing space off the edge of the support/spoilboard. (Only valid for a single router).

Out of curiosity, what board sizes will you guys want to be cutting?
board size 1250mm x 2450mm typ but occationally would like to cut 1550mm x 1550mm

[PEU]

Typical Argentina Sizes (mm):

MDF: 2600x1830
Melamine: 3050x1080
Chipboard: 2820x1830 and 2750x1830 (Aglomerado)
Fenolic Plywood: 2440x1220 (Multilaminados Fenolicos)
Ureic Plywood: 2200x1600 (Multilaminados Ureicos)

Source: http://www.sacheco.com.ar
The prices in this site are in pesos, today exchange rate: 3 pesos=1 USD


Pablo

[servant74]

How much 'extra' width needs to be added to do 2 heads instead of one and be
able to cut the entire desired width? I am in the US, and would like to be able to cut 49 or 50" wide material, but to get both heads to cover the entire width.

Thanks, Jack

[bradm]

I'll take a quick crack at that; someone will correct me if I mess up.

Two heads mounted in the same car, or two cars? For two cars, add the entirety of the car width, so about 17.5". If you plan to mount two spiders in the same car, then it depends on how you mount them; you need to add the distance between the centers of the spindles/routers, plus the diameters of the largest cutters you will have in simultaneous use. As a working approximation, the centers will be 7-10" apart, plus two 1/2" cutters, and you've got between 8" and 11" of extra needed.

But don't take my word for it, spend some time with the drawings until the visualization pops into your head. It'll be well worth it when you're doing the build.

[Gerald D]

Brad, you got it about right (except for adding cutter allowances - they are there already).

Two gantries on one table (add about 850mm to table length -), each with two y-cars (add 450mm to gantry length/table width), each with two z-slides (add about 240mm to table length) will give you 8 tools on the same table! :D
. . . but you may end up with 24 motors/geckos :(

The z-slide was designed so that 2 of them will go into the Y-car, back-to-back. If going that route, you will have the following challenges:
- dust hose route
- maybe a second motor on the back of the y-car for heavy duty cutting on the "back" z-axis, which raises its own challenge:
- rerouting the y- cable chain, or getting the cable chain to wrap around the second y-motor.

[bradm]

Doesn't two z-slides add to gantry length/table width, not table length?

Wouldn't 8 tools be 2 (x1) + 2 (x2) + 4(y1,y2,y3,y4) + 8(z1,...z8) = 16 motors (20 if you double up on the Y cars)? Heck, that's only four or five G540s ;)

Or is this an indication that you're dreaming up a mobile hexapod mounted on six articulated legs?:D

[domino11]

Brad,
I think Gerald meant if you had two gantries, you would have to add to the table length so that one gantry can be out of the way so the first gantry can access all of the cutting area. Two Y cars would have to add to table width (or Y axis) so that both Y cars would be able to access all of the cutting area as well. So if you have two gantries each with two y cars, then you would have to allow extra width (y axis) and length (x axis) to allow all the cutting tools access to all of the cutting area.
Did I get it right Gerald?

This sounds like an interesting machine. I guess you would not have to change tools very often. Dust collection would be a nightmare though. :eek:

[Gerald D]

Standard - one z-slide:
2498



Twin z-slides:
2499

[Gerald D]

Brad, your arithmetic is better than mine . . . yup, not too many motors :)

That's right Heath, every extra tool needs more rail length to get the other tools out of the way.

[bradm]

Thanks for the picture, I missed a 90 degree turn in my visualization of where the twin Z axis go.

[servant74]

Gerald,
I was wondering if you went anywhere with this further than just contemplating. A 50" wide (to accommodate US MDF) cutting area gantry
that could be used on a 'small' table could be very interesting.

I assume the Gantry and Z would be the same, or were you contemplating
come modifications there?

What is the smallest MechMate off the plans? Well, I am very tempted to do a 1200mm [4ft] gantry on a 600mm [2ft] table for making signs at home. In this case I would call the gantry x and the table y.

That gantry would easily transfer to a 2400mm [8ft] table if I want to sell it. I think there comes a point where one considers shortening the table instead of the gantry, since 95% of the MechMate's "engineering" and sweat are in the gantry (and control box) and not in the table. Tables are almost consumable/disposable - unless you are heavily invested in vacuum holddown.

[Gerald D]

I've built the parts, but must still get around to the installation. The gantry and all the moving parts are standard. The short table will be entirely wall-mounted and extend partly over the hood of my parked car in my home garage.

[SteveE]

Hello all, I am at the planning stage of building a MM for plywood and solid surface cutting. I'm a bit confused about what lengths to apply to the X and Y dimensions in the plans. Here in the US, 4x8 up to 4x12 is the standard size for plywood, and solid surface comes in 30"x12' sizes. I would like to size the Y to be able to handle 5'. Does this mean I use 68" for the Y measurement and 144" for the X measurement in the drawings? For example, in drawing 10 10 240 (steel x-rail) the measurement is X + 8.1" between stop blocks. If I use 144" for the X variable, will this allow me to make a full 12' cut? Or should I oversize the X variable (as well as the Y variable)?

Steve E.
(aka newbie)

[domino11]

Yes, I add 100mm of movement to the chosen X & Y.

In an extreme case, you might have a 100mm diameter "cutter", and then you will only just be able to run that "cutter" around the edge of the table.

Steve, as Gerald has said in other posts he adds some extra for wood routing. If you need more than 2 inches you will need to add more. :)

[Gerald D]

If I use 144" for the X variable, will this allow me to make a full 12' cut?

Yes. In fact, the center of the cutter will go 2" beyond the ends of that 144". In other words, if you select the X dimension as 144", your total travel will actually be 148".

[mrloeng]

Hello!
My name is svein (some call me mr seven) and live in Norway.
Sorry my English is not good.
Thanks for this router forum and part list! Geral D
I work with CNC machines and produces tools.
I will build a machine-y-2550 and x-4050.
I want to build an extreme machine that will be heavy and very nice!
But there is one thing that I can`t, and it is all that electronic.
I like servo motors, but look in here that stepper works fine.
I want an exact machine as possible, Mash3 compensate for the back slash?
Hwat can I do to get all the right electric equipment.
Is there anyone here that has a shopping list??? And electrical building map for beginners??? :)
I would like to have the ability to plug in one more motor on the y axis if I need it one day.
Have some answers to my questions?????
Regards from one that can`t noting with the electronics!
Thank you!

[sailfl]

Svein,

Your English is fine.

You have more experience than most of us. I never worked with a CNC machine before I built mine. I had help with some one local but there are many that have had no experience with steel, electronics or software and they have built a machine and it works.

There will be others that can help you with the electronics. Gerald's design takes care of backlash so you do not have to do anything in Mach to compensate.

One of the first things that is suggested to some one just starting out is to download the plans and print them off and put them a large notebook so you can refer back to them as you learn and prepare for your build.

Go through the threads of people that have finished building their machine. You will learn a lot by reading those threads. Start with Gerald's build thread.

Look at the Kitchen table project. You can learn a lot there also.

Good luck with your build. Ask questions when you got them.

[domino11]

Welcome Svein:) Hope you find all you need here and have a great build.

[mrloeng]

Thank you!
Yes, I have to see everywhere in the forum, I think all of my questions can be answered here.
For there are many good builders here.

[stan stuart]

I am looking at buying linnier rails for my MM when I get arround to building it.
The supplier can only supply 3000mm tenghts and I was looking at going 4000mm. The supplier says you can join them but doesn't like to suggest how this should be done.
My main concern is if the joint is the slightest amount out of alinement in any direction it will not only damage the rollers and bearings but will jump or distort the cut.
Has anybody joined rails and how was it done

[sailfl]

Stuart,

http://www.mechmate.com/forums/showthread.php?t=794&page=3

Look at post # 93. There is a picture of the two rails end to end. I did not do anything to the ends that came from the supplier. Before I had the machine up and running, I was concerned that where the two rails meet would be a problem. I even thought when I rolled the gantry over the X rails that I could hear some clicking at the point they joined. Since I am running I have not noticed any problem.

I tapped the rails. Be careful when you drill your holes that the rail is tight against the top of the aluminum and of course tight against each other.

I have one joint on each X rail and one on each Y.

I hope that helps. If you want more pictures, I can take some more and post them.

[smreish]

...Careful alignment and alternating the seam lines so they do not occur in the same Y plane keeps any joint challenges to a minimum. The joint line in the alternate configuration allows for only (1) bearing to see a joint at a time.

....Now I only wish those expansion joints in the highway would have a slight angle to keep my truck suspension from jarring me so much!

Sean

[stan stuart]

Thank You To Sailfl & Sean For The Info Sets Me At Ease A Little And I Hope They Are As Accurate As You Say

[KTM_EXC]

Gerald,
If my working area is 450 x 300 cm, referring to your PDF I understood that in order to calculate X and Y size the calculation can be the following:

10 10 123 - Support board: 38 x 12 + 0,29 x 2 = 456,58 cm --> Length
38 x 8 + 0,19 x 2 = 304,38 cm --> Width

Then:

10 10 322 - Main longitudinal beams: 456,58 (Support board L.) + 60 = 516,58 cm ---> X Size
10 10 302 - Cross bearer: 304,38 (Support board W.) + 42 = 346,38 + 1 (weld space) = 347,38 cm ---> Y Size


Is this correct?
Thanks for all and sorry to bother you with this simply question (I am a very CNC newbe)

Andrea

[Gerald D]

If your working area is 450 x 300 cm, then your X=4500mm and Y=3000mm

From drawing 1010123, you buy a support board 4500mm X 3000mm
- to calculate the cross support spacing, 4500 - (2 X 29) = 4442 which must be divided into spaces of between 350 to 400mm. You can use 12 spaces (13 supports) of 370.2 mm
- drilling the holes in the Y direction: 3000 - (2 X 19) = 2962 which must be divided into spaces of between 350 to 400mm. You can use 8 holes which are 370.25 mm apart

10 10 322 - Main longitudinal beams: 450 cm (Support board L.) + 60 = 510 cm
10 10 302 - Cross bearer: 300 (Support board W.) + 42 = 342 cm (DO NOT ADD the weld space. . . . . it is a space for the weld)

[KTM_EXC]

Gerald,
the very first step is done!
Thanks again
Andrea

[mcca215]

Out of curiosity, what board sizes will you guys want to be cutting? 400 X 1000mm

[Perish]

Hi -I live in florida SA, and i am interested in building one of these machines.
But before i start what is roughly the cost to build one of these machine that could take a standard MDF 9x6 board. And do i get get std part that are locally available.

[smreish]

In US dollars, depending on your ability to alternate source things like steel, enclosures, wire and choice of amplifier cards/breakout board(s) and most importantly spindle/router. You will spend 6-9K. The past 3 builds for me were roughly 5900 (router), 8200 (spindle), 7500 (plasma without the cost of the torch supply unit, otherwise would have been 9000).
\
Hardware cost only. Labor is extra:)

Sean

[rotorzoomer]

It also depends on the exchange rate at the time of your MM commitment to build.

For me in Australia, i would not have even conceived undertaking the project early 2009 when the AUD Currency dropped to 0.62c :eek: Fast forward 1 year and the AUD Currency went to almost parity with the USD at 0.93c making everything cheaper to buy which was the catalyst for me to commit.

[speedysigns]

Hi the common size for me is 5' by 10' boards

[MetalHead]

Is MechMate #1 still for sale in SA?

[CAM Craft]

Hi Mike, yes it is. why do you ask?

[Jim Mulrine]

As we require the Cnc to cut parts for chair and sofa frames. We will be using mdf and ply wood boards (8' x 4' or 2440 mm x 1220 mm). The amount of parts on a board can be anyhing from 8 parts up to 50 parts per cut. What size of machine would I need to process this. I think for the capacity we would require we would be ok with one router head but I would be advised on this. As a designer I am drawing on DesignCad and would need advice on the best software convertor for it. How much would a machine like this cost.

Jim

[Kobus_Joubert]

Hi Jim,

Once you download the plans you decide on the size of the machine. If you want to cut 2.4 x 1.2 meter boards, you use this and the plans indicate that you should add 500mm to allow for the overhang etc. So the table should be min. 2940 x 1720.
Once you have your plan in DXF you import it into something like Vectric V-Carve Pro, set up your cutting paths and export to Mach3 that drives the machine.

[Cas]

Hello everyone. I am yet another Newbie to the CNC Router world and am wondering if the MechMate plans could be used for a smaller unit, more like an engraver with a 12" x 12" routable area (I will also be looking at adding a 4th axis so I can engrave cylindrical objects too). Any comments?

[domino11]

Cas,
I do not think this design would lend itself to a footprint that small. The Y car assembly is larger than that. 4 x 4 feet I would think would be the smallest practical size in my opinion. www.cnczone.com has a multitude of small router designs if you are interested in that size range. :)

[Cas]

Heath,
Thanks for the insight. I still haven't downloaded the plans, but after I posted the question I have seen others say 4'x4' should be the minimum. Your response is appreciated!

[dale1944]

49" x 97"

[mawe]

Hello,

Well like everybody else in here I started my plans for cnc.
The plan is to build CNC router that would be able to cut 2050 x 3050 sheets (because sometimes we need to cut big sheets of pvc) but it also have to be able to cut plywood and over harder plastics.

So the main question is this table size is stiff enough with one motor for the gantry? or should I put to motors or use double shaft servo?

And one more question is about the planas, what is the difference between the plans that you can find everywhere on the net and the plans that you can buy here?

Thanks Thomas

[sailfl]

Mawe,

If I calculate correctly that is a 6.725' x 10' table bed. I do not see any problems using one motor for the gantry.

I don't know what plans you found on the net but if you are interested in building a MechMate then you buy the plans. You also get the support of the forum and users that have built a MechMate and are making money from their machine.

Good luck.

[domino11]

Mawe,
The Mechmate gantry uses two stepper motors and the Y-Car assembly uses 1 stepper motor. There have been many tables built in that size range with no problems.

[mawe]

Thanks for answers ;) well then it's only time to get budget approved and start planing

[timberlinemd]

And one more question is about the planas, what is the difference between the plans that you can find everywhere on the net and the plans that you can buy here?

Thanks Thomas

Mechmate plans are superior:D and you will not 'shoot yourself in the foot' by trying to experiment with different styles of CNC builds

[smreish]

The MM represent a complete, vetted design that works.
100+ almost identical machines that work and make money are a good assessment of a complete design.

[pez1008]

I am in America, Florida. I plan on making a 4" x 8" table. However, I work for a company that wants me to design and make an xy table with a z axis for a medical patch that dispenses a liquid at 10 different points on an EKG patch. In this case the table needs to only be 3x3' or 4x4'. Can I use the software to control the z-axis for dispensing liquid in a controlled fashion use Mach 3 software?

[Mrayhursh]

Yes, you can use the mechmate to do this. The software is Mach3 and someday it will/maybe Mach 4. This software is used all around the world by businesses to manufacture products. This software moves the x, y, z axis to an exact location. your z axis will be a dispenser of some type. How much fluid are you moving. This will depend on the type of pump you are using. Pressure delivery depends on ambient temperature and even current atmospheric pressure. I have a lot of experience with catalyst dispensers. Capillary pumps driven by a controlled motor may be something to look at. The pump diagram can easily be exchanged giving you a method of maintaining cleanliness. The fluid never comes in direct contact with any part of the pump itself. Best of luck.

[Chattermark]

Maybe I use the wrong search strategy, but I did not yet find a general introduction to the MechMate project on this site - all articles get immediately to secondary details like sheet sizes to be processed etc.

Where do I find a general description of the potential result of building a Mechmate, the general concept of the machine, its unique properties, that shows what the machine can (resolution, loads, materials), what is needed to build one (a complete metal workshop including welding and steel milling), what kind of personal skills, what space, what tools are necessary?

Hiding all plans behind a payment barrier is also understandable but not really helpful on the first approach - there are so many DIY CNC concepts in the world today that this is not really inviting - in contrast to the reports of people who have built one.

So, probably all I want to know is here somewhere, just hiding... Or?

Cheers,

U.

[jeep534]

Maybe I use the wrong search strategy, but I did not yet find a general introduction to the MechMate project on this site - all articles get immediately to secondary details like sheet sizes to be processed etc.

Where do I find a general description of the potential result of building a Mechmate, the general concept of the machine, its unique properties, that shows what the machine can (resolution, loads, materials), what is needed to build one (a complete metal workshop including welding and steel milling), what kind of personal skills, what space, what tools are necessary?

Hiding all plans behind a payment barrier is also understandable but not really helpful on the first approach - there are so many DIY CNC concepts in the world today that this is not really inviting - in contrast to the reports of people who have built one.

So, probably all I want to know is here somewhere, just hiding... Or?

Cheers,

U.

Welcome to the forum,
My question to you is where do you want to go with this, router, plasma, cut size in inches or feet Like 4' X 8' cut area or other. for example with a plasma machine you will want the table longer so as to give yourself room as to not hit the carriage with the stock as you are placing it on the table. It all starts with the cutting device, torch, router, plasma.

I will help where I can.
archie =) =) =)

[darren salyer]

Everything you are asking is answered in the build threads posted. Pull up a chair and spend a few hours reading what others have done. The plans are blueprint to follow. Nothing more.

[don15042]

I thin 4 X 8 is the best for me

[KenC]

That is going to be your choice :)

[kiwiken]

Hi,
I'm starting to do all the research for building a mechmate as my second router.
I want to be able to cut 2440x1220 sheets, reading a post above it says I will a table with a min off 2940x1720.
What I need to know is the over all lenght of the Y axis from end of motor to the end of the other motor.
I've got to work out if the table will fit into my car shed.

Regards,
Ken

[KenC]

As a ball park estimate, you need foot print of parking space for 1 car for comfortable operation of a 4x8 Mechmate.

[racedirector]

Ken (kiwiken), to run 1220 x2440 you will need a machine 3040 x 1720, not 2940. Mine is for 1200x2400 and is 3000 long.

Cheers

[kiwiken]

Hi,
Bruce - You would still be able to cut 2440x1220 sheets since the MM is designed
to cut 50mm in all directions, is that right.
My car shed is 6mx3m, so I need to know the max width of the Y gantry from motor end to motor end, so I can see if there's room for me to get passed if. I'm not built like a rake.

Regard,
Ken

[KenC]

Do leave walk way around the Mechmate.

[racedirector]

Yup, the X should be your cutting X + 600 hence my 3000. I haven't yet come across an MDF sheet 1220 x 2440 so I figured that 2400 should be OK for doing 2440 if neccessary due to, as you point out, the MM being capable of going 50mm beyond any side. Give me a little bit and I will chuck the 2 X motors on and measure across them later tonight.

[racedirector]

kiwiken, I sent you a PM so not to clog this thread.

[mouradjaoui]

Hi,Iwould start building a cnc router for Wood working, please could i have an approximatif cost for it
My board sizes are 2070mm x 2800mm
thank you

[domino11]

Builds in North America have been anywhere between $5000 US and $15000. Depending on your skillset and what you already have around for parts.

[Change]

Hi All

Wanna try this but no experience with plans and even welding....what I want to know if I make my main longitudnal beam 3350 long, what board size will I be able to work with?

Am i right by saying it will be 3350 - 600mm = 2750 length board?

[darren salyer]

Sounds about right to me.

[abengineering]

Hi to everyone and thanks for your useful inputs.
I was wondering why MM seems so heavy? Yes, according to steel dimension used for the table and the gantry that seems too much. May be this issue has already been raised and answered but generally speaking a light machine should have better performance (and cheaper), but again may be I am missing something. Any input or link is welcome.

Abe

[Gerald D]

The fully professional CNC routers are much, much heavier. I think you are missing something . . . . .

[Tom Ayres]

Some of us have built certain parts more heavy, some lighter, depends on what feel you require. Some areas of the build can be more critical than other areas and have a greater effect on overall performance, example, I built my gantry with a slightly thicker wall tube because my length was longer, I was able to tap directly into the tube without having to use the fastener strip inside the tube. The idea was to help eliminate a bit of flex and the additional work of an extra set of holes to align. Sometimes material availability and the type of use for the router helps make those decisions. The plans are a very good guide and culmination of ideas and improvements others have shared. Most reasoning for any deviation of the plans has most certainly been argued and there is always room for improvements. If you have ideas, share them, ultimately that's why you chose to build a MechMate.

[servant74]

Abe,

GrealdD is right, many commercial comparable CNCs are much heavier.

Some of the comparative and lighter CNCs use hold-down technology rather than gravity to keep the gantry on the table when pushing down against the material/table.

One of the great things about MM is you can build what you want. If MM is to heavy for you, build it lighter. Depending on your size it may be faster or more susceptible to bending issues.

Let us know what you decide, we are interested. ... Jack

[Gerald D]

It is all a compromise between:
- speed / acceleration (you might be looking only at these and calling it performance)
- flex /chatter / repeatable positioning under varying loads (a massive part of real performance)
- costs
- transportability (especially for companies selling and shipping low-cost machines)

Even the heaviest MechMate shakes like mad when cutting letters on a sign at production speed . . . . . .

[abengineering]

Thank you guys for all these enlightening inputs.
I especially appreciate Gerald last sentence "Even the heaviest MechMate shakes like mad when cutting letters on a sign at production speed . . . " which tells lot about MM experience.
However, I still believe that a lighter MM for smaller passes, moderate speeds, etc. can be considered so the over all weight of the machine may be reduced by 20, 30 and even 50%, depending on everyone's purpose. This can be done using MM structural shapes sizes indicated in the drawings with smaller dimensions (example: use channel CH 120x12 instead of CH 180x21 for the table). Mechmate architecture however is undoubtedly very nice and should be the reference.

[Tom Ayres]

Personally, I find there's little substitute for mass.

[darren salyer]

I agree on the value of mass. Big Iron isn't made that way just to sell it by the pound.

[bradm]

<chuckle> I built a smaller, aluminum extrusion based router before I built my MechMate. After you get past the thrill of seeing it work, you move quickly to impatience with those extra passes, and frustration when vibration messes with your cut quality or snaps a mill.

Sure, you can lighten various pieces, but you won't save all that much on the overall cost, and you'll pay for it over and over later. From a performance standpoint, more mass is better. Now,if you're intending to cut cardboard and foam, then by all means, go for a lighter machine.

[smreish]

I haven't commented in a while, but while trying different "mass of gantry" set ups in my initial build of #5, I found that the heavier of the 2 gantries improved my cut quality significantly. Especially when I was doing high resolution cutting of acrylic and aluminum sheet.

[IMMark]

Hi Sean,
When you mention the mass of number 5, are you saying you went heavier than weight of the "standard, per plans" build?
If so, could one add ballast to the gantry? Just got me thinking?
Good to see you are still hanging around
Mark

[pblackburn]

Mark, the heavier the gantry the more it resists the upward forces that naturally occur while cutting. This helps remove the resonance that is transmitted into the lighter materials however there is a downside to a heavy gantry. You soon exceed the workable range of a stepper and now have to move to a servo. So while the cost increases, your cut quality improves as well. With proper planning and implementation that is.

[MetalHead]

You want the mass. You think you may be making a good choice saving a few buck on a lighter frame by using thinner steel. But in the long run, you will be glad you have a heavier machine. If you want mobility, build a bolt together frame. But I found moving a MM is actually pretty easy even on a fully welded base.

[abengineering]

This is not meant for any controversy, but just exploring a new idea according to everyone's needs. A lighter machine may have some advantages like: economy (cheaper steel and electronics), better portability and easier construction. On the other hand, a lighter machine may not be able to handle heavy duty jobs and that applies, not only to Mechmate, but to any CNC machine. Can we think of a "Mechmate light version"?

[pblackburn]

If you want less weight. ...use titanium. ;)

Joking aside, you do need the weight to help compensate for the forces generated by cutting fast. Unless you gusset and mount solid to concrete footing.

[darren salyer]

AB, design it. Build it. Do whatever YOU want to do with it. We've given you our opinion of it.

[abengineering]

Gerald,

Can you please take a look at this? Parts of the same color are welded, the rest is bolt assembled. Any advice?
http://www.mechmate.com/forums/attachment.php?attachmentid=15374&stc=1&d=1438804233

[Alan_c]

I dont wish to appear rude, but thats going to rock more than Elvis, needs lots more bracing!

[darren salyer]

I'm in agreement with Alan.
I doubt you'll get a lot of interest from Gerald in designing a lighter machine.

[pblackburn]

I don't know about rocking, that normally applies to when something is solid and is moving up off the surface at different contact points. I would say you would have a sway problem. You need sway bracing across the Y and the sway bracing in the X also functions for upward support of the longitudinal beams. Steel will sag and more than you think even with a little weight. I have walked across 50 ton bridge cranes with 3 foot I beams when I inspected hoist and cranes, just walking and the steel will react (no I am not that big either). You can build lighter but with lighter the complex angles of the bracing that will be required are normally outside the capabilities of the average person.

I will say I prefer the concept of Gerald's design and it can be built upon. I will not knock you for trying something different because if nobody ever did, nothing new would be conceived. If you are to proceed with this I would make some changes as the sway braying and sag prevention is not provided yet in this concept. Welding the saddle to the horses you have would be good idea also. In the end, I think the stuff needed will weigh more than the original design. Just my opinion.

[Gerald D]

AB, I am not going to get sucked into a discussion like this.

[bradm]

Cable brace it. After a little careful tuning, you'll have the first symphonic MechMate.

(Not a serious suggestion)

[Gerald D]

I think I still have an offer open for a MechMate singing a recognisable tune :D
The one pictured above will be good for low bass notes :rolleyes:

[darren salyer]

You guys crack me up.

[abengineering]

Thanks Pete for your input.
I realize that more weight for a sturdy machine cannot be avoided. I tried however to make simple and bolting parts instead of welding is much more easier to handle smaller parts and also adds more precision. The table may be easily dismantled and moved to a different place (keeping upper part and rails adjusted) so all is needed in re assembly is table leveling by acting on threaded rod of the shoe plate. Overall weight is about 325 kg.

Thanks Brad for your symphonic compliment.

Thanks to all objectives inputs. Sorry for those who are upset.

Attached is a higher resolution image.

http://imagizer.imageshack.us/v2/xq90/537/U7NlcI.jpg (https://imageshack.com/i/exU7NlcIj)

[pblackburn]

I did a bolt together design based off of Gerald 's design. All crossbearers bolted to main beams, main beams bolted to side legs and cross supports bolted to the side supports. All with sway bracing. If I need to tear apart, I have 1 gantry, 2 sides, 2 cross supports and 9 crossbearers.

[darren salyer]

I don't think anyones upset, AB.
I wish you luck and success.

[bradm]

Yep, nobody's upset. I also have a bolt together machine; beams, legs and X axis bracing welded into two long "side" units, Y axis bracing and the first cross bearer welded together into two short "end" units. The four units bolt together, and then the remaining cross bearers ( with the table surface ) bolt onto the main beams.

[Tom Ayres]

Thought I'd chime in at this point. After earlier conversation about the weight I did a quick rough calculation of mine and weigh in at roughly ~2100 lbs + the weight of 10-12 sheets of plywood stored on the shelf below. I originally wanted a bolt together unit but changed my mind for a fixed base and glad I did. It is rock solid (thank to Gerald's design;) and Darren's overkill build influence:p) with absolutely no worries about movement even running at 700 ipm (setup has got to be right though:eek:). Brad has it right though, if you are going with bolt-together that's probably the best way.

[Boardstiff]

Here in the US, plywood comes in 48" X 96", but Melamine covered particle board is 49" X 97"... don't know why...

The extra is for trimming flush to the board edge. If they were the same size, most would not be able to match the edges up perfectly in a contact cement application.