Decided to build a MechMate - Need some advice though

[r0bs]

Hi All!,

After thinking long and hard, it appears that the MM would be the best machine to build for the uses I'm likely to put it to.

The primary role of the machine will be to cut 15-19mm thick solid-grade laminate for electrical meter panels. This stuff is really hard and really tough.

Ideally I would like to make a machine big enough to handle oversize sheets (1500 x 3050mm), as I can't see the point of going to all the trouble/effort and then not being able to cut 'larger' sheets. Space for the MM is not a problem.

This will be a father & son project and it will be initially located in my workshop in Kallangur, on the Northside of Brisbane, but I am thinking of retiring soon (I'm turning 47 soon ) so it will probably be relocated to my property at Ocean View where it will see out it's days doiing wood-working stuff and some metal cutting.(and making toys/ go-carts etc for my 6 grandkids). one of my employees has built a LumenLabs Micro machine and we use it daily for cutting out plastic boxes for some of our electronics (we make smart energy meters). The electrical side won't be too much of a challenge for us as we use motor controllers, VSD's etc on a daily basis.

There are a couple of questions however:

1. Is it possible to make a replaceable table so you could switch between plasma cutting and routing? I'm thinking along the lines of deeper main rails and fabricating a galv steel "water tank" complete with angle-iron supports for plasma cutting and then pulling this out and replacing it with a 30mm thick MDF table for wood-work use. Obviously the Wooden table would need to be brought up to the same level as the Plasma table?, or is there an easier way?

2. As this unit will be LARGE and will need to be relocated at some stage, I was thinking about making the support stand as a large bolt-together unit rather than fully welded. It would have 4 x legs but the cross-bracing between legs would be completely welded in-fill frames that bolt through using M12 all-thread or large bolts. Can anyone see any draw-back in making the base assembly bolt together? (I know it will use twice as much steel, but I can't see this a necessarily a draw-back). I've seen the wheeled versions, but I think this may be harder to implement on such a large machine?

3. As I will be maching a lot of very hard material, I'd really appreciate some advice on the differences between the Rack and pinion drive and the chain-drive versions. I'd like speed as well as accuracy, so what is the best compromise? Saving money is not the name of the game here, I want a very functional, robust machine (which is what the MM seems to be).

4. If you have built a MM locally already, I'd really like to hear from you and would love the opportunity to view your MM to get my head around the whole project. I'm also open to buying the laser-cut components from someone, otherwise I'll have them shipped from the US.

5. Has anyone implemented a vacuum hold-down system for wood panels?

I just hope that I can match the workmanship of the other Aussies (and especially the Brisbane guys).

Any help/advice would be appreciated.

Regards,



Robert Stewart

[baseball43v3r]

Hi r0bs! I'll try and answer a couple of your questions.

1. most users here tend to square up their machines using the replaceable board and as such, interchanging the top would change the structure of the machine quite a bit. the only alternative i can see is a deep C channel, with a standard tabletop and then building a separate water tank that mounts on top. others with more experience might be able to handle this question better.

2. several users have made bolt together frames, and it is entirely possible.
kobus has one here.
http://mechmate.com/forums/showthrea...2&postcount=60
and see this thread for a general discussion on bolt together machines.
http://mechmate.com/forums/showthrea...t=bolt+machine

3. all the machines built here are based on rack and pinion (i believe), I've yet to read a thread where someone used chain-drive. most machines i've seen on here can cut wood, laminates, plastic, even aluminum, so it is definitely up to the task.

4. can't up with that one, i'm in America, and still in the process of building mine!

5. a couple of vacuum systems have been done, although they aren't included in the plans and you would have to make your own. here is an example of one.
http://mechmate.com/forums/showthrea...8&postcount=37

biggest thing is to read read read! go over everything, and then go over it again. and if you can't find something the search on the forums has helped me numerous times. Hope I helped a little bit!

John

[bradm]

John has given a great summary. A few amplifications:

1. How large a work area do you need for metal? One possibility might be to build the machine a little longer (say 3600mm), and have a 500mm x 1500mm metal area at one end. Or, exploring your idea, how deep does the water need to be? If you can fit the water pan, grid, and work material into a 150mm to 200mm height, you should be able to use the standard design.

2. I (and others) built tables in essentially five welded pieces that bolt together: The (2) C channel, leg and brace units, (2) cross brace units, and (1) tabletop with support channels. For me, that's 8 bolts each to attach the cross brace units, plus one bolt on each end of the (8) support channels. 32 bolts in all.

3. The one machine that tried chain has retrofitted to R&P. Use the standard R&P.

5. Search on 'vacuum holddown'. Here's one.

And as John said, read, read, read! Have fun!

[KenC]

Welcome to the addiction!

Originally Posted by r0bs

The primary role of the machine will be to cut 15-19mm thick solid-grade laminate for electrical meter panels. This stuff is really hard and really tough.

No problem, the issue is how long your cutter will stay sharp, the power of your spindle, feed rate bit speed & bit selection.

Originally Posted by r0bs

Ideally I would like to make a machine big enough to handle oversize sheets (1500 x 3050mm), as I can't see the point of going to all the trouble/effort and then not being able to cut 'larger' sheets. Space for the MM is not a problem.

No problem, there are more then a few actually are bigger then this. Infact mine is longer then that.

Originally Posted by r0bs

1. Is it possible to make a replaceable table so you could switch between plasma cutting and routing? I'm thinking along the lines of deeper main rails and fabricating a galv steel "water tank" complete with angle-iron supports for plasma cutting and then pulling this out and replacing it with a 30mm thick MDF table for wood-work use. Obviously the Wooden table would need to be brought up to the same level as the Plasma table?, or is there an easier way?

Why bother?
Since you have space. Why not double the length of Y-axis maybe 9000mm long & keep one end for Plasma & the other for router. you can then do what ever you fancy with the table.
Or just build 2 separate machines! Water, fire & wood don't get along very well well.

Originally Posted by r0bs

I'd like speed as well as accuracy, so what is the best compromise?

Don't we all

Originally Posted by r0bs

Saving money is not the name of the game here, I want a very functional, robust machine (which is what the MM seems to be).

1stly, you can replace the original rail & roller with 25mm Square rails will over do everything.
2ndly, Build 2 or 3 to double /or triple your production rate.

Originally Posted by r0bs

5. Has anyone implemented a vacuum hold-down system for wood panels?

I did.

[AuS MaDDoG]

Hi Rob,

The guy's have answered most of your questions and my answers would be no different.
I guess I'm one of the Brisbane guys and I would be only too happy to let you see my MM if you are ever over my neck of the woods and I am home, so feel free to drop me a note to arrange when you are ready.

Cheers
Tony.

[r0bs]

Thank you to everyone who responded.

Well, I've made a start on the custom drawings for my MM.

I've taken the plunge and purchased a 3kW water-cooled Spindle with 20mm collet from China via eBay (Thanks AuS MaDDoG). I know this is putting the cart before the horse, but this will give me the motivation to see this through.

I think I have a spare 5kW drive and choke somewhere in the workshop, I'll have to dig it out.

My company ia a MOXA (www.moxa.com) reseller, and we keep USB-Serial and Ethernet-Serial converters in stock so if anyone wants one of these things at the right price, happy to help.

I'm chasing a set of pre-cut and pre-bent parts now. (Sent a PM to rnixon)

I'll use the Rack and Pinion drive. I'm pretty sure I have a cople of rolls of VHB tape lying around from my old sign building days. Also some f-bond (a glue for steel) so stopping the racks from drooping shouldn't be a problem

I've also decided to build a 'wood' only version with a vac table. As suggested, I'll probably make a second smaller machine for plasma later.

Rob