I have some questions about the rails - NJ,USA
 

Hello everyone. I am looking to build a cnc router. I have never designed nor built a router before. I would LOVE to design a cnc router of my own,... but I am kind of in a hurry. In a hurry in the sence that I dont want to waste time designing. I want to get right to the build process.

For the longest time I havent had the space to do anything really. But my girlfriend and I are getting a house with a really big detached garage so now here's my chance to shine.

By nature I like to do everything myself. Design and build. But i think I will sit the design phase out for this build. I dont want to waste any time.

So I have a few questions:

1: On average,... what does it cost to build one of these mech mates?!?!

2: What is the overall footprint size? I assume it hacks up 4' x 8' sheets?

3: What skill level is reccomended? Not that I'm doubting myself. Im just curious as to what people think.

4: How are most of the parts made? Do you guys contract the parts out to individuals with cnc plasma cutters?!?! Or do you just contract someone to build it for you?

5: Whats are some of the most important tools one should have to errect a MechMate? I have some tools and machine. A large drill press, a 140amp mig, angle grinder, and a ton of other various stuff. I am ready to buy what I need to get the job done.

6: I have never read through plans before. I am a bit worried that I will get lost easily. How do the plans for this rate?!?!

I think thats it for now. Thanks!

Charles - we get the same question from all new users - request you to go through the forum -

Each one of your question has been answered multiple number of times in the forum.

RGDS
IRfan

Charles,
Ifans comment is a good suggestion, read read read. There is a lot of info here and sifting through it will take some time. Most people spend a fair bit of time sifting through this sites postings to get a good idea of how the machine works.

to help a little more though,

1. $4000 to $10000 depending on what you have on hand and what you can do yourself. Check out the build threads of guys who have built the router for more info.

2. You can make the Mechmate for any table size see
http://www.mechmate.com/forums/showthread.php?t=63

3. Check out the personal build threads.

4. Laser cut parts are available from forum members. See
http://www.mechmate.com/forums/forumdisplay.php?f=70

5. Check out the personal build threads.
http://www.mechmate.com/forums/forumdisplay.php?f=78

6. Look at the plans first and then ask questions on what you do not understand. Once the build threads are read after looking at the plans I think a lot of your questions will be answered.

:)

Ok thank you. Sorry for not searching.

Charles ,
No problem, take a look around, we will be here when you have more questions. :)

Thank you sir. I'm actually going to create a log right away even though I am not ready to build at the moment. Maybe within the next few months once I've landed a house. What I really want to do is go through the plans and create models of the all the parts so I have a good understanding of how everything is so when it comes time to build I can just get it done with no delays. Plus you guys could use the models to help out others. That is if someone hasnt already created an accurate 3D model of it. Thanks again.

See here

Thanks. I want to create my own model though. This way I know what every part looks like and how exactly it's all assembled.

I have an important question.
 

I have to ask. Here's the deal. I dont know about you guys but I have this problem. Creativity. Originality. Perfectionism. It's a sickness for me. Literally.

I really want to design my own router. But I am clueless when it comes to a lot of things. But a lot of things I am aware of or atleast on the brink of being aware of. I lack the experience so I just dont know how things are.

I love the MechMate design. I really do. Someone from another forum actually pointed me to the mechmate because they saw that what I wanted was very similar and that also, I needed a lot of help too.

I actually broke down for a second and gave up on designing a router for myself. I wanted to just build a mechmate to get my router done. But my sickness has been eating at me for the past few days. I actually learned a lot just by reading though this forum and eyeing the pics available here. I haven't really gone through the MM plans yet because I kind of got lost real quick browsing through them. But just seeing how the MM was designed,... it answered a lot of my questions. This is what my sickness has been feeding off of.

My question is would you guys be willing to help me even though I am designing my own? How do I explain this,... geez. What I want is very similar to the MechMate. It's just that I learned a lot from the MechMate so for me to go ahead and design my router using knowledge that I gained from the MechMate and users from the MechMate forums without mentioning my intentions doesn't seem right. So I am asking if it's ok.

I'm trying to think of it as a heavily modifed MechMate. Heavily. I know that other users modify the MechMate it's just that I dont know where I fit in?!??! Why would I want to heavily modify something thats already proven? I dont know. Thats my problem. Most of the time I like to design from scratch. But for this,... I just dont have enough knowedge of CNC.

So would it be ok?!?! Please:( I could post at another cnc forum but I actually like it here. I'm not just saying that either. I already had a bad experience at another forum from asking to many questions.

Thanks.

Charles, we cannot give you a general "yes we will help" if we don't know what is involved. So, ask your questions here in your own thread and see the reaction. It is not going to help you to start a new thread every time you have a question that is distracting to the "standard" build (you might have noticed your most recent post is no longer in its own thread)

Ok,... so I will just start posting the models I create here so you guys can get a good idea of exactly what im trying to do. I will keep all my questions in here.

Sorry about creating another thread. I was actually reamed out in another forum for asking to mnay question within a single thread. They wanted a new thread for every question I had. So yea.

Thanks.

First few questions. The hot rolled shapes such as angle, square tube, channel, etc,... how do their dimensions hold up from one side to the other?!?! One end slightly larger than the other?!?! How straight are they at long lengths? Would it be better to buy fewer really long lengths and cut what I need out of them or buy several smaller lengths, one for each part and just cut off the excess?!?!

The final alignment of the rails is done with shims - no need to assume you would be scrapping a lot of material.

When I loaded the DXF files into Inventor the dimensions are slightly off compared to what I seeing in the PDF file. For instance,... when I load 1020451PC.dxf there are two dimensions visible, "423.9 mm" and "524.9 mm". In one of the PDF files the part shows "424" and "525"? If I turn down the precision I'll get 424mm and 525mm but that doesnt mean it's 424mm and 525mm, thats just what its showing. Are the parts really 423.9mm and 524.9mm or no?

Would it make a difference to you if it were 423.9 as opposed to 424? As far as I am concerned, after the sub-contractor has laser-cut it, and you have pushed it together and welded it, there is no concern for 0.1mm. How would you measure that difference?

Oh I know that. But I mean,... I was just wondering why it wasn't just plain old 424?!?! I thought maybe I did something wrong in Inventor or something. But all in all it's suppose to be whole numbers then I guess.

When I sit and design, I don't constrain myself to get the major dimensions exactly rounded off to the nearest whole millimeter. And when I make print sheets of those drawings for the guys in the workshop, I don't give them a false sense of needing to use anything more than a standard tape measure.

I thought you were going to build your own model to learn from. Why are you importing things?

Not only am I learning CNC, I am also trying learn CAD. So far,... my ideas aren't making much sence. As said before I am using the MM design as a means of determining whether my ideas make sense. Here's what I was trying to do a bit ago(2 or so weeks):

http://www.theelitemodder.com/worklo...09_008-180.jpg http://www.theelitemodder.com/worklo...09_009-180.jpg http://www.theelitemodder.com/worklo...09_010-180.jpg http://www.theelitemodder.com/worklo...09_011-180.jpg http://www.theelitemodder.com/worklo...09_012-180.jpg http://www.theelitemodder.com/worklo...09_013-180.jpg http://www.theelitemodder.com/worklo...09_014-180.jpg http://www.theelitemodder.com/worklo...09_015-180.jpg

I want two of those. One on each side of the spindle. The spindle would be held on both sides. I ditched this design because I would end up having huge problems with welding deformation. That and I dont know if it makes sense now that I saw the MM. I noticed that the MM only rolls on one rail per side per axis except for the Z axis. Before seeing the MM i would of though that was weird but now I am thinking differentely. Having one rail per side per axis is a lot easier because it less to align. I dont know.

As you've alluded to, that design would have numerous problems. It's essentially the parallel gas-pipe design, (such as Joes' 2006) but made from angle. Joe's machine is excellent, but has a fundamental constraint in the flex of the rails. The rungs of the ladder shown in the drawing above don't mitigate that flex relative to the rest of the machine, they just keep the rails semi-parallel with one another.

I can't say that I think strict adherence to the plans is absolutely vital (my table will be a decidedly non-MM design) but on my machine everything above the X-rails is going to be 100% blue MechMate.

I say this as a retired mechanical engineer with 30 years of experience 25 of which was in CAD. I couldn't do it better than the plans Gerald has drawn. After I've built my first one, I might be able to suggest some improvements, but as of right now, I"m not going to reinvent the wheel.

I don't see the exercise of redrawing the plans in your 3-d cad program of choice as a waste of time; I think it helps to build it on the screen before building it of steel. But speaking for myself, I don't have the knowledge to improve on the current design.

Let me put it this way, if you're using the MM plans as a benchmark to determine if your ideas make sense, isn't it more logical to just use that design? All the ideas will eventually converge on the benchmark anyway.

I agree. I'll just use the MM design then. Initially I just wanted a router to do what I have to do. But once I saw the machine I got all excited to build my own. Maybe one day I'll play around an build something of my own. Anyways.

I agree with Jeff, no need to reinvent the wheel... I still did not start with my build, but to learn something about the mechanics, I modelled it in solidworks, go search my threads, you will find the model for download. There is also a sketch-up model, look around.
Also read-read-read you will be familiar with a lot of details when you finally start to cut/weld/bend and screw :)


Pablo

It think I still want to try and modify a few things. For example,... having two z-axis's one on each side of the spindle. I will model that first before doing it.

I seriously nee to try and figure out why I cant work with the dxf's as a sheet metal part in inventor. The one part I tried wont fold.

The standard design, with the single z-axis, has the whole z-assemby off-center in the y-car, with the spindle center about 100mm towards the y-motor. The space left behind it will accommodate another full z-assembly, bu then you need to figure out your dust hose routing, and whether you need a second motor on the other side of the y-car. Also, you need to lengthen your table top and x-rails/beams if you put a second z-assembly in there.

Yeah I figured that. Well,... I thogh once I have the standard MM modeled that I would go ahead and try to get a second Z in there. I was thinking about completely mirroring the z assembly that already there. That would mean two of everything for the whole z axis. About dust collection,... I'll get something in there. no doubt.

I have to do some reading up on sheet metal parts for inventor. its a bit more complicated then I thought. Not a problem though.

Ok,... hows this look?!?! Here's the first part modeled. Does it look right? I didnt know what bend radius I was suppose to use so I just used the sheet metal thickness of 3/16"(5mm). I can make it smaller but didnt know if I should. The inner crease of an actual part, is it very small? Like so small that it doesnt even look like a radius?

Anyways,...

That looks fine. I draw the inner radius as the sheet thickness,

Ok excellent. thanks.

See: Bending of steel plates - how it is done and calculated

Wow I was just going to ask you about that! I just got done modeling a few parts where both sides get bent at 90deg. I couldnt figure out how to get the inner and outer length to be exact. atleast without moving the bend lines. I knew that shouldnt be done because that wehere you put them. Now for instance, part [10 20 451 W] after being bent has a specified inner length of 50mm. I got 49.214mm. Now I remember what you said before about being able to measure with measuring tape. So I left it alone. Am I correct?

I actually have to change the first two parts that are bent at 60deg because I had the bend start at the bend line.