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have some stupid questions fo ryou guys that built your own tables..



brucer
01-28-2011, 04:26 PM
i'm going to start at the beginning..

i sold a 94 camaro for $3000, can i build a nice solid plasma/router table for $1500?

i dont know alot about the motors or servos or what i should or should not use.. i want this thing stout enough to put an actual router head on it...

so i'll go on to what i have and might have..

i have a stack of what i believe is 80/20 aluminum extrusion i landed for $0, i can use all i want. I'm thinking of making the table 5x5 or 4x4, any reason i should go smaller or is it that much more expensive to go 5x8? i would rather keep it on the smaller side as space is somewhat limited.. maybe even 4x4 so i can cut a 3x3 plate which would be way more manageable lifting the plate up in the machine and such.. i'm only going to make it about 2 or 3ft tall anyways.. i want it close to the ground..


this is where i start getting lost.. a friend of mine had a Burny cnc plasma, this was a high end industrial machine, a few years back it was retro fitted with a newer controller and drive motors, it used the rack setup... when he bought it at the auction he got all the old motors and controller which he kept when he sold the machine last week...

if i were to get pictures of the motors or servos whichever they are would you guys be able to tell me if i can use them or not...
the controller he has is a controller that you load a 3inch floppy in and it reads from the floppy, it also has a serial port on it to hook up a pc to it i believe, only thing i would think you would hook to it anyways.. thats pretty much all i know about it..

or you think i would be better off just buying a kit with the motors and controller, that way i know it all works together?

if i were to buy a kit whats a good kit to look at? i do want torch height control..


i'm currently looking at cnczone and some plans like sosylvia plans...
do you guys have any good sources for some other plans using the 80/20 extrusion and maybe some links to assembly brackets and misc items for the 80/20 extrusion?

from the plans and other tables ive seen i think im going to buy a couple of the double extrusions for the gantry supports then build every thing else with the regular 80/20 that i have..

any and all information would be great..

Gadget
01-28-2011, 05:27 PM
Bruce,
I used the Solsylva plans for mine. If I had it to do over I would build one out of all metal, mine has a wood frame and isn't as sturdy as I would like for routing. If you have servos and controllers I would use them if they are big enough for the table you are considering. Servos with encoders give feedback to the controlling software for their actual position so lost steps doesn't happen. Steppers can lose steps and the control software then doesn't know the actual position of the table for that axis. If you have an adequate supply of the aluminum shown in the picture size shouldn't matter too much. The rails and feed screws are more expensive the longer they are though.
I would use either belt drive or ball screws, you will get faster rapids that way. Of course you could also use rack and pinion to get the speed and have good accuracy too.
I bought a kit for my motors and controller at HobbyCNC | CNC for the desktop machinist and hobbyist. (http://www.hobbycnc.com), I got the 301in steppers. I would go bigger if I had to do it over to get more power for faster rapid speeds.
I use EMC2 as a control software which is free and runs on Ubuntu linux. You can get a live CD with both on it to try the program to see if it will meet your needs.
You can get a THC control at candcnc.com for around $300 which integrates easily into Mach3 controller software but Mach isn't free. I think it's around $150. You might be able to integrate it into EMC2 but it will take some work and you may not get the support you need to get it going.
You should be able to get a table going for $1500 or less if you are careful but that doesn't include a dedicated PC and monitor, CAD program, or Mach if you decide to buy that rather than EMC2.
I've been looking for extrusion like you have for a second table build, I sure wish I had a pile like yours. Oh well, I'll keep looking.
Dan

Charley Davidson
01-28-2011, 06:42 PM
If I were you I think I would scrap the aluminum (.74 a pound)use the extra $$$$ to buy steel since your gonna want to run a router, routers need a very sturdy gantry. Build the whole table out of steel for a more sturdy rig. just my 2 worthless cents

Gadget
01-28-2011, 06:50 PM
Probably good advice Charley

Charley Davidson
01-28-2011, 07:13 PM
Make your gantry stance as wide as you can for router use, the sudden stops and direction change along with the added weight of the router will need all the beef/stability you can give it.

Gadget
01-28-2011, 07:29 PM
Consider a Rotozip instead of a full size router. It's a lot lighter and still has pretty good power.

brucer
01-28-2011, 08:38 PM
after me and my friend looked through the box of leftover stuff he has... he has the x,y,z servos, and a burny3 controller...

i am pretty good with computers and actually have ubuntu and have used it for years on an older computer i have,currently running unbuntu 10.04 ..
i also have a full version of Mastercam 9c at my disposal.... i own multiple computers so computers arent a problem... i have also used mastercam to run cnc mills straight from the computer, but i didnt set it up..

Gadget
01-28-2011, 09:15 PM
I've run mastercam post files on my EMC2 table. I also use 10.04. If you try to post to EMC with your 9x I may be able to help some.

brucer
01-28-2011, 11:41 PM
gadget,

do you know of any good sources for the 80/20 brackets? like the corner brackets, T-brackets and such?


what kind of slides would you think would be better to use?

Gadget
01-29-2011, 08:58 AM
Bruce,
I know nothing about the 80 20 so I can't help there.
As for the linear slides, either a beefy solid round bar slide or one of the bar slides that is connected to a t bar like this one CNC Linear Slide 16mm dia 60" long Fully supported - eBay (item 290527921192 end time Feb-26-11 10:25:37 PST) (http://tiny.cc/msx34) making it easier to mount and also giving it more strength. The solid bar arrangement would be easier to align in my opinion. You only have to have an adjustment on each end and can compensate for misalignment of the frame. A ring mount with three screws each at 120 degrees apart would allow you to fine tune the position.