Author Topic: CNC Router Design (Read 19192 times)

Brass_Machine · « **on:** January 12, 2013, 03:05:40 PM »

So I have been thinking about building a CNC router. It would be used primarily for plastic, wood (gasp!) and aluminum. No steel, nothing harder than aluminum. I had been looking at a design out there by Momus CNC.

It is primarily built out of wood. But there are videos out there of this thing cutting aluminum. The cutting area might be a little small for what I am envisioning. So, now I am thinking of a hybrid build. I have seen some pretty nice machines built out of 8020 Extrusions. I have most of it done in my head.

One thing that I am getting stuck on is the gantry. Which is better? Moving gantry/fixed table or fixed gantry/moving table??

Eric

Country Bubba · « **Reply #1 on:** January 12, 2013, 04:26:25 PM »

Eric,
Having "Been there dun that", It is my opinion the moving table design is more rigid and can handle the loads better for the envisioned foot print I think your talking about In my case, I ended up with a 13" x13" x ~3" machine that has a footprint of about 15" x 26" in the X and Y axis. Used Nema 23 steppers (~239 oz in) and have milled aluminum, brass, plastics, pcb and it seems to be holding up quite well. My spindle (CNC of a Budget) is only 70 watts so it will not hog a 1/2" cutter obviously.
Because of the moving table, I have no problems with a "racked" gantry and used a single screw to move the table (less complication of the mechanics)
I used linear profile rails on all axis. 12mm for the table (off fleebay for cheap) and heavy duty 30mm for the Gantry and Z (because they were given to me

The frame is Aluminum Channel, Aluminum flat bar and is epoxied and screwed together. I also opted for single start 1/2" x 10tpi acme screws as I was looking more for precision than speed. As a result with the Dumpster AB nuts that I used, I have limited my rapids to 80IPM as the screws will get quite warm if that speed is kept up for a period of time.
So far, have been pleased with this setup.

Brass_Machine · « **Reply #2 on:** January 12, 2013, 04:35:17 PM »

Hi Art

Do you have pictures of your setup? I would like to see it. I am making mine on a budget as well.

Eric

Country Bubba · « **Reply #3 on:** January 12, 2013, 04:45:23 PM »

Eric,
Have to take some and will see if I can even approach the quality of what I find on this board:})

Country Bubba · « **Reply #4 on:** January 13, 2013, 03:06:42 PM »

Eric,
Well as usual, go to take pictures and the batteries are dead

So we charge them up and here is what we have. Hope you find it suitable and will be glad to answer any questions you have.

Rob.Wilson · « **Reply #5 on:** January 13, 2013, 03:11:33 PM »

Good to see you making a start Eric

Looks a solid machine Art ,,,,,,,like the name

, did you make the spindle ,is it a high speed one ?

Rob

Country Bubba · « **Reply #6 on:** January 13, 2013, 03:13:41 PM »

Additional views

And the control panel was milled and engraved on this machine. Sure it was slow, but we got there

The monitor is mounted on a "post" using a vesa type wall mount. The computer and control box are in the bottom of the cart the unit is mounted on. In the one picture, you see a MDF spoil board that was first used to try doing pcb's using double sided tape (messy)

So we got a piece of HDPE and made a vacuum chuck (The black piece). Just in front of the table on the left side if you can make it out is a hall effect switch that is used for Home/Limit switch.

Enjoy

Country Bubba · « **Reply #7 on:** January 13, 2013, 03:21:06 PM »

Rob,
Thank you for the kind words. Means a lot to me after seeing the work you do (still would like to know about the nickle plating though:})

The spindle is one I got from Paul Jones at http://www.cnconabudget.com/ and is 3 speed (7500, 15000, 30000 rpm) it only uses a 1/8"shank tool held in by a grub screw. So far, it has worked quite well for me even though it is only rated at 70 watts which is fine for PCB work.

As for the name, I came up with that after numerous changes to the design over a period of about a year and several sleepless nights wondering IF it would work!

Rob.Wilson · « **Reply #8 on:** January 13, 2013, 03:28:51 PM »

Hi Art

Thanks for the link

looks just the job , I will need a high speed spindle when I get my mill finished .

I see you have used linner guides on your machine that must make it nice and smooth .

Vacuum table looks interesting

, What sort of projects have you made on it?

Rob

Country Bubba · « **Reply #9 on:** January 13, 2013, 03:51:34 PM »

Rob,
The intent of this project was to have a small tabletop that I could have in the house instead of trudging up to the shop. I wanted it for two main purposes:
1. Mill pcbs for various projects (want to get away from chemicals)
2. I use TurboCNC as my controller and have made several changes/additions over the years and wanted a machine that I could test stuff on quickly. Again it was so I would not have to trudge up to the shop for a 5 min test. A programmer I ain't and my compilations are by trial and error (mostly error).
As to projects done on this machine, as previously mentioned the milling and engraving of the control panel, the plastic mounts for the hall effect switches used for the home/limit switches, a couple of panels for the control box were milled and engraved, a couple of other projects done in brass cause I was to lazy to carry them up to the shop and do on the RF31 (they were small and consisted of outside profiles in 1/8"x 1 1/2" brass strip with some engraving), the led light bar mounted on the spindle was the first pcb that I attempted.

The linear guides are fantastic. Believe it or not the 30mm ones used on the X and Z axis were going to be thrown out by a friend! Got 4 Trucks and 5' of rail to recycle instead of being sent to the land fill! Originally was going to use a double rail Z axis, but then realized the rail was wider than the diameter of the spindle and it could never produce near the forces the system was rated at! So ended up with a much narrower Z axis and that extended the X travel by quite a bit.

The vacuum chuck works a treat, I have a 3cfm vacuum pump and it will hold 10"Hg on the board and you can hear the leakage. Oh and the chuck was done in-situ on the machine also.

Brass_Machine · « **Reply #10 on:** January 13, 2013, 09:32:16 PM »

Nothing wrong with that machine at all. Looks sturdy enough!

I like the vacuum table. I need to make one myself after I build the router. I will probably be asking a lot of questions!

I am still at a toss up on the fixed/moving gantry thing. I think as much as I want a fixed gantry I will be losing some work area if I go that route. I want a work area or either 1' x 2' or 2' x 2' (I know it will be smaller when all is said and done)

I am going to start building this thing in CAD shortly. I need to find a 8020 CAD model... I don't want to have to sign up at a website just to get the CAD files...

Eric

Country Bubba · « **Reply #11 on:** January 14, 2013, 12:47:45 PM »

Eric,
Thanks and if there is any help that I can give, let me know and will try.

Swarfing · « **Reply #12 on:** January 14, 2013, 03:33:36 PM »

Eric give this site a try

http://www.tracepartsonline.net/%28S%28aey4rr55xdds2x3rmizpvh55%29%29/content.aspx?home=1&class=TRACE

Rob.Wilson · « **Reply #13 on:** January 14, 2013, 03:54:27 PM »

Looked on Traceparts earlier ,dont think they have the same section Eric wants to use .

http://www.tracepartsonline.net/(S(fmryro45ujp2d4u00krwgz55))/content.aspx?ClsID=/ROOT/C77/C77.120/C77.120.T01/&tp=2&st=0&Lang=en&Class=TRACE&fwsid=GLOBALV3&ttl=Aluminium+alloy+profiles

What CAD program will you be using Eric?

Rob

raynerd · « **Reply #14 on:** January 14, 2013, 04:13:50 PM »

Eric, getting in on this discussion a little late, but on my router I've gone for a fixed gantry and moved the table. Pretty damn rigid and a more than capable machine - despite me building it!! Only limitation is the spindle. I made my own spindle using a er16 chuck, and out runner motor. It runs well on plastic and wood but stalls easily when taking any sort of a cut in brass or ally. If I want to cut brass or ally, it takes ages because I have to take such small cuts! That said, I've done some lovely engraving and cut out some nice brass parts up to now.

Do you plan on using Linux CNC or mach3? Despite having a little experience with Debian, I sucked with linuxcnc! I just couldn't get it to work properly. Installed mach3 and all my troubles went away!
I don't know what you are intending to actually cut, but I couldn't ever recommend V-carve highly enough. Truly amazing. Powerful and once you get a grip of how it works, v easy to use.

Keep us posted. Immediately when I made my small CNC, I got a load of extrusion to build a bigger machine! It is all here waiting, so if you do use ally extrusion, plenty of pics!!! - I might copy you!

Chris

Brass_Machine · « **Reply #15 on:** January 14, 2013, 04:47:06 PM »

Quote from: RobWilson on January 14, 2013, 03:54:27 PM

Looked on Traceparts earlier ,dont think they have the same section Eric wants to use .

http://www.tracepartsonline.net/(S(fmryro45ujp2d4u00krwgz55))/content.aspx?ClsID=/ROOT/C77/C77.120/C77.120.T01/&tp=2&st=0&Lang=en&Class=TRACE&fwsid=GLOBALV3&ttl=Aluminium+alloy+profiles

What CAD program will you be using Eric?

Rob

I was able to get an IGS file from one of my suppliers. So I am set on that.

Rob, I use Alibre Pro

Eric

Brass_Machine · « **Reply #16 on:** January 14, 2013, 04:48:21 PM »

Quote from: raynerd on January 14, 2013, 04:13:50 PM

...
Do you plan on using Linux CNC or mach3? Despite having a little experience with Debian, I sucked with linuxcnc! I just couldn't get it to work properly. Installed mach3 and all my troubles went away!
I don't know what you are intending to actually cut, but I couldn't ever recommend V-carve highly enough. Truly amazing. Powerful and once you get a grip of how it works, v easy to use.
...

Chris, I use Mach3 on my CNC mill.

raynerd · « **Reply #17 on:** January 15, 2013, 01:08:47 AM »

Yes, of course....forgot you had the mill!

mattinker · « **Reply #18 on:** January 15, 2013, 09:51:01 AM »

Quote from: raynerd on January 14, 2013, 04:13:50 PM

Only limitation is the spindle. I made my own spindle using a er16 chuck, and out runner motor. It runs well on plastic and wood but stalls easily when taking any sort of a cut in brass or ally. If I want to cut brass or ally, it takes ages because I have to take such small cuts! That said, I've done some lovely engraving and cut out some nice brass parts up to now.

Chris

Chris,

thread jacking, I don't think I'll be too intrusive. I am curious about your spindle, which I've been sort of following. I should have asked earlier, but your recent events led me to think you must be more than busy. I'm thinking along the lines of a ER20 10mm chuck so far only at the thinking stage! What kind of power supply are you using? If it's stalling, is it getting enough power?

Regards, Matthew

raynerd · « **Reply #19 on:** January 15, 2013, 06:27:36 PM »

Matthew, you are right. I'm running it from an atx pc power supply and it just isn't enough. Don't want to hijack Eric's thread but if you have any ideas of a suitable supply let me know, perhaps by pm or on my CNC thread! As it happens I've blown the atx so need to sort something new out anyway. Chris

Swarfing · « **Reply #20 on:** January 15, 2013, 08:37:36 PM »

Chris just gang two atx power supplies together to get 24v

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Author Topic: CNC Router Design (Read 19192 times)

Rob.Wilson

Rob.Wilson

Rob.Wilson