ron39's Solsylva Beltdrive 48x72 log

[ron39]

I've been working on a modified Solsylva machine for about 2.5 months now, a few hours some nights and weekends.

I finally am getting close enough to a point where it's more than just a bucket of parts - it is staring to MOVE!

I really benefited from Coogrr's pictures and videos, so I felt I should try to help out the next guy by putting up some information on my build.

Coogrr and I each took the belt-drive plans and modified them a little - I stuck closer to the original plans with the inexpensive bearings and rail setup - wood table etc. My biggest changes involved increasing the Y axis by a foot (to 4 feet for the gantry), and using 2" x 6.75" poplar on the side rails so I could place a full sheet of 5x5 baltic birch on the table and have a foot or so extend off the table under the X rails.

I initially thought of going with steel for the frame, but I had the wood on hand and after testing the deflection for the expected gantry weight of 50 lbs, and getting results under 0.004" at the center of the span and since I'm planning on cutting plywood I decided to start with the wood.

Some smaller deviations from the plans involved not using the pvc idler pullies and going with just bearings (coogrr's idea) and buying more pullies and using them as idlers (we both stumbled on that one).

I still have to put down the MDF for the Tslots, get my cables out of the way, put my electronics in a case, attach the router and tune the machine - but here's a first indication that I may some day finish.

Video of my messy shop and some initial moves:



http://www.youtube.com/watch?v=wcKtR3Ffd54

Video of running 4 simple lines of Gcode in turbocnc:



http://www.youtube.com/watch?v=wrvvPpmzIyU

[CarveOne]

Nice machine. This is the one I wanted to build from David's plans book but don't have room for it at home. The cost was going to be more than I was willing to part with for a first machine. Hopefully, there will be a second machine build. My boss wants me to build one for his shop. Maybe he will decide on this one. I also want to build a steel or aluminum frame for the one I'm building now.

CarveOne

[ron39]

Well I've finished the major work on the electronics - the controller, powersupply etc., are tucked away into a plastic box similar to the origianl design with air flow holes and a fan installed as well.

I now have all three motors connected and running - and the router is now mounted as well.

I still have to screw down the T-slots and move the table into its final resting spot (a few inches closer to the wall) and add the limit switches.

I took some video showing the machine moving in all 3 axes close to it's limits (however since I don't have limit switches on it yet I was a little conservative).

Here's a video of the machine running some simple gcode.

--edit for some reason the embedded youtube video isn't working - turns out it's a forum issue all capital letters are gone and youtube uses mixed case...



http://www.youtube.com/watch?v=ORpt0f6ttfc

[CarveOne]

Nice moves! Thanks for the video. Wish mine was completed to that point.

CarveOne

[ron39]

Thanks for the compliments - I'm happy with how it's moving right now, I may have to do some adjustments after some test cuts, but right now I'm happy with the design.

I'm curious to find out what my cutting speeds will be and if I have to slow down to avoid racking issues since I have a 4 foot long gantry and am only using skate bearings on black pipe. However I'm only planning on cutting upto 3/4 ply and this isn't a production machine so I'm not too worried.

[CarveOne]

I suppose that it will take multiple passes to cut 3/4" MDF since that is what others are doing. The cutter bit can only cut a certain depth with any real quality no matter how stiff the frame and other mechanical parts are. We'll just have to learn the limits of the cutters we buy and the limits our machines can be pushed to. When we find a weakness we'll need to figure out how to correct it. These things evolve or get replaced with something a lot better.

CarveOne

[ron39]

It cuts! I've started doing some test cutting, and it's great to see that it really works.

I spent part of the weekend getting a 7 year old laptop to run Ubuntu Linux and EMC2. It's a little nicer than turbocnc, and I didn't want to bring one of my nicer computers into my shop to run Mach3. Mach3 was easier to setup initially (as was turbocnc), but once I got linux and the software installed it wasn't that hard to setup EMC2.

My daughter who is a year and a half old loves to watch the cnc move (no cutting, that would be too loud and I'd worry about dust etc.). The first time she and Mom watched it move in a test pattern around the whole table and it came to rest, she immediately asked for more. We finally had to tell her the cnc needed to go to bed for the night.

Oh and CarveOne, yeah I figured I'd be doing 1/4" depth passes, but I may find that is too aggressive at the speeds this machine can do, time / testing will tell.

Now on to all the project ideas that I have (mostly items for my daughter....now where is that dinosaur dxf thread).

[CarveOne]

Excellent!! Wish my machine was at that point. Congratulations.

You might see if you can find some cnc cutters that look like roughing end mills. I saw some small ones recently that a friend had acquired as a set. I'll ask him where he got them so I can order some. I have some 8% cobalt roughing end mills in sizes from 3/16" to 1/2". I plan to try one of them in a router if one of them will fit. If they cut wood as well as they cut aluminum and steel I'll use them.

I re-read your older post about the idler pulley substitutes. I'm not real happy with the plastic coupler with bearings either. It has a sag in the middle due to the coupler ID being a little on the small side. I have a couple of 5/16" ID plastic flange pulleys that I didn't use after changing to 1/2" acme rods. I'll use one of the pulleys for the idler. Thanks for that post.

CarveOne

[ron39]

CarveOne - glad I could help with the pulley idea. I'll work on taking some pictures of the machine components and where I substituted the pulleys for anyone else who's considering it - (I think my current thread is suffering from a lack of pictures - especially when I look at your posts, which are very detailed).

I'd be interested in hearing more about any sources for cutters that you find. I ordered a set of router bits from MLCS (combination of straight, straight up cut, and ball nose cutters) they have good prices and free shipping - and sure beat Rockler (a woodworking chain for those who aren't familiar with it) for selection and price.

I'll post some reviews of the router bits once I've had some time to test them out.

[CarveOne]

Ron39,

I tried the plastic pulley and the diameter is about 1/8" smaller than the coupler. The stepper mounting bracket does not have enough range in the bolt slots to tighten the belt. A new bracket would have to be made so that there is enough length in the obround slot to allow proper tensioning of the belt.

The 1/2" x 1-1/8" bearings I used on the lead acme screws are slightly larger than the coupler and would probably fall within the adjustment slot range. I don't see a good way to provide washer "flanges" that rotate with the outer bearing ring. Stationary flanges would be easy, but I'm not sure that those wouldn't cause belt wear. Not sure that the belt wouldn't run off the bearings if there were no flanges. The 5/16" idler bolt would need a bushing to make it fit the 1/2" ID bearings.

Skimming off the surface of the coupler in my lathe so that it is true all the way across it would also cause the same problem as the smaller pulley.

I'll try skimming the coupler surface first, and only remove the minimum amount. If the stress from pressing in the bearings cause the coupler to split, I'll make up another one and remove a little of the coupler's ID so the bearings fit snugly but don't deform the outer surface of the coupler (It's nice to have a lathe and mill handy.) I only have one extra bearing at the moment but will order more spares later.

CarveOne

[ron39]

Yeah I wished I'd initially bought more bearings.

For anyone contemplating a build that uses skate bearings, do yourself a favor and get more than you need - I think a package of 100 would have cost me maybe $10 or $15 more than I was paying for 30, and I should have done it.

Also CarveOne - depending on where you have the idler bearing, you may not need any flanges. Without pulling out the plans for your machine and just thinking of mine - even when the belt is running in the horizontal orientation and has gravity pulling on it, the pulleys which are under load do have flanges and they serve to do the alignment, so you don't need the idler bearing to have flanges as long as it's wide enough to support the belt in the range of positions it could be.

Hope that makes sense. You can get a better idea of this if you look at Coogrrr's videos where he shows his idler pulleys (both by using extra pulleys and by using just bearings). Or I can try to take a picture tomorrow if you still have questions.

[OzarkCNC]

I'm following this design concept. Ron, Carve, and Coogrr are my heros.

I just bought a set of 100 for $35.00 shipped. A local bearing supply wanted $4.05 EACH!

I laffed in his face.

As long as your belts are in alignment, I don't see the problem with using a stationary flange or even a coathanger. You wouldn't be putting that much force on the side of the belt to cause wear. I would guess that during a JOG would be the most chance for this to happen. Yes?