Ski Builders Forum

I haven't posted much on this yet, figured I would wait until things were nearly complete.

I've been wanting to take on this project for a couple of years, I've just been waiting until I had the time, and the money. This year I had both so I took it on.

I knew building a CNC machine would be expensive. I had a goal of doing it under $2k. In the end, I was a factor of two over that... ouch.

A disclaimer: I definitely could have done more research before just buying/building a bunch of stuff. I am not a member on the CNCZone forum (similar to SkiBuilders but for CNC stuff), and probably should have been. Had I done some things different I could have brought the cost down I'm sure.

I wanted it at least big enough for ski stuff, but I was constrained by shop space so I couldn't do 4x8ft which seems to be pretty standard. I settled on 3x7ft. (actual lateral working area is more like 2.5ft).

I designed the entire thing from scratch in Solidworks, and had virtually the entire thing designed/assembled on the computer before I bought a single part. That made construction go very quickly and smoothly. Everything went together exactly as-designed with no issues. Pretty proud of that!

The frame is made from 4" tall steel c-channel, the gantry is 6" c-channel. I had a number of parts laser cut out of 1/4" steel by a place in Bellingham, Wa. That saved me a lot of machining.

Mechanical parts were purchased from a mix of McMaster-Carr, Ebay, and a few CNC Router suppliers.

The X-axis uses a gear rack and spur gear on each side, powered by a single stepper motor with outputs going to each side, with timing belts/pulleys, sliding on 7ft long 20mm linear bearings.

The Y-axis uses a ballscrew/nut direct drive from a stepper motor, sliding on two 20mm linear bearings.

The Z-axis uses a ballscrew actuator thing I found on ebay, that I had to machine an adapter for to mount my stepper motor (used my small CNC mill to made the adapter )

I built a rolling cabinet for the machine that includes a space for the computer, some drawers for supplies, a few cabinet doors on the front for parts/ski materials, and one LONG cabinet on the back for long ski materials.

Photos:

Some other details:

I'm using a Geckodrive G540 controller, and Mach3. I got the controller box from a local CNC guy that has the G540, power supply, e-stop button, and relay/output to turn the spindle on/off.

Once everything is all fine tuned I will be offering up ski-building services if there's a need for it (templates, mold parts, etc). But that's still TBD right now.

wow steel gantry hea-vy.

Very impressive Twizzstyle!

MontuckyMadman wrote:wow steel gantry hea-vy.

Ha, yeah tell me about it... the c-channel plus the hefty side supports (1/4" steel), plus all the hardware/steppers, its probably upwards of 60lb+. And that doesn't include the z-axis which is easily another 20-30lb. It's heavy but it glides smooth as butter with very little effort. Pretty amazed how parallel/square I got everything, using a mixture of levels and lasers.

That's wicked! Don't beat yourself up too much about the financials, you're going to love that thing man.

Nice burly design. I would have been afraid to do that much welding to avoid possible alignment issues. What size motor are you using to drive the x-axis? Did going the rack and pinion route cost much less than using an 8' ball screw? What kind of backlash are you going to have on the x-axis?

barnboy wrote:That's wicked! Don't beat yourself up too much about the financials, you're going to love that thing man.

Yeah, I had a good bonus from work this year so that covered everything. Plus I figure, unlike any of my other projects, I can actually put this one to work to make a little on the side.

kylea wrote:Nice burly design. I would have been afraid to do that much welding to avoid possible alignment issues. What size motor are you using to drive the x-axis? Did going the rack and pinion route cost much less than using an 8' ball screw? What kind of backlash are you going to have on the x-axis?

All 3 motors are 495 oz in. I haven't done any cutting to really measure the backlash yet, but it should be pretty close to nothing. The rack and gears are from mcmaster. Again something I likely could have gotten cheaper elsewhere. Was certainly cheaper than the ballscrews I was looking at, and made the design a little bit easier. There is a rack on either side, and when I tighten the belt it pulls the lower pulley up, pulling the gear against the rack, taking away any slop.

Wow Twizz! I am impressed. Taking on a challenge like that is very brave. Looks like you nailed it. What software are you going to use? Are you going to install a vacuum hold down?

Using Mach3 (thats what I use on my mill, a small grizzly I converted to CNC a long time ago).

For holding work pieces I am going to drill a grid of holes (I'll have the machine drill its own holes of course!), about 150 of them or so, every 3" roughly (I can't remember off the top of my head) and put 3/8" t-nuts in. Going to use normal machinist clamps with the t-nuts.

Very nice!! I like your choice of the size... it's nice to have a machine that doesn't take a acre in the shop

nice one!
I have gotten a fir way down the road of doing this a few times but never went through with it. Well done!