[louieatienza]

Sorry guys, it's been a while. I had a few priorities I needed to tend to, but I'm back...

It started out as upgrading parts to my original Solsylva machine. I ended up rebuilding everything! I am still using the steppers and leadscrew bearings from my old machine. Here's the YouTube link:

[nomedia="http://www.youtube.com/watch?v=xBm4LWCNMF4"]YouTube - New Home Made CNC Router, Upgraded Parts![/nomedia]
[nomedia="http://www.youtube.com/watch?v=owgIoN9pKdc"]YouTube - New Home Made CNC Router, In Action![/nomedia]

For the frame and gantry, I used 1" black phenolic. Believe it or not, I cut all the pieces with my old Solsylva machine (the burn marks tell the story!) But I had difficulties adjusting the feed/router speed, where my machine wasn't ridgid enough for the speed I needed. It is now .

For the X and Y axis linear rails, I used ROLLON 43-series tracks and trucks. On both axes, I used a T in conjunction with a U rail. The U rail allows for any misalignment, and the T track handles most of the side-to-side load, as well as the leadscrew.

I used roller skate bearings for the Z axis, but integrated them into the carriage sides. This made fitting and assembling the carriage more difficult since there are 6 bearings a side, but I feel it's stiffer than the normal 4 bearing configuration. I adjusted the preload by sizing up the router plate, and the outer bearings are adjustable.

For the X axis, I stayed with the dual leadscrew/timing belt configuration. Because my frame is now slightly narrower, my belt was too long, and ordering a new one right now was out of the question. So I redesigned the stepper mount, where I have now 4 idlers holdoing the belt in a "W" shape. The belt tension is adjusted by raising the stepper plate.

I liked the 24 x 32 cutting area I had with the old machine, so that remains the same. To achieve that, I lowered the side rails all the way to the table, and raised the gantry sides. I could still bkock the machine up if need be, though I think having the frame direct to the table adds more stability. I also tapped holes in the phenolic and assenbled everything with bolts, so everything is tighter now. I hope with the added weight, I'll get evevn more improvement in cut quality (though I did successfully cut aluminum with the Solsylva build.) The gantry assembly with the router is about 60 pounds, maybe more.

I also brought the monitor, keyboard, trackball, and card reader to the top. Prevoiusly they were all in the shelf, and I had to make like a troll to access them!

I'll take pics tonight... Need a new wasteboard, then I can start cutting! Thanks for looking!

[louieatienza]

OK here's a shot of the whole machine...

[louieatienza]

A shot of the gantry and Z carraige assembly. Originally I was going to use steel tube for the linear bearing rails, but opted with the ROLLON rails instead. Also because of this I shelled out the gantry beam to shave weight, but in hindsight I could have left it solid. To avoid those chunks of phenolic jamming up my machine and wrecking my router, I pocketed each hole out, which took some time!

[louieatienza]

Closeup of the Z bearing assembly. Four bearings go through the carriage sides, and the other 8 guide the rails front to back. I made the carriage as square as I could, then cut the router plate slightly oversize to preload the sides. The front bearing is adjustable.

[louieatienza]

Here's the Z stepper and mount. The stepper base actually sits in a pocket I machined out. Material is 1/2" chopping board! The 4 aluminum tubes are set into the plastic, and everything is bolted down tight.

[louieatienza]

The Y stepper mount is similar, though right now it doubles as a holddown for the stepper wires!

[louieatienza]

Here's how the leadnut attaches to the carriage... I lost the other two screws....

[louieatienza]

The X axis stepper mount ended up more complicated than I hoped. Originally I planned on using two idlers. But because my frame ended up smaller than the original, I ended up with a belt a little too long. My solution was to add two more idlers so the belt loops around in a "W" configuration. Maybe not ideal, but it sort of looks cool!

[louieatienza]

The monitor, keyboard, card reader, and trackball are now on top! Wish I did that last time....

[louieatienza]

I wanted to test the ridgidity of my machine, by doing some light aluminum milling. For a first run on the machine, going blind with the feedrates, I'm happy with the results!

Material is Mic-6 cast tooling plate, 1/4" thickness. The diameter of the gear is 3". Feedrate 36ipm, depth of cut .035 per pass. Spindle about 17,500 RPM. Using a 1/8" Amana upcut spiral-"O"-flute bit. g-code generated with Vectric VCarve 5.5...

[louieatienza]

I have the video of the cutting posting now on YouTube, it should be up within the hour...

[louieatienza]

[nomedia="http://www.youtube.com/watch?v=mAsp3_uN7SY"]YouTube - Home Made CNC cutting aluminum clock gear 1/4" thickness Part 1[/nomedia]

[nomedia="http://www.youtube.com/watch?v=EE42RnAGUf4"]YouTube - Home Made CNC cutting aluminum clock gear 1/4" thickness Part 1[/nomedia]

edit: the videos are not the same, I accidentally named them the same; the second video just shows the final product all cleaned up.

[CNC Lurker]

Congrats, that's a stout build if your cutting aluminum without any problem. That was a great idea making it out of phenolic instead of MDF, being that phenolic is moisture-resistant.

[mmcp42]

YouTube - Home Made CNC cutting aluminum clock gear 1/4" thickness Part 1

YouTube - after cleaning up - Part 2

edit: the videos are not the same, I accidentally named them the same; the second video just shows the final product all cleaned up.

yeah I noticed that,
just edit your post!

oh and nice work by the way!

[louieatienza]

Thanks guys! Hope to get some paying jobs on the machine soon!

Paul, there are other benefits to using phenolic as well. It has more mass and stiffness than MDF, which I feel will help a lot cutting stuff like aluminum and the denser tropical woods.

One revelation came to me while I started planning my router design. On my first machine, there were limitations as to how far I could "push" it before it started to flex. Not an issue cutting MDF, or basswood, or even maple; but I ran into some issues with aluminum. Basically it was a mismatch of not enough ridgidity and mass behind the router, with too much RPM on the router. I would tighten my bearings on the carriage, but because of the "imperfections" in construction (the design allowed for this by having 'flex' built in to compensate for material irregularities) they would be loose in spots and tight in others. Shimming was fruitless; some work with a file made things way better, but not where I'd like.

Back to the revelation: Instead of making the bearings as light as possible and pushing the router through the work, it might be better to keep the bearings tighter, use heavier construction, and allow the steppers to push the machine, and let the router do it's work. Even with the preload, the ROLLON trucks glide smoothly on the rails, so even with an almost 60 pound gantry I'm still able to move it easily with the 3N-m steppers and 8-start screws. With the sturdier construction, I was able to mount the larger spindle, and it cuts through without slowing down.

I was thinking of maybe rebuilding some parts in aluminum; then again the phenolic also has some vibration dampening properties which I feel could be helpful. The ROLLON rails are so massive that they themselves became the main structural material, with the phenolic holding them in position!

As for the aluminum cutting; With my first machine, I remember reading somewhere that the recommendedcutting speed for aluminum (maybe mic6 brocure) at 120ipm, with a 4-flute bit, can't remember the spindle speed. But the recommended spindle speed is way slower than my router would go. Thus I reasoned that with the single flute, I could still use high RPM, and slower feed rate. I'm sure that my reckoning would make some machinists cringe, but having no machine experience, I have to work with what I got.

I did a job a while ago that spec'd out the 1" phenolic for a lab countertop. But there are a few places that sell them, as they are used for bathroom stall partitions....

[louieatienza]

OK I have a friend ordering two guitar bodies! I jsut cut the first one, and have some videos and pics...

On the first video, I might have set the feedrate too high and the spindle speed too low. I adjusted both toward the end, but the cut was still good. A bit scary though since it was a 1/2" bit with a 1/4" shank and it was really knawing at the wood! I have since got a 1/2" bit with 1/2" shank.

On the last video, I forgot I had to widen the rest of the tremolo cavity, and the toolpath started just right where the corner of the spring cavity is, and a slight blowout. I was able to clean it up with a 1/16" pass...

[nomedia="http://www.youtube.com/watch?v=eSRUCMHsM_A"]YouTube - Home Made CNC Router Cutting Guitar, Pt.1: Pickup Cavities and Neck Pocket[/nomedia] [nomedia="http://www.youtube.com/watch?v=nPUnSKKDk8w"]YouTube - Home Made CNC Router Cutting Guitar, Pt.5: Body Profiling[/nomedia]
[nomedia="http://www.youtube.com/watch?v=CowGhzzbgGc"]YouTube - Home Made CNC Router Cutting Guitar, Pt.6: Rear Cavities[/nomedia]

Also, I think I'll get even better performance once I get the router speed and feedrates optimized for my new setup. I still like to do the contours by hand, and the fillets I think go faster with a handheld router (unless I can figure out how to do them efficiently on the CNC.)

The second pic shows the finished forearm contour, before the fillet. I cut the bulk with the tablesaw, then feather it in with a rasp, and finally belt sander. I don't like the hard transition usually found on Strats; and prefer a more flowing contour like on some of the very early ones...

[Jesse B]

Very nice, I always love home-made guitars. Your machine seems to cut quite nicely.

Where did you get the belt/pulleys for your X axis if you don't mind me asking? I'm thinking of using one for a design I'm playing around with as well...

[louieatienza]

Very nice, I always love home-made guitars. Your machine seems to cut quite nicely.

Where did you get the belt/pulleys for your X axis if you don't mind me asking? I'm thinking of using one for a design I'm playing around with as well...

Thanks! I used to do these all manually - plane boards down, rough cut with bandsaw, clean up with router and home-made template, beltsand, etc... - now I do the surfacing on the machine as well (I have about 1/2" of clearance after installing my 2" long 1/2" router bit! What once took me over 3 hours takes about 12-15 minutes of machine time, not including set-up.

I get my belt and pulleys here: Precision Mechanical Components Timing Belts Pulleys Spur Gears Couplings Bearings Sprockets Retaining Rings Brakes Helical Gears Clutches Universal Joints I can't remember which ones I got but they were the least expensive (L?) I'm using a 1:1 drive ratio but depending on your stepper/screw you may try a different ratio.

[Jesse B]

Yeah, I can imagine that this machine saves you a serious amount of time

Have you noticed any issues with backlash? Or does having them tensioned eliminate this for the most part?

[louieatienza]

Here's the second body cut. I just have to do the belly cut. Evevntually I will do these on the machine as well, but for now I enjoy doing it by hand.

This will get white/black/white binding. It is quilt maple over sapele. The second image shows the quilt, wetted with xylene to bring the grain out. It looks like yellow waves in a yellow ocean!