Stiffness of the spindle carriage plate

discussion of design changes / improvements / suggestions
Neppo1345
Posts: 17
Joined: Thu Apr 09, 2015 2:12 pm

Re: Stiffness of the spindle carriage plate

Post by Neppo1345 » Fri Jan 22, 2016 9:20 pm

HDVideo wrote:
Neppo1345 wrote:HDVideo, I like that take on it! :D

I thought about extending mine down past the mount as well, but the 1/4 inch plate I had on hand wasn't long enough.

I cut my LH plate cut Wednesday. Didn't make any mistakes with the CAM this time, and played around with some new feeds and speeds that left a very nice surface finish.

Currently have the Z axis torn apart all over my bench with the hole locations marked out; got too tired the other night and had to call it quits (didn't want to make another rushed/tired mistake like I did with my CAM on the RH plate).

Planning on finishing it up this weekend...if it works I'll post up the DXFs.
Thanks Neppo1345, you have a good design there. How many screws did you use to attach to the plate? I put three holes for M5 tap on each. Was going to use four, but spacing didn't work out right. Attached is the Fusion 360 file for my variation of your design. Eager to hear how it works out if anyone uses it.

Well, it wouldn't let me attach the f3d file. What file formats are acceptable?
It's set up for 3x #6-32 stainless screws. There's room for more but 3 per side should be more than adequate.

HDVideo
Posts: 32
Joined: Wed Dec 02, 2015 7:33 pm

Re: Stiffness of the spindle carriage plate

Post by HDVideo » Fri Jan 22, 2016 11:28 pm

If the drawings I'm using are accurate 1.5mm milled off the top of each Z-Axis rail would allow the use of low-profile socket head cap screws to attach the support pieces so that there would be no need to countersink flat head bolts. Rails are 20mm high and I don't think taking a little off the top would cause a problem.

Current clearance between Z-Axis plate and top of Z-Axis rails is 2.1mm.

Low profile socket head cap screw cap is 3/32" or 2.2mm.

Shaving 1.5mm off the rails should result in 1.4mm or 1/16" clearance.

That might not be enough, but maybe there's a way to do it without countersinking, which would mean the mounting holes would not have to be located quite so precisely. All of this assumes the drawings are accurate.

Just a thought.

wunderaa
Posts: 51
Joined: Mon Apr 20, 2015 3:45 am

Re: Stiffness of the spindle carriage plate

Post by wunderaa » Fri Jan 29, 2016 3:12 am

Started on mine! No fusion access so had to draw these up, but same concept. Should have them drilled, tapped and mounted this weekend. 3/8" aluminum.
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HDVideo
Posts: 32
Joined: Wed Dec 02, 2015 7:33 pm

Re: Stiffness of the spindle carriage plate

Post by HDVideo » Fri Jan 29, 2016 1:50 pm

That looks good, wunderaa. Did you cut it out on the Shapeoko? Let us know how it works out.

Fusion 360 from Autodesk is free for hobby users (<$100K annual income from use) and is a hybrid local/cloud based, full featured CAD/CAM package. It's a pretty impressive package and the price is right, at least for hobby use. Here's a couple of drawings I did of a CNCRouterParts machine with stand, all drawn and rendered in Fusion 360. It's a fun program to play around with.

Image

Image

wunderaa
Posts: 51
Joined: Mon Apr 20, 2015 3:45 am

Re: Stiffness of the spindle carriage plate

Post by wunderaa » Fri Jan 29, 2016 3:31 pm

HDVideo wrote:That looks good, wunderaa. Did you cut it out on the Shapeoko? Let us know how it works out.

Fusion 360 from Autodesk is free for hobby users (<$100K annual income from use) and is a hybrid local/cloud based, full featured CAD/CAM package. It's a pretty impressive package and the price is right, at least for hobby use. Here's a couple of drawings I did of a CNCRouterParts machine with stand, all drawn and rendered in Fusion 360. It's a fun program to play around with.
Wow, I have to check that out. That looks fantastic! Yes, the parts are being milled on my SO3.

Neppo1345
Posts: 17
Joined: Thu Apr 09, 2015 2:12 pm

Re: Stiffness of the spindle carriage plate

Post by Neppo1345 » Fri Jan 29, 2016 3:57 pm

wunderaa wrote:Started on mine! No fusion access so had to draw these up, but same concept. Should have them drilled, tapped and mounted this weekend. 3/8" aluminum.
NICE!

I've got mine all finished up.

Sorry I've been so quiet; no time to finish the writeup. I volunteer as an engineering mentor with a high-school FIRST robotics team; its the heart of our build season and I go straight from work to the school.

I ran a job for the team on Tuesday in 6061-T6, cutting out some arm gussets for our robot. Great surface finish and nearly eliminated the chatter I was seeing in the Y direction. Hoping to run another job cutting some motor mounts out of 1/4 6061 this weekend...and hopefully I'll have time to finish the writeup and the DXFs.

Image

I found one other issue with my Shapeoko that I had to address but before I determine if it was 'my bad' or a 'Carbide3d bad' I want to ask the question: Did your guide wheels come with the bearings and washers pressed in already? I don't seem to remember pressing these in myself.

WillAdams
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Location: Pennsylvania --- south of the Turnpike, East of US-15
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Re: Stiffness of the spindle carriage plate

Post by WillAdams » Fri Jan 29, 2016 4:14 pm

For the Shapeoko 3, the V-wheels come pre-assembled, w/ precision shims in-between the two bearings.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

HDVideo
Posts: 32
Joined: Wed Dec 02, 2015 7:33 pm

Re: Stiffness of the spindle carriage plate

Post by HDVideo » Fri Jan 29, 2016 6:39 pm

Neppo1345 wrote: NICE!

I've got mine all finished up.
(snip)
Great surface finish and nearly eliminated the chatter I was seeing in the Y direction. Hoping to run another job cutting some motor mounts out of 1/4 6061 this weekend...and hopefully I'll have time to finish the writeup and the DXFs.
Looks Great!

Was hoping you'd say "eliminated all chatter" (lol), but "nearly eliminated the chatter" sounds like the results are better than before. Good job!

Did you have any problem getting the holes drilled in the router plate in the right spot? Did you just measure, center punch and drill or did you do that on the Shapeoko?

Neppo1345
Posts: 17
Joined: Thu Apr 09, 2015 2:12 pm

Re: Stiffness of the spindle carriage plate

Post by Neppo1345 » Fri Jan 29, 2016 8:32 pm

Lets me rephrase that...eliminated all chatter when taking "reasonable" cuts ;)

I'll take a minute when I get home and post up the photos of how I transferred my holes through the steel plate to the supports.
WillAdams wrote:For the Shapeoko 3, the V-wheels come pre-assembled, w/ precision shims in-between the two bearings.
Okay that's what I thought. So after I got everything assembled I was pulling back and forth on my spindle mount and there was still a considerable amount of play (way more than I was happy with when I was only applying moderate hand pressure). With slightly increased pressure I noticed a 'popping' that was associated with ~0.010 worth of play between the Z axis carriage plate and the aluminum rails.

I tried to trace down where it was coming from: did I have a loose fastener somewhere...? I completely disassembled the Z Axis again and re-assembled, re-tension all of the v-wheels on their rails etc. The play was still there, the 'popping' was still there. It appeared to be isolated to my lower LH V-wheel...so I concentrated on that.

When I disassembled the V-wheel, (and going from memory at this point...I'll check what I wrote down when I get home) I took some measurements and the shim between the two bearings mic'd at 0.042. Measuring the delrin V-wheel itself, it checked with a 0.030 wide internal ridge. The 0.042 shim was allowing ~0.012 of float between the bearings.

Image
Gotta love some powerpoint engineering ;)

I pulled apart all the other V-wheels and found a similar situation. I found some 0.032 thick washers (actually just pulled one of the thinner washers off the V-Wheel stackup) and replaced the 0.042 thick shims that came in the wheels. Popping was eliminated completely, and the flex between the Z-axis plate and X-Axis carriage was greatly decreased. Hopefully the extra 0.002 will prevent me from putting too much (if any) axial pre-load on the bearings. I'll sacrifice a little longevity for more accurate cuts with better surface finish.

WillAdams
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Re: Stiffness of the spindle carriage plate

Post by WillAdams » Fri Jan 29, 2016 8:59 pm

Please let Carbide3D know about that.

There's been a couple of reports of out-of-spec V-wheels --- matching the washer to the size of the inner races is an interesting approach. Our estranged siblings have been using fiber washers instead (which given that apparently their V-wheels are being provided w/ ordinary washers instead of precision shims is a more reasonable choice).

Are there any washers of a suitable size / material to use as spacers to make up for a too-narrow race? I think that would be a better point to address this at (or just get in-spec V-wheels).

Aren't there some heavy-duty V-wheels in the works?
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
Nomad 883 Pro #596 (bamboo)

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