Project log - CNC upgrade

rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Sun Oct 23, 2011 5:53 pm

Hey look, it's a pile of parts:

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rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Mon Oct 24, 2011 11:07 pm

It looks like the design work is approaching doneness, finally. Thoughts?

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GermTheGeek
Posts: 13
Joined: Tue Aug 23, 2011 11:47 pm

Re: Project log - CNC upgrade

Post by GermTheGeek » Fri Oct 28, 2011 1:17 am

rsilk wrote:It looks like the design work is approaching doneness, finally. Thoughts?
The only word that comes to mind is "Sexy". Looks good.

rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Sun Oct 30, 2011 9:30 pm

Update tiem!

Got the X-axis rails fabricated and mounted, and a stand built for the torsion box.
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The lead screws and nuts have arrived, but we're still waiting on all the bearings and such before those can be mounted. In the meantime, I'm trying to figure out a way to tension the lead screws so they don't whip around during fast moves (and to keep backlash down). Here's one option:

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rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Sun Oct 30, 2011 9:59 pm

Hang on, that tensioner is stupid. This one's better.

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mattf
Posts: 18
Joined: Thu Dec 16, 2010 3:55 pm

Re: Project log - CNC upgrade

Post by mattf » Mon Oct 31, 2011 1:56 pm

I don't know if it would simplify your design.. but you can cheat and use ball bearings (like skate bearings) as thrust bearings. I am currently doing this on my mill. (If you think about it, they also server that purpose in roller blades and skate baords). You could put your ball bearings on the outside of your bearing blocks, and back them with your collars (and maybe nuts to allow you to pre-tension before tightening the collars). Looking good though.

-Matt

rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Mon Oct 31, 2011 2:03 pm

It's a bit complicated this time around because I don't have nuts that mate with these leadscrews. Last time I used bog-standard 1/2-10 acme screw so nuts were cheap and easy to get. I'm using a 1/2-8 4-start screw this time around, so the nuts are hideously expensive. The thrust bearings aren't a big deal, and are only a couple of dollars each (and I'm poaching them from the old machine).

mattf
Posts: 18
Joined: Thu Dec 16, 2010 3:55 pm

Re: Project log - CNC upgrade

Post by mattf » Mon Oct 31, 2011 3:33 pm

That sounds reasonable, carry on :)

-Matt

Conrad_Turbo
Posts: 15
Joined: Mon Sep 19, 2011 4:07 pm

Re: Project log - CNC upgrade

Post by Conrad_Turbo » Tue Nov 01, 2011 10:24 am

If you have any worries about flexing you can always laminate the MDF with a sheet of aluminum or steel depending on the configuration and which direction you see the flexing in. Looks pretty cool!

rsilk
Posts: 305
Joined: Wed Dec 01, 2010 11:55 am

Re: Project log - CNC upgrade

Post by rsilk » Sun Nov 13, 2011 2:44 pm

I suppose I haven't posted an update in a while. Lots has happened!

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