ShapeOko Getting Close

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ShapeOko Getting Close

Postby bdring » Wed Oct 12, 2011 1:02 am

Way to go Ed!

Check out this video of the ShapeOko router running on Makerslide. He has a lot of little details to clean up, but the goal of this project is to have a less than $300 router. This will eventually include everything including GRBL on Arduino, motors, drivers, spindle, etc. I have seen it in the flesh and it is really cool looking. He wants to put a handle on the side and you can carry it like a briefcase to the hackerspace and back.

The rapids are super fast and quite.

Blow it up to 480 res to see it better.

Bart
"If you didn't build it, you will never own it."
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Re: ShapeOko Getting Close

Postby EdZ » Wed Oct 12, 2011 10:17 am

I'm a bit worried about gantry wobble: it appears that any bearing play could have a large effect on how far the gantry can laterally shift by allowing the side carriages to slant, especially when rapid side-to-side movement occurs. With the motor mounted on the outside of the gantry moving the centre of mass, that could be the source of the 'high' cut in the test positioned right of centre (gantry, and thus the bit, is lower when the carriages are slanted, raised when sides are perfectly parallel and vertical when carriage is over the centre, then lower again when the carriages slant the other way).
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Re: ShapeOko Getting Close

Postby bdring » Wed Oct 12, 2011 12:55 pm

I can almost guarantee the z problem shown is due to the work piece varying in Z in the gantry direction. He has a very temporary base that looks like a piece of OSB clamped to the router. Everyone who has ever used a CNC router has seen that same issue at some point. It is often fixed on DIY routers by fly cutting the base when it is all done or doing the same on work pieces with varying thickness.

I have seen his machine and it has a very stiff gantry. The supports are 10 ga laser cut steel. You cannot see any shake on those very fast rapids.
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Re: ShapeOko Getting Close

Postby bill griggs » Wed Oct 12, 2011 5:40 pm

The problem is being caused by the bed of the router not being surfaced ahead of time. Basically you place a large diameter router bit in the collet and then create a tool path which mills away a small bit of the surface across the entire cutting area. If you cut 1/64" off the to of the table surface, the top will be flat relative to the CNC machine. Now when you place a piece on the table it will be flat in relation to the X and Y axis.

There is also a process called TRAMMING which allows you to remove any unintended tilt of the router spindle in relation to the mounting plate. I used small shims (playing cards) on my router to adjust the Tram.

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