[Lab] cardboard hold down for cnc

[Darcy Whyte]

I've been thinking about having a roller near the endmill to help hold down
material.

Here's what I'm going to try. Anybody have any experience with this sort of
thing or have any other ideas?



Sheet material hold down on
CNC<http://mambohead.com/2011/04/sheet-material-hold-down-on-cnc/>
BY DARCY WHYTE, ON APRIL 24TH, 2011
 <http://mambohead.com/wp-content/uploads/2011/04/rollerAssemble.jpg>

roller
In ongoing issue with cutting cardboard is that it tends to be fairly
floppy. You can clamp down its edges but the center often bulges away from
the table.

Of course you can lord over the machine and help hold the material down.

This problem happens when cutting a larger piece of hardboard as well. The
endmill sometimes tries to lift the material up as it’s pulling material
away from it.

I thought of adding a small wheel to the cnc machine that can press down on
the material being cut. So when the endmill plunges down, there will also be
a wheel that comes down on the material.

I thought it should be spring loaded and that it should be a castor so it
will follow the direction of the cut.

It may not be clear from the diagrams but I need to add some 1/4-20 threaded
rod. Two pieces to form the axle for the wheel and the lever axis. Another
vertical in the Square hole. A spring is running from the small holes at the
lower right to the hole at the top right.

I cooked this quick design up in Sketchup and will cut it out shortly and
see if it works.
 [image: roller]<http://mambohead.com/wp-content/uploads/2011/04/roller.jpg>
roller [image: roller]<http://mambohead.com/wp-content/uploads/2011/04/rollerAssemble.jpg>
roller [image: toolpath]<http://mambohead.com/wp-content/uploads/2011/04/toolpath.jpg>
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