Hello, I was thinking about the feasibility of fitting a sander and controlling it from the lowrider to finish after cutting. Something like this:
Has anyone tried this?
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@jamiek attached an angle grinder a while back to cut steel tubing so I think that would be similar to attaching a sander.
You may want to spring load the sander so you have a little compliance. That would also allow you to repeatably set/vary the normal force depending on your spring compression distance.
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That was my first thought too. The CNC is trying to keep a specific position, not pressure. The weight of the sander might be heavy enough, you just need to allow a little spring.
A lot of the benefits of CNC go away. You don’t need precise XY positioning (like you would with a router bit or even a pen plotter). You are just trying to automate some annoying movements.
Another concern is dust collection. You have to keep the pad clean. When operating it by hand, you will notice it is clogged. But not when running it automatically.
There is a tool that does this. The drum sander. I am all for replacing specific tools with generic ones. So it would be great if it worked.
Those are the negatives. The positives are that it is really neat. It could save a bunch of money on an expensive tool. It could also allow the user to be more productive, and possibly safer. It could also provide more consistent results. So I am excited for someone to try it.
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Flattening a slab is probably the easiest case, and if that’s all you are wanting to do, then it’s probably relatively simple. You would probably want at least a little compliance, but if you calibrate the Z position, you might get away with no extra compliance. I could see this as a time saver if you are making multiple passes with different grits.
The machine won’t know when you are done with one grit and ready to move on to the next one, so it will be up to you to inspect the workpiece after each pass and decide if it needs another one. You could adjust the feed rate, or perhaps better to adjust stepover, so it’s done in one pass. You will probably have this dialed in by the time you do your 4th slab, and you can just do a final check.
Here is a video from over a year ago that I never uploaded but it is relevant and perhaps a little bit funny.
(Careful, it’s loud)
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The angle grinder sounds a little like Chewbacca
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So i had the thought of using a sanding disc. Put it in my 660 on mpcnc, but sanding is not what i want to do there.
Yeah, if you just want to flatten, you can easily use a planing endmill. Works pretty well, you have to go at least half a mm or a mm deep, otherwise it gets hot and burns ugly groves into your wood. Don’t ask me how I know… 
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Such great replies. The idea is just to “automate” some manual processes, but knowing it would also require a manual effort (lesser, I expect).
@Bigchepin the use of springs is a great idea.
The use of sanding discs and planning endmills are also another interesting Idea. Gota analyze if I will invest on these or try to build a support for the sander.
Thank you all.
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