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Post by Big Man Black T-Shirt(Patrick) on Oct 5, 2018 16:23:18 GMT
I've cut 3 sets of 2-part pieces and on all 3 sets the final cutout 2D contour is shallow on a long side and a short side but not the opposite one. I ran it 3 times and the only difference is that 1 of the 3 times I switched from Conventional to Climb for the final cutout tool path. As you can see in this photo, the results were the same, just the sides switched from left to right and top to bottom. What can be causing this issue, that it's shallow on a top and side on BOTH the upper and lower parts of the 2-part set? I know I can just increase the offset by a few tenths of a mm and solve it, but that won't answer the question of the oddness of the issue.  |
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Post by Derek the Admin on Oct 6, 2018 4:35:26 GMT
I actually don't have a great answer for this one. Did you adjust the zero at all between these?
If I had to guess I'd say this has more to do with clamping deformation of the work piece than anything else. IE: When you clamp things you end up imparting some bow or bend to the work piece. I suspect that's part of what we are seeing here.
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Post by Big Man Black T-Shirt(Patrick) on Oct 6, 2018 4:46:40 GMT
Yes I re-zeroed. As for the clamping, look again at the shallow vs. correct paths. How would a bow make it be shallow on the Top and Left of both the top part and the bottom part of each piece (reversed for the Climb piece)?
It's repeating its Top and Left shallowness twice, within the same piece of wood, and consistently piece to piece!
It looks to me to be some sort of deflection which depends on which direction the bit is traveling through the wood but I can't figure out how it's deflecting UP instead of side to side.
Where it's cutting correctly it's actually cutting a tenth or two into the spoil board, so if I backed off on the depth of cut to make that less, the shallow cut would be even more shallow.
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Post by Big Man Black T-Shirt(Patrick) on Oct 6, 2018 4:49:16 GMT
Saturday I'm going to run two more, one with a second 2D contour path at full depth and one using a downcut bit to see how those compare to these.
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Post by Derek the Admin on Oct 6, 2018 5:10:18 GMT
I'm saying I see what looks like consistency but 2 doesn't make a pattern to me. If more run the same way than I'm wrong (I could very well be here), but the clamping sequence and pressure of the clamps/clamp screws are variables in flux in addition to the change of climb vs conventional.
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Bubba's Workshop
Full Member
Posts: 166
Location: Ludington, Michigan
Machine: M3
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Post by Bubba's Workshop on Oct 6, 2018 14:11:07 GMT
I have the same issue with mine,  |
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Post by Big Man Black T-Shirt(Patrick) on Oct 6, 2018 14:15:49 GMT
I have the same issue with mine, Yours might be the extrusion holding the spindle is lower on one side than the other. When I first set mine up it took me a while to get mine level. Although, if you surfaced your spoilboard that shouldn't be an issue. |
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stever
Full Member
Posts: 133
Machine: Carve King
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Post by stever on Oct 6, 2018 14:53:36 GMT
This has to do with the rotation of the router and the direction of travel. When your router is traveling in the direction it is cutting, it is climbing onto the material that is in front of it. When it is traveling in the direction opposite of of the direction it is cutting, it is digging into the material, that is why it cuts into your spoil board. That is why it reversed itself when you change from conventional to climb milling.
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Post by Big Man Black T-Shirt(Patrick) on Oct 6, 2018 17:46:28 GMT
This has to do with the rotation of the router and the direction of travel. When your router is traveling in the direction it is cutting, it is climbing onto the material that is in front of it. When it is traveling in the direction opposite of of the direction it is cutting, it is digging into the material, that is why it cuts into your spoil board. That is why it reversed itself when you change from conventional to climb milling. That's what I thought given the patterns of the shallow vs. correct cuts. How do I correct it, though? I'm already running at a very conservative 900mm/m feed rate, 600mm/m when I just tried it again with a second pass on the 2d Contour cutout and it still gave the same shallow cuts. I'm about to run it again with another .1mm of depth although I shouldn't have to if I could find the actual solution. |
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stever
Full Member
Posts: 133
Machine: Carve King
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Post by stever on Oct 6, 2018 17:59:45 GMT
This has to do with the rotation of the router and the direction of travel. When your router is traveling in the direction it is cutting, it is climbing onto the material that is in front of it. When it is traveling in the direction opposite of of the direction it is cutting, it is digging into the material, that is why it cuts into your spoil board. That is why it reversed itself when you change from conventional to climb milling. That's what I thought given the patterns of the shallow vs. correct cuts. How do I correct it, though? I'm already running at a very conservative 900mm/m feed rate, 600mm/m when I just tried it again with a second pass on the 2d Contour cutout and it still gave the same shallow cuts. I'm about to run it again with another .1mm of depth although I shouldn't have to if I could find the actual solution. Did this just start? Or have you always had this problem? |
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Post by Big Man Black T-Shirt(Patrick) on Oct 6, 2018 18:33:40 GMT
I've always had level issues, noticeable most often when I engrave acrylic, but this is the first time I've seen such a repeatable pattern to it.
I just ran it again with .1mm added and it came out a clean cut all the way around. Of course, my spoil board has no groove in it on part of the pattern and about a .3mm groove in ti for the other part of the pattern!
Tomorrow I'm going to back off by .1mm and try a Downcut bit and see what that does.
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stever
Full Member
Posts: 133
Machine: Carve King
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Post by stever on Oct 7, 2018 14:12:37 GMT
I've always had level issues, noticeable most often when I engrave acrylic, but this is the first time I've seen such a repeatable pattern to it. I just ran it again with .1mm added and it came out a clean cut all the way around. Of course, my spoil board has no groove in it on part of the pattern and about a .3mm groove in ti for the other part of the pattern! Tomorrow I'm going to back off by .1mm and try a Downcut bit and see what that does. I’m not an expert on this at all, but I don’t really think there’s too much that can be done about it. One thing I noticed on my spoil board is that when I only had it fastened down on the four corners, it would deflect slightly in the middle of the spoil board. It helped a little bit once I put a few fasteners in the center area. I almost only use painters tape and super glue as my hold down method, so I need my spoil board to be as rigid as possible. |
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Post by Mototech on Oct 7, 2018 23:09:54 GMT
.06mm is really good. Thats roughly .0025" or less than the thickness of a sheet of printer paper. |
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