I have an MK2.5 with spindle. I ran these with a 1/32 tbn at 150 ipm feed and 150ipm with a 12% stepover. It seemed the machine was vibrating as it was cutting. I was wondering if anyone could shed some light on what could have caused these witness marks. I have concluded that I should have used a raster cut instead of offset. But i am more concerned about what the vibration came from. Any help would be appreciated
@Wzeranski To me, it looks like your Z height varies from one group of passes to another group. You see a group of passes that are at one level, then the group next to it is lower, then higher, and so on.
I don’t have a Longmill so can’t provide much help. Slippage of the spindle assembly due to its weight? But if that was the case, I wouldn’t expect the levels to go down and then back up.
Your 12% stopover might be too high as well. But I don’t think that would cause what you are getting.
@Wzeranski What CAD/CAM application are you using. If Vectric, did you do a roughing pass first? If so, how much material did you leave for the finishing pass?
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Hi Walso,
Using the roundabout toolpaths on a 3d rampage without clearance can, no will create these lines due to deflection of the tipical longer tapered balnoses and some flex in the xaxis the lm is more prone to have. At least it looks like that to me and if I was blunt, I would tell you this with confidence.
If the probem is more deflection than machine flex, you can fix bij removing most of the material with a roughing path, and use the tbn for details only.
Another way to decrease the marks is indeed using a scanning toolpath rather than the roundabout. The devides the number of deflection and flex movement by 2
Can you feel flex in the machine when you wiggle the mill around?
Another thing that caught my eye, prollly because my mind has not been fully upgraded into adult os is the unfortunate position the glass is at for the left person. I got jumped by that straight away and had to fight hard to unsee it into what everybody can deduce it to be. If this was my product, I would find a way to edit it in such a way that the illusion would no longer be there. Either complete the glass or simply leave it out (wich might create a problem to the right.) Having the glass like this would degrade everything. Every amount of experimenting with the right toolpath, searching and eliminating machine flex, sanding, varnishing.. gone in giggles, because no one was blunt enough to point it out when it still could be fixed.
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I am using Vectric Aspire. I didnt check to see how much i was leaving behind after the roughing pass.
@Wzeranski You should check that. A bit that small, even a TBN, will flex at those feeds and speeds if you are taking off much material.
What is your speed setting?
You definitely should be using a raster toolpath and I would go no larger than a 10% stepover.
I was getting getting issues like that when my dust boot was set too low, which was causing deflection. It doesn’t look like that cut is deep enough for it to be same issue, but maybe your dust shoe bristles are stiffer than mine.
@Wzeranski Leaning on the table to get a close look at what’s going on can also cause unwanted deflection.
How interesting, I have a few thoughts on this but before I divulge and If you ruled out the above, would you attach or link the file you are using.
Sometimes there is a “grain” in the design itself that can happen when taking a picture and running it through the relief program.
I never use Offset for my cut I always use Raster when doing 3d carves
I have had horrible results when using layered plywood but I couldn’t tell if yours is plywood by the image.
and a few more thoughts. But having the file would help a lot.
Now that is funny! And now that you mention it, I can’t unsee it either.
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Saw it right away lol