Hi. I have been using Estlcam for about a year now, and really like it. HOWEVER, I would like to do the following:
I want to do a roughing pass with offset of 1.1mm off the final size with 0.5mm DOC
Then do a pass 0.1mm from final size
Then drop down and repeat this process
In other words, create a slot around the part 1mm wider than the bit so chips can get out .
Finally, do the final pass to size, removing the final 0.1mm of material.
However, I can’t see a way for Estlcam to do this. In Estlcam, one can leave a 1.1mm offset, and do a final pass to remove this extra material, but to do the cut and remove an additional 1mm cycle before dropping down and the full depth of cut final cut seems not to be possible. Can anyone help? And if Estlcam can’t do this, then what CAM software would you suggest?
I’m not sure if EstlCAM actually has a way to do this, but have (accidentally) done it by installing a bit of one size but calling it a larger diameter when I make my first cut. That moves the center of the cut away from the edge. The I make a second g-code file with the correct tool selected in EstlCAM.
In other words, I was cutting the holes with a 1/16" bit but selected a 1/8" bit from the tool menu. That made the holes too small by half the diameter (1/32"). Then selected the same holes to cut but selected the 1/16" bit. That moved the center of the tool path 1/32" closer to the actual edge of the hole and the finish cut was right on dimension.
Now in my case I was correcting a screw up. but I can see it useful in other cases.
Of course, if EstlCAM has an automatic feature, then is a strange way to do it.
I don’t think Estlcam can do this, unless you are willing to create multiple separate toolpaths for each depth, but this is not really feasible if you are stepping down a small amount many times. Estlcam can perform an offset, but I don’t think it can use a non-zero offset for the finishing pass (unless you use @mbamberg’s trick of fooling it using an incorrect tool diameter). And furthermore Estlcam won’t alternate between roughing and finishing at each depth. It will do roughing at all depths and then finishing at all depths.
Your best bet might be to modify the artwork to have an additional outer offset perimeter so instead of cutting a part, you cut an island. You might not be able to control whether it cuts the outer perimeter or inner perimeter first, but both will be cut at each depth before going to the next depth. In the artwork, the offset width of your “moat” would be your tool diameter plus 1.2 mm, so when you offset by 0.1 you end up with 1mm clearance beside your tool.
One potential problem with the island approach is you won’t be able to define holding tabs unless you also insert those into your artwork.
If it were me I would probably define an outer perimeter in the artwork and cut an island, but not to full depth. By defining an offset of 0.1 and no finishing tool specified, it won’t cut the finishing pass. Then define a second toolpath as a “part” that goes to full depth with holding tabs, and if the remaining depth from the first operation is not too deep, the chips are probably okay. The second toolpath would also have a roughing offset of 0.1 so it will continue all the way through the stock with the same offset, and then the finishing pass will perform the final cleanup from top to bottom.
Hi. Thank you. That’s an interesting idea, and might work…
I’ve been threatening to move to Fusion360 for my CAM work, but Estlcam is just so damned easy and convenient.
I get really good numbers from Estlcam. I typically do something like a .4mm finishing pass with wood and plastic and am really happy with my results. Adding 2-3 finishing passes does not seem like the right approach to me.
Maybe it is just as simple as retesting your recipes?
I have not done enough testing in metals. For those, tolerances are looser because I am always happy to get a part and not break a tool.
I just did a bunch of poking around and I am seeing 5-10% tool diameter for a finishing pass. So for an 1/8" .16-.32mm I would say scale that with material hardness is a solid guideline. I will need to poke around a bit more on my next cuts. Too little and you will rub not cut, and too much and you will get poor dims from high load deflection.