? Change move speeds during a 3D carve??

[cliffn]

I carve 3D reliefs. When the file first starts out carving, it is carving just a straight edge. After about 10 to 15 straight line moves with little Z axis moves, it gets to the picture level. At this time the X axis slows down greatly and the Z axis goes into overtime cutting all the hills and valleys in the picture. The question is, would it be adviseable to change the feedrate at this time to a faster feed rate during the cut? It seems to me that setting a feedrate that matches chip load rate during the long quick moves is null and void during the short slow moves of 3D picture detail cut. It appears to me that the cutter is no longer getting the proper feedrate to take a big enough chip to cool the cutter during that time. Varying spindle speed during the cut would seem to resolve this problem, but is not aviable solution as it has to be done manually and would me to much of a guess. Varying the feedrate seems more logical, but is this a good solution. At different times in the picture, the carving can be a flat river or sky, that intersects with rough mountains and trees. I don't know if there is a proper solution, but cutter life is an issue here. They seem to be getting dull to fast. Any Help? I have included a picture to give you an idea of what I am talking about. If you need an .art file (2008), please send me an email. Thank You!
7763

[Brady Watson]

Cliff,
Generally speaking, chipload is not much of a consideration when cutting 3D, unless of course, the chipload is grossly too high. Looking at your RLF, it seems to me that it would benefit from a higher 3D Threshold setting in your VR command list. This will desensitise the Z axis while cutting that stippled background, allowing the X to move a bit quicker. You may also want to reduce the Minimum Distance to Check and reduce your Move Ramp Rate to 0.1 - You can read up on ramping and how to adjust them in my latest column Brady's Bits & Pieces (http://www.shopbottools.com/BradysTricks.htm) Keep in mind that you may have to read it a few times in order to grasp all of the concepts...but in the end, it will be worth it!

Another quick shot in the arm for 3D cutting, since you are using Pro, is to reduce the tolerance setting when you create your 3D file. I reduced mine from 0.0001 to 0.0025 and noticed a huge difference in cutting speed & smoothness, with no reduction in captured details that I could tell. Give it a try...

-B

[cliffn]

Brady,

Thanks,

I will read your info, and try these settings. My tollerance setting is already changed to .0025 and I too noticed quite a difference. The picture was included to be an example of the type of backgrounds I work with. Much work goes into reducing the stippled effect before I actually carve. The picture is an over emphasis, but it seems to have worked as an example. I wondered about the ramp settings but did not understand what changes to really make. Hopefully, your article will answer most of my questions about it. Thank you! I will try to remember to comment here about my findings so that others can readily benefit as I have.