3D Problem

[TCSpooner]

Hi

I have a funny problem with Sprut CAM. I use a home built 3D router controlled by MACH 3 with open loop controls. I was trying to run a fairly complicated part
today and was baffled by the fact that for each new roughing pass level the tool path would shift along the -X axis by 1/2 the cutter diameter. What puzzled me was that the Y and Z axis' stayed true. As in no shift from what the tool path was supposed to be. Any suggestions would be appreciated. If you want a copy of the code be warned it's about 200,000+ lines long.

tcspooner

[GaryCorlew]

there is a program called ncplot, do a search on the forums for it. Run your code in it and see if it shows the same as what your seeing on your router, if it is the same then it is called step over. The type of bit will dictate the amount of step over ex. a .25 flat bottom bit will step over about .1875 while the same sized ball end mill will be about .02 to about .03 per pass. If it is not the same then you are losing steps and need to slow down you feed speed or make your depth less

[TCSpooner]

Thanks for the quick reply. The cutter is indeed moving about .1875 per pass it's a 3/16in ball nose so that seems to fit your description I'll look for ncplot and try it out.

tcspooner

[TCSpooner]

Hi

I got to thinking about this step over issue and it may be the machine but I have tried complex 3D tool paths coded by Sprut CAM on to other machines than mine and we experienced the same step over problem. I'm wondering if it might be something in Sprut CAM which I am missing? I have only been using it for a few months and the documentation is sketchy at best. Most of what I have learned comes from exp. with master cam and various tutorials supplied with Sprut CAM.

[GaryCorlew]

I have never used spurtcam and never seen it, but most cam programs work the same. With a 3/16 ball end mill or any ball end mill you should not be stepping over 100% of the tool dia, this would leave ridges in between each pass are you seeing this? Also I need you to explain what it is your trying to do. Basically its like this if your tool never steps over then you will not make any progress at finishing the part, it will just run back and fourth in the same spot. Does spurtcam have any kind of a backplot function?

[David Bord]

could it be a post processor problem? I'v never experienced this with sprut. If you are using mach2-3, maybe try the tormach post processor.

How about trying to duplicate it in a smaller project to ease the troubleshooting challenge.

David

[TCSpooner]

Hi

I'm trying to mill a foam plug for a wood burning stove top casting. I have tried to mill a smaller model on two other machines each time I have had the same problem. I am using the Mach2 post processor supplied by sprut. I will try the Tormach post processor and see if it improves things. I also downloaded and tried NCplot I showed some stepover but I must admit I am not familiar with the fine details of using NCplot. Which means I don't really know what to look for. I'm not really concerned about the ridges left by the milling at this point I would like to sort the step over problem first.