3d machinig bad finish, Help!

[jeremy83]

Im am new to mastercam, my boss just bought it and expects me to learn it on the fly, he knows nothing and justs expects magic I guess! My question is I have figured out through tutorials and some poor instruction from our mastercam dealer, to do basic 3d work, but the finish isnt very good, its smooth but you can clearly see the machine marks. Can some one explain breifly on what dive and check mean, and how can I blend the toolmarks better thanks!

[chuy]

Drive surface is what your toolpaths are generated from....check surface is telling it what not to touch....i.e. if your doing a pocket surface and you don't want it to touch the walls than those walls would be your check surfaces... to get a nice finish it's usually a stepover issue the smaller the stepover the nicer the finish...Hope that Helped

[Khalid]

if u r using end mill cutter the finish will not good. and if u r using ball mill then keep the stepover between 10% to 14% for best results.

[jeremy83]

Great exactly what I wanted to know!!! thanks you guys rule!

[Bowman]

Depending on the 3D shape your working with you might also explore using different types of cutter motion strategy. I use FeatureCAM and I can set my toolpaths to use a circular motion, straight lines back and forth and also diagonal. This can be of benefit depending on what your trying to do.

For the most part the stepover is the biggest issue. Also a sharp ball endmill is very important. The only problem with step over is that the finer you make it the long it adds to the run time. Key is to hog off as much as you can leaving that little bit for a finishing pass, you can change to a new endmill for this to get the best finish. The best finished I have seen would take a LONGGGG time to run on my Sherline lol.. Not sure what you had it set to but for a really good finish it needs to at most .005" IMO and many go smaller than that. Remember with a ball endmill and a small depth of cut finishing pass only the very tip of the cutter will be in contact with the stock while cutting. When you do the math on the radius size you will see how the step over really needs to be small to get that nice finish.

Also make sure you have your scallop settings optimized to get the software to help smooth the finish out as well.

Bo