[ka71001950]

I'm a beginner.
This is a picture of the finishing process.
The G-code looks correct but surface isn't smooth.
I don't know where to start.

I'm using tinyrobo and mach3.
The tool used is 1r, 0.4r ball endmill.

[awerby]

It looks like the finishing passes worked okay in the hair and crown areas, but didn't remove all the marks left by waterline roughing in the face. This is usually caused by an error in Z. Either the tool has retreated into the collet, which can happen during plunge moves if it's not tight enough, or you've lost steps in Z, which can also happen during a plunge. To figure out what's going on, establish a Z zero level away from the piece itself, then try touching off the tool tip there after doing each pass. Before running the next finish pass, make a mark on the tool where it enters the collet. If the tool has pushed up into the collet, you should be able to see that in your mark after running the program. Check the roughing pass as well as the finishing pass this way. If the mark is unchanged but the tool tip is still too high, it's probably lost steps, either in the plunge of the finish pass, causing it to cut too shallowly, or in the retract of the roughing pass, causing it to cut too deep.

If your CAM program can ramp into a cut at an angle rather than plunging straight down, it can help with problems like this. Otherwise, slow down the plunge rate, or lower the acceleration value for Z.