Poor 3d cut quality

[fsrdoug]

I have a PRS 9648,2 years old and I have always had poor cut quality in 3d. The top surface is great but the sides are very rough and uneven. In the past I have just sanded the sides but now I have a project where that is not an option and it seems to be getting worse. I use a PC router and have tried several, even a new one, always with the same results. From the top looking down the edge looks like a saw blade.
Thanks for any help

[myxpykalix]

It sounds like maybe your stepover is too big and leave material between each line of cut? If the sides look like that then the top would too. What does the top look like? Maybe a picture or two might help diagnose your problem.

[jimmya]

I also have a PRS 96x48 and mine does the same thing.

[ken_rychlik]

Is your bit tapered? If so the sides of the taper are cutting when the program does not think it is.

Kenneth

[fsrdoug]

Jack, the stepover is at .01" and the top quality is great, just bad sides.
Kenneth, the bit is tapered 1 degree. For cuts on the x or y axis there is no problem but just a slight bit off and I start having problems even if the depth of cut is .25" on a round over.
Will try to post a picture tomorrow.

[ken_rychlik]

I think if you run a straight bit with no taper, the problem will be gone. All the program sees is the tip of the bit, so to speak. The taper is cutting and the program is not taking this taper into account. I have had the same issue on deep carvings. I have to step up to a 1/8 bit and no taper. My stepover is normally .005, but that won't help with the taper of the bit issue.

[rcnewcomb]

Can you post a photo?

[butch]

Doug
Try using a ball nose bit. I use a 1/8" ball nose and the sides are fairly clean. I do this with a .01 stepover. I had similar problem using tapered bits, but fixed it by going to ball nose.

Also check the bit is sharp, and that the pinions are tight.
Butch

[curtiss]

I have a PRS 9648,2 years old and....

9,648.2 years old? wow...

[fsrdoug]

Curtis, Didn't think shopbot was around that long?
How do you think Noah built his ark?
lol