Z again have Pixs

[david_bravo]

My painter is about to kill me If I don't fix this.
All is well with tool marks untill the bit lifts and goes back down. Never to the same depth. Help!
5910

[blackhawk]

It looks like you are having the same problem that I am. Take a look at this thread.

http://www.talkshopbot.com/forum/messages/29/47163.html?1256145585

[GlenP]

David can you give us more info such as bit you are using, toolpath settings etc. When pocketing my preference is a 2 flute end mill. It does leave some tool marks but I am not using vacuum holddown so the substrate has the ability to vibrate slightly. I usually do a textured background around the letters and it eliminates any issues and adds to the design.

[david_bravo]

I'm using a 2 flute end mill .25" with a 40% pass at 1" per second. The Z axis has no play and I just surfaced my table. I have a PRS Standard.

[cabindoors]

David,

I've had a similar problem but not nearly that extreme. I solved it by putting home made "bean bags" filled with sand on the foam or thin HDU that I am cutting. They are simply weighted bags filled with sand. (We've used them in the old'in days in drafting class to hold our drawings down or rest our elbows while drafting). Just have your wife sew some 6" - 8" dia naugahyde material in order to fill with sand.

Tom

[GlenP]

IF it is substrate creeping up and down with vibration while cutting I have also used two sided tape to assist in holding stuff down while cutting. I don't have vacuum hold down and probably never will so I guess it is the poor or cheap man's version. Your picture looks excessive for material movement while cutting. Have you tried doing a cleanup pass after major pocket cutting is done to help with tool marks?