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Old 05-02-2014, 12:20 PM
Jadendo Jadendo is offline
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Default Chatter marks on cutting acrylics

I need help guys. The Acrylic that I cut have chatter marks on the Y direction.
The X direction cuts smooth. Does this mean my machine does not hold the Y direction tightly?

I use 1/4" All Purpose O-Flute Spiral Upcut tool, 1/4" cast acrylic, down pass of .060".

Thanks.
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Old 05-02-2014, 02:54 PM
Xray Xray is offline
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I take it you are referring to a profile cutout.
What thickness of plexi ? Feed speeds ? What is your holddown method ?
New bit, or has it been used some, and on what ?

Don't mean to bomb you with questions but the problem is most likely due to one of the above rather than mechanical ,,, Would be advisable to post a pic if able.
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Old 05-02-2014, 05:12 PM
Jadendo Jadendo is offline
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Default ......

Thanks for asking the questions.

Thickness: 1/4" cast acrylic
Feed speed: 100 in/m
RPM: 16,000
Bit: fairly new single O flute
Suction hold down with Hurricane.

I am thinking the piece is moved while it's cutting in the Y direction.
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Old 05-02-2014, 05:19 PM
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Gary Campbell Gary Campbell is offline
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Jadendo...
IF you are getting chatter when moving in the Y direction, most likely there is a mechanical looseness in the X axis. The invers is also true. In either case, check belt tension, gear to rack clearance (spring tension) and look for debris in the rack gears for both. Plastic is famous for loving to stick in the gears.
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Old 05-02-2014, 05:52 PM
Jadendo Jadendo is offline
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Thanks Gary. I'll check. My Stinger III is 1 month old.
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  #6  
Old 05-02-2014, 06:19 PM
Xray Xray is offline
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Might want to try screwing directly into spoilboard and see if situation changes. 2 screws kitty corner should do.
Even when screwed thin plexi can easily lift, especially with an upcut bit. This lifting/flexing will always cause chatter/nicks/rough edges.
Feed seems about right, though I sometimes slow to 50 with the thin stuff ... Also reduce RPM's if possible, just to avoid any melting issues.
If problem persists I'd try a downcut bit.
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