Cutting Sintra

GVP

New Member
Greetings,

Does anyone have any tips regarding cutting out simple flat panels of 1/8" Sintra?

I'm finding if I use an up-spiral bit, it lifts the material off the bed in places and can cause the shape to come away, often hitting the bit and ruining it.
If I use a down-spiral, the kerf fills up with the chips and often re-welds itself back together. Perhaps I need better feeds/speeds? Currently around 16000rpm & 125ipm using a 1/8" bit.

Any suggestions appreciated - we don't have a vacuum hold-down and clamp everything down.

Thanks,
Graham
 

letterman7

Member
125ipm? You sure about that? Way, way too fast if it is. Back it down to 2, maybe 3 ips depending on your machine. Are you using a climb cut or conventional with the upspiral? Try cutting the opposite way with the upspiral and see if that changes anything.
 

J Hill Designs

New Member
125ipm? You sure about that? Way, way too fast if it is. Back it down to 2, maybe 3 ips depending on your machine. Are you using a climb cut or conventional with the upspiral? Try cutting the opposite way with the upspiral and see if that changes anything.

Just checking my math here, but doesnt 2 IPS = 120 IPM?!?
 

Ditchmiester

New Member
Use a straight O Flute From Onsrud, They cut with no up or down pressure. I cut plastics with them all day long. I love them. I run about 12K RPM and 100IPM.
 

SebastienL

New Member
one pass with the up cut, leave .025" on the bottom(Don't break thru) and .025" on the wall. Finish with the downcut.
Upcut will evacuate chip better, Downcut will leave a cleaner edge on top.
If it's very small part.... Transfer tape on the back, Spray "3M Super 77" or equivalent glue on the tape. Just peel off after cutting.
 

synergy_jim

New Member
1/8" 2 flute straight - 2 pass - 300 ipm 18000 rpm

1/4" 2 flute straight - 1 pass - 400 ipm 20000 rpm

1/4" 2 flute downcut spiral - 400 ipm - 20000 rpm



The enemy of thin plastic is any upcut bit.
 
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