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View Full Version : bad sheared edges of plastic...



Linda Kroeker
08-21-2009, 11:47 AM
Would anyone be able to tell me which laserable plastics cut the best with a combo shear (cuts plastic and metal)... I do quite abit of plastic engraving
and it is much cleaner and less time to us the shear we bought, thinking it would be best since we were just
starting our business to get the combo instead of the exspense of 2 shears. At this rate though its taking more time to sand the edges smooth...
I was told from the company that i bought the cutter from that the reason that the edges get splinttery is because of all the acrylic that is in the material.
I normally us Romark...finally my question is which material of laserable plastic works the best with a shear??? The company suggested changing plastic manufacures or buying a designated plastic cutter...Does anyone else have this problem?

Scott Shepherd
08-21-2009, 12:15 PM
Wow, if a shear can't cut rowmark, then there's something wrong with the shear. The manufacturer is telling you it's the material because they want to pass the buck to someone else.

Just my opinion.

Dave Johnson29
08-21-2009, 12:46 PM
Can't help with the questions but I suspect the shear adjustments is the problem.

Check the cutter-blade has no free movement in the slides allowing the cutter to move out from the shear edge on the bottom platen.

Check the clearance between the cutter and the shearing edge on the bottom platen.

Get a piece of 0.005" thick shim brass and try cutting. If it bends down and smooshes (technical term :)) the cut then there is either cutter movement in the slides or too much clearance between the cutter and the shear edge.

Garrett Nors
08-21-2009, 1:00 PM
Can't you just vector a line into the plastic? Even if you didn't want to cut it all the way, putting a shallow mark will allow you to snap the plastic away from each other. Works for me :D

Randy Digby
08-21-2009, 1:01 PM
The post above gave you good info about checking your shear. I can't add to that but just offering a work-around until you get your shear operating properly. I am new to lasering and have a large stock of laminated for rotary engraving. My supplier would not do a stock swap so I'm stuck with it. That ended up not being so bad since it engraves just fine - just can't laser cut it. I score my sheets by doing a one pass vector cut at 30p 2s and 1000 dpi. The end result is almost identical to scoring with a sharp blade. The material snaps clean and is always the exact dimensions. My cutter always draws material slightly, especially on large pieces. The rotary material is a little more pliable that then laser material so I've decided to continue to use the rotary material for my base product for reliability purposes. I have laserable material for special run items and special size jobs and other non-rectangular products. Good luck resolving your shear problem.

Linda Kroeker
08-21-2009, 1:08 PM
Thanks Dave, the cutter seems to be ajusted fine, seems to have no gaps anywhere, cuts brass fine also.

Garrett, If I was to vector part way through wouldn't I still have residue to clean off? and what would my settings be to vector a line? I also have a 45watt Helix...

Thanks for the advice...thinking I might just have to by a plastic designated shear...

Linda

Garrett Nors
08-21-2009, 1:41 PM
Thanks Dave, the cutter seems to be ajusted fine, seems to have no gaps anywhere, cuts brass fine also.

Garrett, If I was to vector part way through wouldn't I still have residue to clean off? and what would my settings be to vector a line? I also have a 45watt Helix...

Thanks for the advice...thinking I might just have to by a plastic designated shear...

Linda

Depends on the plastic, sometimes I have residue but most of the time it's very minimal (just a quick swipe with a wet rag works well). If you DO have residue, the easiest thing I've found is to use a regular pencil eraser, works great on plastics!

Lets take Rowmark's Multigraph 299-204 (white on black). I usually cut it at about 100s 20-40p 500f, and it has no residue and snaps very easily.

This is with air assist set to 22ish psi and an exhaust setup.

If you want I can upload a video :D


Edit:

http://www.youtube.com/watch?v=H5Vs21SKmSc

There you go :D

Linda Kroeker
08-21-2009, 3:17 PM
Wow Garrett thanks for the video...I'm a visiual person...I will give it a try.
Do you cover your plastic with masking everytime you vector, even if it
isn't cutting completely through?

Garrett Nors
08-21-2009, 3:50 PM
Wow Garrett thanks for the video...I'm a visiual person...I will give it a try.
Do you cover your plastic with masking everytime you vector, even if it
isn't cutting completely through?

Nope, for that demo I peeled the mask off (don't know if it's clear in the video but the blue part is the mask)...I'm too lazy to peel the mask off of each piece after cutting so usually I'll just peel it all off :p

Mike Null
08-22-2009, 8:35 AM
I believe you need to buy a plastic cutter blade for your shear. There is a difference between a metal shear blade and a plastic shear blade.

Check JDS or Johnson Plastics, both show metal and plastic shears.

Patrick Licata
08-22-2009, 5:18 PM
I believe there is a difference in the material itself. I can cut rotary engraving plastic with my shear with no problem. However, with the laser plastic I get bad edges with the shear as well. Both are Rowmark. It must be the composition of the materials used. Maybe we can find out from Rowmark themselves.

Bill Cunningham
08-23-2009, 9:03 PM
If I'm doing name badges, or labels, I usually engrave them all, then clean the surface. After cleaning I put transfer tape over the sheet, and vector the score lines (and burn holes if needed) The hole are set for a higher power to go right through, and the plates are scored about 2/3 through. I can then shake out all the holes, peel off the mask, give the sheet a cleanup, then snap off the plates. I have no edge issues, and if the edges get a bit sticky, leaving them over night seems to solve that problem.. One of my shears is a 20 year old ideal trimkutter that has had tons of use, the blades are real dull, but it still cuts better than those sample you've shown..