Acrylic... Cast Vs Extruded - or Darn, I bought the wrong stuff!

[TimBobTastic]

Hi Everyone.

I have had a few issues with some "cheep" clear 6mm acrylic I purchased... It engraved horribly (clear not frosty) and nearly always suffers from small cracks at the cut edge after being cut.

I think the engraving issue is because I have purchased the wrong stuff... (that's why it was cheep, lesson learnt ) BUT, I would like to use the material for something (shapes, decorations, coasters, or even jigs and fixtures if needed...... If only I could get it to cut without cracking....

Do I need to cut slower or faster because it is extruded? or should I adjust the power level? currently cutting at 8/85

I also have the occasion problem cutting mirrored (which I understand is also extruded), not with cracking though.... with distortion and difficult removal (I think it is fusing behind the cut occasionally).

I also notice a little more flaming (under the acrylic) when cutting both of these materials.... Would a stronger air pump / compressor solve that?

60W LS3060 with Chiller & BOFA

Everything else cuts as expected... 6mm acrylic (I know its cast, its even branded as perspex...), 6mm laser ply... 3mm laser ply, and even 6mm solid oak... its just this darn extruded acrylic....

Thanks in Advance

[Spooky]

I think the engraving issue is because I have purchased the wrong stuff

Yup, classic issues of cutting or engraving extruded acrylic. Try 6 and 65

I also have the occasion problem cutting mirrored

A lot of mirrored is cast, check the thickness variation, cast varies by +/- 0.3mm, Extruded by +/- 0.1 or so

I also notice a little more flaming (under the acrylic) when cutting both of these materials.... Would a stronger air pump / compressor solve that?

To some extend it will, extruded is great for some jobs although the raised edge that usually forms can be a pain.

Extruded has a lot of surface tensions, cutting or engraving unequally releases them much like machining one side of rolled steel bar

[TimBobTastic]

Arhhhhhh the nightmares of getting steel flat on the Bridgeport mill or even pomalux Acetal... That was always a nightmare.... I have just finished therapy... The flash backs... Lol.

It makes sense....not something I had considered.... Thanks for the tips, I will have another try later....

[Tom]

Hi Tim
Extruded can be a pain to cut if you've got sharp internal corners and has a raised edge
But a good Extruded it will cut a bit faster
Could it be a hard clear styrene you have which looks like acrylic but melts and chips when cut

Tom

[TimBobTastic]

It was purchased as acrylic... But to be honest, nothing would surprise me.... It is unbranded.... So no real way of knowing for sure... But, I do not get a raised edge when I cut it.....

[Daven]

Extruded stinks worse - even the good stuff!

[Tom]

It smells like spray paint and peardrops to me
Stinks

[TimBobTastic]

Its definitely extruded then... it stink when I cut it...

[Spooky]

It smells like spray paint and peardrops to me
Stinks

Dam that takes me back Tom, the bonding agent in IR Flares smells like peardrops as well