1/2" Cast Acrylic

Beyond the Manual
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I had a need to made some parts out of 1/2" clear cast acrylic. I bought the material from Inventables using my GlowCredit, and after a few stabs in the dark, wound up with this mess:

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And, the first fire I had to put out.

It was time for something more methodical.

I give you:

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These are single line, 1/2" in length cuts at various focal depths and cutting speeds. All are at 100% Basic Power.

.433" at 100 GlowySpeed gave fairly consistent cuts completely through. There were a couple of spots that didnā€™t quite make it (or melted back together, donā€™t know which), but for the most part it was a full cut.

After deciding that .433" focus was giving the best results, I made the multi-pass attempts:

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2 passes: 125 (barely), and slower all cut clean through. 100 left an undesirable undercut on the bottom.

3 passes: 140 and slower cut clean through.

Best bets:
2 passes at 120 was the best for a quick cut, with a kerf of .014" measured at mid cut depth.

3 passes at 120 left the cleanest looking cut, the least amount bottom distortion, and the same kerf:

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The graph is great. :sunglasses:

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Graphic designer I ainā€™tā€¦ :wink:

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Some very useful testing. Thanks for sharing!

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That is so helpful, thank you. Russ at SabarMultimedia would be proud of you.

My pre-release always did the thick acrylic in two passes as default. Somewhere along the line, the defaults changed, but I really had to keep my early unit on to two passes.

A little clarification for me, Iā€™m not quite figuring this out. 2 passes at 120 was a quick cut, but 3 passes at 120 left the cleanest cut and least amount of bottom distortion. But both went all the way through?

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They both went through, and without any ā€˜stuckā€™ parts. But, the 2 pass version leaves a small flare at the deepest part of the cut. Gives the piece a seventies throwback look (bell bottom).

The 3rd pass removes that flare, and has a small polishing effect on the cut.

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Thanks for the test and numbers. It could not have come at a better time.
I have to make a couple of filter supports for my Glowforge filter I am building.

Yep he went crazy and is making it out of 1/2" Acrylic, and over built too.

I will have two of the carbon filters after the replaceable pre-filter. The left side in the picture is the 4" inlet, 12"x20" pre-filter and then the two carbon canister filter and 4" outlet. I have an exhaust fan that is 250 CFM I will add to the outlet side. The top will be removable for replacing the filters.

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Very handy, thanks for sharing! :grinning:
(Added a Settings tag to your post so we can find it again.)

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Thank you!!! This is why I heart GF and its community.

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Your testing is much appreciated! Iā€™ve bookmarked, and recorded your notes. Thank you!

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Very cool! Thanks, you have way more patients than I do. I have heard that getting it up off the honeycomb can help a lot too, in this case I guess you would need to remove it because of height restrictions.

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Yay, research and sharing!

Iā€™m curious what settings to use to set it on fireā€¦

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Wow. Half-inch.

FWIW, Iā€™ve had a lot of issues with 1/4"" and cuts melting back together, especially if I make other nearby cuts.

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That was during my ā€œclick and burnā€ early sessions. I think those were something like 3 passes at 100 with a .250" focus. The acrylic turned to a Jelloā„¢ like consistency.

Was kinda neat until the flames started getting big - FAST.

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I was making this part:

Pivot Block_X2_500

Which is only about 1/4" of material, all around, so melting acrylic was a definite issue.

With 120/Full/.433" at 3 passes, it came out perfect.

Though, I cut two of them in the same operation. So the passes alternated between parts. That may have made a difference, as it would give a little bit of time for heat to dissipate.

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Outstanding guide. Thank you!

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Great guide! Thank you! I donā€™t have my Glowforge yet, but on other units I use, multiple passes on acrylic that thick always works better. Less melting and distortion.

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