DISCUSS Laser NO GO Material #2: > 1mm Polycarbonate/Lexan

Laser
#1

Taking @Photomancer’s advice and breaking out each of the Hateful Eight into its own thread. Less for me to moderate. Let’s knock these out. Off the top of my head…@pinewoodnut, @talkers, @tomthm, @motopilot, @PearceDunlap, @merissa, @JoshW, @gbeauw, @somecallmery, @bpamplin, @BLOOM, @Kati .

https://dallasmakerspace.org/wiki/Laser_Cutter_Materials

Material: “Thick ( >1mm ) Polycarbonate/Lexan”
Danger!: “Cut very poorly, discolor, catch fire”
Cause/Consequence: “Polycarbonate is often found as flat, sheet material. The window of the laser cutter is made of Polycarbonate because polycarbonate strongly absorbs infrared radiation! This is the frequency of light the laser cutter uses to cut materials, so it is very ineffective at cutting polycarbonate. Polycarbonate is a poor choice for laser cutting.”

Question: is there even a reason to OK thinner sheets?

EDIT: Click “like” if original wording is still OK.

#2

Polycarbonate makes a mess. It leaves white particulate stuck to everything around the cutting area. And it can, depending on multiple factors, release carbon monoxide when cut. Strongly recommend it not be used on the laser cutters.

It does cut well on the multicam. Take the basic and advanced multicam classes if you need to CNC polycarbonate.

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#3

This is a great suggestion…adding alternative solutions for cutting these materials.

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#4

The introductory paragraph on the page (not in the list) says,

For example, Polycarbonate/Lexan produces flames and lethal chlorine gas which will rapidly corrode the machine into uselessness, and is extremely hazardous to the health of people nearby.

I find it interesting that we’d allow thin Polycarbonate to be cut given the way we vilify it in the intro. These seem to be contradictory.

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#5

I remember from my training that no exception was given for thin Lexan. All Lexan was bad.

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#6

I think there is an error in the page then. I’ve seen no documentation of lexan releasing chlorine when cut or burned. Just carbon monoxide which is scary from the combination of being odorless and cumulatively binding to hemoglobin such that you usually pass out before you realize anything is going on.

From the perspective of materials one is likely to want to laser cut, releasing chlorine is pretty much the realm of Poly Vinyl Chloride, and all the forms it is hiding in.

#7

The SDS’ I’ve read both state that polycarbonate fumes are non-toxic (but may cause eye, skin and respiratory tract irritation).

However, they both say that burning causes black soot. I don’t know if this is detrimental to the laser optics. Further, the GE one states,

“Extinguishing media. Water spray and foam. Carbon dioxide and dry chemical because their lack of cooling capacity may allow re-ignition.”

Once the committee decides whether to allow polycarbonate or not, I’ll be glad to edit the top part of the wiki page to match, if that’s helpful.

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#8

There is a particularly prolific, messy, and I would almost say sticky white mess I have seen on the laser work grates a few times, and my recollection is that it has been attributed to lexan. So at least in some cases, vaporization doesn’t exactly match combustion results. Will see if I can find some time to try and hunt down a reference on the CO emissions.

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#9

Agree. I think there is a lot of incorrect information on the web. People see it, re-use it or quote it, and don’t research it back to the original source. It becomes an urban legend.

On a related note, should we add Kevlar to the “NO CUT” list? Dupont’s SDS (formerly called MSDS) states in section 10, page 6:

Hazardous thermal decomposition products: Carbon dioxide, Nitrogen oxides (NOx), Hydrogen cyanide (gaseous), Ammonia, anhydrous, Aldehydes, Hydrocarbons

#10

I consider SDS/MSDS sheets the most definitive and reliable source we have available. If there is a conflict between two manufacturers then that needs to be addressed. But companies that issue these know it a is legal document they are accountable for and not an off-the-cuff-opinion.

I don’t think we can go wrong in relying on them for that is what they are primarily intended for: The End User. Others upstream use it for handling, transportation, and storage.

#11

MSDS are also know for being frequently hyperbolic, as a direct result of that legal status.

https://www.ulsinc.com/materials/kevlar

#13

3 posts were split to a new topic: Laser Cutting (very thin) Polycarbonate