Small Lasers Class?

Anyone willing to teach a small lasers class some time in the next couple weeks? I didn’t see any currently on the schedule.

I don’t really need the capabilities of the larger lasers, so figured it would be better not to hog time on those. Just trying to precision cut some 1/64" or 1/32" PTFE sheeting for some custom gaskets.

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Matt, don’t conflate “smaller” with “simpler”.

The large lasers are bigger but the workflow for using them is easy to understand, they’re straightforward to operate, and the software for controlling them is wonderful. Check out Lightburn and watch a few of their videos for some insight.

The small lasers have reasons for being but don’t dismiss the large lasers for their size.

Fair enough, although I wasn’t making any assumptions about simplicity, just the needs of my project and optimal use of the space. It seems like the big lasers tend to be booked more, so if I can accomplish the goal on the small lasers, that seems like a win-win.

If it makes more sense to use the large lasers, then I’ll happily do that.

The big lasers definitely tend to be booked more, so you do generally end up with more schedule options (especially last minute ones) with the small lasers.

@wynd @mcmancuso – do we have more small laser classes coming up soon? I want to say they are usually once a month or every 3 weeks.

I’m seeing mixed info on whether the PTFE is safe to cut.

Very good catch, Danny! I skipped right past the material Matt wanted to cut.

Everyone, when cutting a material not commonly used with our lasers it’s important to check its Material Safety Data Sheet. This isn’t to be a stickler but to confirm no fumes from cutting are harmful. I’ll usually search the document for BURN or FIRE and read all the entries. In this case, the fumes aren’t safe so I’d recommend you don’t cut PTFE on the laser.

Using a CNC would be a safe way to cut your project without burning.

FYI, below is the language that gave me pause:

Inhalation of fumes from overheating (above 300 deg C) PTFE (Polytetrafluoroethylene) may cause polymer fume fever, a temporary flu like illness with fever, chills, and sometimes cough, of approximately 24 hours duration. Trace amounts of carbonyl fluoride and hydrogen fluoride may also be evolved when PTFE is overheated or burned above 400 deg C.

Inhalation of low concentrations of HYDROGEN FLUORIDE can initially include symptoms of choking, coughing, and severe eye, nose, and throat irritation. This is possibly followed after a symptomless period of one to two days by fever, chills, difficulty in breathing, cyanosis, and pulmonary edema. Acute or chronic overexposure to HF can injure the liver and kidneys.

Inhalation, ingestion, or skin or eye contact with CARBONYL FLUORIDE may initially include: skin irritation with discomfort or rash; eye corrosion with corneal or conjectural ulceration; irritation of the upper respiratory passages; or temporary lung irritation effect with cough, discomfort, difficulty in breathing, or shortness of breath.

Individuals with preexisting diseases of the lungs may have increased susceptibility to the toxicity of excessive exposures from thermal decomposition products.

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I see some nuances here. Many things on the laser cutter like acrylic fumes are pretty toxic in high concentrations. That’s why we have exhaust.
Also hydrogen fluoride is an acid which could corrode like if you cut PVC.
There’s a little-known problem that more people should know- teflon cookware will kill pet birds. Seems to happen if it’s left on the heat with the cookware dry and burns the coating, even when the damage to the cookware seem trivial. The fumes of decomposition are really lethal to birds.
Burning like this is going to involve those combustion products in a big way. There’s stuff about cutting it industrially but a mention that the exhaust needs to be contained and treated.

I’m inclined to add it to the Prohibited list.

Universal says OK Teflon® - Laser Cutting, Engraving & Marking Teflon | ULS
Trotec says NO: Materials not suited for laser processing

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As with many things, safety is usually a matter of mitigating risk, not eliminating it entirely. By their nature, SDSs give you the worst case scenario (as they should), because people need to know what the worst case is, and because whoever is producing the SDS needs to ensure that any possible risks are documented so that they aren’t held liable for use. Check out the SDSs for many common household products and chemicals we use every day at home and at Asmbly.

A CO2 laser cutting PTFE is an inherently different process than heating bulk PTFE on a stove or with a flame. While polymer fume fever is a real thing, I have not been able to find any cases of it occurring during laser cutting operations. All cases I found referenced occurred during welding or after hours of exposure in an enclosed space when a pan is left on high heat. That’s not to say that fumes aren’t released, but with exhaust that risk can be mitigated. Another factor to consider is that the more harmful degradation products (i.e. HF and carbonyl fluoride) require the presence of moisture to form. By using dried air or bottled nitrogen, that reaction pathway is eliminated until the products are exhausted, simultaneously protecting the instrument from any corrosion.

In a relevant related example, metal fume fever is essentially analogous to polymer fume fever, occurring during metal welding. Despite that risk, we have an entire area of the shop devoted to welding. It isn’t the exact same situation, but my point is that we rely on people to use good judgement on personal and shop safety every day.

At the end of the day, if the laser stewards and board aren’t comfortable with it, then I will of course abide by that, but I am willing to take steps to mitigate any potential risks.

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@mkmiller6 I appreciate you laying out some very valid points on this and engaging in discussion here to find the most reasonable conclusion on laser cutting this material at the space. I’ll defer to @dannym @TravisGood @Jon and @JoeN on this one as I think they are our most knowledgeable stewards on this topic.

That was why there was a nitrogen generation system for this. But things happened

Matt,

I really appreciate your depth of thoughtfulness and judgement on this topic.
This calibre of thinking is not what I would normally be deliberating over.
It’s the careless “Anything goes!” attitude by some that we guard against.
That said, Danny surfaced doubt and your logic is pretty compelling.

Was your need for a fairly small volume of short duration cuts?
If so then moved by your reasoning (and if Danny agrees) then I’d be inclined to say “Do it”.
You are obviously aware of the risks so lite use with good fume extraction should be accommodated.

In general, however, without material expertise and with occasional careless user behavior
a makerspace needs a methodology to determine what’s safe and not safe.
For me that has long been referencing the Material Safety Data Sheets.

Danny, I agree because most users will go into a cut unaware of potential consequences.
Since your Takin could be affected, in the case of Matt’s contained use, if you disagree
with my conclusion then please nix his request … CNC is definitely a safer path.

And I appreciate you guys considering my thoughts and being open to changing your minds!

I don’t know the current setups of our laser cutters, but if we already have or could setup a dried air or nitrogen system on one of them (which I’m more than happy to help with if there isn’t one in place), then I would be interested in going ahead. If not, or if it would be too much of a hassle right now, then I’ll just go down the CNC route.

The cuts I’m looking to make are quite small and the quantity is low. Just a few gaskets in the .5-1” OD range.

@mkmiller6 there isn’t a nitrogen system setup at the space and the one @dannym mentioned is quite large and has not had a thought-out proposal submitted for consideration, so the nitrogen approach isn’t one that could be utilized anytime soon. For the sake of time, it might be best to go the CNC route. Not sure if there are other means of dried air in the laser that could be attainable.