Why orange plastic for CO2 lasers?

Any details on design? :smiling_face:

I was awake most of last night considering what to make. Its going to be 1000 x 500 probably.

I will draft something in fusion, but I will probably just buy and build as I did with my CNC.

Lots of advantages with Laser Vs CNC, I’ve got fed up with buying end mills mostly.

I will post my experience on here, I love this forum, lots of experience and many people happy to help.

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Interested to hear your thoughts so far! If you name it, you can use a hashtag as a design and build log as I’ve been doing. :+1:

If I didn’t have floor space that happens to be a great fit for my current overall external size and gives me a little flexibility for odd jobs, I would have designed out from a bed size that I could buy easily. :slightly_smiling_face:

I definitely think of my CNC router and upcoming laser as complementary.

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Every commercial CO2 laser I know is equipped with clear or gray tinted acrylic. Orange tinted is best for UV diodes, as far a I know.
On our Lasersaur we have gray tinted acrylic and I’m happy about that, because the backflash when cutting can be very bright (white).

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Hmm, gray tint and additional UV blocking… There are inexpensive static films to apply to windows for blocking UV which also have a fairly neutral gray tint. I could add that to transparent acrylic and it might be cheaper than tinted OP-3 which I’m not even sure where I could buy near me. The plexiglass would block the IR very effectively, and the plexiglass and UV film would block UV, and the neutral tint would reduce the glare from cutting.

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A lot of what I’m finding is mirrored sputtered-metal film, like this:

I guess if I mount enough LEDs inside the case that would be OK. But I’m going to keep looking for non-mirrored film options. Here’s a 2 mil PET sheet that has a datasheet available. It has 99% UV blocking and 83% transmittance, and low (less than 4%) reflectance:

It looks like there are lots of brands of UV-blocking PET film. This seems like a good route, and I don’t have to decide right away.

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But UV is the opposite of IR?

Yes, it’s the opposite end relative to the visual spectrum.

It seems clear that both acrylic and PC block far-infrared at the 10.4µm and 9.4µm wavelengths (the primary and secondary characteristic wavelengths of CO2 lasers) essentially completely even in thin samples (3mm / .118"). As a result, I expect this to be sufficient protection from specular reflections of coherent laser light.

However, clear acrylic (and both soda and quartz glass, for that matter) transmits lots of IR in the 700nm - 2800nm near IR range. This range can burn your lens; “glassblower’s cataracts” are the result of glassblowers being exposed to wide-spectrum IR from black-body radiation in molten glass. It’s why I have special safety glasses for my kiln; the same kind used for oxy-acetylene welding and for the same reason.

I expect the “white” light of material being laser-cut to be wide-band light including near infrared, and quite likely UV as well. Both near UV and near IR damage eyes; I think near IR damages the lens and near UV damages the retina (but I’m not a doctor nor do I play one on the web).

Therefore, the idea of blocking both near IR and near UV, as well as attenuating visible light to some degree, is attractive.

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I took mine out and replaced with 3mm aluminium sheet. That keeps the UV in and ensures no stray laser light can escape. I have remedied the lack of vision by using a web cam and the pc I use to run whisperer. Works well for me. I did it because for one engraving job i coated the wood on masking tape (painters tape) the tape caught fire and melted a hole in the orange plexiglass.

Catching fire and burning long enough to melt a hole in the plexiglas — was it running momentarily unattended?

I was in the workshop but engrossed in sanding another project. I never leave the machine unattended but tend to multitask in the vicinity. I have smoke alarm and 2 fire extinguishers. I used vinyl transfer tape which is not as sticky as other tape. Now I don’t use tape just give everything a good sanding.

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Just a note for the next person who sees this that vinyl often omits chlorine gas when laser-cut, which is unhealthy for both people and machines. :slight_smile:

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I don’t think he’s talking about actual vinyl tape, just the transfer tape used for vinyl lettering. I use this type of transfer tape all the time for masking myself and never had a problem. Not sure why the transfer tape would catch fire unless you weren’t using an air assist.

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I’m guessing that sneeze shields really squeezed the market, so the price of glazing has been really high. I finally worked out that three 30" x 36" sheets should be perfect, and $46.70 each is the best price I can find right now, which came to about $150 with tax. It looks like I need 5 feet of the UltraCool unless I can get away with 4 feet, so 5 * $27.32 = $136.60 so I expect it in the end to cost about the same as the polycarbonate shipped and taxed. I’m going to wait on that and work right now on building the door; I can add the film later in the project.

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3 posts were merged into an existing topic: Putting together the lid

https://lasersafetyindustries.com/windows/

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Hi. I want to build an enclosure for 2 types of laser. What recommendation would you give for a vision protection glass for both wavelengths 455 and 10600nm?

All acrylic (e.g. plexiglas) is opaque to 10,600 and 9,600 primary wavelengths from CO2 lasers in normal thickness, so any acrylic suitable for 455nm will also be suitable for CO2; the addition of dyes that absorb at 455nm (Plexiglass 2422 is reported to be such, and you can buy tested and certified versions of it) won’t make it transparent to 10,600nm or 9,600nm.

Thank you for your prompt reply. I think the designation in Germany is Plexiglas/acrylic glass GS 2C04, which will probably be the same. Do you think 3mm would be enough?

I’m not an expert, I have only looked into this for my own laser. Here’s the quote I had previously noted:

$ units
You have: .118 inch
You want: mm
	* 2.9972
	/ 0.33364474

I know nothing about German acrylic designations; even the 2422 designation I mention is quoting others and isn’t first-hand knowledge.

So basically, this thread has collected some resources, but whether it’s enough is ultimately your call.