Laser Engraving PVC

[Bryan Cowan]

All the topics I could find about the dangers of lasering PVC involved cutting various thicknesses of the material. In our business, traceability is important and one of our product's housing is made of PVC. We need to laser engrave a serial number, date, and other textual information on the PVC housing.

Here is our current exhaust blower - http://www.pennstateind.com/store/DC3XX.html

The engraving doesn't need to be deep, only deep enough to be legible.

Is this as great of a risk to the laser as I'm led to believe from other threads? This also is not an everyday item. We could run a batch one full day and not have to do it again for a month or better.

Thanks for the input.

[Darren Null]

PVC gives off chlorine gas when lasered. This turns to hydrochloric acid in contact with moisture. Quite probably your exhaust system can carry the fumes off fast enough to prevent lung damage. But it's not going to do your lens, mirrors or electronics any good. At best you'll decrease their lifespan; and you could b0rk them totally. You can minimise damage by light, fast burns, but you will -at the end of the day- be releasing hydrochloric acid into your expensive machine.

[Bryan Cowan]

Thanks Darren. We'll look into other ways of marking identification onto this product without releasing HCl.

[Darren Null]

You're welcome. I haven't been able to find out any info about the amount of chlorine released so you could make a more informed decision. For me, as it's my personal machine, my decision is to keep PVC the hell away from it. For a business machine; where it's more of a cost-versus-utility thing -and given that you're going to have to find some way of marking the PVC- is a slightly different matter.

My ninja instincts tell me that 1 full day of burning PVC wouldn't be a good thing though.

[Bryan Cowan]

We may use an electric hand engraver for the PVC housing. Like you said and what I've read, it's not worth the risk in the long run.

[Mike Null]

Depending on the volume of work and the amount of time involved I wouldn't be too concerned. If it is high volume with long run times that's another matter. Either way a good exhaust system is vital.

Check the Synrad applications site.

[Dave Johnson29]

Is this as great of a risk to the laser as I'm led to believe from other threads?

Hi Bryan,

This is really going to bring out the PVC crowd. The amount of Chlorine given off is tiny and the level of humidity in the air will affect how well it is converted to HCL.

I have a 600+cfm exhaust system which is pretty much all PVC piped and I regularly cut profiles on the ends of PVC pipe. There is not a single spot of rust in the machine, but after some months, the blower impeller did show small signs of light surface rust. This was easily cleaned off with steel wool.

I have since removed the impeller and painted it with a rattle can of Rust-kill, kill-rust or something like that I got from the Ace hardware store. It has been 6 months and no signs of any further damage. To me it has to be down to exhaust system efficiency.

I have no details on potential damage to the lens and mirrors but in my machine the exhaust is moving the smoke away so fast there is no way I can see it getting on the mirrors, lens or anything else. I mean the smoke trail is horizontal and about 1/16" of an inch above the material being cut.

There is no doubt the HCL will cause rust if it gets converted and successfully deposited, but it is going to take some pretty determined molecules to swim upstream in the draft in my laser.

Let the controversy reign. :D:D:D But, I would say just do it.

[Rodne Gold]

PVC contains up to 60% chlorine by weight , you could weigh a piece , laser it and see how much it weighs after?
I occasionally kiss cut sign vinyl and have lasers that are already 6 yrs old and have no corrosion effects.
You could proabably minimise all risk by putting some vaccum to your air assist tube if its possible and letting it suck up any fumes rather than letting your exhaust fan do it all...

[James Stokes]

I have cut sign vinyl in small amounts and had no problem. One day I had a very complicated and busy mask to cut. After cutting it my rack was rusted very bad the next day and the head was stuck. Small amounts no problem, larger amounts can be a problem and I have a 2500 cfm exhaust

[Rodne Gold]

James , did you kiss cut or zap areas of the vinyl?

[Larry Bratton]

It has been said that if you want to check a materials toxic content, burn a piece of it. I burned some sign vinyl just out of curiosity and it burned with a yellow flame, no green (which is supposed to be the bad) and then the stuff just melted. I will on occasion cut it, but usually very fast at 100speed and 10power. I stay away from engraving or cutting closed cell PVC at all.

[Bob Savage]

It has been said that if you want to check a materials toxic content, burn a piece of it. I burned some sign vinyl just out of curiosity and it burned with a yellow flame, no green (which is supposed to be the bad) and then the stuff just melted. I will on occasion cut it, but usually very fast at 100speed and 10power. I stay away from engraving or cutting closed cell PVC at all.

Being colorblind, depending on the shade, darker yellow and light greens can look very similar to me. Is material that melts a fairly certain sign of toxicity, or does that not necessarilly follow?

[Dan Hintz]

Is material that melts a fairly certain sign of toxicity, or does that not necessarilly follow?
That doesn't follow. I posted a link to a chart a while back that will help you identify most common plastics... let me know if a search doesn't turn it up.

[Michael Hunter]

To do the test properly, you need to burn the material whilst it is melted onto some clean copper wire.

Not everything that melts is bad - in fact most of the "good" plastics that we use will melt (especially when something goes wrong in the middle of an important job).

[Darren Null]

http://www.texloc.com/closet/cl_plasticsid.html

You guys carry on with your PVC.

I'll be watching from over here

[James Stokes]

I blasted the vinyl Rodney. I put the vinyl on the glass I was doing and rastered it. It was a fairly large piece and really made a mess of my laser.

[Rodne Gold]

Yeh , thats not good , I know 3M used to make a PVC free vinyl , might be worth investigating.
We often use paper based self adhesive material for glass blasting , wont hold for a deep blast but seems to be ok for decorative blasting..you will most likely have to experiment with various brands or thicknesses

[Tim Wooldridge]

To me, running PVC isn't worth it due to the buildup that occurs on your lenses and what not.