There’s an interesting post (title notwithstanding) on reddit that raises some questions and concerns, I’m really no expert in any of the topics so I’d like to hear from Dan on these, if possible.
Link: Reddit post on GlowForge
Thanks !
For legal reasons it’s best if I not shoot my mouth off about safety (our lawyer informs me), but I’ll just say that this poster isn’t talking about anything that we haven’t considered from the drawing-board stage, and that there’s a thicket of laws and regulations that ensure we build electronics in general and lasers in particular safely.
This is an interesting Reddit post. There are a couple of things I would like to bring up to add to the discussion.
First my credentials: I am a fellow mechanical engineer. Graduated 2014, USU. I use a fiber laser at work regularly. I dont have 20 years of experience. But im pretty sure I understand how lasers work.
Second: I thought it was interesting that “Security concerns” was the only comment that Conundrum68 has ever posted. His account is very new. Im not saying this discredits it, just gives a little bit of a troll vibe to me.
Third: The following are my responses to his concerns.
- The whole laser shooting across the room and injuring people is a long shot. But lets walk through some math and discuss why.
So the laser doesn’t come out of the laser tube ready to cut anything. That is because when cutting things with lasers, the power density is what is important. That is how much energy you are focusing into a area. A great analogy is sunlight and a magnifying glass. Sunlight doesn’t hurt, but a magnifying glass will burn. Not because the sun got stronger, but because the energy was condensed.
Now according to Wikipedia Laser cutting - Wikipedia, the laser beam comes out of the tube at about .080". Lets assume that’s what the GF does. At this diameter (and power density) the laser cant cut anything. That is why, it passes through a magnifying glass.
Now at the focal point the laser has really great power density. It was mentioned in the Tech Specs, that the GF have a .008 kerf. So Im gonna guess it has a .005 Beam diameter. With that diameter, it has about 2200000 W/in^2. To give some perspective the sun is about .08 W/in^2. So its a TON more.
Because of the magnifying glass, the light will have a conical shape to it. And when it is reflected, it will continue that shape. This means that the farther the light travels the bigger the cone will get and the lower the power density will be. But how low you ask? Will it be safe? Lets look.
Here is the spreadsheet where I tossed around some numbers.
Google Spreadsheet
I would love for someone else to look over it and see if I’m on track. I kinda did this in a hurry as im trying to go camping this weekend.
But here is the gist. IF you had the GF pro at max power and decided to etch a mirror (why? idk). Here is a list of power density with respect to distance after it bounces off the mirror.
-at focal point 2291830 W/in^2
- 2 inches away 8950 W/in^2 (a 99.6 % reduction in power density)
- 4 inches away 2238 W/in^2 (an even smaller number)
- 8 inches away 559 W/in^2 (really small)
The take away from this is that the power of the GF dies off REALLY fast.
Now it still strong? Ya, like 1000 times stronger than sunlight. But here is what put my concerns to rest. The laser is never in the same spot. It is moving around quite quickly, so even if the stars align and your object happens to reflect the light just perfectly, it is moving too fast to do any damage, it wont visit that bad spot again, and the power dissipates too quickly cut anything.
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I am no chemist and I dont know what the chemical process of the filter is. However I do feel like this point is exaggerated. He states “For example, when processing a wood product like cardboard/paper/pressboard/wood, substantial amounts of Formaldehyde and Carbon Monoxide are produced”. While true, I have stood around plenty of bonfires and never died. Remembering that your kerf is .008" when you do a project the total wood burned is probably similar to burning a matchstick or two. With no filter, it would make the room smell. And with NO ventilation, it would be a bad idea. But all of those things are easy fixes.
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The electrical worries are blown out of proportion. Yes, the glowforge has dangerous power, its a really big laser. But lethal power is also found in every house electrical socket, car battery, TV (expecially the old ones :), microwave, electric stove top and computer. I’m sure GF would do their best to mitigate risk. But this is a “toy” that should be treated with respect like any other big boy toy.
“Don’t stick a screw driver in it while its running!” - my Dad
So I hope this adds some clarity to the concerns brought up. They are concerns that should be talked about, but they are also avoidable, preventable, and difficult to produce. And I would feel confident having one in my house.
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An unfocused 40W laser will still burn the hell out of you and destroy your retina. The danger isn’t getting cut in half or some dramatic sci-fi scene. And the real danger is the beam going astray BEFORE it hits the focusing lens due to mirror misalignment…especially if it hits the plastic enclosure. I’ve seen damage done to the inside of METAL enclosures by 40W lasers, burning off large parts of powder coating and such. In the GF the laser will either burn clear through and escape the enclosure, or worse catch the enclosure on fire. Most laser fires are caused by plastics (HDPE is a major offender) or small bits of material falling through the holes in the honeycomb base and getting heated by the unfocused laser enough to catch fire instead of vaporize.
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The problem with inadequate filtration isn’t that a bit of noxious vapor will escape from a small job. The real issue is that anything that doesn’t get filtered or exhausted outdoor will accumulate indoors over time. One job improperly filtered job might be OK but 100 is not. That’s why there are long term exposure limits.
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The electrical worries are out of proportion. The chances of you touching the leads to the laser during operation should be exactly zero in any system with appropriate safety interlocks. And silicone tubing sleeves are usually applied to prevent arcing.
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I can’t imagine the smart folks at Glowforge would not be aware of all the concerns mentioned in that article, and then some. Releasing a product for sale in the US is not easy as there are countless regulations to comply with. And it’s not like Glowforge wants to release a product that is dangerous, as I’m sure they hope to continue selling these to happy customers for quite some time.
Seems like the author of that article is just an alarmist that’s cashing in on the fact that Glowforge has not released much information about the product yet. Most of what everyone knows about the product is from a single marketing video, and marketing videos never touch on safety or safe operation as those are not key selling points. We’ll get that information later, likely online and in printed form when the device is delivered.
It’s also important to keep in mind that laser cutters are tools, not unlike table saws and drill presses, and tools can be dangerous. There’s a reason every shop I’ve used a laser cutter in has a sign saying not to leave it unattended… and that sign is usually not too far from a fire extinguisher. And that’s not because they are overly dangerous, but responsible operation means knowing what could go wrong. As long as we are responsible Glowforge owners and take the time to read up on the safe operation of the tool (when that information is available), and we read the material safety data sheet (MSDS) on any new materials we want to cut we should all live happily ever after and make cool things with lasers.
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Well, I think the points raised are valid - chris, you’re right we have little information, but that’s exactly the reason those questions are being asked.
Obviously I’m excited for the product, but it’s quite a chunk of change I’m putting down, and it’s true that we’re dealing with powerful stuff here - it’ll cut through wood and acrylic ! And while I’m confident the team at glowforge is doing its homework, it doesn’t mean I wouldn’t be reassured by having some things explained in more detail.
I’m hoping we’ll have more information and demos made available in the coming weeks/months that’ll help clarify some of this stuff !
While I understand you could get sued by Darwin award medallists in the US, my main concern is fire. You should require taking a picture of a CO2 fire extinguisher at the start of the day when you open the lid.
I wrote that as a joke, but why not? It will protect you from people with burnt down houses that say it wasn’t clear that it could catch fire. But make it possible to get rid of it by some process that will keep your back free.
Also, just throw in protective goggles for the pro, they’re $5 on eBay (unsure about the quality of those though) - if they are easily available people will use them, if they have to search for and buy them, maybe not that many will.