Laser attachment for Shopbot

[Chuck Keysor]

Hello Shopbot Friends:

I have long wished for a laser engraver attachment for my Shopbot. Rockler sells an attachment for one of their little CNCs. I am surprised that no one makes such a thing for Shopbots. I have attached an ad for their product.

I have made some very fine V-carvings of old-time wood-cut engravings, but these are very difficult, and hugely time consuming. And one problem is the need for an absolutely flat surface, and then being able to hold down material so that it remains perfectly flat. All hard to do. And then post carving clean up (cleaning out all of the gunk from within the carved grooves, something almost like re-melt), is even more terribly intensive.

Here is a little bit of the type of image I want to laser engrave.http://www.talkshopbot.com/forum/attachment.php?attachmentid=29390&stc=1
Thanks, Chuck

[jTr]

Chuck,
That is a very attractive looking way to add a laser to any CNC. No surprise they're over-sold. Wonder if you could adapt for the shopbot - seems likely if an available signal output on control board. Just need to find a way to generate code for triggering on/off as it works.

jeff

[Greencarvings]

There is a lot of webpages and videos for using the blue diode lasers one can get to do this for a fraction of their cost.

One specific one is:

https://jtechphotonics.com/

[Chuck Keysor]

Thanks Green Carvings.... I looked at the link you supplied and was quite intrigued.

I saw they had a Vectric based interface, but I wasn't really clear on if this would help me or be sufficient to my running this with my Bot. So I have emailed the company with specific questions. I'm not a software guy, so I'd need a pretty straight-away, almost plug-and-play interface to the Bot.


Does anyone else know of a similar product that would plug and play with a Bot and Aspire?

Thanks again, Chuck

[RossMosh]

If you want a laser, buy a laser. While both machines are CNC's, their construction and design are completely different. Lasers are designed to be built as light and strong as possible so the head can fly back and forth as fast as possible. For example, an average laser (Epilog, Universal, and GCC for example) engrave at around 80ips or 4800ipm. Chinese machines (slow) engrave at 20ips or 1200ipm. Not only that but they get up full speed quickly. Typically within a couple of inches.

If you thought about converting your router into a laser cutter, that's one thing. But to engrave, it's just not practical and that's why very very very few people are doing it. If it made sense, people would be doing it and profiting from it.

Chinese lasers are about $6k imported directly from China. $8-9k if you buy from a US seller. You can get a used Western machine for between $6-15k. New machines range from about 12-40k.

I should also add, without knowing the size, but guessing around 12x12, you could likely get it laser engraved for about $50 assuming you provide material and clean files. Relatively cheap all things considered.

[Chuck Keysor]

Hello Ross. Thanks, and I appreciate your input which is very helpful. But one key requirement I have, is that I want to make big images. The biggest I have made is 4 feet tall, and because of all the problems with fine details, needing perfect flatness that is about my limit. And the work to do that was very difficult, as I had to go back an make little patch files, to re-engrave areas that were slightly under-cut. I'd like to be able to make 4 x 8. I have experimented with "tiling" to make a larger image, but I didn't like that result.

A friend of mine in South Elgin has a Trotec laser, and it is a great machine! But he can only engrave things up to 17" x 27".

Thanks, Chuck

[Chuck Keysor]

PS: However, a concern is that with a big old gantry, things can't move very quickly, and with the super-fine lines involved, it may take so long to burn a big image, that it would not be practical.

Seeing my friend's Trotec fly back and forth, it took maybe 10 or 15 minutes to burn the image I gave him. My gantry will never be able to fly at a fraction of that speed.

But I don't even have a clue if a laser engraver mounted on a gantry would simply raster back and forth across the entire table (allowing it to get up to fast speeds on the straight a-ways), or if it would cut like V-carving, where it would be just tracing/following each vector, so that the gantry could never reach a high speed because of all the inertial forces resulting from so many sharp turns.....)

[Greencarvings]

The ones I saw, with the Aspire would be like V carving. I believe they only have a signal wire that wires into your controller. So pretty simple to set up.

[genek]

the LASER THAT WAS SHOWN WAS VERY SLOW. AT 2.5 WATT IT WOULD TAKE A LONG TIME TO ENGRAVE ANYTHING. that IS MORE FOR THOSE THAT WANT TO DO PENS OR VERY SMALL ENGRAVING. IT WOULD TAKE DAYS TO ENGRAVE ANYTHING BIGGER THAN A 12 X 12... LIKE Ross SAID I BACK. I have a epilog laser. For engraving it moves exceptionally fast. You also have some health and safety issues with a laser attached to a cnc. Shop bot looked into attaching one years ago and even tested it. It was un safe and very slow ....

[RossMosh]

If 4x8 is the goal, I think you need to seriously test the following: Tiling (as you've mentioned). Outsourcing the work to a local company with a Kern laser. Direct UV printing.

[willnewton]

I have one of the jTech Photonics lasers installed on an MPCNC 3d printer/laser engraver I scratchbuilt.

Does it work? You betcha! Beautiful detailed images and simple operation. You should be familiar with light G-code use and possibly a bit of programming depending on how you install it. You will also need to fabricate a mount and do some experimentation for power and speed for your material. Also, some light wiring duties. I am not sure how the SB would interface with the laser controller. You might have to use the SB prototype 3d printer software to drive it, as it can run off the fan PWM speed control.

Is is it fast enough to be profitable? IN NO WAY IS IT FAST ENOUGH. I did some tap handles in exchange for beer, but each lasering was smaller than an index card and took about three hours each! Sure you can make it go faster, but when I read the sizes the original poster wanted, I had to comment on it. It is not a practical solution to your problem.

That being said, it sure is cool.

It sure is dangerous as well. My MPCNC is about 3x3 and has an open frame. It is surrounded by walls and machinery on three sides, but the top is open. I have a simple laser shield panel on the front and wear laser safety glasses. I was a bit lackadaisical my first day of setting up and paid for it with gritty welder's eyes from being stupid a few times. I also watched it start a controlled fire in just a few seconds, when I tested what happened if the laser was just on, but not moving. When it runs I am about 15-feet away working at my bench wearing safety glasses while I work or on the other side of an open partition wall with a webcam running a live stream on desktop. In terms of destructive power to property from fire and instantaneous blindness just from being in the same room, it is THE MOST DANGEROUS TOOL I OWN.

The thought of a laser running on an open frame 4x8 Shopbot is interesting, but I can not imagination an installation that would be more dangerous, without EXTREME safety precautions, especially if you work with others that could be harmed by stray beams. These laser systems are fully enclosed for a reason.

For small, simple hobby stuff done for fun, it was a worthwhile purchase for me, because it is just for occasional use and just to learn. I have built several CNC machines from scratch and if you are familiar with the technology, it is a fun build.

You better be careful, because when it is running, this the reality-

When turned on, you have a loaded weapon firing invisible lasers while you intentionally try to start a fire for several hours at a time in your shop. It is serious business.

-update- And you need ventilation/smoke extraction too! Not fun to breathe the laser fumes.

[steve_g]

Way to go Will. You sure dampened my enthusiasm…
Thanks for the reality check!!!
SG

[chiloquinruss]

Will, I have an FS laser and use it almost daily but I have to admit your reality check description of 'what a laser is', is the best, most accurate, I've ever seen, When turned on, you have a loaded weapon firing invisible lasers while you intentionally try to start a fire for several hours at a time in your shop, I'm still laughing! :D Seriously you are quite right about the safety issues but I still got a good laugh. Thanks for posting. Russ

[Chuck Keysor]

Wow! Thanks for all of the great replies! Especially Will Newton's! Well, I guess I can scratch off one pipe-dream from my list. Thanks again, Chuck

[willnewton]

Hey guys, I just want you to play safe.

As for me, I have taken a laser cutter class using an enclosed laser system and felt very comfortable with that machine. I also own a laser welder for jewelry and it is an amazing piece of machinery that I used near daily for six years. These were pro systems designed with lots of failsafes and containment and instruction.

The homebrew stuff has some interesting options and good potential. The tradeoff is often safety. You just need to manage expectations on the speed and capabilities. There are many things we do everyday that are dangerous, just got to keep your risks managed.

[Chuck Keysor]

Will, it was the combined facts that making such a large image would take untold hours, AND the danger of the operation that deep sixed this for me. Maybe had it been able to engrave quickly, I could have worked up the courage to risk it. But that did not appear to be the case. Thanks again, Chuck