sidetracked - using a 3d printer with a laser

[zeeprogrammer]

As I mentioned on my 'micro-lathe maybe' thread...things were going to slow down.
Here's why...

I got involved with a couple of friends in a 3D printer project.

Except it's not just 3D printing.
I got a printer kit and instead of installing the extruder (print head), I installed a laser.

LASERS OF THIS POWER ARE DANGEROUS!!!

They can blind you in an instant. Precaution and proper safety procedures are required.

So here's a pic of the printer and the safety glasses.
NOTE: Safety glasses are not the same for machining and lasers. Nor are they the same for different wavelengths.

BE SURE TO USE THE APPROPRIATE GLASSES!!!
And keep everyone out. Standing across the room is not good enough. That beam can ricochet.



I machined the heatsink for the laser.

Here's a video doing some engraving on a piece of leather.
What a stink! Needs a fan to keep the smoke away otherwise it interferes with the beam.
NOTE: Depending on what you burn...be sure the fumes are non-toxic. Better yet...exhaust outside anyway.

This was just an initial run. Calibration is not complete.



As you can see...it uses a blue diode laser. It won't cut/burn/engrave certain materials depending on the materials' ability to absorb that wavelength.

Now you can see why I was talking about processors and software earlier.
This uses an Arduino Mega (Atmel 2560) processor board and stepper motor driver shield (daughter board) with Pololu drivers.
I use the Arduino IDE but SlickEdit as my editor.
I wrote my own PC program (Visual Studio using C++) to transmit g-code instructions to the printer.
The firmware in the Arduino board is Marlin which I had to modify in order to control the laser.

The project is fairly long term and given it's not really related to this fine forum I won't bore you (too much) with it.
Just wanted to let you all know what I was up to.

Not that I tell you everything. 

[Don1966]

Carl I would say that's a great project. It sure has me interested and I would like to see more on it as you progress with it. The only programming I do is PLC's. Not quiet a complicated a C++. Although I tried learning it once upon a time but could not stay with it because at that time I work a lot of hours. Keep it coming bud. I like...........

Don

[GailinNM]

Zee,
I think that it is a very appropriate topic for the forum.  I have an old used 30 watt CO2 laser engraver that I drive directly out of ACAD.  There are very few engine builds that I do that I don't use it for at least a little bit. Great for cutting gaskets out of many materials and since I learned how to cut PTFE safely (Thanks MIT) it works well for that too.

Cardboard and acrylic mockups are a snap to get a feel for how something is going to look.  I have even done small patterns for dry sand castings. Close density styrofoam and white glue make a really quick and dirty one off pattern.

And I know your have seen the control panels and name plates on some of my engines.  Panel is engrave and cut out with all the holes at one sitting then the engraving is filled with solid paint.  Brass nameplates are just spray painted polished brass with the paint blown away where you want the brass to show.

PC boards.  I just spray paint 1 ounce copper clad and then burn away where I want the copper to disappear and etch.  A few cleaning steps get involved but mostly it's art to part ready to drill in under an hour and that includes a coffee break while the board is etching. 

I do have outside venting with a 2 HP blower and use air assist to keep the optics and other things clean.

So keep us informed as to your progress on this project.  What laser are you using. Curious minds want to know.
Gail in NM

[Alan Haisley]

Zee,

I'm  as to why the laser has a Z axis movement. You are doing flat work in the video but the programming moves the laser head up and down during part of the process.

Alan

[zeeprogrammer]

Thanks Don. I appreciate the support.

Gail...the laser is a 2W 445nm (blue) M140 diode laser. Hopefully a pic of it attached. It gets hot so a heatsink is required. We'll be doing a PCB as well to provide a quick disconnect...you'll see why in a moment.

Alan...for the most part you're right. Since this is built on a 3D printer, the Z axis has to be homed and then moved to the desired height position. That's the part you see before it starts burning. At the end is another home operation.

In any case, the Z axis is there because the idea is to allow different modules to be used. The laser is one. The original extruder head for 3D printing, possibly a motor for milling, or anything else we come up with. Which is why a PCB will be added to provide quick connect/disconnect between the modules and the control board.

The laser's beam doesn't diverge much (there is some) but the spot isn't a perfect circle. It has a slight oval shape to it. We're considering an additional lens to correct for that. That would likely introduce a focal point that would have to be found and calibrated to. The Z axis makes that process much easier.

There's also some interesting blue-sky dreams we talk about that brings the Z axis into play. How about 3D lasing? Or a 4th axis?

In addition to the heatsink we'll probably add a small fan but it will have two purposes. One is for cooling and the other is to direct the smoke away. You may notice in the video that some of the letters are partial. This was due to smoke getting in the way and blocking/reducing the laser.

Because of the dangers of the laser, the unit will be enclosed with a kill switch installed so the laser won't work if the unit is open. A bigger fan will be used so that fumes can be exhausted outside.

However, the idea is for anyone to be able to build their own system. Which means they can bypass the kill switch and/or not install the fan. All we can do then is provide sufficient warning.

I'm involved with two other guys. One is a hardware engineer with experience in lasers from a prior job. The other is a mechanical engineer with experience in plastics. I provide the cheese-steaks. A pretty good team of skills for this.

Thanks again for the support and interest. I'll keep you all updated with major milestones.

[zeeprogrammer]

A little update...
Finished putting together the 3D printer as a 3D printer.
Then made my first print.

Printed a piece of crap.

It was supposed to be a 1" cube...but after a while it was apparent...it was crap.
Stopped the print. (Or..."cut if off" as some might say.)

Thought I'd see if it was really crap.
Showed it to T expecting she'd ask what it was.
She asked "What is that crap?"
Proven.
It IS crap.

Well...I've polished crap before. Back to calibration.

This is what (this) crap looks like...



It's actually not so bad as a first print. The sides (which you can't see) look okay.
They just have a lot of crap around them.

[zeeprogrammer]

She asked "What is that crap?"

Bad test. I'd forgotten that's the usual response when I show her my prizes and treasures.

[Kim]

I'd say that's a pretty big success for a first print!  Sure, you've got some fine tuning to do.  But its a lot closer to a 3D printer than you were a couple months ago!

Lot closer than anything I've got

Looks like the extruder didn't stop extruding on the edges.  But then, maybe its not supposed to stop, I dunno.  I have no experience here.

Regardless, I think you shouldn't be quite so hard on yourself Carl.  A little tweaking here and there and you'll have it!
Kim

[zeeprogrammer]

Looks like the extruder didn't stop extruding on the edges.  But then, maybe its not supposed to stop, I dunno.  I have no experience here.
Regardless, I think you shouldn't be quite so hard on yourself Carl.

Thanks Kim.

You're right about not stopping on the edges. I mean, it wasn't supposed to. It's just off.

I'm really not that hard on myself. Actually quite pleased and wasn't surprised about the outcome. I was more surprised it did anything at all. There were several early attempts when it didn't do anything. I couldn't figure it out. Initially I could manually control the heaters and motors. Then I tried the print and nothing happened. That happened several times. Then suddenly it started. I haven't determined what was different.

I hope to do some tweaking soon. First I have to head to Cabin Fever and pull some guys out from under the bar. 

[Kim]

Yes, definitely!  First thing first!   

Be sure to document with pictures, so that those of us following along at home can experience it vicariously 

Have fun!
Kim

[zeeprogrammer]

I've been asked to post a little about my experiences with this printer.
So here's today's adventures.

A key aspect is getting the initial layer to stick to the bed. If it doesn't then subsequent layers pull it off and you get...what I got.
Some people use painter's blue masking tape on their bed. Which I tried. I later found out it has some kind of 'wax' coating which defeats the purpose. It's been suggested I use some isopropyl alcohol and wipe it down.

Another key aspect is getting the Z travel well calibrated. If you're a tad short then as the model builds up the error gets larger and the extruder begins to hit what's already been laid. This causing motor steps to miss and you find yourself printing in air.

No point in pictures as yet. 2nd attempt resulted in bits and pieces of unrecognizable plastic (because it didn't stick to the bed).
The 3rd attempt looks much like the 1st (because my Z calibration is off).

When I get a decent part I'll post it. Right now I'm just trying to print a 20mm cube.

[Don1966]

I am glad to see you're still at it Carl. It is a great project and I am differently looking forward to some good results. Keep plugging buddy you have my attention.

Don

[b.lindsey]

Glad to see you made it home safe and sound Don.  Zee, I have seen worse crap come out of commercial printers, at least when things are out of whack!  Not sure if it will help but the ones I am familiar with use a separate and different plastic to first lay down a foundation on the build plate. Whatever it is really sticks to the plastic build plate to the point it has to be scrapped off with a sharp putty knife. Whatever it is also sticks to the build material (ABS alloy) but to a lesser extent.

Bill

[zeeprogrammer]

Thanks Don and Bill. And I'm also glad everyone who's home made it safely and I hope the others are still enjoying their trip.

Bill...these printers can't really do different plastics in a sitting. At least I haven't seen it yet. These printers use PLA or ABS plastic. I'm using PLA. Learning little things like not leaving the plastic in the extruder or it can crystalize.

For those who don't know...

The bed (on which the print is made) is just a plate of glass sitting on top of a large PCB that is a heater. The heat is needed to keep the plastic soft for a while since it tends to shrink as it cools and will pull up otherwise.

But plastic doesn't stick to glass very well so people usually cover it with something. I'm using painter's bue masking tape.

The plastic is a filament that is fed into an extruder. That's nothing more than a heater and stepper motor. The stepper motor feeds the filament through a hobbed bolt that has an idler wheel pressed against it.

Made progress on the last attempt. I wiped down the tape with isopropyl alcohol. Print stuck to the tape and was building up well before things went awry.

At first I thought my Z axis wasn't making enough steps per layer. That would cause the extruder to eventually collide with the print and miss steps in X or Z.

I checked my Z calibration and saw I was a little over. Not much so I thought I'd be good. Didn't figure that over time a layer would get too much above the previously laid layer. Printing in air produces globs. It fooled me because the extruder would hit the glob, miss steps, and it would looked like I hadn't gone high enough.

Getting close! My buddy said I was a lot further along than he was when he started. So that gives me some confidence.

This thread properly belongs on another forum. But I like being here. ("I love you guys."...and gal.)
If it truly bothers someone (someone I care about  ) let me know by PM.

[AussieJimG]

Thanks Don and Bill. And I'm also glad everyone who's home made it safely and I hope the others are still enjoying their trip.

Bill...these printers can't really do different plastics in a sitting. At least I haven't seen it yet. These printers use PLA or ABS plastic. I'm using PLA. Learning little things like not leaving the plastic in the extruder or it can crystalize.

For those who don't know...

The bed (on which the print is made) is just a plate of glass sitting on top of a large PCB that is a heater. The heat is needed to keep the plastic soft for a while since it tends to shrink as it cools and will pull up otherwise.

But plastic doesn't stick to glass very well so people usually cover it with something. I'm using painter's bue masking tape.

The plastic is a filament that is fed into an extruder. That's nothing more than a heater and stepper motor. The stepper motor feeds the filament through a hobbed bolt that has an idler wheel pressed against it.

Made progress on the last attempt. I wiped down the tape with isopropyl alcohol. Print stuck to the tape and was building up well before things went awry.

At first I thought my Z axis wasn't making enough steps per layer. That would cause the extruder to eventually collide with the print and miss steps in X or Z.

I checked my Z calibration and saw I was a little over. Not much so I thought I'd be good. Didn't figure that over time a layer would get too much above the previously laid layer. Printing in air produces globs. It fooled me because the extruder would hit the glob, miss steps, and it would looked like I hadn't gone high enough.

Getting close! My buddy said I was a lot further along than he was when he started. So that gives me some confidence.

This thread properly belongs on another forum. But I like being here. ("I love you guys."...and gal.)
If it truly bothers someone (someone I care about  ) let me know by PM.

It doesn't bother me Carl, I see it as the first faltering steps towards making engine parts or patterns for moulding them. I am very interested.

Jim