A new lasersaur is born!

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Scott (Strataforma.com)

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Jan 4, 2019, 9:41:57 PM1/4/19
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Today I finished up my 17.03 machine and made my first cut! Excited to start making some stuff with this, and hopefully recoup the cost of the machine before too long. Who do I talk to about getting on the map?


I've been filming my whole build process in pretty good detail, and have an idea to put together a step-by-step video assembly guide for the machine. If I can find the time that is...


064.JPG


As a side note, does anyone have any tips on getting honeycomb to lay flat? I expanded mine by hand, and there's some area that rise up off the bed frame. I tried weighing it down for a few days, but it just springs back if you don't bend it much.


Jondale Stratton

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Jan 4, 2019, 10:14:41 PM1/4/19
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Welcome Scott,

I've struggled with this too a bit and often use clamps or weights.  I've seen people with angle iron around the edges.  I think you can even buy it this way for more money.  I wonder what it'd take to attach it yourself.

Anyone done that?


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roryrennie

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Feb 3, 2019, 1:24:50 AM2/3/19
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Its just cheap aluminum. It needs a rigid steel frame. I found one on amazon a few years ago but had to reduce it down from 5’x2’ to 4’x2’ and it wasnt fun. If you have welding or metal shop people it is best to frame the aluminum in a rectangle with rods running through all the honey combs as stabilizers.

Adam Haile

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Feb 4, 2019, 7:52:47 AM2/4/19
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Scott,
In my completely unprofessional opinion those thin aluminum honeycomb grates aren't worth their weight in aluminum and should be summarily discarded.

Total side note... I just noticed your website in your name above... were you at World Maker Faire in September? I saw some really cool maps like that and the name sounded familiar.


They are the perfect size, have ~1cm square holes, are *much* more rigid than that thin honeycomb junk and have been quite happy to stay nice and flat on top of my aluminum extrusion table. Plus they are cheap... < $100 shipped for the 2 pack in the US (I just realized you might not be in the states in which case that link is useless, but it's just an HVAC component so I"m sure you could find it anywhere).

And don't discount the benefits of having 2 of them :) I swap mine out depending on what I'm cutting.... basically one is for "carbonic" material such as wood or cardboard and the other is for plastics. I found that when I only had one, I'd get carbon buildup from cutting wood and then when cutting acrylic it would cause more flare ups which would ruin the surface finish on the acrylic. So having 2 fixes that.

Another thing to note since people mentioned steel weights... even though my grid stays pretty flat I've found having the weights good to have around.
I highly recommend going here: https://www.onlinemetals.com/merchant.cfm?pid=10003&step=4&id=802
Then choose the "Random Length" option. These are basically cutoff remainders from other orders. I bought a dozen and then wrapped them all in blue painters tape because that was easier then trying to wash all the oil and stuff off of them. Each weighs around half a pound and and thin enough that I can stack 2 or 3 on a workpiece without risking the nozzle hitting when I need to hold something down.

Johannes F.

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Feb 6, 2019, 7:15:43 AM2/6/19
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Hi Scott,

congratulations on you new Toy! ;)
I see you also opted for the collinear red-laser? We have one too, and it makes adjustments so much faster!
It seems like your red laser (and possibly the CO2) does not hit your lens in the center. I printed a crosshair that fits nicely on the lens-tube and allows for easy positioning of the red laser in the center.
https://www.thingiverse.com/thing:3148235
Our lens seems to sit a bit deeper in the tube, which is why the central part is lowered in the designs, in order to get it close to the lens surface. If i find time, i can upload a flat design, which would work with your highrt positioned lens.

Cheers,
Johannes

Scott (Strataforma.com)

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Jun 8, 2019, 3:22:29 PM6/8/19
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I finally have my machine in a state that I really like, so I wanted to share some of the modifications I made!

 

Also - Adam, thanks for the tip on the honeycomb replacement, I picked up two of those aluminum grilles and they're working perfectly.

 

First off, a beauty shot of the machine in my small workshop. I built a lasersaur-sized table to size for it to sit on, with two shelves: a strong one near floor level to hold the chiller, fan, air pump, and supplies, and a thin one just under the main surface to store sheets of wood and acrylic. 

 

The laser I ended up getting was the SPT Tr100, which is a 100W laser with a red dot sight. I highly recommend getting a tube with the red dot sight - it make aligning mirrors 100x easier, it's a safety factor so you know where your beam is pointed, and it lets you 'preview' alignment of cuts/engravings before doing it for real (very useful for engraving phones, for example). The laser cost me $435 + $400 shipping from China to the US (probably more now with this trade war..), and with a laser power meter I got I measured the peak output of the tube at 102W so I can confirm it's legit. 

 

 

 

First up for modifications is the custom control panel on the front right. I wanted to be able to control the power to all the different equipment from the front, to have the emergency switch easily accessible, and to be able to monitor current through the laser and from the wall at a glance. Below is a close-up of that control panel. I arranged the switches so that you turn them on from left to right - the drivebard and chiller should always be on, the red dot goes on next to see the laser path, and the air assist and exhaust starts before you give power to the laser. The current for the laser is measured through the high voltage RETURN line, which I routed from the laser tube up to the front ammeter, and back to the laser PSU. You do NOT want to do this with the high voltage supply line, as that is a serious 18kV safety and sparking hazard. Measure the current after the voltage has dropped through the laser tube. 

 

 

At 100W, my laser is drawing 32.5 mA, which put total laser power consumption at 32.5mA*18kV = 585W (meaning a laser efficiency of 102/585 = 17.4%, about what you'd expect). This means I'm dumping 485W of waste heat into the chiller. Right now I have a CW3000 chiller, which pulls out 50W/degC. The Tr100 recommends a max 5degC room-laser temperature difference, which means that the chiller will only pull out 250W under recommended conditions. All this to say, I didn't understand before buying why people said to go with the CW5000 as a chiller, and now that I did the math it shows that the CW3000 is pretty drastically undersized. If you're starting out, I wouldn't use it for anything over a 60W tube. I'll eventually pick up a CW5000, but in the meantime I'm addressing this by running at a max of 75% power (better for tube life anyway), keeping an eye on chiller temperature, and relying on the fact that the laser isn't at 100% duty-cycle during operations which will keep waste heat down.

 

For mains current, during peak power cutting I'm only seeing about 8-9 amps for all the equipment, so pulling from one outlet is just fine (breaker for this part of my house is at 15A). The white light below the Mains ammeter is on when the Emergency stop is letting power through, and switches to red when it is pressed and blocking power.

 

How do these switches control power to the external hardware you might ask? In the back right corner of the machine right above the inlet holes for water/data/power, I made a power distribution panel. Power comes from the wall, through the E-stop and Mains current meter at the front, through the switches for the relevant external equipment, and back to the internal electronics and these plugs for the external equipment. The two Auxiliary outlets here are just overflow not hooked up to any switches, in case I need to plug anything else in. So, I can control the power going to these outlets mounted on the machine with the front switches. I really like this setup - it's tidy and there's no fidgeting with power switches on all the equipment every time I turn on or off the machine. 

 

 

For the exhaust, I cut a long rectangle out of the left side of the machine at bed height for the air inflow. Some simple air filter fabric went over that to keep particles from flying in. That air flows to a hole on the right side of the machine, where I 3D printed an adapter to go from that hole to 8" diameter ducting. I originally had an air filter over this, but it got clogged super quickly from the smoke, so I left it open. This ducting attaches to an 8" 735 CFM inline fan, which pushes the air through more ducting that dumps out the window. I don't have a filter on the end of it right now, but the neighbors aren't that close and haven't complained yet. I originally tried using a bouncy castle blower as the exhaust fan, and that worked okay, but it was super loud and also burned out after about 20 minutes of continual use. I think they're built to run at slower speeds with a lot of backpressure. The inline fan is working really well right now, and I get good airflow that clears the smoke quickly.

  



 

 On the topic of 3D printing, I highly recommend picking up a printer when building a lasersaur. It was invaluable for making brackets and adapter when things on the machine didn't fit quite right. In addition to the exhaust port adapter, there's a couple other pieces for the machine that I made. First is new brackets for the magnetic door switches, since I was having trouble getting them to line up close enough. Second is two inserts to close the gaps on the door between the two translucent acrylic panels. I didn't like that there was an optical path out of the cutting volume that a rogue laser beam could bound through, so those closed those gaps up. Third are some guides that I mounted to the bed, so that I can frame up my sheets of material in the same (0,0) position each time. That's been really useful. And the last which I don't have a picture of, is a little cover that fits over the test button on the laser high voltage power supply, so it doesn't accidentally get pressed.

 




The only other "mod" I should mention is that I used a 1:3 ratio of normal automotive antifreeze to distilled water as my coolant. This room is in a cold part of the house, and I don't want to worry in the slightest about the water freezing and cracking the tube if the power goes out in the winter. I also put in a bit of green dye, which looks cool but also lets me see any bubbles in the coolant lines a lot easier. 

 

That's about it for the hardware mods! In addition to that, I've been poking at the driveboardapp source code. I've mostly finished porting it from python 2 to python 3, and got some new bells and whistles put in. I'll send out another email with a link to the codebase and an overview of changes when I'm done, but I think the most exciting thing for the folks on here is that I've got raster engraving making cuts on the backwards pass as well as the forwards, which is cutting the engraving time almost in half.

 

That's all for now - if anyone has any questions about this setup, let me know!

 

Cheers,

Scott

Adam Haile

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Jun 8, 2019, 3:41:00 PM6/8/19
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Very nice! I love all the control mods :) Looks slick.
Concern about your tube current though.... 32mA sounds much too high. Mine runs at about 26mA (from a max of ~30mA). Check with your tube supplier of course, but I've not found a 100-120W tube that ran above 26-28mA continuous. You can of course, but your tube life will be dramatically less.
I'm actually about to install a meter finally on mine :P I've measured it, but during setup with my multi-meter. Though I admit I'm too lazy to run wires all the way to the front (since it's already built and all). I'm just going to mount a meter facing forward on the left side... since the tube return line is on that end anyways.

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Scott (Strataforma.com)

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Jun 8, 2019, 3:50:11 PM6/8/19
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Thanks! I've decided to run it at a max of 75% power (75W) in order to keep tube life long, and at that level I'm seeing 24.5 mA. I can't pretend that I know enough to know what a "good" current level is, but hopefully that's low enough that it does the trick. :)
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Adam Haile

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Jun 8, 2019, 3:53:27 PM6/8/19
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That should be fine :) I just wanted to make sure you weren't running with it at 100% all the time... and heck, I don't have a laser power meter like you do ;)
My tube is actually 120W peak and 100W "nominal".... basically, doing what you are doing but having a higher peak so the nominal output is still 100W.... though I paid a lot more. I'll keep yours in mind for future builds.
Especially with the integrated red dot laser!!! I'm so damn jealous.

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jet townsend

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Jun 9, 2019, 10:05:23 AM6/9/19
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On 6/8/2019 3:22 PM, Scott (Strataforma.com) wrote:
> I finally have my machine in a state that I really like, so I wanted to
> share some of the modifications I made!

A+! I never thought of putting gauges on the front, that would make my
life so much simpler.

Where you have switches on the front of the lasersaur I have two power
strips beside mine. One is for the chiller/exhaust fan, the other is
for the lasersaur CPU, lights, and my laptop. I'm still doing coding on
my replacement UI and I like being able to toggle the chiller/fan with a
single switch.




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jet townsend

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Jun 9, 2019, 10:09:01 AM6/9/19
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On 6/8/2019 3:50 PM, Scott (Strataforma.com) wrote:
> Thanks! I've decided to run it at a max of 75% power (75W) in order to
> keep tube life long, and at that level I'm seeing 24.5 mA. I can't
> pretend that I know enough to know what a "good" current level is, but
> hopefully that's low enough that it does the trick. :)

Check with the manufacturer of the tube and PSU. I ran a non-RECI PSU
for awhile with an internal adjustment around 30mA. You adjusted the
internal power before it sent the power through some other circuits and
to the laser.

PhotoBooth biz

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Jan 29, 2020, 1:15:24 PM1/29/20
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did you ever get a chance to put together a tutorial video? looking on youtube I can't find any.


Josh Lotts

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Jan 30, 2020, 6:35:37 AM1/30/20
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27mA is what you want. That tunes it so you're getting about 90% from 100% power inputs. The rule of thumb is 90% for a long life tube.
If you're running a laser PSU that doesn't have a POT dial for regulating current, you can use a 5k potentiometer between the signal input wire and laser psu to regulate the high end current limit without decaying your power resolution point count.
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