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Messages - ggallant571

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31
General Discussion / 3D lithophane
« on: August 19, 2019, 12:13:39 PM »
Entirely new to me: https://www.instructables.com/id/How-to-3D-Print-a-Photo-Lithophanes-101/

Took a dragon that I had laser etched (png) and used the referenced browser utility. It printed quite nice on the first try. Image was strictly 2 tone BLACK/WHITE and the red filament was not a good color choice. Going to try a multi toned image with glow in the dark filament,

32
Engraving / Re: Machine stopped mid job????/
« on: August 18, 2019, 06:26:17 PM »
There is no how-to book of laser etching and if there was is probably wouldn't apply to my setup. Glad to hear you were able to salvage the project.

I put small uninterruptible power supplies (UPS) on the bench for laser etchers and 3D printers. We have a whole house generator that takes about 15 seconds to kick in so the $50US from Staples works fine.

33
T2 Engraving / Re: machine 'seized' during burn
« on: August 17, 2019, 08:05:38 AM »
As a rough guide I use:

  NEMA17                8watts
  2,5W Laser Diode      17W (15% efficiency)

For a 3 motor fixture that comes out to 41W. A 60W supply should be sufficient. The problem is none of my EBay 60W supplies can deliver 40W for even 2 minutes.

I don't understand the -/+ question. Our typical controller with the 2.1mm modulate power plug has GND on the outside and +12 on the inside.

34
T2 Engraving / Re: machine 'seized' during burn
« on: August 16, 2019, 07:04:05 AM »
I think 4.5A at 12V is marginal for a 2.5A fixture. Chinese 4.5A is probably 3A on a good day.

35
Engraving / Re: Machine stopped mid job????/
« on: August 16, 2019, 06:59:31 AM »
1. Clamp the disc to the fixture to keep the registration.
2. Coat the disc with brown painters tape to act as a waste test media.
3. Edit the image to erase the currently etched region.
4. Test burn on the painters tape at lower power.

When I do large round discs I 3d print plastic brackets which are screwed into the fixture wasteboard, I edit the image to isolate independent shapes and etch separately. Each image is the same size so a homing operation gives fairly good results. If you don't have limit switches etch a pattern to at as a manual known good reference spot.

Good luck!!!!!!

36
Projects / Re: Laserable Paints
« on: August 14, 2019, 03:30:12 PM »
I would also like to do that. I await your posting show the great results.

37
Projects / Re: Laserable Paints
« on: August 13, 2019, 08:49:39 PM »
When etching glass I have had some success with paints made for wood stove or automotive exhaust duct work. They appear to have a metallic ingredient that melts and fuses to the glass. Getting a repeatable recipe has been elusive and I can't tell if it is on the surface or in a fissure. Are you looking to paint the entire surface and remove the unwanted or deposit an image?

38
T2 Engraving / Re: machine 'seized' during burn
« on: August 13, 2019, 09:46:16 AM »
Obvious question - Do you have the power supply configured for your environment?

I live in a rural area with a backup generator. When the power goes out it takes 15 seconds for the generator to kick in. Installed USP units on laser and 3D printers to handle the interruption.

39
I think the 5.5W lasted for about 18 months of light usage. It was good for etching slate which started my addiction.

BTW - I don't think there is a considerable difference between 2 and 3 wire modules, especially for cutting. Both take a TTL control signal and convert to a constant current source. Some of the 2-wire modules have a large capacitor (user removable) that limit the diode ON/OFF response. Might negatively effect very short burns but would only delay the start on stop times for longer burns.  The 3-wire just moves the high power switching circuit closer to the diode. Definitely a better electronics design and probably cheaper to manufacture.

The ability to burn is dependent on the energy per unit area. Cutting the radius of the focal point in half reduces the burn area by a factor 4.  The diodes and optics are sorted by quality and the "good" go to industrial applications, the average to to "quality" vendors, and the rest go to Chinese EBay.

My 5.5W laser has a rectangular beam pattern. The ratio is about 5 times long to narrow. When cutting rectangular patterns, I adjust the focus so that the beam is at 45 degrees to give a more consistent X/Y kerf. When etching I adjust it to be vertical and sometimes compensate in the artwork.


40
I started with a 5.5V for cutting, then engraving, then the junk box. Bought a 1.6W unit that cuts and etches better. Then purchased a 2.5W for etching on slate.

I recall that the 5.5W uses about 3.5A at 12V. Do you have a bench supply with power meter?

41
Engraving / Re: Batch engraving
« on: August 11, 2019, 04:57:39 PM »
You could also burn a target on the waste board to align for multiple runs.

42
What is the power rating of your 12V supply?

Another possible cause is the Y stepper motors are drawing too much power.

43
Benbox / Re: New to Laser x moves but Y doesnt
« on: August 09, 2019, 08:11:16 PM »
Did you check the current limits on the stepper drivers? The Y axis need twice the current of the X axis. If the drivers were setup by the vendor and you swapped them this would be the expected behavior. For the typical A4998 you should measure a voltage between the trim pot case and ground of approx 0.4V for X and 0.8V for Y. Setting the limits too high will results in excessive heat, too low and missing motion.

44
It is necessary to match the firmware in the controller with the host application. An easy way to get started is by using a trail version of T2 or BCL. They support GRBL-1 firmware and have provisions for downloading and setting the initial operating parameters.

The older firmware used a different I/O pin on the embedded CPU which does NOT support PWM (Pulse Width Modulation). Some controllers have a jumper to select the pin. I would expect the always ON condition if you have the old firmware with a newer controller.

45
General Discussion / Re: TTL.
« on: August 04, 2019, 05:19:41 PM »
Are you using one of the test/calibration patterns?

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