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Author Topic: The Laser Project.  (Read 844900 times)

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Re: The Laser Project.
« Reply #1090 on: October 04, 2019, 01:02:32 AM »
Great, thanks for the response!!  already ordered TIP 125 to control the pos side of the laser and will report once installed. This way I can use default low pin 7 on parallel port.

Side note, any thoughts on these?
https://www.ebay.com/itm/450nm-15W-Laser-Module-W-Heatsink-Fan-Support-TTL-PWM-for-DIY-Laser-Engraver-P/264005907159

Offline Tweakie.CNC

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Re: The Laser Project.
« Reply #1091 on: October 04, 2019, 01:12:56 AM »
What software are you using to create your Gcode for laser use ?

Quote
Side note, any thoughts on these?
https://www.ebay.com/itm/450nm-15W-Laser-Module-W-Heatsink-Fan-Support-TTL-PWM-for-DIY-Laser-Engraver-P/264005907159

No practical experience but they look good.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: The Laser Project.
« Reply #1092 on: October 04, 2019, 02:00:55 AM »
For pics the engrave.dll plug in... however I don't know if I have most current version.

Aside from that Solid works DXF into Mach3 or Cambam.

You?

R

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Re: The Laser Project.
« Reply #1093 on: October 04, 2019, 02:44:06 AM »
It is a long while now since I made any revisions to the plugin.dll but everything was always done and tested assuming the Digital Trigger output would be Active Low. When you are constructing your transistor circuit perhaps bear this in mind.

The latest .dll can be downloaded from here;
http://tweakie.byethost10.com/Engraving.zip

Hope this helps,

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: The Laser Project.
« Reply #1094 on: October 13, 2019, 09:19:01 PM »
Ok so some success, and some failure it would seem.

New TIP 125 power transistors arrived and I wired up the circuit very simply using Pin 17 as digital trigger active low.
Pin 17 feeds direct from LPT Port to 1Kohm resistor to the base of the TIP125.

Under ports and pins when I set digital trigger to pin 17 and select active low, the laser is off. When I select active high the laser is on. Just as expected.
Interesting note, when pin 17 is set high and the laser is on it pulls a full 1.7 amps which burns the wood nicely. When off it barely glows such that you can just see the dot on the board, actually quite helpful for lining things up.

Here's the rub, when I go to engrave and image the laser is pulling no where near the full 1.7 amps it can. In fact it's closer to 40ma (0.040 amps) MAX which won't even mark the material (wood in this case)

If I flip the scenario and make pin 17 active high and then do NOT invert the image in the engraving plugin I get a darkly engraved image but the laser is also burning the background as it moves as it never fully turns off.

So it's as though the Digital trigger is not fully going low when active low and not fully going high when active high. Is the duty cycle flipped on me and I'm getting 90% off time when it should be 90% on time...? I would think that would end up with a negative of the image though in that case.

However it will go fully low (ground) and fully high (5V) when activating the pin through ports and pins config screen.

I've tried different images as well in case I've got a problem with a particular image for some reason.

Also the plugin you sent, when pasted in to the plugins folder causes the tab for engraving in Mach 3 to disappear....


Well, regardless I'm learning so that's good I suppose  :P

Thanks for the help so far!
« Last Edit: October 13, 2019, 09:21:06 PM by getrobarnold »
Re: The Laser Project.
« Reply #1095 on: October 13, 2019, 10:44:55 PM »
*edit*

After some further deliberation I'm thinking the 40us pulse time is too short, however unchecking that box has no effect on amperage draw.

So unless the turn on time for this laser is incredibly slow I'm unclear on the issue...