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

What software are you using to create your Gcode for laser use ?

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.

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

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.

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 

Thanks for the help so far!

*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...

Hi All,

Could someone please point me in the direction of a clear "How to" on this?

I essentially need to know which pin on the parallel port controls the laser, which G-Code command to use and what I need to set in Mach3 to get it to toggle that pin. I have a little PIC board I've made with a dial so I can set the power if the parallel pin is just on and off, I just need to see that pin toggle.

Thanks

I just realised that I was trying to test everything on my dev PC which is windows 10.

That explains why I couldn't get anything on the parallel port.. 

Hi All,

Could someone please point me in the direction of a clear "How to" on this?

I essentially need to know which pin on the parallel port controls the laser, which G-Code command to use and what I need to set in Mach3 to get it to toggle that pin. I have a little PIC board I've made with a dial so I can set the power if the parallel pin is just on and off, I just need to see that pin toggle.

Thanks

 

Tweakie.

An interesting technique for laser engraving ceramic tiles called the Norton method is well worth further investigation for any that are interested. The process involves initially coating the tile with a thin layer of paint (I used ‘rattle-can’ white primer) then, when completely dry, lasering the tile with a dot-dithered, or other suitable half-tone image. When complete any remaining paint is removed with thinners / stripper, etc. and the image remains.

Both the paint and the tile glaze have a degree of latency so to obtain the best results the lasering has to be completed slowly (less than 1200 mm/min.) so the whole process takes some time and may be more suited to diode lasers rather than CO2 lasers which are usually operated at feed-rates in excess of 4000 mm/min.

The end result is quite remarkable in so far as that, as far as I can determine, the paint has been carbonized and taken up by the ceramic glaze resulting in a permanent and extremely black image which cannot be removed with thinners, stripper or scraping and although slightly raised from the surface forms part of the glaze.

The following pics show;

My initial, rubbish, test tile where I experimented with different laser power levels and feed-rates.
A magnification of the image construction in the glaze.

Tweakie.