Setting PicConvert Board

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kenmon
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Setting PicConvert Board

Postby kenmon » Wed Jun 22, 2016 2:17 pm

Hello. Recently iI have bought a 2.8 Laser kit and PicConvert (DAC+PWM) Converter Board from Jtech photonics. I have also tried and bought PicLaser. I have a DIT CNC 3 axis with Mach3 and smooth stepper. The drivers are Keling and I have a C10 breakout board.

I have set Pic Laser with 0.15 mm pixel size and 2000 mm/min feedrate.

I have a problem with grey scale.
As one can see from the photos the gray scale begins only from the third row.

There are also a white line.

P_20160619_215835_1_pC.jpg
P_20160619_215835_1_pC.jpg (211.52 KiB) Viewed 11222 times


In the second image there are a dark lines where there should be no.I have already write to jtech because the Dac board not respond exactly.

P_20160619_221914_pC3.jpg
P_20160619_221914_pC3.jpg (476.08 KiB) Viewed 11222 times



Thanks in advanced for your help

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Picengravertoo
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Re: Setting PicConvert Board

Postby Picengravertoo » Wed Jun 22, 2016 5:55 pm

Try setting the Step & Direction pulse in motor tuning to 3. Are you including the G64 in the precode and are you using the Std. Gcode engraving profile in PicLaser?

It looks like your focusing could be improved also. The J-Tech lens does not focus to a round spot, so you may need to raise the laser up until it's out of focus. The beam will be a retangular shape. Loosen the screw on the front of the heat sink and rotate the laser module until the long side of the beam is parallel with the 45D engraving angle. Tighten the set screw back up. We use a 3" (76.2mm) focal distance from the heat sink face to the material when focusing our lasers. A black anodized piece of aluminum works best to focus on to see the smallest spot size with laser safety glasses on. You will need to power up the laser slightly when focusing.

Jeff

kenmon
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Joined: Mon Jun 20, 2016 4:36 pm

Re: Setting PicConvert Board

Postby kenmon » Sat Jun 25, 2016 2:40 am

Hello jeff

I have set the board and the laser as your suggest. The output voltage now is ok.

P_20160624_223206_1_p copia.jpg
Toulip wood
P_20160624_223206_1_p copia.jpg (287.55 KiB) Viewed 11172 times


P_20160624_182936_1_p copia.jpg
Birch plywood
P_20160624_182936_1_p copia.jpg (422.42 KiB) Viewed 11172 times


I have also tried to engrave a photo with PicLaser but they are too dark or too blank.

thank you very much for your patience.

Best regards

Gian Piero

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Picengravertoo
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Re: Setting PicConvert Board

Postby Picengravertoo » Sat Jun 25, 2016 7:04 am

We have good results with Birch Ply, Poplar and Basswood. We found Birch engraves better if sanded across the grain with fine sandpaper. If the engraving is too dark, increase the feedrate. If the lower end shades do not show, set the min value to increase the laser power. Each type of wood requires it own settings on how it burns.

If you want to engrave on Oak, it's best to Dither your image and then set the settings to min 0 and max -,6477. It will then pulse the laser on/off and be more forgiving of the grains.

kenmon
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Re: Setting PicConvert Board

Postby kenmon » Sat Jul 02, 2016 3:55 pm

Hello jeff

I have done a lot of tests

UltimaProva.jpg
UltimaProva.jpg (463.84 KiB) Viewed 11104 times


I have some question.

What resolution must have the photo?300 DPI or more?

I have test poplar but it burn too much.
1.jpg
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2.jpg
2.jpg (272.14 KiB) Viewed 11104 times


I use m07 for power on the laser. Is it possible set PicLaser to write M07 instead M03 in the gcode?

Why Jtech photonics suggest a 30 mm focal distance an you 76.2mm?

Thanks in advanced

Gian Piero

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Picengravertoo
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Re: Setting PicConvert Board

Postby Picengravertoo » Sat Jul 02, 2016 5:19 pm

No less then 100DPI.

Why are you using the M07 to turn the laser on? You can just swap the pin # your using for the coolant command over to the Spindle output so the M03/M05 commands can be used. Or, you can add the M07 in the pre-code.

Like I said before, you need to increase the feedrate so it does not burn too dark. I'm not sure I understand the numbers you have written down for each test. If your using Metric units, you need to set the DAC axis steps per in Motor tuning to 393.7. Set the accel the same as your X&Y axis's and use a 0 Min to Max -.6477 setting range in PicLaser. This will give you the 0-5v PWM range to the driver. You adjust the feedrate & Min/Max to get the proper shade range on your material.

The 30mm focal distance is for cutting from what I understand J-Tech's theory is, not photo engraving. At 76.2mm the focal spot is smallest a longer distance so It's a little more forgiving if your material is not quite flat or varies slightly in thickness.

kenmon
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Re: Setting PicConvert Board

Postby kenmon » Tue Jul 05, 2016 3:50 pm

Hello Jeff

I use the cnc with router and i have set M03 for spindle ON. It's no problem I can set another profile only for laser in Mach3.
The numbers i have write are with minus from 0 to -0.6477. The first is the min and the second the max. I have set the axis as you have advised me and all is ok. I have some problem to work over 2000 mm/min.

This is the last test:
Donna10.jpg
Donna10.jpg (372.72 KiB) Viewed 11052 times


I have used Hard maple and 1800 mm/min feed rate.

I noticed that the lens isn't very firm. In another post i have read to use a glue. Now i have used a tape of teflon and it seems very firm. I have not yet proven.

I 'm not sure I understand how does PicLaser work about resolution. If i resize the photo the resolution is about 3.9 pixel / mm (about 100 dpi).

how should I set it to increase them?

Thanks in advanced

Gian Piero

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Picengravertoo
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Re: Setting PicConvert Board

Postby Picengravertoo » Tue Jul 05, 2016 4:48 pm

Hi Gian,

I mentioned using hot melt glue, but teflon tape on the threads works good too. It's just more tedious to apply. Are you limiting the feedrate (velocity) because of the Kernel speed setting your using in Mach3? It's a good idea to setup a separate Mach3 profile just for the laser.

Looks like your gaining on it, but it still appears your focusing still needs some improvements.

Jeff

kenmon
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Joined: Mon Jun 20, 2016 4:36 pm

Re: Setting PicConvert Board

Postby kenmon » Tue Jul 05, 2016 5:25 pm

Hi Jeff

I'm set the Kernel speed at 75000. I have a smooth stepper and i don't lose step. The problem is the geometry of my machine. It's born to work with wood and bit with large diameter. It's is really heavy. At rapid it travel at 3600 mm/min but with G01 only 2000 mm/min.

I have tried to focusing the best. I haven't rotate the beam at 45°. I will tried soon.

Thanks

Gian Piero

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Picengravertoo
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Re: Setting PicConvert Board

Postby Picengravertoo » Tue Jul 05, 2016 7:59 pm

The only way to be able to increase the velocity is to change your drive ratios (timing belt pulleys?) and lower the steps per for the X&Y axis. I had to do this on our Servo ball screw CNC router. The Kernel speed is set at 45K with a Parallel port controller and I'm able to laser engrave photos at a blended feedrate of 220IPM (5588mm/min).

https://www.youtube.com/watch?v=4YY3U-bSfvU


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