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Re: 80w seems to be rapidly losing power
Posted: Tue Oct 14, 2014 1:23 am
by NickWL
Ain't it just a GREAT feeling when you solve something tiny that makes such a huge difference!
Enjoy!
Nick
Re: 80w seems to be rapidly losing power
Posted: Tue Oct 14, 2014 6:26 am
by MitchL
NickWL wrote: Ain't it just a GREAT feeling when you solve something tiny that makes such a huge difference!
Enjoy!
Nick
Indeed. I'm sure there will be a few more issues to resolve (I have a small amount of backlash that needs measuring), but now the stuff at the top of the list is pretty mundane, like what color to powdercoat the skins
.
80w is a scary amount of power. I figured that by the time the beam reached the bottom of my machine (far, far past the focal point) that it would not be able to hurt the MDF tabletop that the machine sits on. That appears to be an incorrect assumption, so I'll make a steel tray to sit there, and make some brackets to protect the Z-axis lift belts that can be in the path of the beam way down there.
Thanks Nick, and thanks again Marco!
/Mitch.
Re: 80w seems to be rapidly losing power
Posted: Thu Oct 16, 2014 6:36 pm
by MitchL
OK, unfortunately I'm back to this topic ... I haven't had much time to work on the laser the past few days, but I did tonight, tried to cut some 3mm acrylic with the power supply now set for the right voltage.
I *still* can't cut acrylic, even super-thin 1/8" (3mm) stuff..
At 100% power and 5mm/sec, the 80W laser almost scores the paper on the back. This doesn't seem right.
- The ammeter (my DMM) is still reading 26ma (good).
- The frequency on the PWM signal is 20KHz.
- The duty cycle on the PWM signal is 90% at 100% power. If I reduce the power, the PWM percentage goes down.
- I think my focus is good. I've tried moving the table up and down by short amounts just in case it was incorrect. When I run a high-speed/low-power cut, the paper mark is well under 0.2mm, so I'm definitely not way out of focus.
My optics seem fine. I'm using the near corner of the table, double checked with tape burns, the laser is dead center on the mirrors.
I believe the AWC608 parameters are set properly (set for glass tube, 20KHz PWM, not using PPI, max power 98%).
Questions: Is there a this-way-up for the beam combiner's mirror? It was not marked, so I figured it didn't matter.
Is it possible I have too much air assist? I use a little airbrush compressor for my air assist.
Any more experiments to try?
The mystery continues!
/Mitch.