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Dec 21, 2014, 01:54 PM
AndyKunz's Avatar
Thread OP
I will monitor both, actually, so the signal is properly gated.

The PWM controls the power by controlling the time that the laser is turned on relative to being turned on all the time.

I have to check the timing with a scope to know what I can implement it with. I used to do lots of PIC programming (it's how I made my living), so it's actually quite simple with one if I can run the processor fast enough. I would use TMR1's "gate" mode to measure it, and every time it overflows just bump a counter telling me that so many microseconds (depends on clock speed) have accumulated.

Read up on T1GSS and T1G0 to see what I mean. Just a little glue logic in front of it (controlled by TTL from controller) will do what I need. Should be brain-dead simple. I also plan to include the regulator to take the 24V down to 5 or 3.3 depending on the CPU.

Andy
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Dec 22, 2014, 04:38 AM
HJG
HJG
HENRY
Looks like you have it solved already Andy, will follow thread with interest.

Henry
Dec 25, 2014, 05:58 PM
AndyKunz's Avatar
Thread OP
To make it easier to work with the laser, I added some 6' shelves to the wall above the laser. This is sorted from 1/32" to 1/8" bottom to top, with 3" stock against the wall and 4" stock closer to me. There are also some sheets of ply and some wider wood up there as well.

Each stack is then sorted by weight, making it easier to get matching sheets when I need them, or to make individual parts from lighter or heavier material.

That wood used to live in 36" boxes from my old kit business. That was good because it kept them stable. I expect to be cutting it quickly enough that it won't matter too much

Oh yes, and MERRY CHRISTMAS!

Andy
Dec 25, 2014, 06:28 PM
Registered User
looks great, Andy, and Merry Christmas to you, too!
Dec 26, 2014, 01:10 PM
Lynx Heli Team Pilot
eolson's Avatar
This his been an amazing project to watch and I am blown away by the speed with which it has come to fruition. It really looks like a great machine and the short videos I've seen of it working are way too neat. Seems really exciting to be able to manufacture pieces/parts/kits to your own exacting specifications and to be able to quickly edit and cut a new piece that might not have worked originally.
I won't blow any more smoke Andy....but...outstanding!
Dec 26, 2014, 01:50 PM
AndyKunz's Avatar
Thread OP
I'm glad you enjoyed it. I just cut lettering using it. I had the power a little too high, so the backing is cut through in places. I forgot the right setting to use, but I just found it again

I have some Monokote trim film that I picked up at a swap meet our club hosted a few years ago. I also had a PDF of the text I wanted. One of the guys at work took the PDF and made a DXF file. After a little fiddling with paper to make sure the letters were shaped OK (they weren't, and I had to tweak them manually, and they're only OK now, not perfect), I put the film in and cut it. The edge is as nice as knife-cut vinyl.

Next I weeded them and then used transfer tape to keep them spaced properly when applied to the model. A little Windex to the wing allowed me to position it properly and remove any bubbles. Right now it's drying off.

They aren't as nice as Callie does, but I can do them here. When I need good ones, I still know where to go for them. It'll take a lot more practice for me to be making them as nicely.

Andy
Jan 03, 2015, 08:38 PM
AndyKunz's Avatar
Thread OP
Last night and today I was able to cut and mount some sheets to enclose the frame. This is mainly to keep dust out and laser reflections in.

The clear top is 1/4" Lexan and the red sides are 1/4" acrylic sign material. I still need to add a wood panel behind the door over the laser tube, and I need to cut the control panel to replace the luan-and-paper one you see here. That will require air assist, which I'll be able to do after the adapter arrives next week.

Andy
Jan 03, 2015, 09:14 PM
Registered User
Cherokee Flyer's Avatar
Looks like your almost ready to be a real cut-up!

L.
Jan 03, 2015, 10:56 PM
Neophyte hacker
portablevcb's Avatar
Andy,

Took a pic of my laser bed when cleaning it today. The bed itself is al box. You can see the cross struts that support the honeycomb.

charlie
Jan 03, 2015, 11:13 PM
AndyKunz's Avatar
Thread OP
Thanks Charlie. Looks like it's about the same idea as mine! Good to know I'm not that far off base.

Andy
Jan 04, 2015, 05:12 AM
HJG
HJG
HENRY
Hi Andy,
Well done with your laser build, thanks for your detailed build log, If I attempted
a build log people would fall asleep waiting for something to happen.
Must go into the shed , put the heater on and shake off the January "blues",
my laser is still work in progress. I am going to try and place my limit switches in posn today on the X axis , must check on your build to see how you did the Y axis.
So TTFN & belated happy new year wishes to all.

Henry
Jan 04, 2015, 09:47 AM
AndyKunz's Avatar
Thread OP
There were pre-drilled holes for mounting both limit switches for the origin. I have considered adding switches for the high limit but the software seems to do a good job there, so I haven't gone further.

I still need to install a switch for the door interlock. The wiring is in place, the software is configured, but the leads are just shorted together for now. I'm looking at a refrigerator switch to control it, but Marco recommends a proximity switch.

Andy
Jan 04, 2015, 08:40 PM
Neophyte hacker
portablevcb's Avatar
Andy, you might want to add max limit switches as well. Or have overload protection for your motors. There always seems to be a way to make the head take a "nose dive". Sending a file that is offset, wrong scale, setting wrong max and min, etc, etc, etc.

Any switch should work for the interlock. Mine has hall effect switches, but, just about any micro switch should work.
charlie
Jan 05, 2015, 09:06 AM
Registered User
Quote:
Originally Posted by portablevcb
Andy, you might want to add max limit switches as well. Or have overload protection for your motors. There always seems to be a way to make the head take a "nose dive". Sending a file that is offset, wrong scale, setting wrong max and min, etc, etc, etc.
I come from the industrial motion control field. We always had limit switches and the only time I've seen them needed was because of the programmer - me.
Jan 05, 2015, 09:43 AM
Neophyte hacker
portablevcb's Avatar
Exactly.

Watched two multimillion dollar accidents from just that issue. 25,000lb objects spinning because of software glitches and no limit switches ("the software will control it, no problem").


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