Author Topic: kerf madness  (Read 797 times)

crutch

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kerf madness
« on: June 25, 2017, 01:33:20 PM »
I cut a small piece to make a calibration sample for slots and tabs

the kerf is not uniform across the board - I thought it would be.

I made 1,3,5 and 10mm tabs and the same with slots.

here are the measurements for the tabs

0.98, 2.98, 5.05 and 10.05 mm respectively

for the slots

1.2, 2.98, 5.02 and 10.10

I thought the amounts off would be consistent across the type - slot or tab.
they are not.

is this normal?  or do I need to do some refining on my rig?

nottingham82

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Re: kerf madness
« Reply #1 on: June 25, 2017, 02:12:39 PM »
it could be that the focus is actually a small rectangle instead of circle.  depending on if its a horizontal or vert cut it will affect it differently. 
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Re: kerf madness
« Reply #2 on: June 25, 2017, 02:53:42 PM »
What material are you using? Wood?

I've done some extensive testing in this area. Because we are using low powered lasers, and if you are using woods, you are going to get uneven results.

The wood material will burn different beam widths depending on the glue the beam hits, and how much glue, but the direction of the wood grain is the big one however. If you're using a 40 watt CO2 laser, I don't this becomes a problem because at 40 watts you can pretty much cut (blast) through any kind of wood without worrying about glues used or the grain direction.

The other factor is your laser frame itself. Most folks think their frames are perfectly square and their belts are adjusted perfectly. Not so...even on my own machine. I'm up to my neck doing photo engraving tests with BCL and I recently wasn't getting the results I was looking for. After making a belt adjustment...bam...like magic...the image was engraving damn nicely again.

The box tabs laser cutting work I was doing six months ago told me you're going to get different results each time you laser a box. You're not going to get Tab A to slide snugly into Slot B...every time. It's just not going to happen.

My laser is a 1.6 watt unit so it's pretty damn weak but with the right software (BCL), I can do some pretty amazing things with it. Most recently I cut through 3/8 inch thick (9mm) plywood with it!! It was a lab experiment and I did it and I could do in the real world but I wouldn't want to. 3/8 inch thick cutting belongs to the CO2 laser world.

Paul and I are getting world class photo engraving results from a 1.6 watt non-TTL laser diode on the world's worst wood to engrave on: Craft Plywood. Absolutely horrible stuff to engrave anything on, but we're getting outstanding engraving results using BCL. The quality is right there with the much more powerful CO2 lasers.
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crutch

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Re: kerf madness
« Reply #3 on: June 25, 2017, 03:43:27 PM »
this was on 3mm plywood, grain was running in the x direction.

I was using 120mm and 8 times with air assist.  air assist was at 10-15 psi,  I need a larger tank to support higher psi settings.

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Re: kerf madness
« Reply #4 on: June 25, 2017, 03:48:50 PM »
I use air assist and run about 40 LPM...this isn't much air pressure. I have the capacity to double that but don't because I find stronger air pressure blows the soot across the surface of the material and smears it. It sounds like you're using a lot of air flow. Please let us all know how it works for you.
Admin -- Ralph -- support @ BenCutLaser dot us
https://www.dropbox.com/s/lgy21u9kz6or62l/SetupBenCutLaser3.1h.zip?dl=0
BCL Paid license: $49.95
via Paypal to bclpp@primemail.com