Perforation mode on paper/card, low speed/high power

So, here i am again with my rubbish motion system about to revisit card/paper cutting issue tomorrow. Thought i’d ask for advice, maybe someone had this worked out already.
I have terrible issues with head movement above 30mmps, vibration in motion. Cant really do anything about it as serious mechanical reworking is needed to fix this nonsense, but hear me out.
Machine is 80W.
Cutting paper requires little power (can do) and fast speed (absolutely cannot do). I want to force machine to slow cut paper by moderating power using perforation mode to prevent overburning/charring/catching fire. Kinda like superfast pulse beam. Is it something that can be done with good outcome ?

I will be trying this tomorrow, this is a preemptive question, maybe someone weighs in with something constructive, besides “fix your damn laser”. :smiley:

Usually cutting 3-5mm materials no problem, accellerations were set for that, but my previous trials at paper were woeful… I lower acc/decc too much - machine becomes super sluggish.

I’ve never tried perforation mode but I’m curious if that helps with your problem.

How thick is your paper?
With my 80w machine I cut .010" card stock at roughly 150mm/s and 35% max, 6.5% min power.
If your top speed is really limited to 30mm/s then I think you’re going to have a hard time.

How low can you go and still get your machine to burn? I can get decent reliable ignition down to about 7% power on mine, but once the tube is lit it will fire down to about 5.5%.

At 30mm/s what’s the lowest power you can use and still cut?
Maybe if you can snuggle up really tight against the low end of your tubes working range you can make it work?
Can you show some of your “best” cuts on your paper of choice and share the settings you used to get there?

In my case after super-fails of my trials couple of years ago, full machine overhauls, etc, i just put out all the thoughts of “fast and little power” out of mind and never retried.
Last pics i have of my trials:


Waviness is not in the design. Belts are not loose, lenses/mirrors not rattly, etc. And still it will absolutely not hold 50mmps, let alone 100mmps.
Only yesterday i did a bit of mdf cutting with vector engraving just to see the same problem rear its ugly head again (at 50mmps).

Last i tried i figured you need to run about 150-200mmps with continuous beam (at low power) to get charless cuts, but in my case they all were wobbly cuts with lots of missed steps etc.

At present i’m not bothered by paper/card thickness, i want to try to achieve, say 20% power 25-30mmps burn on paper, with a fast pulse instead of continuous beam.

The picture you are showing above looks like acceleration wobbles. Have you tried lowering the acceleration/jerk settings?

I think that pic might have been pre-serious-rebuild-reconfig.
However, in this pic below, i did the cut yesterday. The score cut was done at 50mmps and its wavy as heck.
Last i did any playing with acc-decc/jerk was to get cutting speeds to behave, while discounting any and all fast motion.

I’ll take a peek at settings later on to post them here. But at this point i i’m more interested in perforation trickery.

Wierd. Do you have v wheels for your motion? I’ve seen things like that on mine when bearings are going out or I get junk built up on them.

Machine is a mish-mash of nonsense. X (gantry) is linear guide and block (12mm?), the Y however is bs made of round rail (10mm?) on the left and just an aluminium angle on which flat wheel rides (think cheap k40). Nothing is to be done about Y as it requires ripping it out completely and replacing with linear guides and belt drive components, which involves angle grinder… Also belts are 10mm and no way to replace them to wider ones in situ without heavy modding.

Done some tests today. It appears that PWM override (1kHz) is better at keeping clean edges over perforation mode (0.05 cut/skip interval).

Cuts were:
Left - 15pwr, 30mmps spd, perf 0.05 skip/cut, no PWM override;
Right - 15pwr, 30mmps, no perf, PWM override to 1kHz

I’m not sure how visible it is on the photo but PWM is cleaner looking by eye.

Also, clean honeycomb is a must :smiley: Notice how right one (with better edges) is overall dirtier - thats because its been cut on portion of dirty bed, with crap underneath being deposited on top (i think). So the backflash is there as well, but not on the try on the left.

The left (cut on clean bed) has hardly if any backflash at all…

Just cleaned the bed last week, then cut some crap plywood…aaaaand now it needs cleaned again, apparently. I might need to invest in smaller steel honeycomb just for card cutting…

Ah, and the paper is 210gsm thick.

Another test on some very heavy card i found in the house (250gsm+?). These are actual cards, die cut to shape, i cut out the design on the front. For the most part is very clean cut, with either blown bits flying about in couple of places or dirty bed underneath.

Underside is surprisingly clean too. Cut straight on honeycomb.


1 Like