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Laser won't cut all toolpath

edited December 2014 in Archived Issues
Hi.

I've tried cutting a simple image on a white photocopy paper, but the laser just won't cut all the way of the toolpath. Not sure what happen.

This is the result: http://bit.ly/1wMxgxQ

The toolpath: http://bit.ly/1GymcDR

The preview on G-Code Visualizer: http://bit.ly/1z5FIaz

Help!

Comments

  • White paper is very difficult to cut. A slow feed and max power, and more than one pass is frequently needed.
  • I don't think the problem is the material. Other tool paths had been cut just fine, but only left the starting and the last tool path.
  • edited December 2014
    Hi AFIF,
    The first thing to try is slowing your feedrate down or increase your power as John suggested.

    Sometimes on white paper like this, the direction of the grain is enough to prevent the initiation of the material starting to cut. When the laser changes directions, the deceleration around the corner is enough to get the material cutting.

    Please let us know how you go.
  • Well, I've just tried playing with the power level and the feedrate and it works haha! Thanks guys for the explanation and the help! Can't wait to try other materials and settings!

    1. BTW, is it OK to use 100% laser power all the time? I believe that will shorten the lifetime?
    2. What is the advisable method (power and feedrate)?
    3. Should I be concern with the loud noise from the stepper motors when the feedrate is low (e.g. 5mm/sec)?
  • 1: It is Ok to run at 100% power but as you mention, it will shorten the life of your laser. The standard kits we shipped have the 100% current to the 9mm diode set to 1.8amps. In our longevity testing, we ran the diodes continuously for a few weeks at this power level without any noticeable loss in performance.
    Having said this, many factors affect the life of your laser diode. Things such as ambient temperature will affect how well the diode is cooled along with the types of jobs you are running. Longevity is a difficult value to predict.

    2: I am not sure what you mean by question 2. Can you explain a bit more?

    3: The loud noise you are hearing is most likely resonance in the motors / machine. There is noting to be worried about, other than at some speeds it can be quite loud and annoying.
    Each machine we have built has had a slightly different resonance speed. We are working on a way to reduce / eliminate this effect.
  • AFIF, I have been using laser diodes for 3 or 4 years now, and have often run my diodes at full power when raster engraving images in mirrors for two or three hours at a time with no apparent loss of power. I, too, was concerned at first with diode life. Now I consider that eventually I will have to replace a diode, but my "cost per hour" of use is very low. As Domenic has said, I keep the current to my diodes at a safe maximum of 1.6 to 1.8 amps (depending on the diode type) I'm using. Adequate cooling is important, and now having seen the Emblaser's heat sink design, I am comfortable with running it at full power without concerns.
  • edited December 2014
    Sorry for that question 2. It is related on question 1. What I'm trying to say is, to achieve longer lifetime of the laser diode, is the best method would be to operate at the lowest possible power (but still able to cut/engrave, depends on the material) with lowest possible feedrate?
    For example, during my test cut on a white paper, I found that the lowest laser power to be able to do the job was about 45-50% with 5mm/sec feedrate.
  • Yes, you are correct. It will become a balance of power level and feedrate. You will also find that some materials cut better with more power and faster while others are the opposite.
    Always have enough material on hand to experiment with.
  • @Domenic
    Noted. Thank you very much! :)

    @John Champlain
    Thank you very much for your opinion. As you guys may have noticed, I am totally new to this laser cutting/engraving so every helps and advises are really helpful and much appreciated :)
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