Experiencing Poor Cutting Quality?

Experiencing Poor Cutting Quality?

If you are not getting a good quality cut on your machine, this short troubleshooting guide may help get your machine performing well again.

  1. Clean the lens at the end of the laser tube, this lens can be contaminated by smoke, dust and fumes, which will reduce the effective cutting power.

    Isopropyl Alcohol – https://amzn.to/32Bzwf1

  2. Check the mirrors well aligned and clean.  You may have performed a mirror alignment in the past and had everything spot on.  Make sure the adjustment knobs are secure, if the locking nut is loose then vibrations and movements may result in the mirrors slowly going out of alignment.  This de-alignment of the mirror may not be noticeable right away, but as they continue to move it will drastically decrease the quality and ability to cut effectively.

    Dirty mirrors will not effectively reflect the laser beam light and this results in reduced power at the material being cut.

    Co2 Laser Mirrors (LINK)

    When aligning mirrors, don’t forget to make sure the final alignment of the lens through the laser nozzle is coming out centered.
  3. Check the nozzle for contamination.  Remove the laser lens nozzle, and clean it.  Dirt and splatter from materials being cut can start to clog the nozzle.  As a result the laser beam will need to burn away this material, causing a reduction in power before the beam hits the material being cut, reducing the efficient power at the material.
  4. Check the air assist.  To reduce fouling of the laser focusing lens and build up of contaminants ensure you have a positive air pressure at the nozzle at all times while cutting and engraving materials, and clean the nozzle regularly.

    Ultimate Air Assist Kit (LINK)

    If using high pressure air for cutting check the pressure used is the same as you have previously used and tested on your material.

    If a water trap is installed on the air line drain it regularly to prevent condensation on the focusing lens.

    Oil & Water Separator Trap Regulator – https://s.click.aliexpress.com/e/_9u7sVF
    California Air Tools 8010 Steel Tank Air Compressor | Ultra Quiet, Oil-Free, 1.0 hp, 8 gal – https://amzn.to/3n8hVox

    Check the laser focusing lens is clean and correctly inserted, carefully remove the lens and clean with a lint free cloth.  If possible do not handle the lens, use a holder or soft cloth.

    Take note of the lens orientation, is the convex side if directed up towards mirror three.

    Co2 Laser Focus Lens ZnSe – (LINK)

  5. While cleaning the lens check to make sure it is not cracked or scratched. Check the correct focal length lens has been installed, and it is installed correctly.

  6. Check your focus gap.  This is more overlooked with machines that use an autofocus system, where users take for granted that the calibration and autofocus system remains accurate.  Check the focal gap with a step gauge to ensure accuracy.

    Co2 Laser Lens Selection & Ramp Test – https://www.youtube.com/watch?v=gGfg2zJioT8

    Auto Focus Sensor – https://s.click.aliexpress.com/e/_99J349

  7. Check that the laser bed is level, and make adjustments where required.  A simple way to check this is using an engineers square, with one edge on the laser bed and then measure to the underside of the X Axis Rail in all areas of the worktable.

    Engineer/Carpenter Square – https://s.click.aliexpress.com/e/_AdU0aN
  8. Cutting speed and power settings.  Compare the laser cutting and speed settings with those that you have previously known to achieve good cuts quality with.  Test these on the material to determine if you require additional power or slower speeds to achieve a quality cut.  If you find that this is required then it may be that your laser tube or laser power supply may need replacing in the near future.

    If you have a milliamp (mA) meter installed, A good tip is to record mA from your laser tube and the power % for a known cut and monitor this over time.  For example you may have 50% Cutting Power = 20mA, then in a future test you may notice that 50% Cutting Power = 17mA.  This is a good indication of a slowly deteriorating tube or laser power supply.

    Ammeter Analog – https://s.click.aliexpress.com/e/_AppDk5
    Ammeter Digital – https://s.click.aliexpress.com/e/_AMwJ9B

    The lifespan of a standard Glass Co2 Laser tube is around 10,000 hours.  So for a machine operating for 4 hours a day, this is 10,000 hrs / 4 hrs = 2,500 days or approximately 7 years.  However the gases can permeate the glass even while the laser is not in use, so normally 3 years is the expected lifespan of a Glass Co2 Laser Tube if it is used in good conditions.

    HM Laser – Glass Co2 Laser Tubes  https://en.hmlaser.com/

    HM Laser Tubes are Available in Australia (& New Zealand) From MW Laser  https://mwlaser.com.au/product-category/co2lasertube/ Contact me directly for a quotation or more information.

    I hope you found this helpful – A video to accompany this post can be found on my YouTube Channel here

Until next time
Take Care
Cheers Matt

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