Bad laser engraving quality

Why is my engraving not solid and why am i using more power

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One of my clients informs me he is having issues with his engravings, he is having to run the job at a higher power to engrave and cut and is getting bad results, intermittent lines, gaps etc.

My first step in troubleshooting this issue is for him to change from X swing to Y swing, when engraving the head will pass from right to left scanning and marking the material. This is X swing. Y swing is when the head scans up and down whist marking the job.

 

Rdworks changing from x swing to Y swing

By changing the swing direction and analyzing the results allows me to see if the issue is caused by the side to side swinging motion, backlash etc. After completing the same engraving with Y swing the problem was gone. This pointed me in the direction of the X axis.

First things to check are belt tension, without a force gauge it is all down to feel. I try to aim for 1 cm of belt deflection with moderate force on the x axis of a x700. if you can pull the belt any more than this tension is required. To the right of the laser head where the belt connects you will find two set screws either posi or hex head. Tighten these clockwise until the desired tension is achieved.

Next things to check is the motion transmission components. Is the stepper motor mounting loose? is the idle belt roller free to move and not binding on the mounting?
In this case the grub screws had come loose on the left hand idle roller and the roller had migrated and was chafing on the mounting. This was giving the x axis a ‘notchy’ feeling as you moved the head left to right by hand.

Now the head was moving freely left to right without any tight spots, strange sounds or resistance.

It was time to move on to the laser head itself.

CO2-Laser-Head-RED-Dot-Pointer-Module-Positioning-Integrative-Mount-50-8-100mm-Focal-Focus

Check that the laser head assembly is secure, remove the adjustable focal length tube and place to one side. The tube that is still attached to the laser head check for any play in the threads and that this is tight.
On this particular machine i found this tube to be loose and have lots of side to side play. I removed the tube by turning counter clockwise and refitted with a generous amount of green 270 Loctite. This tube should never come loose or be removed so i decided to use the strongest thread lock available.

co2 Laser lense head fix

Finally it was time to move on to the lens, focus tube and its air assist nozzle.

A test i like to do to ensure everything is tight and as it should be is to tap the assembly, if the lens is loose you will feel and hear it moving. In this case the lens was loose. I took this as an opportunity to remove the lens and clean with an optical wipe. Always install the lens with the curved side facing up. Re tighten the lens retaining ring with a suitable tool, do not use any threadlocker here!

Finally i finished off by cleaning the air assist nozzle and ensuring the air fitting was tight before refitting.

The final test was to check the quality of engravings at a number of speeds.
The problem was cured and the customer praised me claiming i had doubled his cutting speeds for 4mm ply.

One thought on “Why is my engraving not solid and why am i using more power

  1. I’m having to re-do all my material power and speed tests. It’s a GREAT problem to have 🙂
    Seriously thanks for your help. I can’t believe how fast I’m cutting plywood now!
    As you know I’m not very adept, technically, and having you on my doorstep is a godsend.
    Warren is highly recommended by me folks for all your laser requirements

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