100w problem cutting with dots!

Hello everyone.
Only 50days new chinese 100w 6090 laser and out of sudden curved lines start to get cut with dots. I tried anything I could with settings, but no results. Help!

You need to add or increase air blowing down on the cut.


Sent from my iPhone using Tapatalk

It seems like the long, slow arc did not display the jagged line segment problem. As you already examined the settings, why not check for: (1) Loose belts, in either direction; (2) A wobbling mirror/reflector; (3) A wobbling focus lens; (4) arcing at the red heavy insulation cable, either inside the white connector to the power supply or at the laser tube electrical connection; (5) Visible light fluctuations in the tube while laser cutting; (6) Listen near the enclosed high voltage power supply for internal arcing.

Further, you could rotate the job orientation by 180 degrees then run again to see if the problems persist in the same places in the cut design.

I cleaned the mirrors, belts/bolts/cables are ok. Same results, but only at smaller cuts. I quess maybe the motors are low quality...

A few observations and suggestions using your photo:

1. Red circles show sticky fumes that cast back down onto the workpiece. This can be caused by a change in the location of the laser beam in relation to the center of the nozzle. In other words, if the beam is not aligned properly, then during the cut process, the change in air flow in relation to the laser beam can cause re-cast.

Another reason can be that the laser beam is piercing, or making its first hole at these locations. Now, if you think about it, it takes more time to perform a pierce than it does to run the laser beam along for laser cutting after the material is pierced (is cut all the way through). So, what we nonmetal laser cutting machine operators do, is simply set the cut speed slower so that pierce time is equal to regular cut speed. This method is not the best. Metal cutting laser owners always select a pierce time independently, then a cut speed. You can do the same by changing the delay-on time in your configuration file. Here is an example, using the syscfg.ini file from Lasercut 5.3

LaserCutDelayMoveTime=0.000000

The unit values for the parameter above is in seconds, so if you simply increase from zero to say a quarter to half a second then you can run the job slightly faster (increase speed), and also optimize for speed.

2. Green circle identifies problem of cutting in segments.

For the line segments issues, you should examine your configurations file's pre-programmed speed settings for smaller segments (as you identified as a potential problem).

Next, check the following parameters in your configuration file:
LaserCutSpeed=3.500000
LaserCutGWAcc=6.000000
LaserCutCircleSpeedNum=0
LaserCutCircleSpeed0_MinR=0.000000
LaserCutCircleSpeed0_MaxR=0.550000
LaserCutCircleSpeed0_Speed=15.000000
LaserCutCircleSpeed1_MinR=0.550000
LaserCutCircleSpeed1_MaxR=1.050000
LaserCutCircleSpeed1_Speed=20.000000
LaserCutCircleSpeed2_MinR=1.050000
LaserCutCircleSpeed2_MaxR=1.550000
LaserCutCircleSpeed2_Speed=25.000000
LaserCutCircleSpeed3_MinR=1.550000
LaserCutCircleSpeed3_MaxR=2.050000
LaserCutCircleSpeed3_Speed=30.000000
LaserCutCircleSpeed4_MinR=2.050000
LaserCutCircleSpeed4_MaxR=3.050000
LaserCutCircleSpeed4_Speed=35.000000
LaserCutCircleSpeed5_MinR=3.050000
LaserCutCircleSpeed5_MaxR=4.050000
LaserCutCircleSpeed5_Speed=40.000000
LaserCutGWTime=0.010000
LaserCutTrackSize=100
LaserCutMaxSpeed=400.000000
LaserCutConnerPower2=30.000000
LaserCutWorkPower2=50.000000

Also, you mentioned bad motors. Perhaps you meant backlash (mechanical slop that can be caused when changing direction, such as by loose belts gearing, worn linear bearings, etc.). See this backlash setting.

LaserCutOneAxisBackLashLength=0.000000
LaserCutTwoAxisBackLashLength=0.000000

In summary, there are many available parameter settings to address a variety of visible quality issues for laser cut parts. In my experience, most owners are either un-aware or not using them, or not trained or their use and benefits.

One last item--I use the Mahoney laser power meter probe to check for problems with laser tube power fluctuations. If your input voltage fluctuates during the job it can affect the high voltage laser power supply, thus changing laser power on-the-fly. You may find that your blower or chiller is pulling down the power fed into the high voltage power supply, on your circuit. So, you could check your circuit's amps and voltage to make sure that it is properly sized. The high voltage power supply's manual typical states, very clearly, that changing the input voltage will change the HV out to the laser, thus changing its power.

Finally, when cutting wood, a tiny orifice nozzle makes a huge improvement in wood cut quality. Increasing and decreasing air pressure to adjust for quality, and also adjusting the nozzle position, independently of the focus is important. https://www.cnczone.com/forums/attac...d=470184&stc=1

https://www.cnczone.com/forums/attac...d=470182&stc=1

I tried without air assist, just to be sure, but same results... Going to change power cable now, maybe its some electrical fluactuations.