Waves in Engravings

[Dave Hein]

I have just purchased a Transon 1390 CO2 laser engraving machine. It is a 100 watt water cooled laser. I have been getting strange ripples in the materials i am trying to engrave. I am using software called LaserCut 5.3. Every power and speed setting combination I try is giving me the same results. I have checked the belt tension, the alignment of the mirrors, made sure the machine was grounded properly, and have still getting poor results. It there anyone that has had this same problem with their machine or can help me resolve this issue? I will post pictures of what I am talking about for a better understanding. Any help would be greatly appreciated.

Dave

[Ross Moshinsky]

Is that MDF? MDF is sawdust. It's an inconsistent material. Get some acrylic and run the test again.

[Mike Null]

I don't understand the first picture. What is it and what is it supposed to be?

The second picture looks like bad circle might be caused by a loose mirror, lens or bearing/belt issue.

In the last picture it looks like you're using flexible plastic for exhausting your machine. I would suggest using flexible metal or rigid metal for that.

[Dan Hintz]

I'm I'm reading that first pic correctly, you're getting changes in depth that look wavy? If so, you have a serious problem with power control at the tube's driver.

[Chuck Stone]

If so, you have a serious problem with power control at the tube's driver.

Don't say that, Dan. This is the same problem I've been having!

[Neville Stewart]

Looks worse in the x direction too. It that was mine, I'd be thinking, loose motor/pinion or something straining on the X mechanism.

[Michael Hunter]

I'm with Mike Null - look for something loose or wobbly and fix that first.
Only if you still have a problem need you start worrying about the laser/electronics.

[Zsolt Paul]

As far as the circle is concerned, I was getting the same wavy lines when a bearing went on my machine. However, it could be anything loose that causes vibration.

[Dan Hintz]

Don't say that, Dan. This is the same problem I've been having!

A change in depth can only be caused by a few things:
1) Changes in power
2) Changes in substrate density
3) Changes in carriage speed.

The changes shown are very periodic and regular, which removes cause #2 from the running. If it was #1, I wouldn't expect the rows to match up so well. A bearing/pulley that's slipping and/or catching (#3) could cause such a pattern, but that one is pretty darn regular.

[Rodne Gold]

The extremely wavey circular vector cut points to a mechanical issue , could be a bad stepper motor, bad shaft encoder if it has one , a bad motion motor driver chip or a bad bearing , try move the head by hand without power to the machine and see if it catches or feels jerky, try the same with the machine powered up , if possible

[paul mott]

Dave,

The Chinese, unfortunately, never seem to have any quality control on their machines when they are assembled and you will have to check everything.
There is a good chance that this problem is mechanical - screws come loose on stepper pulleys, mirror mounts, lens mount etc. during transit or may not even have been tightened properly in the first place.
Also, they do not seem to understand 'earth bonding' so paint is seldom removed beneath the screws which are supposed to make electrical contact with the earth straps so it is worth checking these also.
The lens mount should be checked to make sure the lens itself is not loose, be careful here - the lens is fragile so do not over tighten.
Check everything.

Paul.

[James Jaragosky]

What kind of file did you run this with. If it was a dxf file I would check for mechanical problems like others have suggested. If it is a plt file I would try running a circle using the dxf format.