Engraving acrylic

[Jan Mrovec]

Hello

I have a problem with the engraving acrylic.(GCC - Mercury)
Laser makes vertical stripes. Engraving is not clear.(photo)
I replaced the X axis (axis, motor, bearings) ... the same.
Do not know what may be the problem?

thank you

[Tony Lenkic]

Jan,

Does your laser have a "Tickle" adjustment? Try to lower it down.

[Jan Mrovec]

Hello

I am a newbie in the laser.
Please, what is "Tickle" adjustment

Thanks

[Tony Lenkic]

TICKLE
This is the term used to define the small pulses sent to keep the plasma inside the laser, energized.
Ask your GCC dealer for info on locating and adjusting tickle voltage.

On my machine (ULS) there is a set of DIP switches on tube assembly for this.

[Richard Rumancik]

Tony, I am not disagreeing but what makes you conclude that it is the tickle problem? Usually a tickle problem is associated with extraneous bits of engraved lines outside the graphic boundaries (if tickle is too high.) If set too low it will fail to fire soon enough on a return stroke so there will be missing "pixels" in the graphic. It is not obvious to me that this is a tickle problem . . .

Jan, contact your GCC dealer for instructions on adjusting tickle if you want to experiment with this, but note where it was to begin in case you want to put it back to original condition.

I don't know what is causing the problem. What color is the background you are rastering? If it is 100% black then as a test maybe try to change it to 90% black and see if the look improves. I won't say this will solve the underlying problem but might just hide it enough to be passable.

What kind of acrylic is this? Cast acrylic will look better when rastered. If this is extruded then you can get an uneven effect when rastering as it will not turn white like cast.

Hopefully others will have more ideas of what the actual problem is.

[Scott Challoner]

It could be the bearings on your X carriage too. Make sure the rails are clean and inspect the bearings. If they have little flat spots on them, replace them. Richard is right, extruded acrylic (the stuff you buy at Home Depot etc) won't turn out well. It will look more melted than frosted.

[Rob Bosworth]

I think you need to replace the X axis belt. When you replace it, also clean out the drive gear and the idler pulley.

[Scott Challoner]

I think you need to replace the X axis belt. When you replace it, also clean out the drive gear and the idler pulley.

Interesting how the verticle lines look about the same as the cogs on the X belt. I may change my mind and go with Rob on this one.

[Jan Mrovec]

Hello
The technician replaced a complete X-axis (motor, belt, bearings, head.....all X-axis)
still the same.
Engineers and the manufacturer does not know what it is.

And when I edit the photo in the "Photograph" (500dpi)
and engraving 500dpi ...laser makes vertical grooves (photo)



vzorek_2.jpg

[Glen Monaghan]

Whatever it is, they look like they are spaced at regular intervals but that could be either of mechanical, electronic, or software origin. You could try moving the axis by hand over the engraving and see if you can match up the spacing to something like a full revolution of a shaft or a weld on a short belt.

Also, maybe it's just my eyes, or maybe something in the photo, but it also looks to me like there are some horizontal bands as well...

-Glen

[Gary Hair]

Try changing the resolution in your driver - up or down won't matter, just change it. I had the same problem with a very large acrylic piece I engraved and changing res solved it.

Gary

[Rodne Gold]

To me it looks mechanical , when did this all start - is it sudden or is it a problem that got worse?
I would clean the X axis slide and see there are no "sticky" spots and replace all the bearings and rollers the head uses - also replace the ribbon cable to the head. Disconnect the X axis motor from the head , run the head back and forth over the X axis , ANY change in the smoothness will tell you where the problem is. Check the mirrors and lenses too , the beam might be hitting some scratched or damaged part , which would also give rise to odd engraving at specific parts of the table...I assume that lines are "static" in that they appear all the time in the same place. Try rotate your picture and see if the lines still appear in the same place.