Need Help!- streaks on laser engraved image

[identilase]

I have an LC6090 80 watt Jinan G Weike laser cutter/engraving machine.
i am using mainly for engraving images onto slate and granite, i use lasercut 5.0 software, upload .bmp images at usually 300DPI. 100% power 500mm/min.
i have got air extraction and an air blower into the nozzle!

I have had very few issue's with this machine apart from the following:-

-I sometimes have an issue with streaks the full width of the engraving intermittently.

-When engraving very large images (600mm x 900mm) i find there is usually faded patches spotted around the engraving??

-When engraving an image with text next to the image, i find the image will be faded in the exact place of where the text is (on the same 'X' axis path).

Any help would be much appreciated, i am new to this site and would be happy to give any advise as to my experience of this machine and my process.

Regards

[zax15uk]

Hi, and welcome to the zone!

The fading sounds like an alignment issue, if the locations are constant it is almost certainly the problem. The beam spot is fairly large until focussed, so what is happening is part of the beam isn't going into the lens aperture. This results in lower power. If you adjust the mirrors so your beam is parallel to the axis it will not drift off center. Make sure the final spot is centered on the final opening in the head assembly, where it is directed down to the lens.

It is possible your streaks could be related, or they caused by loose belts or other 'play' in the mechanical system. Check the carriage (head) is firm on the ways and doesn't have any slop, then do the same for the beam.

Shipping can cause things to shake loose, and they haven't discovered anti-vibration washers or lock nuts in China yet.

I would also suggest lowering the DPI on granite, it helps achieve crisp results. You may be able to reduce the power too, I don't recommend running at 100% power. It significantly reduces the tube life.

Zax.

[SkipW]

I agree with Zax. If you use 100% power, your tube life will be shorter. I try to never go above 90%. My original tube is still going strong after 1 1/2 years. Also, for the LC model, 500 speed may be too fast. Try slowing it down some. The LC (cutting) and the LG (engraving) models have different drive systems.

Check the mirror alignment and slow the speed down a little. That may take care of your problems.

Skip

[Armis]

thanks, for the question and the replies.

it would have been great to get follow-up reply from OP, but ...

[bpoulin]

Originally Posted by Armis thanks, for the question and the replies. it would have been great to get follow-up reply from OP, but ...

Wow dude you resurrected a 2 year old thread without anything to actually add to the conversation....

[Armis]

Originally Posted by bpoulin Wow dude you resurrected a 2 year old thread without anything to actually add to the conversation....

Yes, I know, it's my simple way of marking threads that are important to me.

Now go poke someone else.