Interesting discovery on glass!!

[Zsolt Paul]

I just discovered something very interesting. I had been testing glass engraving on glasses and bottles today. I do NOT have a rotary attachment, so I wanted to see what my limit is without one. I used a 4" lense b/c that will give me a greater focal length, which allows me to "wrap" more around the glass. WHat I had discovered that besides the usual power and speed settings, adjusting the BIDIR setting is very important. This can be verified by rastering a bunch of straight and 45 degree diagonal VERY THIN lines. The thin lines really show off if the machine's travel one way is exactly lined up with its travel on the way back. This is what bidir is for those who may not know. Bidir is mostly effected by speed.

This alone is not new, I alway check the bidir. However, what is interesting is that this same speed, power and 4" FL on wood and tile for example, requires a -0.04 bidir setting. On glass (again, same speed) I had to bring it to -0.02 for it to line up. Now, I don't know if this is only due to the fact that I am rastering onto a rounded surface (glass) as opposed to flat, but I don't think so. I will report back on that. Just b/c the glass rounds off away (in depth) from the lense, vertically the lines should still line up. This doens't make a lot of sense to me, but hey, what does when it comes to glass? It did however help tremendously getting finer detail and nicer white b/c it is chipping more where its supposed to.

[Dan Hintz]

Uhm, what's "BIDIR"?

[Zsolt Paul]

Really? You guys don't have to adjust the bidir? Is that something unique to Vytek machines? Bidir stands for bi-direction(al). It has to do with the back and forth motion of the the actual laser nozzle as it engraves. For example, lets say you are engraving a very thin straigh line vertically (along the X axis, perpendicular to the back and forth motion of the engraving) that is the thickness of one dot. When the nozzle travels along the Y axis one way and puts a dot where the line is and then comes back the other way and also puts a dot where the line continues, these two dots are supposed to line up perfectly right? Well the faster the laser travels, the more this alignment can be thrown off. We adjust for this in the BIDIR settings.

I am really curious if this is unique to Vytek. Don't see how it could be... There must be a way to adjust for this in case needs a fine tuning in other machines too. If you are interested, try to engrave the thinnest line possible, perpendicular to the travel of the laser head. It is best to copy this line a few times and have a bunch of them spreading over at least 4-5". See picture attached for example. I also did diagonal lines too. I would be curious to see how your machine does in this test.

[Rodne Gold]

The GCc machines I use also have a way of tuning the "bidir" for best results. It's called "image tuning"

[Zsolt Paul]

I figured there must be something similar, just not called "bidir". I would imagine all machines would have to have this. Unless smaller machines may not need it b/c they don't "rock and roll" as much as when my 51" x 51" bedsize starts rockin'??

[Dan Hintz]

Ah, tuning... yeah, most of the better machines have it, but I've never seen it referred to as "BIDIR", hence my confusion.

[Jack Burton]

I am guessing that it means BI-DIRectional :)

Making sure that the pulses line up an - and + passes as much as possible (tuning on a ULS machine)....