Lightobject.com Support Forum

Hi Guys,
Just letting you know I have now installed the 2x beam expander on the machine and I'm having very good success with it so far.
I can cut very fine details with it in card stock with a 1" lens and engraving is also very much enhanced to the point where I need to go back and extensively reset all of my settings to adjust for the difference.
My old scan width was 0.08 but now I need to set that at 0.02 or 0.03 to make sure all the lines are engraved without missing some.

For the past year I have been only able to engrave at 100mm/sec and my motors would lose steps if I went higher and I put up with it until I just got bored with the extra time the engraving takes with the expander on it so I went looking for the age old earthing problem and finally found it.

My earth wire wasn't screwed down on the wire but on the insulation around it. Missed it by a millimeter. I repaired that and now I am back up to speeds of 700mm/sec and above. 500 seems to be about the best range as any higher than that and the laser head has to move too far to the side to get a run up to get up to speed.

The extra fineness of the cut means it takes about 3 times longer to engrave due to the fine step over when engraving but the quality is there. I am now engraving at about 600dpi where before I used between 250 - 300 dpi.

I will try and get some pictures up here of the differences to show you all.

Is it worth using an expander? A very loud "YES". It's money well spent.

I have mounted mine just before the 3rd mirror on the gantry that bends the beam across the x axis. I had to realign all the mirrors so the laser was almost perfectly in the middle so the expanded beam didn't hit the outside of the mirror holders and it also has to be straight and inline with the beam. If it isn't straight or parallel with the beam it tends to bend it a little and throws out the alignment. Common sense really.

When you set your focus height with the inclined card you can really see the difference in the cut width and how fine it is.

I am happy..........For now!

Rich.

Rich:

I though you would install the beam expander right after the laser tube, means that settle it in between the laser tube and the 1st mirror.

Question: after using the beam expander, was the light beam getting a little bit wider right after the focus lens? That mean, the cutting surface will get more 'slop' (incline surface), am I correct? I assumed that is true so I usually my customer to switch the focus lens to the next longer focus point. For example, if you're using 50.8mm, then I'll suggest 63.5 or 68mm instead.

Looking forward to see some pictures if available


Marco

Hi, do you gain any cutting speed (for cutting,not engraving) with narrower kerf ? Thanks

Itran: It does seem to cut a bit quicker and I can cut very fine details as well.

Marco: I had to place the expander between the 2nd and 3rd mirrors as I had no room for it at the tube output end. It fits quite well where it is and I can take it off or put it on when I like. Simple to clean and I can place a small plastic bag over it to keep the dust off it when I am finished. Also the cut slope is wider as you suggest and using a longer focal length lens would be helpful but I want fine details so I use a 55.2mm and a 25.4mm lens. I have a 3" lens but I haven't used it yet. I was saving it for cutting styrene foam or the like if I need thick cuts.

I've been a bit busy lately with my home renovating but I will get back to engraving soon.
Rich.