View Full Version : Versalaser spot size is now bigger

Harry Radaza
04-27-2008, 11:21 PM
my versalaser ULS V300 30 watts is about 2 years old now. It has been working well. Did change the lens about 6 months ago.

I only noticed about 3 weeks ago that the spot size of the laser has gotten bigger. Thus resulting in bigger marks when cutting and engraving. I have always used manual focus so it cannot be an auto focus problem.

All lenses are clean. Any ideas >?

Dan Hintz
04-28-2008, 7:13 AM
Dot size is strictly due to the lens, so....

Mike Null
04-28-2008, 7:26 AM
Are you sure you replaced the lens with the same focal length lens?

Scott Shepherd
04-28-2008, 8:22 AM
Sounds like dirty optics. If your optics are dirty, the spot size can easily double. Make sure the lens is clean. If not that, then it sounds like the focus calibration needs to be adjusted.

Peter Meacham
04-28-2008, 9:09 AM

I know on my Trotec that the lens has to be installed with the convex (curved out) side up for proper focus - any issue like that for your model laser?


Richard Rumancik
04-28-2008, 12:28 PM
Harry, when they manufacture and mount a lens there are some tolerances on the focal length. Did this change happen with the new lens and you did not notice it right away? I think you should do some tests where you adjust focus up and down from the "probe" length and see if there is a point where the beam is smaller. (Do some test cuts and measure kerf width with a feeler gage.)

Some lasers have a tuning function with autofocus enabled, where you can compensate. But I assume that if you are using a manual focus you may have to make a special probe length for the specific lens if the factory probe does not match it well.

Mike Mackenzie
04-28-2008, 4:40 PM

Richard is correct when you replace a lens you may have to re calibrate the focus tool.

The easiest way to do this on the versa is to start with the focus tool you currently have. Focus onto the plate preferably anodized alum or coated brass. Typically the plate thickness is 0.20-0.30 so once you focus to the plate bring the table up 0.20 and engrave a line then bring it down 0.10 and engrave it again. Once you get it to the sharpest point then adjust your focus tool to the carriage. You may have to adjust the table up or down by as little as 0.001 to get the best focus distance. You should be able to get it calibrated in about 10 minutes or so. Just engrave one line of text and then move the table up or down and once you get the best engraved line then adjust your tool to that position.

Rodne Gold
04-28-2008, 4:41 PM
Most likely alignment has changed over time , if the beam does not hit the lens at the right angle , the spot size will change.
Do a beam alignment and see if that makes a difference.

Harry Radaza
04-29-2008, 12:15 AM
well you guys are all right. It is just the focus. after using the manual focus we experimented and found out that we had to do SIX ( 6 ) clicks UP to bring the table up and get the spot size that it was before.

What baffles me now is how this came about? There is nothing missing from the cutting table.

Could it be the alignment that rodne talked about? How do I go about checking that?

Mike Mackenzie
04-29-2008, 12:58 PM

This is not UN common when you change lens the mfg of the lens have a tolerance that they must keep however there are also the MFG of the brackets that holds the lens. Any slight difference with either of these parts could have this effect.

It also could be that the Z axis on the system needs to be re calibrated. This is an easy process I will see if I have a pdf that I can post here for you. It might be too large to post so if you would like me to e-mail it to you let me know. You can send me a PM with your e-mail add.

Harry Radaza
05-01-2008, 1:22 AM
hi mike. thanks for that recalibration for the Z. I would definitely need it. Just email to hdradaza@yahoo.com

we noticed something else today. Using the 2.0 lens we need to click 6 steps up. Installing the 1.5 lens we need to click 12 steps down.

now this is really getting weird. And yes I was using the appropriate manual lens focuser (2.0 and 1.5 lengths).

Rodne Gold
05-01-2008, 7:41 AM
If alignment is out , the beam strikes the focussing optic obliquely and the focus point changes see diagram (it's very simplistic but it illustrates the point) , I still think you should check alignment.

Harry Radaza
05-01-2008, 8:41 AM
hey rodney, that drawing makes sense as to why it turns out to be different z focus on different lenses.

how to I check alignment and recalibrate it? anyone?

Dan Hintz
05-01-2008, 8:44 AM
If alignment is out , the beam strikes the focussing optic obliquely and the focus point changes see diagram (it's very simplistic but it illustrates the point) , I still think you should check alignment.

While I understand your pic is an extreme for illustration purposes, that kind of beam change would be due to the final optics being tilted in the holder (something that may not have been clear in the description of the problem). Any beam offset that would be problematic enough to prevent a good spot would result in the beam never entering the optic in the first place and heating up the flying head. That said, I would suggest the OP check the final optic is seated squarely.

Rodne Gold
05-01-2008, 9:27 AM
As I said , its simplistic , but one has to remember that the beam that strikes the optic is coherent unlike normal light and its diameter is much smaller than the optics diameter, so the conventional lens that collects all light that hits it and focuses it type scenario doesnt really apply.
If you think about it , a misaligned beam will cut with a slope , if the beam slopes , the focal point has to have changed and the impact/spot point will no longer be round , it will be eliptical.
The fact that spot size is changing and that focal lengths are variable with respect to a focus tool point to some optical misalignment. At the very least , an alignment will assure you that you are getting max power and will assure the power delivery is constant all over the table. 2 years of use what with taking in and out mirrors for cleaning is pretty much begging for at least an alignment check.

Mike Mackenzie
05-01-2008, 12:22 PM

I will e-mail you the instructions on how to check the alignment and to re calibrate the Z axis. You will do this for each lens you have. I will try to get it to you by this evening.

Mike Mackenzie
05-01-2008, 12:52 PM

I am not sure how your systems get aligned however all of the ULS systems have a fixed 90% mirror mounted above the lens. So the beam comes straight down. In your diagram this mirror would not be perfectly set to 90% if you get the angle you are describing. This would not be the case on these systems. The alignment adjustments allow for the beam to adjust up and down and left and right. There really is no way that the beam would change the angle that it hits the focus lens unless the lens itself was incorrectly mounted or the surface was not properly ground. The possibility of this is slim especially with the problem happening with both lens.

Rodne Gold
05-01-2008, 2:01 PM
Oblique is probably not the right word and my diagram is too simplistic, if the beam does not hit the focussing optic dead centre , which can easily happen with a fixed last optic , the lens does not work as it should and bends the beam. The focal point thus changes and the spot becomes eliptical as the cone described by the focus becomes oblique or slanted and when it hits the flat object its focussed on it loses energy as the spot size becomes bigger for the same energy.
Apart from that , if the beam is not 100% aligned , the beam wanders about the focus optic as the head changes distance in the X and Y direction and the spot and focal point vary with that making the engraving or cutting somewhat inconsistent. You would see that if you have a red dot pointer and move the head about the table , the red dot pointer will not hit the last fixed mirror at the same point all the time as it moves (assuming the red dot pointer is aligned with the beam)
The problem is actually with the lens itself , the types we use are generally very simple lenses , plano convex and arent ground to cater to a beam hitting it at anything other than dead centre. Heres a better diagram. The ideal situation woud be if the lens diameter would be exactly the same size as the entry beam diameter , but this would mean that alignment would have to be 100% spot on all the time , impossible to achieve with these type of lasers with their multiple mirrors and mirror mounting systems.

Rodne Gold
05-01-2008, 2:14 PM
Ideal lens scenario

Harry Radaza
06-28-2008, 1:51 AM
I just recently noticed that under my driver ... VL300 ADVANCED DRIVER
Under Advanced tab, there is a a setting that says

Tuning.... -15, 0, +15

It was set to 4. I dont know why. Could this have something to do with the z axis setting?

Scott Shepherd
06-28-2008, 9:51 AM
Tuning has nothing to do with the Z Harry. I seem to recall reading in the manual when we first got our laser that it should be a value in there, so I'm assuming the 4 is a valid factory setting.

Tuning helps refine the burning (as I understand it). When the head travels back and forth, the motion is to the left, then to the right for the next line it burns. With every laser, the beam has to ramp up and down before it turns on and off. If the head is moving at 140 inches per second, and it needs to fire at X 8.000, and it's coming from the right to the left, then at some point, the beam has to be turned on prior to the X8.000 position, since the head is moving at 140 IPS. Otherwise, the burning would start somewhere less than 8.000. Now, on the same note, go to the next line in the burn, it needs to stop at 8.000, and it's coming from the left to the right, so the signal to stop burning has to coming prior to actually hitting the X8.000 number on the encoder.

It's really clear when you're doing ascenders and decenders on text, for example the lower case "g". You can run into problems with those areas since it's a small area and it's burning one line from the right, one line from the left.

If you look at most engraving done on a laser under a magnifying glass, it you can clearly see a pattern. The edges of every other line are lined up, but the one's in between are shifted a little. This comes from the left/right burning.

Tuning allows you to adjust for each material (materials are all different) and you can tune the burning so that there isn't this mismatch. If you look at the burning after it's been tuned, the ends of the lines will all be dead in alignment.

That's the way I understand it. I've tuned a handful of materials and it certainly makes a difference in quality.

I could be wrong about the tuning in the "System" area of your control panel, but I think it's all similar. I'm sure someone here knows exactly what that one is and can expand on it.

David Lavaneri
06-28-2008, 10:54 AM
This is kind of on topic.

I had a friend engrave some coated aluminum for me and I noticed the vertical lines of the image were wider than the horizontal lines, making a Helvetica Regular look more like Helvetica Bold.

What could cause that?


David "The Stunt Engraver" Lavaneri

Scott Shepherd
06-28-2008, 11:03 AM
I've seen that happen with a dirty lens.