Getting around auto focus override glitch?

Beyond the Manual
#1

How do I get around the auto focus override glitch?

Specifically where the machine ignores the material thickness & manual focus if it’s too close to the auto focus reading?

My laser consistently cuts very poorly on all dark materials and I’d prefer not to mask the entire surface with masking tape every time. Keep in mind the same settings for the same material (but brighter color) will cut consistently every time.

The laser (IMO) should not even run the auto focus before cutting if I’ve manually set it for each cut.

I now have to build into each cut a series of bogus cuts just to see if the dang thing is going rogue.

#2

Just set one of them to be 0.01" or so different from the other.

The laser (IMO) should not even run the auto focus before cutting if I’ve manually set it for each cut.

Absolutely correct. Causes a blood pressure spike every time I click the PRINT button!

2 Likes
#3

I’ve tried that and still not consistent… I’ll try more. This is a terrible flaw.

Edit It still won’t come close to focusing correctly when the material thickness is set to 0.06 and the cut height is 0.058.

1 Like
#4

What if you use set focus instead? Just mask a small section to focus the red dot on?

#5

I’ll try that, good suggestion.

1 Like
#6

That sounds like a different problem unrelated to respecting your manual Focus. Unless your system acts different than everyone else’s and how it’s intended to work. While it will still do the scan, it should always respect your inputted focus height if that value is different than the material height.

If you are getting varying results (out of focus with manual focus height), it could be a mechanical focus problem with the lens, material not consistent, or something with the crumbtray giving varying material height (distance from lens)

4 Likes
#7

Thank you all for your help.

I kept lowering the focus height as I had suspicions that it was focusing much higher up, this appears correct.
Ultimately I’ve gotten the best, as well as consistent, performance at a focus height of 0.00 and thickness to 0.059. I does appear that if I could focus at a negative height (perhaps I can) it would actually improve a bit more. I’ll look into fake cutting without a crumb tray tomorrow.

I did try doing the set focus on a piece of tape (verifying each time) before every test cut as I lowered the focus. I can’t say if it helped in any way or not as I’ve not tried without it. I ran out of time and beggars can’t be choosers tonight.

As for it having a mechanical issue… it may that and it may be isolated to small thicknesses (less than 1/8") because it cuts 1/8" acrylic perfectly every time and I’ve run hundreds of new plates through it.

#8

Can you throw an example picture up of what your cutting lines look like?

If it’s cutting 1/8” perfect though and not anything thinner, it definitely sounds mechanical to me.

#9

image
image1380×514 192 KB

#10

In speaking with IT they are trying to figure out how to make manual settings actually be manual but they don’t seem to know yet.

Currently when I use set focus it only is applying to the first layer cut. If I only cut single layer images I guess I’d never know but I do and set focus doesn’t work because the system is overriding it.

The only fix currently, since set focus does not work as I would expect and since manual focus is perpetually overridden by the auto focus, is to cut one layer at a time and cut each layer as a brand new print.

Bottom line is Manual isn’t manual and Set Focus is very temporary.

#11

Still trying to figure it out, IT is trying there best…

Set Focus only applies to the first layer because it needs all layers set to Auto to apply to all layers.

Since I still have the manual settings listed (using a preset) it overrides the first layer then goes to Auto Focus in a random spot (a key problem) and overrides the following layer’s presets before continuing with whatever thickness it thinks the material is.

Oddly enough, we know it defaults to Auto Focus if the manual settings are too accurate but it would seem there is a similar default to Auto if the manual settings are too far apart. Beings it’s focusing considerably too high and and we know it’s not reading thickness correctly I would have expected it to default to manual settings (big enough perceived difference) but it’s defaulting to Auto Focus instead.

#12

I should add, I can’t save a new preset with “Auto” as the focus height… it says Auto, I save it… then when I go back in I discover it’s simply changed it to 0.05" every time.

#13

Don’t know if this helps, but it’s the explanation for the heirarchy of choices that the software makes for determining focus point:

2 Likes
#14

That’s a disappointing validation of what I suspected I was experiencing.

Really defeats the point of a manual setting when all the if/then statements point to ignoring it. Perhaps a change in the future or some rational that helps others and not myself.

Perhaps I can tape over the sensor forcing it to throw an error and use my manual settings!

#15

Well taping over the sensors didn’t seem to force a manual mode as far as I can tell or caused a secondary issue.

Waiting on IT as I’m also getting a generic error and request to refresh Chrome browser that keeps coming back. Apparently this surprised them and who knows, may be the key.

#16

IT helped fix the error, just unplugged the head unit and plugged back in.

They have also been very diligent at trying to help.

In a possible stroke of luck discovery it appears the Set Focus is failing somehow.

Two print attempts ran identically except one used Set Focus (red) and one used Auto Focus (green).

Both used the same masking tape to measure and only ~2" apart. Waiting to have IT analyze both runs.

PXL_20201110_140339674~2
PXL_20201110_140339674~23024×4032 1.55 MB

#17

very helpful. thanks

#18

IT really did their best to help and had several back and forth interactions with them. I was hoping the manual process would have more control and I think a software update complicated what I was trying to do.

What has worked (for the most part) was to put a piece of masking tape in the center of the cutting image, since the auto focus would scan that spot, manually enter the thickness. I ended up lying on the thickness as I got the best cut at 0.01 vs. the reality at 0.065. I also set the focus for 0.01 because even the slightest difference in focus height would cause very unfocused cuts.

Oddly enough I can no longer cut using any of the previous methods that worked… so this is what is working now. I’m keeping all my previous notes incase it changes again.

Also an odd change. the maximum speed I can cut material at has change repeatedly with each of these updates. Currently I can successfully cut at a speed of 145 while at it’s best I was easily cutting at 220. I assume this has to do with a software change, perhaps things were turned down to prolong the equipment life.

At this point it’s cutting consistently and has been for several weeks so I’m not touching it (o: