Can PRU borrowers make modifications to their machines? (evolved into camera focus and material height discussion)

[dan]

@Hirudin

So, with the (not affecting performance, non-destructive, reversible, easy to identify, and easy to correct) screw situation, the user would be expected to wait to be told to tighten it up? To put it a different way: anything beyond putting a ring around the button is verboten without the “go-ahead”, right? That is routinely my policy when I lend things out.

As I write this I can see that it could be coming across as a “gotcha question”. That’s not my intent. I’ve just been curious a couple times since the PRUs started being shipped and didn’t want to interrupt other threads to ask the question.

No worries! In practice we handle this on a case-by-case basis.

@henryhbk

I had this exact scenario. Since the purpose of PRU is to debug production I specifically didn’t just tighten the screw, since clearly support needed to understand why a screw with blue-gunk came loose to make sure final production models don’t have this issue. I even ended up bore-scoping to see what happened on the inside since it was behind something so you couldn’t directly see if anything was loose, for support, and then at their instruction simply tightened it back up after all their debugging.

This was kind of awesome when it happened. Pictures of problems make our lives much easier.

@soldiercoleman

why not have an option for the head to come over and measure material height if the user needs a more exact optical placement?

Great suggestion for the hopper! (cc @tony)[quote=“rpegg, post:19, topic:7739”]
is the overhead camera actually refocused or is the lens a fixed focus?
[/quote]

The lid camera lens is fixed focus.

@rpegg

I knew from comments that the camera could be focused by messing with the mechanical focus ring (not an approved adjustment).

The lens should be glued in place. You can permanently destroy the camera by adjusting it (depending on how well stuck it is), so it’s something we only do if it’s critical.

@takitus

It doesn’t change focus, but it does make a change to the way it corrects for barrel distortion when you change the material height.

Correct.[quote=“Hirudin, post:29, topic:7739”]
I’m looking for the height from the top of the bottom of the Glowforge to the bottom of the bracket that holds the head. I’m just curious about the maximum height an object can be before it’ll physically interfere with the movement of the head.
[/quote]

The lowest point is actually the air assist fan, tucked away behind the head, not the carriage plate directly under the head.

@rpegg

it’s not really the head that you need to worry about, it’s the air assist port that is much, much lower. The bottom of the head is just over 1-1/4" (31mm) to the top of the crumb tray. But the air assist port is only ~0.51" (13-14mm) above the crumb tray.

…wait, what he said.