To get focus height

[markevans36301]

Equal and opposite adjustment to how far out you are. Old marksmanship term.

[mad_macs]

Yah. The focus and alignment processes are shockingly behind in development. If there is anything that will make me pause over the “accept your Glowforge” button, autofocus and head camera alignment are them.

[rpegg]

Yeah, the engraving is very forgiving. The cuts need to be precise only if you are trying to get through material precisely without over cutting/charring.

[Clone]

@mad_macs

Yah. The focus and alignment processes are shockingly behind in development. If there is anything that will make me pause over the “accept your Glowforge” button, autofocus and head camera alignment are them.

total understatement its not fun at all … and I think they are going to leave it that way to make anything but PG super annoying to use

[mpipes]

1.95" is the max height from floor to bottom of the air assist fan, I factored in about .010" of clearance from the fan based on dimensions from my unit.

Floor to bottom of Head: 2.73"
Top of Bed to Bottom of Head: 1.34"
So 0.00" (top of bed) = 1.39"

So focus height = (Total material thickness) - 1.39"

I’m seeing a .400" max focus height so that makes max material thickness = 1.79"

[Clone]

so 8 sheets of PG ply as shim + .75 (stock to engrave)= 1.75 - 1.37 = focus of .38 focus ?

[mpipes]

Yep.

Wait, no that’s .36" (1.39" not 1.37") but the .02" isnt going to make a difference.

[rpegg]

I’ve seen the 0.4" max focus from your earlier posts. Not sure why yours would be different from mine. I have always been able to type in 0.433" for focus/material thickness. Just did it again to make sure nothing changed. Have seen the same 0.433" from a couple others.

[Clone]

would be nice if GF would just give us the official numbers (after all they have the design specs) … but guess they don’t support that … /sarcasm /annoyance

[mpipes]

I just double checked, and you’re right. Max focus height is .400" while using PG materials, but once a custom material thickness is entered (and I can use .433" there) then the focus height can also be bumped up to .433".

I just havent done much with thicker materials, and I remembered running into the .400" limit mostly because I was trying to widen the kerf for a project.

[PrintToLaser]

Seems to me without the tray in place we are doing something that is neither recommended or supported. It’s just possible. I wouldn’t expect much help from glowforge to enable it, considering the skittish nature of lawyers.

[Clone]

lawyers is a copout on this

if it was evil then it should be permanently attached and not documented anywhere as to having capability or capacity to do it

[newbies_234]

There really shouldn’t be any need for guessing at all here, the laser has to know where 0 is in order to focus up from that, in order to do that the trays must be all the same height, or within a tolerance the laser can adjust for. If every tray is different, every focus would be different and the streets would run red with the blood of 1000 sacrificed proof grade sheets.

So uhh, can we get the official tray height?

[jkopel]

In the tutorial thread @henryhbk measured the height as 1.4".
Later in the same thread Dan commented

Tutorial: How to cut without the Crumb Tray (Honeycomb)

The crumb tray dimensions are pretty much the same between every 'forge and unlikely to change, so you can crib from @henryhbk’s homework.

[caribis2]

@PrintToLaser

Seems to me without the tray in place we are doing something that is neither recommended or supported.

If that were the case the FNL would have insisted they add a hall effect sensor and not allow operation without the tray installed. The doesn’t work if the software team doesn’t know the zero-point distance. Rather than let people measure, and wind up with these threads, they could simply say the top of the tray to the floor of the unit is x.xx inches, the rest of the math(s) is up to you. Or if that simple, but very important, detail was overlooked, chiming in with a “yes, the height measured by mpipes matches our drawings.”

[paulw]

@mpipes

1.95" is the max height from floor to bottom of the air assist fan,

If you really like to live dangerously, you can put in taller things as long as you don’t engrave/cut more than about 3" from the “top” edge, so that the air assist vent never tries to run over the material. I do not recommend this myself.

[scatterbrains]

@caribis2

chiming in with a “yes, the height measured by mpipes matches our drawings.”

See comment above yours and substitute henryhbk for mpipes.

[chris1]

@newbies_234

There really shouldn’t be any need for guessing at all here, the laser has to know where 0 is in order to focus up from that, in order to do that the trays must be all the same height

Doesn’t it measure the height before it starts printing? I thought that’s what that scanning step was where it goes over and boops it with a red dot. I understand continuous autofocus isn’t ready yet, but single point focus is a thing, no?

So why can’t it just measure the height, crumb tray or not (as long as it’s within min/max range)? Is this something that’s deliberately disabled for non-Proofgrade materials?

[kennethclapp]

Actually, that’s not true. They advertise the max material thickness as 2", or 1.5" or whatever. That assumes no tray in place. It’s advertised as a feature by the company, not a hack.

[rpegg]

Unsure what it is doing internally when trying to measure material height on non Proofgrade. But either way the UI requires you to put in a material height for non-proofgrade before you can Print. It uses that number to correct the bed image. Without it, design placement is way off. Not sure why the scanning step doesn’t do this earlier but hey, I didn’t write the UI.