When and Why to Print without Crumb Tray

[simplygage]

Could an experienced user provide the details on when and why someone might want to print without a crumb tray?

[dr.krawetz]

Well, I can’t speak for others, but I have only needed to remove the crumb tray when doing tall items.

The crumb tray only give you about 0.5 inch of vertical height. Removing it gives you another 1.5 inches. If you look through the forum, you’ll see different people have posted jigs for raising objects. This way, you can have something taller than 0.5" but smaller than 1.5" and you can lift it up with the jig so it’s at the same height as the crumb tray.

[simplygage]

okay so if an item is say 1.6” tall- no riser needed?

what if i have a small bowl that is 1.4” tall but i want to engrave bottom of bowl?

And based on your explanation, is it safe to assume that the distance from the laser to the object being engraved should be about .5”?

[GaryZ]

This post (and the file attached) are handy:

No-Math Focus Ruler

Leveraging the recently-released Set Focus tool, I’ve designed a tool to help place materials when the crumb tray has been removed, no maths required. If your material is between the lines while resting on the bottom of your GF – not the crumb tray, you should be able to use Set Focus in the UI. If the top of your material is below the bottom line, use your favorite method (sheets of PG, tiles, 3-D printed stands, matching sets of trained hedgies, etc.) to elevate it and recheck. Repeat until …

Cut the ruler (best from clear acrylic, so you can peer right through it) - it’ll show you the zones where you can and can’t work without the tray. Get the top surface of your material in the “OK” zone and use the “Set Focus” tool in the GF interface and you should be golden.

[dr.krawetz]

Here’s the tech specs: https://glowforge.com/faq/tech-specs

The maximum height with tray is 0.5".
The maximum height without tray is 2".

There are different jigs out there. I made some risers that support any height in 0.25" increments.

With the tray, the laser head has about 1" clearance. So if the sides of your bowl don’t rise higher than 1" above the tray, then you should be good to go. Without the tray, you’re good with 3" height for the bowl sides. However, I don’t think the laser can focus that far down.

The top of the crumb tray is considered 0" height. I’ve heard of people lasering a quarter inch below the crumb tray (focus height: -0.25"), but I’ve never tried it myself. I don’t think it can focus much below that. (If I’m wrong, I’m certain that someone with more experience will correct me.)

[eflyguy]

@simplygage

what if i have a small bowl that is 1.4” tall but i want to engrave bottom of bowl?

If you’re talking about engraving down inside of a 1.4" bowl, you can’t. The laser can’t focus down “inside” an object beyond ~0.75" from the base of the head.

If you’re talking about engraving the underside, however, then you would just need to elevate it slighting to fall within the range of focus.

[simplygage]

perfect. that too is what i was looking for!