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

Very good writeup. I’ve been using 1.361 as my crumb tray measurement. I only engraved on cutting boards and didn’t have to worry about the lid focus measurement for placement. Will have do do some more testing. The biggest issue is not having something too thick that the air foil scoop for the air assist doesn’t grab it.

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Oh thank you so much! I only did it once and I’m pretty sure I did it pretty much the same as you (it worked fine anyway), but it’s great to have a step-by-step to refer to for next time. Otherwise I’d have to do it from scratch again.

Thanks for the details write-up!

As a father and, well, a human being, I have a ton of LEGO blocks that I think I’ll use to build stands with the tray removed. It’ll allow some pretty decent scalability I’d think. I realize they’re not a laserable material, so maybe a top layer of cardboard will be in order. Guess I’ll try it and see how it all works.

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I have a couple dozen 12"X12"X3mm BB ply on hand all the time for prototypes & POCs (after my initial attempts on chipboard) so it’s easy to slide a couple (or a few) sheets under my oversized pieces. Makes it easy to adjust the height pretty quickly.

Not unlike my K40 when I first got it (I’ve since put in a lab jack to use as a Z-axis adjustable table base) but it’s 100 times easier because if the big front door that makes crumb tray removal/replacement simple as cake.

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Nice write up! Another option is to put something rigid across to top (with the door open!), measure down to the crumb tray, and subtract the thickness of your cross piece. Then repeat with the crumb tray out.

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

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I threw out all my cheap calipers that looked like yours because they all had a bug where they would jump 0.2". Some did it from new and some developed it over time. I read that it is because they ripped off the Mitutoyo design but got something wrong. I bought a couple of genuine Mitutoyo ones at great expense and they work very well. Unfortunately they don’t do inches, so I really hope GF will support metric units. Otherwise I think it will be the only non-metric equipment in my home apart from a few expansion rulers and a micrometer I inherited from my father. Everything else is either dual or just metric.

Why do you need to enter a material thickness? I thought GF currently measured it with the head camera for auto focus. Can it not measure it with the crumb tray removed? It isn’t really thickness, it is actually the Z position of the top surface.

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I’m gonna have to reread that , but thank you sir. I believe I just learned more ,and I am mathing again. YAY

You are correct it is the Z of the top surface, but you enter it into a field called material thickness, so that seemed easier to use.

I believe (since that is when you see the effect) it is for the lid camera to determine the size of the object for alignment.

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Seems to make the auto focus pointless if you need to measure your sheet and enter it first. I don’t see why it can’t get a rough image of the object with the lid cam, accurate enough to send the head camera to measure its thickness and then correct the lid camera image for that thickness.

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You enter material thickness only to correct the distortion for the lid camera. The image is significantly different if the distortion is adjusted with an incorrect assumption of material thickness. The actual material thickness measurement from the head is made after you have optically positioned the design over your material. Yes it could be done automatically if the unit knew where on the bed you wanted to take a measurement. It doesn’t, so it can’t.

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Good idea, and seems trivial to indicate the desired spot in the GFUI. Paging @Dan - can we get that in the hopper?

It does give a crude image (parallax distorted of course without depth), you still need to do the above calculations to make sure you are in the focal range of course, but yes we could eliminate typing it in.

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Yes although you could make a pair of depth gauges to judge the gap to the head is in range, which is the way cheaper lasers are focused.

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Shars sells some nice middle of the road calipers that seem to be accurate, display metric and Imperial units, and some models have a large display for aging eyes. The main issue I have with them is that you have to press the on/off button to power them up and some brands will power up when you move the jaws.

http://www.shars.com/products/measuring/caliper

Same number of steps whether you enter thickness at the beginning or you enter position for the head to take the thickness. There is no way for the S/W to figure out where you want the design cut until you overlay the design. Easier for me to remember the material thickness for stuff that I have already used than it is to measure an X,Y every time. And you can’t place the design over the image until you have a good undistorted image, which means you would have to wait for the head to measure the thickness before placing the design, and if it measure in the wrong place on non-flat material or material that already has been cut then the material thickness is off.

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Hopperized! (cc @Tony who has been thinking about this experience)

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Great idea for a sanity check. Not a gauge from the lens, but more easily from the case bottom. I’ll get that out ASAP. Thanks for the suggestion.

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I’ve started a topic aboat calipers, in case anyone wants to put in their two cents…

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Great post.
I have a good supply of 3/4" goods, and measurements led me to 1/2" blocks on the bottom with an 1/8" shim on top supporting the 3/4 material, and telling the forge it’s looking at an 1/8" puts me in the ballpark.

With Dan’s assurance the tray dimensions are final I decided to bang out a platform of that I can drop in when I am addressing 3/4" material.
Kind of a go-nogo gauge from the bottom with increments like @dwardio’s that will land me in the focal range will be a handy project.

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Another post that has saved me a ton of time today. Thanks! Put it all in Excel so I’m good to go in the future. I’m an accountant so Excel is what I know… :slight_smile:

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