Great write-up and it will come in handy in the future. I have a question though… a few days after I got the unit I was asked by a friend to engrave a large piece of wood, I posted about it in the forum (titled “Will it fit?”). The thickness of the piece of wood never came up in that post.
Long story short, I put a 1 7/8" piece of wood in the glowforge, entered the thickness in the uncertified material spot and it seemed to engrave it just fine. didn’t pop up any errors because of the thickness or anything. any thoughts on that?
I put in the total material height and did not adjust for the crumb tray being removed. I thought the machine and software would “sense” that the crumbtray was removed and figure out the difference magically
It kind of does. As I understand it, the “material thickness” you enter in the “use uncertified material” dialog is used to adjust the camera distortion to allow you to place your design accurately. If you put the wrong number in there, it will increase misalignment between what you see on the screen and where it prints, especially further from the center.
But the second thing is focus, which is entered in the “focus height (in inches)” box for each cut/score/engrave step. That height defaults to the same thing you put in the Material Thickness field, with one strange caveat: if you never touch the number, it will actually ignore what it says in the box and use the red laser to scan the height and auto focus. But if you change the number, it will ignore the laser auto-focus and use the focus height you set.
The practical upshot is that as long as you got your design close enough to where you wanted it and didn’t worry about camera alignment too much, the focus may have been done automatically even if the “wrong” number was entered.
That’s the way it has been explained many times, although I find it a super confusing way of designing a UI.
speaking of cutting without the crumb tray. Say I want to cut all the way through some 1 inch thick foam… what would you guys recommend putting underneath the foam? assuming I can cut through 1in thick foam.
a half inch (+) of wood - like a couple or three sheets of 1/4" Baltic Birch. That gets you in focal distance without bumping the head and if it cuts through (it should), you’ll be hitting the sacrificial wood and not the metal base plate.
Based on this write up, is the largest items you could engrave with the Glowforge 1.8" ?
I have something I’d like to engrave but when I measure it with my calipers it seems like it is 1.85", which tells me I shouldn’t do it. I was hoping that without the tray in I could just sit the item on the bottom of the GF and just engrave away!
I figured I’d ask in case I’m missing something… Thank you!!
@henryhbk I have a GF Basic and I read in the specs we can use something that is 2” in height, but I’m not sure that is aligned to your tutorial (unless I’m misunderstanding)
I have a box/sign I purchased from AC Moore that is around 1.85” tall.
If I do the calc of:
1.85 - 1.4 (tray removed) = .45 material height.
It seems like, based on what I am reading, it will be too tall to engrave…yet the object is still less than 2” tall…
Remove the crumbtray. Put the sign on the floor of the GF. Enter 0.45" for material height. The max material height entry has been increased to 0.5" since this topic was started back in May 2017.
Thank you! This really gave me some confidence. I used a more rudimentary method. Use a rigid scrap to measure the top of the crumb tray when partly inserted with a mark on the scrap. Remove the crumb tray and place your piece with a riser piece underneath to lift it around 1/4" above the crumb tray height. I wasn’t cutting, just etching. Mark the height of the surface of the piece to be etched on the same scrap. Measure the difference from the first line to the second line (convert to decimal on Google) and that is the number to be entered in your material thickness! Worked great.
This was incredibly helpful. I was testing cutting on a wood cutting board without the honeycomb tray with no success. Then I stumbled on these instructions and fixed my problem. The results are beautiful! THANK YOU!
glowforge calculator.pdf (16.9 KB)
Not sure if anyone wants this, I took the steps above and created a PDF calculator that will help with your final number.
I get 1.35" for the tray height. If you pull the tray out and measure the plastic sides (which it sits on… not the legs that go down in the notch), and then subtract the little lip height between the side and the honeycomb, I got 1.35".
Somewhat minor difference, I’m not sure how much it matters.
I’m new and just got my Glowforge. Let me get this right…even without the crumb tray, the top of the material needs to be in the 1/2" zone between where the honeycomb tray sets and the laser head? Therefore, I cannot enter a material thickness with a negative number to set the height of the material if the crumb tray isn’t in place? Instead, I would need to build up the material with another object to get it to this zone? I just want to make sure that I understand. Thanks in advance… Matt
