Insights about open lid error

I have the common problem of a GF that says the lid is open when it isn’t. Like many of you, I have tried every test and fix that I could find out there, and was very thorough. One problem is that the forum topics are closed so fast that I could not see what happened with other people in my situation. I opened a topic with the intention of sharing my full experience, but it was closed on the second day. Once you start emailing the support staff, they will close your thread, which means that most of the trickiest problems and solutions are taken out of the community space.

So I will just tell you that, for me, it seems to be a problem with the black lid cable. They have a life span because they flex. The black cable on the lid doesn’t have to break in any visible way. It can just be flexed too many times, and the lid can stress it too much just by being too open. I was trying to fix a different problem, and so kept opening the lid a little too far in order to have more space.

The support people offered me a $20 replacement at the time of this writing. Sending it in would cost at least the $200 shipping charge. I have read from others that the new machines have slightly longer black lid cables to avoid this problem.

The other really common problem that I saw a lot was that people didn’t realize that their front door wasn’t closed properly. There can’t be crud or anything else messing with the front door closing.

I myself had a lot of temporary fixes, but if it’s a connection issue, the problem seems to get worse over time. No amount of re-plugging and cleaning will help after a certain point of wire damage within the cable. Hope this helps someone.


It won’t avoid the problem. Replacements have failed as well.

The cable is made from a material that holds its shape when flexed. It has thin and narrow (~0.1mm) copper traces printed on it. In my opinion, it is a poor choice for the lid-case connection and we can all expect that cable to fail at some point.

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I think that the leading problem is the choice of the insulation material. I have ribbon cables with just as many thin traces in my 3D printers. They undergo thousands of bends every print and I have never had one fail. I suspect that the thick, stiff insulation on the cable has brought the bend radius away from the traces to the outside of the insulation. This will put tension on the traces and lead to failure much faster than simple flex cable. I also think it is possible that the tight bend radius at the anchor points is contributing. My experience with this type of cable points to the insulation more than the inside traces or wires. It may be that some of the traces are thicker than standard to carry the LED current which is leading to higher stress.

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I am not a metallurgical engineer but I can tell you that flexing metal will work harden it. Eventually the point of folding will fail.
I know zero about the construction of ribbon cables, but my horse sense would tell me that a stranded conductor would give the desired service as opposed to a solid conductor or a thin trace.
That’s my argument from ignorance.

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It depends on the metal. Copper and its alloys are work hardening. Some steels are also work hardening, but not all. The idea is to keep the metal in its elastic deformation state and not move into the plastic deformation area which is where the work hardening starts.
The goal with a cable is to keep the bend radius large relative to the thickness of the wire or trace. Most cables that are made up of multiple strands of wire will have a bend radius of 12x the diameter of the cable. A flat ribbon cable might have a total thickness of 0.015 inches. This means you can get a very tight radius without damage because the amount of bending in the actual wire is within the elastic deformation range of the material. The other way this works is the thin flex cables have a very small distance between the sheath and the conductor, so they act as one unit during bending and there is little to no pull on the individual conductor. When you have a thick, inflexible insulation layer the inside of the insulation is where the bend happens, which causes the conductor to stretch, moving the conductor into the plastic deformation region very quickly since it has a low cross-section and therefor low tensile force resistance. I suspect the latter is the main contributor to the Glowforge failures.


Like the one that connects to the head.


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