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While testing Juhas new DEV version I encountered a dangerous flaw in the Z axis control.

What happened?

I had the needle above the camera hole and accidentally activated the needle height calibration.

Usually the Z axis moves down and the lower limit switch is activated by the needle beeing pushed up from the table surface or the PCB.

But over the hole the needle touches nothing and the whole Z axis sled crashes on the rim of the camera hole!!

Due to the fact, that during homing to upper Z position is defined a security height should be used to define how far the Z axis may move during needle height calibration

Hi Mawa,

Thanks for sharing this warning with us, maybe it's an idea to protect the camera lenses by a piece of glass or transparent PVC?
Glass will not scratch that easy, but might break if it's not thick enough.
On the other hand, I believe software can protect our hardware also to prevent damage.

mawa wrote:But over the hole the needle touches nothing and the whole Z axis sled crashes on the rim of the camera hole!!

I put plexiglass over the upcam to prevent this. The top surface is flush with the table.

did Plexiglas solve the problem?
Recently we used lexan for an other project, this might also be an alternative material.

RinusDamen wrote:did Plexiglas solve the problem?

Yes, although I've more recently replaced it with real glass. Lexan/plexiglass/acrylic claim to be "scratch-proof" but in reality the scratches are just too small to see with the naked eye. But the webcams can see them.

Real glass works much better.