Auto focus probe broken :(

[Peter Boyford]

I own a GCC Mercury and have been very happy about it's work so far. But today things went differently.

I started the machine as usual - jogged the auto focus probe to ensure troublefree use and pressed "Auto Focus".

To my great dispair the laser table just kept going up after having activated the probe. A crunchy sound was heard before I got to turn off the machine.

Luckily, nothing bad happened (as far as I could see), but the probe just wouldn't activate. Not even by manually pushing it while auto focusing.

Have anyone had this problem - and been able to fix it?

Best regards
Peter

[Angus Hines]

It's a 35.00 part from SignWarehouse....Plug and Play.

[Vicky Orsini]

Exact same thing happened on my Explorer ... twice. It's the wire that rides in the carriage behind the head. It gets frayed as the head moves back and forth. I simply can't trust it anymore, because it's fully enclosed so I can't see if it's frayed at any point in time. So I go with manual focus at all times now. I've actually removed the AF probe to give me a tad more clearance on rotary items (like beer mugs ... those handles are scary!). Manual focus takes an extra second or two, nothing detrimental.

[Richard Rumancik]

Well, I have strong feelings about the autofocus. After a couple of accidents like yours I retired it. Some people are happy with it but it could cause a serious damage, and with no emergency stop you have to be quick on the power button to avoid damaging the laser.

[Peter Boyford]

How exactly do you guys manual focus? Trial and error?

[Richard Rumancik]

You should have received color coded aluminum manual focus probes (not sure what GCC calls them.) There is a blue one for 1.5" and 2" lenses and a red one for 4" lens. You place it in the hole on the side of the carriage and raise the table till the probe tip touches the face of the material. I usually watch the gap at the top of the probe (where it seats) as it is easier to see. You can move the carriage around manually and see how level the material is.

You could make your own probe with a short piece of rod and a shaft collar with a setscrew. I could give you a starting dimension by measuring mine.

If you want to laser out-of-focus, above the workpiece surface, you can place a shim on the workpiece before focusing. The shim thickness will dictate the focus offset.

If you want to laser out-of-focus, but into the surface, you can place a washer on the manual probe before inserting. The washer thickness will dictate the offset. This will make the probe appear shorter and so the table will rise more (thus you are engraving into the material.)

If you decide not to replace the broken focus probe you may need to disable the autofocus circuit so that it cannot attempt an auto-focus operation. Otherwise you will have a crash again if the autofocus button is accidently pushed (and it will be.) If you need help on this let me know.

In some cases, people lock the autofocus probe up high out of the way (to clear a fixture, or when using the rotary). This is a dangerous condition as activating the autofocus button will cause the table to rise, it won't find the probe, and will crash.

You might find that because of tolerances the factory manual focus probe length isn't exactly right for your lens. To fine-tune it you may need to do some trial and error marking. I believe there is a setup procedure to program the laser to correct for probe errors but don't have the info handy. It should be in the manual.

[Angus Hines]

I dis abled mine and then I put a piece of 1/4 acrylic under the limit switch to raise it just enough for, No more crashes.

This is my recommendation lose the auto focus it will give you more flexibility in your project designs.