I only bet on blue.
So we have a few things to do on the list for the large laser, Anything else anyone can think of?
- Repair/replace 3 prong male connector
- Add medium strength blue loctite
- Calibrate Laser to new sensor
- Level the front to back Z axis (off by .2 aprox degrees)
- Replace the pneumatic cylinders, so the door can finally stay open…
hydraulic*
Have certification classes.
Good work to try to get it working again 
This will work for a bit, but as Bill said this was the original type of sensor that came with the machine, and this type of “touch” sensor had some issues on laser cutters. Unlike the “touch” sensor on the CNC that is removable afterwards, this sensor will remain there while cutting. It runs into materials and ruins cuts because it dangles too low for any type of uneven material, and shifts the material mid-cut. And I’m not talking super crazy warped wood, we’re talking a couple millimeters of difference. The other reason why we wanted to go with that other non-touch sensor type was because it is the same as the little laser, making the machines easier to transition from learning to use one to both, since they are exactly the same.
Also there /should/ be another sensor of the “non-touch” type down there (the one that was on there before). We had a spare, not sure where that is though. It probably would be in the boxes of parts on the machines.
Sorry I haven’t been following every thread closely on the list, so I could have helped out sooner. We’ve had a lot of traffic here and on leadership email lately (over double the regular amount in the last couple months). It’s hard to keep up with so many discussions!! 
Anyhow, thanks for taking the initiative to get this working again! It sat for a long time because a lot of us were just too busy to do it! Well done. It’s always nice to have a functioning machine. And in the process I bet you learned a bit about the cutter that you didn’t before
I wonder if we can retract the sensor or put an offset and use a spacer.
Be fun to look into.
Brad
Could it be possible part of the issue you are describing was from an un-level bed as well? I mean the bed was off by more than a few millimeters(even before I made it worse, but leveled it out again), Never saw it happen before. Just a thought…
I left it in it’s factory location, The sensor is indeed adjustable, we can raise it up. We could raise it up to the location where laser nose is located and calibrate it to the new location.
OTOH I am not quite sure how you would manage to appropriately use the induction sensor and the 4th axis which was also purchased for the machine from what I understand, but I suppose there is a lot I don’t know about the machine to be fair.
There are two induction sensors, one is still on custom mount the other I believe is located in the laser cut box on the laser.
Andrew,
I meant things I could fix lol.
Brad and Elly,
Here is an example of what I described in my last post.
https://www.youtube.com/watch?v=zk1pqGYNfjI
Okay, I’ve actually looked at this on the bench and here’s what I see,
The prox sensor failures were due to an electrical issue in the laser, not the sensors. I will spare you with the transistor theory and bridged impedance, but if we simply tie a 330K ohm resistor across any of these sensors, the sensor will act like it wants to and the laser will see the input it wants. The issue could be any number of things (impedance is complex and weird), but I found a reliable fix, and I don’t care to debug the whole circuit. This happens a lot with these kinds of sensors and loads.
So, how about this:
- We use this sensor to get us going. It’s good to have around as a spare too.
- We use ultimaker (which is back) to make a solid Nylon mount for omron sensor. We’ll use this sensor’s cylindrical form factor so it slips right in to the collar and holds tight and level. I can whip that up.
- We have 2 omron sensors. Both might be just fine. I’ll bench test them.
Let’s get it working / leveled now, get the omron done right, and then we’ll have both options.
The 3 prong connector to the sensor was melted a bit by whomever soldered it on to the laser. It’s not really a problem if it makes good contact and the connectors are dust free & won’t come loose. Otherwise, just solder on a new one. There are numerous in the electronics parts boxes. It’s a polarized 0.1 3 terminal SIL header
Lorin
I think you could teach a class. It’s not like using the laser is rocket science, it’s simpler than the CNC.
Nice work I need to catch up on the big laser, since i’m fab lab warden now…but not even certified on it! I definitely support having some classes in the near future. Elly and I were going to find a time to get me up to to speed as instructor. Maybe we could make it on an opportunity for a few more members to become instructors too…
Tim, where did you put wiki documentation? Was looking on “Big Laser” page but didnt see it…
Mike
I believe I added to the very bottom of the page the part about a resistor. The wiki isn't loading for me right this second so I'm not sure.
When I mentioned offsetting the mechanical sensor I meant it could be shifted up the height of the special chunk of Aluminum used for the prox sensor. Then you would still set the chunk on the material then lower the laser head until the sensor (prox or mechanical) tripped. The offest would be the same amount.
I would still like to order replacment and a spare focusing optic for the laser. I missed measuring the diameter of the lens on Tuesday. Does anyone know the diameter, or know where the other lenses are? Also what is the preferred focus distance. I think 50mm is very common but you can get various distances.
Brad, I found these in the plastic boxes on top of the laser, I see a measurement of 20mm on one and what appears to be a lens.
I still have not adjusted the height as we will likely have to remove any adjustment I made when replacing the focus lens.
Bill, In the same box I found the old touch sensor, I totally see where this one would have been a problem. It has probably 3 times the spring tension on the inside. I had to press uncomfortably hard on this to get it to the point it would have triggered. The new one requires much less force. Have a feel.
Lorinn, I have replaced the 3 pin male connector, tested, confirmed it worked and shrink wrapped it for good measure.
For anyone else still reading, I updated the work log with the information from before in further detail and included a table so anyone could walk up and understand what is going on.
Sweet. Thanks for all this work.
So the diameter is 20mm do we know what focal length we want?
I’m guessing we have 2" or 50mm in there now. We could measure the distance from the lens to the focus point.
This isn’t a major priority, I think it is working, so no big rush. Since we know it’s cracked we should get it replaced though. It will also improve the overall performance for minimal $.
Thanks,
Brad
Brad, I am not an expert on this machine by any mean but with Bill's previous concern of the pen dragging on the material, I would imagine that the larger focal point would be helpful.
OTOH if we move the pen up to match the height of the nozzle, I don't think it will matter and sticking with what we are used to would be suitable.
For anyone else still reading, I updated the work log with the information from before in further detail and included a table so anyone could walk up and understand what is going on.
Tim for official Hive Laser Wizardling!
I think shifting the sensor up the height of the Aluminum block used for the prox is a good idea.
Then the setup is basically the same: place the block under the sensor and then have the table raise slowly until the sensor is tripped.
Have the correct offset in the software.
Then the mechanical sensor is well above the material being cut.
I don’t know if the mechanical sensor can be raised that much with the existing bracket.
I could look at it this weekend if you like.
I still need to do the calibration on the big CNC.
So much to do . . .
Tonight I levelled the bed. Only thing left to get it back 100% working is fix the back-off for the Z probe. The mechanism first needs to be raised so it doesn’t drag on the surface of the work. Does anyone know where in the software to set the Z-level back-off?
Yep. I’ve done it a few times when it got mildly messed up before. I can help with that.