Needle height calibration

[mikehibbett]

I understand that. And that is what happens. And the limit switch opens before the head moves of the PCB, triggering a Tingy issue.

Am I still missing something?

[JuKu]

something is off. You can try to increase z homing acceleration (the probing is done using homing settings). TinyG starts decelerating using that value when the switch triggers. If homing acceleration is slow, it might go too far in, so that the small backoff movement isn't enough to clear the switch. I'm not in my lab with m machine, but I think I have something like 5000 as homing acc.

[mikehibbett]

I'll take a look, thanks.

[mikehibbett]

That worked, Thanks. Now I am just stuck on the optical homing issue on the other thread from today.

Cheers,

Mike

[mikehibbett]

From my machine, I consider this issue closed. Having set up the homing function, this procedure works.

FYI, these are the values I had in my settings - I am not sure whether putting these in were relevant to the process now working for me:

Z0 to PCB: 38.8
Backoff 0.2
Switch hysterisis: 0.2
Placement depth: 1.0

After calibration, Z0 to PCB changed to 38.75, Back-off to 0.5

Cheers,

Mike

[JuKu]

You want to adjust the switch so, that the backoff value is higher. In other words, so that the head moves deeper after the nozzle tip touches the pcb. The backoff is how much you need to take the head up from full down to “just touching”. Aim for more than one mm. The placement depth tells how much more from “just touching” the nozzle goes down. You want this to be less than backoff. For example, if you have 1mm of backoff, you can use 0.5mm for placement depth and still have another 0.5mm margin for false switch triggers.

[mikehibbett]

Understood, thanks. (I'm glad I posted my figures so that you noticed!)

I'll go back and adjust the microswitch.

Cheers,

Mike

[mikehibbett]

Another evening wasted, no success. I cannot get your calibration routine to complete with a backoff value greater than 0.2mm.

[JuKu]

I'm sorry to hear that. Here is an image of my switch setting:
https://kuusama-my.sharepoint.com/:i:/p ... w?e=rLgukP

And here is a video of probing, and jogging the nozzle up. Probing does the same as height calibration first step, and hopefully you can see how I need to jog a couple of mm's before the nozzle doesn't touch down anymore. My backoff is 2.2mm.
https://kuusama-my.sharepoint.com/:v:/p ... A?e=bx5anU

[mikehibbett]

I see it now. I re-read one of your comments

>When you manually push the tube up from the nozzle tip, these should happen, in this order: The tube goes up, triggering the switch. Then, the bottom collar goes up

I had the lower spring too tight, so it was working in reverse. My back off is getting larger, so I'm getting there.

Cheers,

Mike