Switching from servo/microswitch ABL to prox probe, need help

Hello.

I use a servo and microswitch on my machines and they work well. Pretty reliable. Although there are times that they do require some z offset adjustments. I print thousands of parts a month so it is natural for the mounts/switches/bolts/nuts to loosen over time and cause changes to the true offset of the switch in the extend position.

That being said, would I gain anything by going to prox probe?

LJ18A3-8-Z/BX

I want to get rid of the mechanial slop of the servo/switch combination and bring my z offset precision up.

I am already set up properly for ABL thanks to Roxy, but I want to take it a step further with prox probes.

tl;dr

1. Is there any benefit to going from an already functional ABL system with servos to prox probe?
2. I make the switch, and I already have ABL in place on my machines, what will be needed to make the switch hardware + firmware changes?

Thank you

I am a little bit skeptical that a Proximity Probe is going to be more accurate than a micro-switch on a servo driven probe leg. It might be. But I would want to see one in action and take some measurements before I convert my printers over to it.

I am confused about what this Proximity Probe puts out. It appears it does a Normally-Closed when nothing is close. And it says NPN when it is close. NPN? Is the output driven by a NPN transistor? It would be helpful to see a sample circuit diagram with this part in it.

And lastly... It says it has 100 hz output response. I'm guessing that is as fast as it can switch and not really the output signal. Because if it puts out a frequency as the response, it is going to take firmware changes to recognize it is close to something.

Quote:

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Originally Posted by Roxy

I am a little bit skeptical that a Proximity Probe is going to be more accurate than a micro-switch on a servo driven probe leg. It might be. But I would want to see one in action and take some measurements before I convert my printers over to it.

I am confused about what this Proximity Probe puts out. It appears it does a Normally-Closed when nothing is close. And it says NPN when it is close. NPN? Is the output driven by a NPN transistor? It would be helpful to see a sample circuit diagram with this part in it.

And lastly... It says it has 100 hz output response. I'm guessing that is as fast as it can switch and not really the output signal. Because if it puts out a frequency as the response, it is going to take firmware changes to recognize it is close to something.

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Hi Roxy, I am the wrong person to ask about the output response and internal circuitry diagram. But I do remember seeing people use this probe, with ramps + arduino machines and it literally was plug and play (or close).

I just want to know, if it is more accurate and repeatable than servo/microswitch.

By the way Roxy, what type of microswitch do you use? Do you use one with a roller at the end of it? How long an arm should I go on the switch? What is the most repeatable switch? I guess I am asking.

Quote:

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Originally Posted by DBFIU

I just want to know, if it is more accurate and repeatable than servo/microswitch.

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Just to be clear... I don't know the answer. There has been a lot of good success stories about using inductive probes but they always seem to be associated with very high dollar parts. Not a $5.95 part from eBay.

Quote:

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Originally Posted by DBFIU

By the way Roxy, what type of microswitch do you use? Do you use one with a roller at the end of it? How long an arm should I go on the switch? What is the most repeatable switch? I guess I am asking.

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But what I do know for sure is even the cheapest micro-switch from China bought off of eBay will produce very good results if the rest of your mechanics are good. I am using almost the cheapest one possible. It looks like this:

http://www.ebay.com/itm/New-Roller-L...wAAOxycgVTfqZ2

And I can get .002 mm repeat-ability every time. Given I usually print with .28 mm layers, the micro-switch isn't the source of any problems I hit.

Quote:

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Originally Posted by Roxy

Just to be clear... I don't know the answer. There has been a lot of good success stories about using inductive probes but they always seem to be associated with very high dollar parts. Not a $5.95 part from eBay.



But what I do know for sure is even the cheapest micro-switch from China bought off of eBay will produce very good results if the rest of your mechanics are good. I am using almost the cheapest one possible. It looks like this:

http://www.ebay.com/itm/New-Roller-L...wAAOxycgVTfqZ2

And I can get .002 mm repeat-ability every time. Given I usually print with .28 mm layers, the micro-switch isn't the source of any problems I hit.

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I also very readily hit high precision (I can hit 0.15mm first layers once the machine is calibrated). The micro switch/servo method is not bad by any means. I just wanted to know, if a 6 dollar part could possibly improve it.

The brackets are made of ABS, and since I run my machines very hot (I print a lot of Polycarbonate) the ABS bracketry that supports the switch and servo, over time, starts to warp. I could have the parts machined out of aluminum but I would rather not since I have many machines and this will be costly.