<p>It makes a huge difference if you want to measure the internal nozzle diameter or the &quot;typical&quot; wear when using an abrasive filament. CNCKitchen has a nice article,<a href="https://www.cnckitchen.com/blog/how-much-abrasive-filaments-damage-your-nozzle" rel="nofollow noreferrer">How Much Abrasive Filaments Damage Your Nozzle!</a>, about the typical wear.</p>
<p>TLDR is that most of the wear comes from moving your nozzle through parts of the last layer during travel moves. This way, your nozzle tip gets shorter.</p>
<p>If that's what you want to measure, you might use your bed-leveling sensor for that. If your leveling sensor is precise enough, you could measure the distance to the bed with your BLTouch or other sensor. When your nozzle is new, you can take a second measurement by &quot;pressing&quot; the nozzle into the bed and detecting when motor current spikes, or by lowering it to a conductive edge of your print bed. This way, you can save the distance of your bed leveling sensor in relation to your nozzle tip. If your nozzle wears out, it should be shorter, and you should see that you can move your hotend lower before closing an electrical circuit or before your stepper driver uses an increased current (because it pushes into the bed).</p>
<p>I need to mention that this is just an idea and I have never seen a solution like this. Doing this might pose problems I didn't think of.</p>
<p>As you mentioned in possibility 3, a loose hotend screw can make the measurement of the distance difficult. Maybe you can remove that error by probing against a metal that has the inverted shape of a nozzle (just an inverted cone) which shouldn't change with nozzle wear, and then probe against a flat surface afterward and examine the difference. For this to work, you would of course have to clean the nozzle before any measurement.</p>

CC BY-SA 4.0
2024-01-20T12:25:14.800Z
Welcome to this site and thank you. Very nice answer. The 'second measurement' you've described is effectively the same as, or can be used for, automatic z-offset determination, right? Where in effect, the z-offset is automatically adjusted as the nozzle becomes shorter due to wearing?
Bob Ortiz
CC BY-SA 4.0
2024-01-20T23:54:37.610Z
I'm glad you mentioned the wear modes, I would have never thought about that.
WhisperingShiba
CC BY-SA 4.0
2024-01-20T12:15:13.947Z
2024-01-20T15:10:15.483Z
2024-01-20T15:10:15.483Z
Ratzupaltuff
<p>I'm thinking about implementing some kind of nozzle wear sensor. My question is simple: Do such sensors or automatic approaches already exist? Although I expect not and I know nozzles are cheap, it's just a fun educational challenge, not financially viable but that's not the purpose anyway.</p>
<p>I thought about using a simple camera with a proper lens and computer vision to do either one or more of the following things:</p>
<ol>
<li>Have the extruder retract, perhaps brush the nozzle, then have a zoomed camera and light pointing up from under the nozzle, in an attempt (with some reference image next to it) to determine nozzle diameter size.</li>
<li>Have a camera from the side of a nozzle, brushing it clean, extruding a few cm of filament, and analyzing how straight the filament flows down when extruded</li>
<li>Take two precision measurements from under the nozzle somehow, one of the heat block and one of the nozzle-end, and determine the difference, although I have no way to account for other variables such as the nozzle not being screwed in properly, maybe non-standardized nozzle-height et cetera.</li>
</ol>
<p>Does something like this or another approach to achieve the same already exist? If not, is this a proper approach or are there other things to consider?</p>

CC BY-SA 4.0
2024-01-19T22:21:44.983Z
Are you talking about internal nozzle diameter wear because you are using abrasive filaments?  I would not use optical.  If you have some worn nozzles and some new nozzles, I would see if your multi-meter can detect the difference in resistance between a node one one side of the nozzle, and a node on the other side of the nozzle.  You might need to find a very sensitive ohm meter, but optical gets expensive pretty quick
WhisperingShiba
CC BY-SA 4.0
2024-01-20T13:43:38.460Z
If it would cost over $100 there is hardly any point to do it – get a Diamondback polycrystalline diamond nozzle and there's literally nothing that can wear it down, so no sensor required.
Mołot
CC BY-SA 4.0
2024-01-20T15:39:50.850Z
@Mołot that an interesting thought, although it is an alternative solution to the problem. It's worth  being mentioned in this context. Thank you.
Bob Ortiz
<nozzle><printer-building><sensors>
What is a good approach to develop a 'nozzle wear sensor'?
Bob Ortiz
# What is a good approach to develop a 'nozzle wear sensor'?

(Asked by: username_0 on 2023-12-25)

I'm thinking about implementing some kind of nozzle wear sensor. My question is simple: Do such sensors or automatic approaches already exist? Although I expect not and I know nozzles are cheap, it's just a fun educational challenge, not financially viable but that's not the purpose anyway.

I thought about using a simple camera with a proper lens and computer vision to do either one or more of the following things:

1. Have the extruder retract, perhaps brush the nozzle, then have a zoomed camera and light pointing up from under the nozzle, in an attempt (with some reference image next to it) to determine nozzle diameter size.
2. Have a camera from the side of a nozzle, brushing it clean, extruding a few cm of filament, and analyzing how straight the filament flows down when extruded
3. Take two precision measurements from under the nozzle somehow, one of the heat block and one of the nozzle-end, and determine the difference, although I have no way to account for other variables such as the nozzle not being screwed in properly, maybe non-standardized nozzle-height et cetera.

Does something like this or another approach to achieve the same already exist? If not, is this a proper approach or are there other things to consider?

**Tags:** nozzle, printer-building, sensors

> **Comments:**
> **username_1**: Are you talking about internal nozzle diameter wear because you are using abrasive filaments?  I would not use optical.  If you have some worn nozzles and some new nozzles, I would see if your multi-meter can detect the difference in resistance between a node one one side of the nozzle, and a node on the other side of the nozzle.  You might need to find a very sensitive ohm meter, but optical gets expensive pretty quick  
> **username_2**: If it would cost over $100 there is hardly any point to do it – get a Diamondback polycrystalline diamond nozzle and there's literally nothing that can wear it down, so no sensor required.  
> **username_0**: @username_2 that an interesting thought, although it is an alternative solution to the problem. It's worth  being mentioned in this context. Thank you.  

---

## 1 answers

### Answer by username_3 on 2024-01-20. Score: 2 | Accepted answer

It makes a huge difference if you want to measure the internal nozzle diameter or the "typical" wear when using an abrasive filament. CNCKitchen has a nice article,[How Much Abrasive Filaments Damage Your Nozzle!](https://www.cnckitchen.com/blog/how-much-abrasive-filaments-damage-your-nozzle), about the typical wear.

TLDR is that most of the wear comes from moving your nozzle through parts of the last layer during travel moves. This way, your nozzle tip gets shorter.

If that's what you want to measure, you might use your bed-leveling sensor for that. If your leveling sensor is precise enough, you could measure the distance to the bed with your BLTouch or other sensor. When your nozzle is new, you can take a second measurement by "pressing" the nozzle into the bed and detecting when motor current spikes, or by lowering it to a conductive edge of your print bed. This way, you can save the distance of your bed leveling sensor in relation to your nozzle tip. If your nozzle wears out, it should be shorter, and you should see that you can move your hotend lower before closing an electrical circuit or before your stepper driver uses an increased current (because it pushes into the bed).

I need to mention that this is just an idea and I have never seen a solution like this. Doing this might pose problems I didn't think of.

As you mentioned in possibility 3, a loose hotend screw can make the measurement of the distance difficult. Maybe you can remove that error by probing against a metal that has the inverted shape of a nozzle (just an inverted cone) which shouldn't change with nozzle wear, and then probe against a flat surface afterward and examine the difference. For this to work, you would of course have to clean the nozzle before any measurement.

> **Comments:**
> **username_0**: Welcome to this site and thank you. Very nice answer. The 'second measurement' you've described is effectively the same as, or can be used for, automatic z-offset determination, right? Where in effect, the z-offset is automatically adjusted as the nozzle becomes shorter due to wearing?  
> **username_1**: I'm glad you mentioned the wear modes, I would have never thought about that.  

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