<p>I figured it out!</p>
<p>Their firmware apparently has a M750 command in which you can set the pressure of the printhead for x amount of microseconds. So I can simply use the G0 command to move the printhead to a specific coordinate, and then the M750 command to extrude for x ms at that coordinate while it remains stationary.</p>
<p>I don't know if this command is applicable across all 3D printers, but it can be used for Cellink bioprinters.</p>
<p>Additionally, to answer 0scar's question regarding how the EMD printhead is able to extrude droplets: through the printing interface (and g-code commands M2065 and M2067), the open time and cycle time can be set. These times are in the microsecond range and therefore droplets are extruded.</p>
<p>For an explanation of these g-codes, see the 'BIO X EMD Printhead' User Manual.</p>

CC BY-SA 4.0
2024-04-09T09:53:14.447Z
Well done! Many thanks for the info, this implies that they have written an extention of a known printer firmware source!
0scar
CC BY-SA 4.0
2024-04-09T10:01:37.940Z
Thank you for the help!
Rishi
CC BY-SA 4.0
2024-04-09T10:49:12.167Z
Excellent. Don't forget to mark this as the accepted answer (you will have to wait 48 hours or so).
Greenonline
CC BY-SA 4.0
2024-04-09T12:08:10.570Z
You're welcome, I find these questions fascinating! If we loo up code [`M750`](https://reprap.org/wiki/G-code#M750:_Enable_3D_scanner_extension) you'll find it is a specialized command only known for RRF firmware, I imagine the `M750` of these bioprinters is a further development of the `G4` code. I imagine the `M750` is basically a macro that: a) uses the `M2065` and `M2067` settings values to turn on dripping, b) wait for the specified time, and c) then turn dripping off before continuing to the next G-code instruction. Very interesting!
0scar
CC BY-SA 4.0
2024-04-09T09:21:41.953Z
2024-04-09T09:21:41.953Z
Rishi
<p>I have this electro-magnetic droplet (EMD) printhead from Cellink that allows for extruding droplets. I would like to extrude droplets at specific coordinates while the printhead is stationary, preferably for X amount of seconds. However, I cannot find a G-code command that allows this, so help would be greatly appreciated.</p>

CC BY-SA 4.0
2024-04-05T11:19:11.160Z
Hi Rishi, and welcome to 3DPrinting.SE! Do you need to activate and deactivate the elctro-magnet each time to get a droplet, or is it "fire-and-forget", meaning it it is activated it starts dripping?
0scar
CC BY-SA 4.0
2024-04-05T11:46:44.507Z
Thank you for your comment 0scar. The electro-magnetic droplet (EMD) printhead basically functions as a normal printhead. So if you have a g-code that says 'G1 X1 Y1 E1' (for example), the printhead will move to that coordinate while extruding droplets. On the 3D (bio)printer interface, you can set the frequency and duration in which the droplets are extruded.
Rishi
CC BY-SA 4.0
2024-04-05T14:46:58.960Z
OK, then use `G4 [P<time(ms)>] [S<time(sec)>]` to stay a predefined amount of time at that spot. Does that answer the question? It can then be made an answer as answering in comments is not allowed.
0scar
CC BY-SA 4.0
2024-04-06T19:22:47.733Z
I find it strange that the "droplet extruder" can be addressed by the `E` parameter. But this could well be handled by a piece of firmware running on this special extruder. I wonder what the difference between a `E1` and an `E10` is? With electromagnetic switches you'd expect using an `M` code instead, like [`M42`](https://marlinfw.org/docs/gcode/M042.html).
0scar
CC BY-SA 4.0
2024-04-08T09:47:11.890Z
Using G4 would not do it, because that command simply puts the printhead stationary without it extruding at that position. I want the printhead to be stationary at a specific coordinate, and extrude while it is stationary at that coordinate.
Rishi
CC BY-SA 4.0
2024-04-08T12:08:04.250Z
So your droplet extruder is just a simple thing, I hoped it had a PCB that received input from the G-code to instruct a dripping pattern. If that was true, the `G4` would do the trick. My last question, G-code is not real-time, due to acceleration and deceleration you would not obtain precize time from the feed rate. How is this droplet extruder supposed to work? Does it normally have a different firmware? To make a drop you need to activate and de-activate the magnet? Is it one drop on the location, or is it dripping at one loacation? Please update the question with more information.
0scar
<g-code><extrusion>
G-code for stationary extrusion
Rishi
# G-code for stationary extrusion

(Asked by: username_0 on 2024-04-05)

I have this electro-magnetic droplet (EMD) printhead from Cellink that allows for extruding droplets. I would like to extrude droplets at specific coordinates while the printhead is stationary, preferably for X amount of seconds. However, I cannot find a G-code command that allows this, so help would be greatly appreciated.

**Tags:** g-code, extrusion

> **Comments:**
> **username_1**: Hi username_0, and welcome to 3DPrinting.SE! Do you need to activate and deactivate the elctro-magnet each time to get a droplet, or is it "fire-and-forget", meaning it it is activated it starts dripping?  
> **username_0**: Thank you for your comment username_1. The electro-magnetic droplet (EMD) printhead basically functions as a normal printhead. So if you have a g-code that says 'G1 X1 Y1 E1' (for example), the printhead will move to that coordinate while extruding droplets. On the 3D (bio)printer interface, you can set the frequency and duration in which the droplets are extruded.  
> **username_1**: OK, then use `G4 [P<time(ms)>] [S<time(sec)>]` to stay a predefined amount of time at that spot. Does that answer the question? It can then be made an answer as answering in comments is not allowed.  
> **username_1**: I find it strange that the "droplet extruder" can be addressed by the `E` parameter. But this could well be handled by a piece of firmware running on this special extruder. I wonder what the difference between a `E1` and an `E10` is? With electromagnetic switches you'd expect using an `M` code instead, like [`M42`](https://marlinfw.org/docs/gcode/M042.html).  
> **username_0**: Using G4 would not do it, because that command simply puts the printhead stationary without it extruding at that position. I want the printhead to be stationary at a specific coordinate, and extrude while it is stationary at that coordinate.  
> **username_1**: So your droplet extruder is just a simple thing, I hoped it had a PCB that received input from the G-code to instruct a dripping pattern. If that was true, the `G4` would do the trick. My last question, G-code is not real-time, due to acceleration and deceleration you would not obtain precize time from the feed rate. How is this droplet extruder supposed to work? Does it normally have a different firmware? To make a drop you need to activate and de-activate the magnet? Is it one drop on the location, or is it dripping at one loacation? Please update the question with more information.  

---

## 1 answers

### Answer by username_0 on 2024-04-09. Score: 4 | Accepted answer

I figured it out!

Their firmware apparently has a M750 command in which you can set the pressure of the printhead for x amount of microseconds. So I can simply use the G0 command to move the printhead to a specific coordinate, and then the M750 command to extrude for x ms at that coordinate while it remains stationary.

I don't know if this command is applicable across all 3D printers, but it can be used for Cellink bioprinters.

Additionally, to answer username_1's question regarding how the EMD printhead is able to extrude droplets: through the printing interface (and g-code commands M2065 and M2067), the open time and cycle time can be set. These times are in the microsecond range and therefore droplets are extruded.

For an explanation of these g-codes, see the 'BIO X EMD Printhead' User Manual.

> **Comments:**
> **username_1**: Well done! Many thanks for the info, this implies that they have written an extention of a known printer firmware source!  
> **username_0**: Thank you for the help!  
> **username_2**: Excellent. Don't forget to mark this as the accepted answer (you will have to wait 48 hours or so).  
> **username_1**: You're welcome, I find these questions fascinating! If we loo up code [`M750`](https://reprap.org/wiki/G-code#M750:_Enable_3D_scanner_extension) you'll find it is a specialized command only known for RRF firmware, I imagine the `M750` of these bioprinters is a further development of the `G4` code. I imagine the `M750` is basically a macro that: a) uses the `M2065` and `M2067` settings values to turn on dripping, b) wait for the specified time, and c) then turn dripping off before continuing to the next G-code instruction. Very interesting!  

---

