Manipulate Voltage Output to Control Extrusion I am working on a custom 3D-printing setup where I could change my extrusion speed by changing voltage output to a DC motor. I basically want to run two wire leads to an external control board and vary the voltage across them between 0-10V. I am trying to find a simple way to modify a RamBo printer board, so the printer can change the voltage based on the amount of material to be extruded, just as conventional set-ups vary the number of motor "steps" to achieve this control. So here are my main questions, Would it be easier to somehow convert the 4 lead extruder stepper signals to a 2 lead voltage manipulation, or use one of the PWM heater outputs? If I use the stepper signals, would I need to run the stepper wires through an additional controller, or just modify the RamBo firmware? If I use a PWM output, how would I achieve a variable voltage gradient as opposed to a simple on/off effect? Additionally, is there a simple way to modify Slic3r gcode to account for this change in the "E" commands? Those are the methods I came up with, but I might be making it too complicated. If there is a simpler way please feel free to share. I am also open to building a printer board from the ground up to accomodate this functionality if that would be easier, but I figured working with existing firmware would be beneficial. I should mention that this extrusion would be termperature independent, because I have a separate set-up for that. Any advice or comments would be greatly appreciated. Zernebog https://reprap.org/forum/read.php?1,594571,594571#msg-594571 Sat, 13 Jun 2026 15:03:25 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,594571,600847#msg-600847 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,600847#msg-600847 epicepee General Fri, 25 Dec 2015 22:35:46 -0500 https://reprap.org/forum/read.php?1,594571,600842#msg-600842 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,600842#msg-600842 JamesK General Fri, 25 Dec 2015 21:33:10 -0500 https://reprap.org/forum/read.php?1,594571,600833#msg-600833 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,600833#msg-600833 epicepee General Fri, 25 Dec 2015 19:52:12 -0500 https://reprap.org/forum/read.php?1,594571,594706#msg-594706 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,594706#msg-594706
Quote
nebbian
Just make a frequency to voltage circuit, hung off the 'step' input to the stepper driver.

[www.google.com.au]

Nebbian, could you elaborate on this setup? I am looking at your link, and I am seeing a number of different pre-constructed circuits on the market out there. Do you know of one that is specially made for this application?

Quote
o_lampe
The power of a DC motor has highly exponential relationship with voltage, while the step signals and the corresponding extrusion is linear.

You would better put a encoder to the DC motor and control the extrusion in a closed loop. There are several fresh threads about this topic.
-Olaf

Olaf, I already have closed loop control of the DC motor setup on a separate control board. This is how I know that I have a linear relationship between my voltage and motor speed; however, maybe there is a simplified way to construct the control. Could you point me to some of the fresh threads you are referencing?

Thanks again,
Zernebog]]> Zernebog General Wed, 09 Dec 2015 08:24:42 -0500 https://reprap.org/forum/read.php?1,594571,594611#msg-594611 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,594611#msg-594611
You would better put a encoder to the DC motor and control the extrusion in a closed loop. There are several fresh threads about this topic.
-Olaf]]> o_lampe General Wed, 09 Dec 2015 03:16:31 -0500 https://reprap.org/forum/read.php?1,594571,594574#msg-594574 Re: Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,594574#msg-594574
[www.google.com.au]]]> nebbian General Wed, 09 Dec 2015 00:01:19 -0500 https://reprap.org/forum/read.php?1,594571,594571#msg-594571 Manipulate Voltage Output to Control Extrusion https://reprap.org/forum/read.php?1,594571,594571#msg-594571
So here are my main questions,
Would it be easier to somehow convert the 4 lead extruder stepper signals to a 2 lead voltage manipulation, or use one of the PWM heater outputs?
If I use the stepper signals, would I need to run the stepper wires through an additional controller, or just modify the RamBo firmware?
If I use a PWM output, how would I achieve a variable voltage gradient as opposed to a simple on/off effect? Additionally, is there a simple way to modify Slic3r gcode to account for this change in the "E" commands?

Those are the methods I came up with, but I might be making it too complicated. If there is a simpler way please feel free to share.

I am also open to building a printer board from the ground up to accomodate this functionality if that would be easier, but I figured working with existing firmware would be beneficial.

I should mention that this extrusion would be termperature independent, because I have a separate set-up for that.

Any advice or comments would be greatly appreciated.

Zernebog]]> Zernebog General Tue, 08 Dec 2015 23:46:05 -0500