(Help) I'm starting to work on Compiling Custom Marlin could use help

Hi Rep Rap community. I have a project that I could use help with. I'm quite good at functional printing and understand slicer operation pretty well. I only know the most basics of firmware though and could use a little bit of help in that area.

The project is a Creality CR10 V2/3 with a mini Pellet/Granulate extruder.

I'm most of the way there. I've got all the hardware and measurements to input into VSC Platform I.O. and at least one firmware (written by someone else) to build from.

I tried to do everything that I wanted to do and the build was successful but I doubt I did everything that's needed or correctly.

I'd appreciate if I can give the parameters that are needed
(where the pellet extruder nozzle sits compared to the stock hotend) and a few things like that along those customized firmware files and if someone could take a look at them and tell me how much I didn't do correctly in those areas that would be great.

I even tried A.I. for assistance but that mostly didn't work out and did most of it myself.

If there is a problem posting printer code here please let me know what I can do in order to share information quickly and efficiently to help you help me.

Thanks in advance.

-Brian

Edited 1 time(s). Last edit at 08/16/2025 11:44PM by brianmh13.

Hi Brian,

... there shouldn't be a problem with adding printer code - but not as plain text, embedded into the post, but better as attachment (preferable zipped for less size).

When the pellet-extruder works as basic extruder (pushing the pellets into the heater and so pressing the molten material throughout the nozzle) and a "stepping" motor, it's not too different to a "normal" extruder -- simply adjust the material volume per moving length (steps count).

It's different, if it's a prefill - then it's mainly using the subsequent extruder for the 3D-printing ... and in a separate job secure the amount of extruded filament by the pellet-extruder, so the printer won't run dry ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hi Viktor thanks for reaching out. I do have a value for increased E steps added. That was easy to do. I'm mainly concerned with the X,Y,Z motion as far as the endstops and travel limits. All of that is what I have a feeling I probably didn't get correct.

I'll post again shortly with the initial attempt I made with firmware and a description or the printer, pellet extruder and what I'm trying.

Creality CR10 V2/3 has Creality 2.5.2 board with ATMEGA2560 Chip, 2208 Stepper Drivers

GreenBoy 3D Pellet Extruder (GB or PE) 24v 70w Heaer Cartridge, NTC 100 Thermistor, 2 4040 Radial Fans

Wants/Needs

-Extruder Steps need to be 445

-Increase E Stepper Current (optional)

-Nozzle of Pellet Extruder sits at approximately Z -30mm Y -11mm X -.7mm
(This should be very close to the difference from the stock CR Hotend)

-Disable Filament Runout Sensor

-Max Temperature 290

-No Bed Leveling Sensor



My idea was to adjust the Z End Stop to +35mm. I mounted it with v-slot nuts and fixed it at 35mm up from where it was stock. Other than that nothing significant has been changed with the printer itself to prepare for the Pellet Extruder.

The Hotend offsets and methodology for setting up the Pellet Extruder in such a way as to retain as much print volume, standard homing position and usual function as possible is what I'd like to achieve. I did reduce the Z Axis Max Dimension by 35mm from 400 to 365. In the original config.h file at (Travel Limits After Homing) it was written 400 // 410 for Z. I replaced 400 and 410 to 365 // 365. that maybe should read 365 // 410? Or 365 // 375? I didn't quite understand this perhaps 410 is a max (optional) dimension that could be increased via the printer screen?

I don't know if I set the Min and Max Software End Stops or Correctly. This is the primary area of concern for me is getting all relevant Extruder Offset and Motion configs correct. I would like to install the PE and do the minimum set up needed like Level the Bed, fine tune the Z offset, maybe a PID tune (if possible with the firmware) then start test printing. Id like to not see the Extruder crash into the bed or frame the very first time I use the Homing sequence.

I'm trying to do it right but I have doubt that I changed the configurations correctly. I honestly could have put - values for an Axis when they should have been positive and vice versa or not entered values in an area that should have them.

I'd "bought into" The Green Boy Pellet Extruder while it was in Pre-Production a bit over a year ago. I received it about 4 months ago purchased the CR10 as a platform for it and basically ready to go now with the exception of a known good firmware build. Green Boy 3D promises a wiki page with extruder assembly instructions, marlin and klipper firmware set up, troubleshooting, etc. but that wiki is lacking those still. Information such as the E Steps starting point of 445 I got from other owners at a forum for the Green Boy.

Any further information you may need for reference, any questions, or suggestions for this please say.
I may have included my first attempt at a firmware build for this project along with this post if allowed as a zipped file.

Thank You in Advance for you're guidance.

Ok I was going to post a zip of the firmware but then realized I dont know what file(s) that you need to see. I was going to post the Configuration_adv.h, Configuration.h, _Bootscreen.h, _Statusscreen.h but then remembered that those may be machine code (non readable). un I think those are correct to inspect. Im confused but'll post those whatever the case.

If there are any other files you need to look at please inform me what and where those are.

I just saw that there is a Marlin Simulator. I suppose that could be used to work on my project/another custom printer build in the future.

I wasn't aware of that program. Maybe for now though I can get assistance from people here.

This looks like an awesome forum I was browsing and saw a bunch of sub forums that I am interested in checking out. Lots of great projects and skilled makers I'm certain.

... when modifying Marlin (Marlin4Due) and Pronterface for paste-dispensing, I've set the E-step value in the firmware to 1 (!) and then adapted the E-value with the G-code for the correct volume per line-length (was pretty perfekt for laser-engraving too).

Essentially, in Pronterface, I've calculated the G1-line-length as XY-difference from the actual position to the target point and set the E-value to the needed step-value.

E.g. - if want to step the dispenser-motor 30 steps per moved mm, the G-code would be look like:

G0 X10.0 Y10.0 Z0.0; // moving to a defined starting position
G1 X60.0 Y10.0 Z0.0 E1500 F2000; // moving a 50mm line with 30 dispenser-step-pulses per mm

Edited 1 time(s). Last edit at 08/19/2025 04:33AM by VDX.

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hey Viktor thats an interesting way of doing the extrusion, I'll keep it in mind but the 445 value should work to get started and that part of the customization to the firmware is one of the easy changes for me to make. The parts I need help with are the offsets/endstop set up to make sure my extruder/nozzle doesnt crash into anything or go printing off the edge of the bed. Are you able to advise on those parameters?

... IIRC the offsets were managed in the PC-software too (Pronterface) -- there I had the working ranges/limits for the axes too.

The other point was solved with "clamped moves" - here it was "forbidden" to move beyound the limits and controlled either in the firmware or software - don't remember which

Edited 1 time(s). Last edit at 08/20/2025 01:34AM by VDX.

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]