In previous articles, I described switching from Marlin to Klipper, installing a bed probe, and separating the control of the two Z-axis motors.
My Graber i3 was gradually becoming easier to configure, but one characteristic of the old printer remained — the noise it made during operation.
The stepper motors were particularly noticeable whenever the axes moved.
So the next stage of the upgrade was replacing their drivers.
Where the Noise Comes From
My Graber i3 uses a RAMPS 1.4 board with replaceable stepper motor drivers.
These drivers control the current flowing through the motor windings, allowing the motors to rotate and hold their positions.
The way this current is controlled affects not only how the motor operates but also the sound it produces.
With the old drivers, axis movements were accompanied by a characteristic high-pitched sound. It was especially noticeable during speed changes and rapid movements.
Of course, the motors aren't the only source of noise in a 3D printer. There are also fans, bearings, belts, and the mechanical structure itself.
But I decided to focus on reducing stepper motor noise first.
Why I Didn't Replace the Control Board
I didn't want to replace the printer's entire control electronics, and I didn't see much reason to do so.
After all, the Graber i3 was still an old printer, and investing in a new control board didn't seem worthwhile.
Besides, switching to Klipper had already allowed me to work around the main limitations of the 8-bit controller on the Arduino Mega 2560.
Motion planning calculations were now performed on a Linux-based TV Box, while the microcontroller handled direct hardware control.
The RAMPS 1.4 board was more than capable of meeting my needs.
In fact, during the previous upgrade, I had already used the spare second extruder channel to control the two Z-axis motors independently.
And because the stepper motor drivers on RAMPS 1.4 are installed in separate sockets, they can be replaced without changing the rest of the electronics.
This approach suited the way I wanted to restore my Graber i3: avoid replacing working components unnecessarily and upgrade only the parts I actually wanted to improve.
Replacing the Drivers
My main goal was to reduce motor noise while keeping the printer's existing electronics.
To achieve this, I decided to replace the old drivers with more modern ones that support quieter stepper motor control modes.
The design of RAMPS 1.4 makes this kind of upgrade considerably easier.
The drivers are separate modules, so replacing them doesn't require soldering components or changing the entire control board.
However, there are a few important details to consider.
Despite their similar appearance, different drivers may have different pin layouts, current adjustment methods, and supported operating modes.
That's why it's important to check their compatibility with RAMPS 1.4 before installation.
Correct module orientation is especially important. Installing a driver incorrectly can damage the electronics.
Setting the motor current is equally important.
Too little current can cause missed steps, while too much can lead to excessive heating of the motors and drivers.
After replacing the drivers, it's therefore necessary to check each axis and make sure the motors move correctly without missing steps.
Configuring Klipper
After replacing the drivers, the next step was configuring Klipper.
One of the convenient features of this software is that the necessary parameters can be changed directly in the printer.cfg configuration file.
There's no need to rebuild and upload the microcontroller firmware every time a setting changes.
The specific settings depend on the installed driver model.
Some drivers operate in the standard STEP/DIR mode, where the microcontroller sends step and direction signals.
Others also allow current and operating modes to be controlled through UART or SPI.
However, RAMPS 1.4 wasn't originally designed with dedicated connections for these interfaces at each driver socket.
As a result, using these additional features may require wiring modifications.
Regardless of the control method, the main objective is stable motor operation.
After configuration, it's important to check axis movements, operation at different speeds, and the absence of missed steps.
Quieter Doesn't Always Mean Better
When replacing drivers, it's worth remembering that the lowest noise level doesn't always mean the best motor operating mode.
Different current control algorithms can vary not only in noise level but also in how the motor behaves under load.
This becomes particularly noticeable at higher speeds and accelerations.
That's why I didn't consider quiet operation to be the only priority.
The printer needed to run more quietly while maintaining accurate movement.
Ultimately, the goal was to find a balance between noise, reliability, and the capabilities of the mechanical system.
Upgrading Without Replacing All the Electronics
Replacing the drivers was another step in modernizing my Graber i3.
At the same time, I was able to keep the existing control electronics, which continued to do their job.
Switching to Klipper allowed me to keep using the old 8-bit microcontroller without replacing it with a more powerful one.
RAMPS 1.4, in turn, allowed me to replace the drivers independently of the rest of the board.
For me, this was another example of how even old hardware doesn't necessarily need to be replaced entirely.
Sometimes it's enough to understand its capabilities and address specific shortcomings.
However, upgrading the electronics doesn't solve every problem.
Even the most advanced drivers can't fix mechanical play, misaligned linear guides, or binding moving parts.
That's why my next focus was the printer's mechanical system.
What's Next
After upgrading the electronics, I continued working on the mechanical components of my Graber i3.
The carriages and several other structural components needed particular attention because their shortcomings directly affected print quality.
These problems could no longer be solved through Klipper settings or driver replacements.
I had to work on the mechanics themselves.
I'll cover that in the next article.