Installing the MKS Gen L with TMC2208 Silent Stepper Motor Driver


Introduction

After watching Teaching Techs video about the MKS Gen L replacement board for the Creality Ender 3 or Ender 3 Pro, I was instantly hooked. This board provides many upgrades over the stock MELZI Mainboard.

Source: Michael from Teaching Tech. https://youtu.be/LNdMYgwez8Y?t=80

Without getting to far in to the specifics, the MKS Gen L has a better microcontroller that allows us to change the firmware without having to compromise on features, a bootloader already installed so that you don’t have to flash one, changable stepper motor boards, and multiple servo outputs so you can easily add multiple upgrades like the the BL Touch or filament runout. The one drawback is that you will be losing the built in SD Card support but there is a way to add it back.

Source: Michael from Teaching Tech. https://youtu.be/LNdMYgwez8Y?t=113

If you are planning on adding on upgrading your printer or would like it to be nearly silent while printing, I HIGHLY recommend making the upgrade to the MKS Gen L. This isn’t a step by step guide per say, as most of it is covered in Teaching Techs video, but a few of us over at the Sudomod Discord have found a few things that are different between the Creality Ender 3 and Ender 3 Pro.

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Materials, Tools, and Downloads

Materials

For my setup, I chose the MKS Gen L mainboard and TMC2208 Silent Stepper Motor Drivers. You are able to choose any stepper motor drivers you wish for though. For instance you can keep to the stock A4988 Stepper Motor Drivers if you would like to save a little bit of money.

You also have the option to change out the case fan if you would like. Noctuas are the most popular and are generally much quieter than the stock fan. We have options for this. We can have the options of 40x40x10mm or 40x40x20mm and 5v or 12v for each. The 40x40x20mm 12v would move the most air through the case and you can plug it in to the mainboard fan slot so it is not running all the time like the 5v would. But here are the links for each option:

Tools

There are a few tools needed for this project:

  • Phillips screwdriver
  • Craft/Utility knife
  • Multimeter
  • Small flathead screwdriver is helpful (like the one that came with the Ender 3)

Parts to Print

Downloads

Arduino IDE
This is the program that I use to make the necessary edits and to be able to flash the firmware to the MKS Gen L. The version at the time of writing is 1.8.8
Marlin Firmware
Think of this as the operating system for the printer. This is what we flash to the MKS Gen L to process and execute the GCODE we send it. The current version at the time of writing is 1.1.9.

Guide

Printing Parts

Before you can do anything, you need to print a case for the new mainboard. These prints will vary based on what printer you have:

Original Ender 3

I printed the original case made by Michael at Teaching Tech and found that the screws for the top and bottom were about 8mm off. I modified the case to account for this defference. The stock fan for the enclosure is set for a 40x40x10mm fan. I have also made an option for a 40x40x20mm fan. Both of these options can be found on Thingiverse.

Ender 3 Pro

The case that Michael made was designed for the Ender 3 Pro and can be found on Thingiverse. The case allows for a 40x40x10mm fan but I have also modified that case for a 40x40x20mm fan and can be found in the comments section.

Other Parts

I highly recommend printing some sort of cable protector for your printer. The extrusion railing can be very sharp and easily slice through the outer coating of wires and possibly causing a short. I printed this cable protector by Supavitax and it works like a charm.

Choice Time

I present you with two choices:
1. Continue on as normal.
2. Edit and flash the firmware and jump back here later. This is the better option if your printer is not close to your computer.

Powering Down and Labeling

The next thing you should do is power down the printer. You should do this by having the printer on and then unplugging it from the wall or printer. You should not just turn the switch off because that would allow residual power to be left in the components.

The next step is to start disconnecting and labeling wires. But before you start pulling wires, you need to take off the hot glue that is holding them in place. This is where that small flathead screwdriver comes handy. If there is a connection to the board and it isn’t in a green block, there is most likely glue there. It should be relatively easy to peel away once you get under it.

Once you have all the gue off from the connectors, you can start pulling wires off the mainboard. I would start with the stepper motor wires because they are already labled and simply pull out. When you start getting to the unlabled wires, the easiest thing to do is to take a piece of masking tape or painters tape and label each wire as you undo them. You can use the following image as a guide to label the wires.

Source: Michael from Teaching Tech. https://youtu.be/LNdMYgwez8Y?t=265

I personally just used the lettering over the picture and marked that on the tape as they match up with putting them in the the MKS Gen L.

Before you disconnect the 24v power (“A” in the picture) though, we should grab the voltages from the built in A4988 drivers. This is where our multimeter comes in. First, we are going to find where we need to place each prong of the multimeter.

Getting the V Reffs from the MELZI Board

Make sure that every wire but the 24v power is disconnected and out of the way. Plug your printer back in and power it on. Basically, you are going to set your multimeter to the 2v setting or the 20v setting if your multimeter doesn’t have a 2v setting. You place the black lead wire on the screw that is above the black input wire. Now, very carefully, you place the red lead wire on top of the potentiometer circled in red ONE AT A TIME. Record the voltage for each the X, Y, Z, and E (extruder). Mine were very close for the X, Y, and Z, but my extruder was about .12v higher.

Once you have the V refs, power down the printer by unplugging it and then disconnect the remaining wires. At this point, you can remove the metal housing from the Ender 3. If you printed the cable protector, now is a good time to put it in. And finally, take the MELZI board out of the housing because we will be reusing the screws to attach the MKS to the new printed housing.

Changing over to the MKS Gen L

This is where we will be putting our TMC2208 Silent Stepper Motor Drivers on to the MKS Gen L. On the bottom of both the MKS and the stepper boards, you will see some small writing. Basically, you want to match up the lettering. It may vary a little. If you are using the stepper boards I linked, you will see a black spacer and a blue spacer on the pins. The MKS board has a black spacer and a green spacer. You can probably guess: match the black and black spacers.

For the both versions of the Ender 3, we only need to install 4 stepper motors since we are running 3 stepper motors and a single extruder. You would leave the “E1” (the one the farthest away from the green wire block connectors) slot empty.

Now, make sure that the printer has no power to it. Make sure that the screws are all the way open. You can see an example of what to look for in the image below.

Source: Michael from Teaching Tech. https://youtu.be/LNdMYgwez8Y?t=358

You basically want to put the wire in the little hole in the middle. Look at the bottom of the board to see which one is positive (+) and which is negative (-). Once the wire is in, tighten the screw on the top until it is tight. It is a good idea to give a little tug on each wire after tightening them to make sure they will not come out.

Now, you need to tune the new stepper boards to match or have a similar V-ref of the previous board. Now the process is basically the same process except that you will need a screwdriver to adjust the voltage. One thing that I like to do is to take a set of alligator clips, clip one end to the red lead on the multimeter and hook the other end to the metal part of the screwdriver. This way, you can use one hand to hold the ground lead on the ground screw and use the screwdriver to make adjustments without having to stop multiple times to test the voltage. Just be very careful to touch only the screw for the potentiometer and non of the other components or you might short something. Ask me how I know.

Adjust the voltage for each stepper board to get them as close of values to the MELZI board as you can. Just be cautous because the slightest movement can have a pretty big impact. A little bit of difference is not going to hurt.

Once you have the stepper drivers dialed in, unplug the printer while leaving the power on to drain any of the power left in the components. Once all the power is drained (the LED turns off), we can continue to plug the rest of the components back in to the printer.

At this point, I put the case on the Ender 3. I loosely attached the 2 screws in the front of the machine and then screwed in the top of the case before tightening the two front screws. Then I attached the remaining wires in for the bed heater, hot end, hot end fan, and part cooling fan before placing the board in the case. If you put it in the case before connecting those wires… Well good luck! And this is the point that I attached the board to the case making sure that the wires were in a position that they wont get pinched. Use the screws that were holding the MELZI board to the metal housing to attach the new MKS board to the printed housing. And finally, start attaching the rest of the connections according to the image below. Just don’t attach the endstops (K-X, K-Y, and K-Z) just yet because we need to modify them.

Source: Michael from Teaching tech. https://youtu.be/LNdMYgwez8Y?t=443

Before you go and try to put the endstops back in to the MKS, you need to modify them just a little. Teaching Tech does a good job explaining it in his video at the 6:20 mark. When you shave off that key, you can plug them in to the MKS.

Now, If you are forgoing the micro SD card slot like me and using the stock LCD screen, we need to make another easy modification to the ribbon cable. Basically we need to remove the key on the screen side of the ribbon cable. This is because we need to flip the cable on the screen side so that it works (at least for the original Ender 3. I will post any differences that we find). The easiest way I found to do this is by using a pair of flush cutters rather than a craft/utility knife. After you have the key cut off, insert it in to EXP3 on the back of the screen backwards of how it was previously plugged in. The other end on the MKS goes in to the EXP1 slot.

Firmware Configuration

Now you need to make a few firmware edits to get everything working as it should. In Michael’s video, there is a step for the screen that I had to reverse to get the screen working. The following edits are the barebone ones I made to get my printer working. I do not have a BL Touch or the screen with the SD card. Stock screen and that’s it.

If you already have a customized firmware, you can skip over this next paragraph as I assume you already have the correct setup for the Ender 3.

If you do not have the Arduino IDE installed already, do that first. After that is complete, unzip the Marlin Firmware folder to some place you know where it is. I placed mine on the desktop. Navagate to the \Marlin-1.1.x\Marlin\example_configurations\Creality\Ender-3 folder. Copy all the files in there and paste them in the \Marlin-1.1.x\Marlin folder overwriting any files it needs to. While in the same folder, double click the Marlin.ino file to open it with the Arduino IDE.

The first thing we are going to do is to to Tools > Board and select Arduino/Genuino Mega or Mega 2560. Next, go to Tools > Manage Libraries. Let the library update and the search for U8glib by oliver. Install that. When that is done, close out of the library manager.

The following edits we going to be making is in the Configuration.h tab. Hit Ctrl + F so open the search box.


Search for: MOTHERBOARD

Replace: BOARD_MELZI_CREALITY with BOARD_MKS_GEN_L

Should look like: // The following define selects which electronics board you have.
// Please choose the name from boards.h that matches your setup
#ifndef MOTHERBOARD
  #define MOTHERBOARD BOARD_MKS_GEN_L
#endif


Search for: INVERT_X_DIR

Invert the true and falses for INVERT_X_DIR, INVERT_Y_DIR, INVERT_Z_DIR, and INVERT_E0_DIR.

Should look like: // Invert the stepper direction. Change (or reverse the motor connector) if an axis goes the wrong way.
#define INVERT_X_DIR false
#define INVERT_Y_DIR false
#define INVERT_Z_DIR true

// @section extruder

// For direct drive extruder v9 set to true, for geared extruder set to false.
#define INVERT_E0_DIR false
#define INVERT_E1_DIR false
#define INVERT_E2_DIR false
#define INVERT_E3_DIR false
#define INVERT_E4_DIR false

Save the file by hitting Ctrl + S and then switch to the Configurations_adv.h file.

Search for: E0_AUTO_FAN_PIN

Replace -1 with 7

Should look like: #define E0_AUTO_FAN_PIN 7

Save that file.

Flashing the firmware

Now that you have your firmware edits completed, you need to flash the firmware to your printer. This is pretty straight forward. First go to Tools and hover over the Port line. Make a mental note of the objects in the list. They should look like “COM#” where # is an actual number. Now plug in the board to the computer you are using using the USB cable. Open the Tools > Port menu again and you should see a new entry. Click on the new entry. It is also worth double checking that the board is selected as Arduino/Genuino Mega or Mega 2560. We do not need to have the board powered as the USB power is enough to be able to flash the firmware without it having to be connected to the printer.

Now to push the firmware to the MKS. You can hit Ctrl + U, or go to Sketch > Upload to push your firmware. This will check for any errors before building and pushing the firmware to your printer.

If you skipped to flashing the firmware before installing the board, you can now jump back up to Powering Down and Labeling.

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