Ender 3 – MKS Gen L and BLTouch Upgrade

After breaking my Ender 3 board by acciendent, I decided to switch to a MKS Gen L board. Contained in this article are the steps that I’ve taken to swap boards. I am writing this after the fact, I do apologize if I miss any details.

WARNING: This deals with handling electronics and electricity. Follow at your own risk.

Required Equipment & Software

  • MKS Gen L Board
  • Computer
  • Arduino IDE
  • Screwdrivers (insulated one for adjusting stepper drivers)
  • Multi Meter

Step 1 – Print a Case & (Optional) BLTouch mount

Print a case for the MKS Gen L board and optionally the BLTouch mount beforehand. Following are the models I’ve used:

MKS Gen L Case by TeachingTech: https://www.thingiverse.com/thing:3311643

BLTouch Mount for Ender 3 created by registerdthing https://www.thingiverse.com/thing:3003725 .

Step 2 – Label current connections

IMPORTANT: Turn Power Off and Unplug Power Cord

After opening the case, label the current connections on the Ender 3. Below is an image describing what everything is.

Step 3 – Write down current Ender 3 Firmware settings

Write down/take photos of current Ender 3 Firmware Settings for acceleration, steps, etc.

Step 4 – Measure Stepper Drivers’s Voltage

Measure the stepper drivers’ voltage when it’s powered on. Only connect your multi-meter negative lead to the main negative terminal and positive lead to each stepper driver potentiometer and record the voltage value. These will be used for future reference in tuning the external stepper drivers.

Step 7 – Install Stepper Drivers

Install stepper drivers onto the MKS Gen L board. Keep track of which stepper model you use, they may be needed for preparing the firmware.

Step 5 – Prepare MKS Gen L Firmware

Next we will be preparing Marlin 1.1.9 Firmware to be flashed onto the MKS Gen L board. Obviously, we will be including the configuration for the BLTouch and we are keeping the original Ender 3 display. Note: Since we are keeping our original display, we are going to lose the SD card functionality. To get this functionality back, replacing the Ender 3 original display with one that has a SD card.

  1. Download Marlin 1.1.9 release firmware from github.com. Direct link: https://github.com/MarlinFirmware/Marlin/releases/tag/1.1.9
  2. Extract files from the zip or tar.gz archive
  3. Copy files from Marlin Example Configurations/Creality/Ender-3 to Marlin Folder. Overwrite files that already exist.
  4. Within Configuration.h change the following:
    1. #define MOTHERBOARD BOARD_MELZI_CREALITY to #define MOTHERBOARD BOARD_MKS_GEN_L
    2. #define INVERT_X_DIR true to #define INVERT_X_DIR false
    3. #define INVERT_Y_DIR true to #define INVERT_Y_DIR false
    4. #define INVERT_Z_DIR false to #define INVERT_Z_DIR true
    5. #define INVERT_E0_DIR true to #define INVERT_E0_DIR false
    6. #define E0_AUTO_FAN_PIN -1 to #define E0_AUTO_FAN_PIN 7
  5. (Optional) BLTouch Configuration.h changes:
    1. //#define BLTOUCH to #define BLTOUCH
    2. //#define BLTOUCH_DELAY 375 to #define BLTOUCH_DELAY 375
    3. #define X_PROBE_OFFSET_FROM_EXTRUDER 10 to #define X_Probe_OFFSET_FROM_EXTRUDER -42
    4. #define Y_PROBE_OFFSET_FROM_EXTRUDER 10 to #define Y_PROBE_OFFSET_FROM_EXTRUDER -5
    5. //#define AUTO_BED_LEVELING_BILINEAR to #define AUTO_BED_LEVELING_BILINEAR
    6. //#define Z_SAFE_HOMING to #define Z_SAFE_HOMING
  6. Install U8glib package under Sketch -> Libraries -> Manage Libraries
  7. Configure the stepper driver settings under Configuration.h. Search #define X_DRIVER_TYPE and change the options to match the same models used. A4988 is automatically assumed the stepper driver for all stepper locations.
  8. Try click on the check mark on the top left, this will compile the project and ensure no errors shows up on the bottom status window.

Step 6 – Flash Firmware

Connect the MKS Gen L board to the computer with Arduino IDE installed. Ensure under Tools -> Board is set to Mega 2560, Tools -> Processor is Mega 2560, and you’ve selected the proper port. Then click the button on the top left with an arrow pointing right.

Step 8 – Swap cases & boards

Warning: Turn off power and unplug power.

Unplug and unscrew everything from the Ender 3 board, by now each should be labeled to where they go. They should correspond with the labeling on the MKS Gen L board.

Note for the Ender 3 sensors, you may need to trim off the bottom left notch as shown above.

Step 10 – (Optional) Install BLTouch

I installed the BLTouch Mount for Ender 3 created by registerdthing https://www.thingiverse.com/thing:3003725 .

For plugging in the BLTouch, the 2 pin connector goes into the z min sensor with black to the middle pin and white to the S(signal) pin. The 3 pin one (brown, red, & orange pins) plugs into the last 3 pin socket as shown in this picture.

Step 9 – Adjust Stepper Drivers

Turn on the power and adjust the stepper driver potentiometers with an insulated screw driver and measure with a multimeter to get as close as you can get to the values you’ve written down under step 4. Essentially, the same as measuring in step 4.

Step 11 – Calibrate

With BLTouch, include G29 after G28 command in all GCODEs and adjust the bed corners to be within 0.1 mm or better of each other. Also, adjust the Z offset when Z axis is at 0 after G28 and G29 commands using https://nate15329.com/3d-printer-calibration/.

3D Printer Calibration

Here’s what I use to calibrate our 3D printers. There are many guides out there for most of the methods and didn’t see the need to go into heavy details.

Calibration Tools used:

  • Pro-Grade Electronic Digital Caliper 82806
    • Know your accuracy tolerances, ours was +- .02 mm for lengths below 100mm with a resolution of .01 mm
  • Thin Wall Calibration https://www.thingiverse.com/thing:342198
  • Single sheet of paper

1.Initial Extruding Calibration

First thing we will need to calibrate on a new 3D printer is the filament extrude rate. It is very important to get this as accurate as possible, minor tweaking can be done with extrusion multipliers.

To figure this out by telling the printer to send 30 mm of filament through with the hot end disconnected and measuring with a caliper to see if the amount is accurate. Then update the stored value of Esteps/mm under Marlin Motion options by following this formula: Current Esteps/mm * 30mm / Actual amount of filament pushed

For example:

  • Current Esteps/mm: 93
  • Tell printer to extrude this amount of filament: 30mm
  • After measuring the amount of filament extruded: 29.33 mm
  • New Esteps/mm value = 93 * 30/29.33 = 95.124

2. Bed Leveling

Bed leveling is crucial for it will either allow your print complete properly or outright fail later on besides filament run-out or the disastrous thermal runaway. There are numerous ways of getting this done usually by sliding a piece of paper between the heated nozzle and heated bed, or something similar to a BLTouch or a conductive sensor.

The methods that are used often:

  1. 1st is done with piece of paper between heated nozzle and heated bed at normal printing temperatures for the printer. Since I print mainly in PLA, the temps would be at 200 C and bed at 70 C. Then manually level the middle, then the 4 corners where the paper is slightly catching between extruder and the bed
  2. Next, print Bed Leveling squares that looks like the 5 dot side on dice, 1 mm height and slightly adjust our leveling while it prints and wait a few lines are printed after adjusting and see if its flat and clean looking and doesn’t come off of the bed easily. An example of these squares on Thingiverse: https://www.thingiverse.com/thing:2789086

For Auto Bed leveling, a great bed visual is from OctoPrint with the plugin Bed Visualizer. It will highlight which corners need to be readjusted much better and readjust the dark red and blue slightly. Just keep an eye on the visual scale as it will re-adjust.

3. Wall thickness

Next up to calibrate our Wall thickness, please note that this will affect your bed leveling, extrusion multiplier, and/or Esteps/mm. Essentially with .2 mm nozzle, print a hollow cube with .2 mm thick walls with a layer height of 0.16 mm (80% the size of the nozzle), then measuring with a caliber. A good resource to use are the Thin Wall calibration files created by MEH4d at https://www.thingiverse.com/thing:342198

Once the .2 mm thick walls have been printed, measure the wall thickness with the caliber but exclude the bottom of the walls. The bottom will usually be a tad off due to 1st layer height/bed leveling is a tad off. If the thickness is off try adjusting the multiplier between .9 and 1.1, but keep in mind of your calibers limits. For example, if the measured result was .19, you could be very will be accurate.

If you had to adjust your multiplier to get best results outside of this range, place the multiplier back to 1 and adjust your ESteps/mm. Lower if the walls were too thick and the opposite if the walls were thin. After readjusting, you may need to readjust the bed level and layer heights.

Usually, a good max layer height for each of the nozzle sizes are at 80% as shown below:

  • 0.2 mm nozzle = 0.16 mm layer height
  • 0.3 mm nozzle = 0.24 mm layer height
  • 0.4 mm nozzle = 0.32 mm layer height
  • 0.5 mm nozzle = 0.40 mm layer height
  • 0.6 mm nozzle = 0.48 mm layer height

4. XYZ Calibration Cube

At this point, print a calibration cube and measure with the caliber. Usually, it’ll be within measured dimensions that are to be expected. Check how the cube looks by actually looking for infill, speed, and other issues and try to correct them in our slicer program. Slowing down the speed improves many issues at this point.

5. Stress Test

Now its time to stress test your printer. Good set of models to use are by ctrlV on Thingiverse especially https://www.thingiverse.com/thing:704409 and then part fitting a M4 nut in the slot. Also, look at how well the filament retraction works and increase or decrease the retraction length.

MRRF 2019

1st time going to MRRF (Midwest RepRap Festival), We had enjoyed going to it. I had meet and talked briefly with few well known content creators.

  • Barnacules Nerdgasm
  • 3D Printing Nerd
  • Nerys
  • Ben Heck

I had gotten a few sample filaments to try and will be making the Sample Spool by Nerys (https://www.thingiverse.com/thing:2942019) relatively soon

  • Filament PM: MARRBLEJet
    • Figured this would be a good one for Statue Art pieces
  • Carbon Fiber Extreme from Atomic Filament
  • Glass Fiber Nylon from FiberForce Italy
  • Filament PM: RUBBERJet 88Blue
  • Filament PM: GLOWJet

I was always curious on how the fiber and rubber based filaments quality would work with my printers. Proto-Pasta metal infused filaments are another type to try out sometime this year. Since I don’t have any harden heads for these abrasive filaments, we’ll just sacrifice my brass ones and get them replaced after tinkering.

3D Gloop and their latest project Glooped! was interesting. 3D gloop is basically a stronger superglue for PLA and ABS prints. Meanwhile Glooped! is a primer layer to be applied on top of any print to smooth layer lines and chemically bonded to the plastic. I had picked up a small tube of 3D Gloop to try it out on a few prints. Glooped! as far as we know isn’t available yet.

The following things that I think could make MRRF better:

  • Larger area
    • The walking paths were often narrow and crowded which made it hard to move between booths
  • Map layout and defining table areas
    • Reduce the need to bring cards and a quick reference for all of us of where certain booths are

New 3D Printer – Ender 3

Due to having problems with my version of HyperCube 3D printer, I’ve decided to acquire a Ender 3.

I like having the latest printer firmware installed, mostly for safety concerns. I’ve upgraded the Marlin Firmware to the latest and using the sample Ender 3 config by using a USBtinvisp v2.0 board.

Currently, I’ve upgraded the Ender 3 with the following addons: