[graaja]

DIY | Upgrading my Prusa i3 Mk3 3D Printer to Mk4

I recently upgraded my Prusa i3 3D printer from Mk3 to Mk4. This thread documents this experience.

Likes:

• Automatic first layer calibration that produces perfect finish on the first layer
• "Input shaping" technology that increases print speed by 40%
• Graphic LCD display provides a refreshing look to the printer
• Network printing
• New extruder design with ease of disassembly for maintenance

Dislikes:

• Very expensive. The upgrade kit cost me almost the same price that I paid for the new printer in 2018. The price of the new printer has gone up too, of course
• Need to print all the required plastic parts. Though this is fun, I had to discard one batch which had a small glitch due to power.
• Some of the original bearings have to be re-used. I realized this only during the assembly and had to install the old worn-out bearings. These will have to be replaced sometime soon.
• The disassembly adds extra time compared to assembling a new printer

Prelude: The Prusa i3 Mk3

For many of my hobbies like electronics, astrophotography etc., I had to make custom parts like enclosures, adapters etc. In 2018, I decided to get a 3D printer for this.

At that time, after lots of research, I decided to get the Prusa i3 3D printer. There were many cheaper options available in the market, but I had read that most of these printers are not reliable and one has to spend significant time troubleshooting to keep these printers running.

Prusa printers, though expensive, had a reputation for reliability and quality of prints. They had several useful features like automatic bed leveling, filament detection, resume a print from power failure etc. So, went ahead and ordered the Prusa i3 Mk3 printer. The printer came in both assembled and kit forms. As I love DIY, I got the printer in kit form and assembled it myself.

The complete kit


Assembling the printer


The assembled printer


The printer served well during the past 6 years. Though I still consider the printer to be under-used, I printed lots of interesting stuff with this printer. A few of them are below.

Designed and printed this adapter to connect my camera to the 6" SCT telescope.


Downloaded and printed this adapter to fix my phone to the dovetail base of my equatorial mount to perform polar alignment.


Adapter to fix a webcam to the telescope.


Did some fun stuff too.

Designed and printed this sewing thread organizer for my wife.


The printer lived up to its reputation for reliability. In the past 6 years, there were only a couple of problems I had faced.

1. Once the print nozzle clogged up, and I had to replace the nozzle. But this can be considered as a wear and tear replacement.
2. The LCD display lost contrast and would be legible only when viewed from an angle. As this did not affect the printer's functionality, I left it as is for a couple of years, though this was an eyesore.

Through the years, there were several updates to the printer. But as none of them were significant (like midlife facelifts to cars), I never considered upgrading. A couple of months back, I saw that an upgrade kit for Mk4 was available. This is like a new generation of cars - F30 to G20. I found several interesting feature additions.

List of new features:

1. A completely new extruder assembly with an easy-to-remove print nozzle
2. A 32-bit processor board with a graphic LCD display
3. A technology called "Input Shaping" that can increase print speeds by 40%
4. Automatic first layer calibration - more about this later.
5. Network printing. Earlier, I had to copy the print file to an SD card on my PC and transfer this SD card to the printer. Now I can directly send the print file through the local network.
6. New stepper motors that have 2x the resolution of the previous generation.

After checking out several reviews and considering the new features, I bit the bullet and ordered the upgrade kit.

The kit arrived from Prague in 5 days. I had to pay a hefty customs duty, but FedEx handled the process smoothly.

The package.


The content. I did not unpack all the boxes and take a picture as there were lots of components grouped in the boxes.

[graaja]

Part 1: Printing the Plastic Components

Before I could start the upgrade, I needed to print all the plastic parts necessary for the upgrade. The new printer kit comes with all the plastic parts required for the printer as part of the package. These parts are not included in the upgrade kit. Instead they provide the 3D model files of all the required plastic parts and we have to print these parts using the existing printer. There were 40+ individual components to be printed with a total print time of 40 hours.

I printed these parts over a period of 3 days. All these parts had to be printed using PETG filament which has more tensile strength compared to commonly used PLA filament. The filaments needed to print the parts were shipped as part of the kit. They had sent two colors - black and orange.

The following pictures show the printed parts.

Cable guides and covers.


Extruder components #1


Extruder components #2


LCD Display components


Y Axis components


X and Z axis components


Parts Packaging and Assembly Instructions:

Before proceeding to the next part, I would like to mention the attention to detail shown by the company in putting together the kit and in writing the assembly instructions. Every single component needed for the assembly is packed in pouches with labels on the pouches listing all the parts. Screws and fasteners of all sizes carefully packed in individual packets with a few spares. A spare component pack with a mix of parts that can easily get misplaced or damaged during installation. During the assembly, I had dropped a pin that holds the belt pulley. Even after spending 30 minutes, I could not locate this pin. Luckily, this pin was also in the spares packet and saved the day.

An example of how the parts were packed with labels on each cover listing all the parts inside.


The assembly instructions were available online. Every single detail has been listed in the instructions.

Assembly Instructions

An example screen shot of how the instructions are explained in detail with clear pictures.

[graaja]

Part 2: Disassembling the Printer

Once the plastic parts were printed, it was time to upgrade. The first step in this process was to disassemble the printer. Only a few parts from the existing printer would be re-used for the upgrade. Everything else will be replaced with new components.

Components reused:

• Frame
• Power supply
• Heated print bed
• Y-axis base, linear bearings, and smooth rods
• X-axis linear bearings, and smooth rods

Components replaced:

• Processor board
• LCD display
• Extruder assembly
• X, Y and Z axis motors
• Z axis smooth rods and linear bearings. These have been increased in size from 8mm to 10mm for smoother operation
• Wiring harnesses

A few pictures from the disassembly. This took about 3 hours to complete.

Working on disassembly.


A work-in-progress picture.


The printer completely disassembled.

[graaja]

Part 3: Assembling the Printer

Assembly took almost 12 hours. Most of this time was spent in reading and understanding all the steps described in the instructions manual, and locating all the parts - plastic components, screws, pins etc. from various packets. I also made some mistakes during the assembly and had to redo the process sometimes. If I were to do this again, I may be able to do this in 6 hours.

Following are the various main functional blocks that have to be assembled.

• Heated print bed
• Graphic LCD
• Processor board
• X-axis motor, smooth rods, and bearings
• X-Axis carriage
• Extruder assembly
• Z-axis assembly - motor, smooth rods, and bearings
• Y-axis assembly - motor, smooth rods, bearings, and heated print bed

As the assembly was very involving, I missed taking pictures of many functional blocks. Below are some pictures I managed to click during the assembly of some of them.

The heated print bed: This is a magnetic bed on which a metal sheet is placed and the parts are printed on this metal sheet. Depending on the material printed, the bed is maintained at a temperature to keep the part sticking to the bed while the print is in progress. This bed can be heated to 100+ degrees Celsius. A thermistor is used to sense the temperature and control the heater. The printer maintains the bed to within 1 degree of set temperature.


The extruder: This is the part that pushes the filament through the heated nozzle. For Mk4, they have developed a new design with planetary gears to push the filament through. The extruder assembly also has a built-in load cell that is used to do the first layer calibration. This is a fascinating design and was a little complex to assemble.

The parts needed for the extruder.


Extruder assembly in progress. The planetary gear is assembled.


The fully assembled extruder assembly.


The processor board: This is the brain of the printer and has a 32-bit microcontroller that controls all the operations of the printer. The board is placed inside a metal enclosure and has connectors for connecting various components like motors, sensors, power cables etc.

The processor board is installed inside the enclosure.


All cables are plugged into the respective connectors.


The WiFi adapter board plugs into the processor board.


A few work-in-progress pictures. The living room looked like a battlefield for 2 days.






X-Axis Assembly: This assembly carries the print head and moves in the X Axis. The assembly has a base that holds a breakout board with connectors to connect various components of the print head like heater, thermistor, extruder motor, filament sensor, load cell etc. A wiring harness runs from the back of this assembly and connects to the processor board. The extruder assembly is mounted on this carriage.

The X-axis carriage assembly with the breakout board.


The wiring harness connects the X-axis carriage to the processor board enclosure. Note how neatly the wires are bunched inside a sleeve. A nylon wire runs along the wires providing necessary mechanical support to the wires.


The extruder is mounted on the X-axis carriage.

[graaja]

Part 4: Powering Up, Calibrations, Test Print, First Impressions, and Conclusion

I started the work on Saturday morning at 9 AM and completed the work on Sunday evening at 7 PM. The total time taken was about 40 hours for printing all the plastic parts and 15 hours for the disassembly and assembly.

The final result.




Powering up the first time. The printer performed several diagnostics and calibrations like finding the home positions of X, Y and Z axes, testing the heaters of the print bed and print nozzle, testing the load cell on the extruder, testing all the stepper motors etc. This took about 10 minutes and was a very smooth process.


First test print.




The great satisfaction was that everything worked the first time the printer was turned on. All because of the great attention to detail in putting together the upgrade package and the detailed assembly instructions.

Printing the cell phone adapter for polar alignment for a friend.




Having some fun. Printing a Porsche. This model is very small and printed at 200-micron layer thickness. With a 100-micron layer, this should turn out to be smoother.


First Impressions and Conclusion:

It has been just about 10 days since the upgrade and I have printed a few parts. Other than the dislikes I had mentioned earlier which were more on the upgrade kit than on the printer itself, my experience has been positive. I love some of the new features.

Automatic first-layer calibration: First-layer calibration is where we have to set the distance between the nozzle and the print bed for the first layer to print. Too short a distance the first layer will become too squishy. Too long a distance, the first layer will separate into individual threads. To get the perfect finish on the first layer, in the previous version, I had to perform a manual calibration by printing a test pattern multiple times and adjusting the first layer distance till I got the perfect finish. I never managed to get that perfect finish. But in the new version, the printer automatically does the first layer calibration. The printer moves the nozzle and touches the print sheet and senses the pressure using the load cell and accurately sets the first layer distance between the nozzle and the print bed. With this automatic first-layer calibration, I get a very smooth finish on the first layer. This is by far the best feature I like in this version.

Network printing: I can now send the print job directly from my PC to the printer through the home Wifi network.

Graphic LCD: Compared to the dot matrix alphanumeric display in the older version, the graphic LCD shows lots of cool information about the print including the picture of the part being printed.

I have yet to test the improvement in print speed or the improvement in print quality from the increased resolution of the stepper motors. I will do these tests in the coming days. So far, I am very happy with the upgrade.

After a long time, I got a chance to do a complex DIY project. Overall, a very satisfying project, and time and money well spent!

That's all folks I have for now. Thank you for reading!

[BulZire]

Raaja Sir, this is super interesting!. Thanks for sharing .
you are seriously a character to get inspired from. Technology, Fitness, Cars, Stars and what not that we don't know about you yet ?

[sagarpadaki]

graaja, this is a pro level DIY! I like the meticulousness and the attention to detail that you give to your work!

I noticed perfect crimps on the insulated terminals. Can you share what crimper you use?

[graaja]

Originally Posted by BulZire

Raaja Sir, this is super interesting!. Thanks for sharing .
you are seriously a character to get inspired from. Technology, Fitness, Cars, Stars and what not that we don't know about you yet ?

Thank you so much for the kind words! I do a little bit of farming and do some DIY stuff there too

Originally Posted by sagarpadaki

graaja, this is a pro level DIY! I like the meticulousness and the attention to detail that you give to your work!

I noticed perfect crimps on the insulated terminals. Can you share what crimper you use?

Thank you so much for the kind words

For this DIY, I did not have to crimp the terminals. The wiring harnesses with proper crimped terminals were part of the upgrade package.

For my other projects where I do my own wiring harnesses, I use the below crimping tool.

[sagarpadaki]

Originally Posted by graaja

Thank you so much for the kind words

For my other projects where I do my own wiring harnesses, I use the below crimping tool.

Attachment 2590758

Attachment 2590759

I have a similar one for crimping ferrules for wiring terminations In panel boxes. Indespesible tool for me once I started using it!

Wanted to get a proper one for crimping insulated and non insulated terminals and thought you had done the crimping from the pics.