Recently, technologies have been taking leaps and bounds across the planet. In the memory of only one generation, there were typewriters, then dot matrix printers, inkjet, laser. Finally, 3D technologies burst into our world, printers began to print not only text and pictures, but also various details. At first, such 3D printers were expensive, but thanks to the development of technology and DIYers who began to assemble them on their own, they became available even for the poor.
The next step is bioprinters. Bioprinters work in much the same way as 3D printers, with one key difference – they apply layers of biomaterial, which can include living cells, to create complex structures such as blood vessels or skin tissue. It is clear that while at home there is no need to print skin or grow an ear, but using such a printer, you can, for example, print with food gels. And in the world there are already developing companies specializing in meat printing.
This project was developed for the author's graduation project. The goal was to turn a commercial FDM 3D printer into a bioprinter with the lowest possible budget. Usually bioprinters are very expensive – from 20,000 to 500,000 euros.
The challenge was to make this technology available to every user, and the best tool a DIYer has is their own 3D printer. With very few and simple tools, materials and knowledge, anyone who wants to can do it.
As for the capabilities of this printer, the master used hydrogels for printing, which are modern materials. It is also possible to print on chocolate, gelatin or even meat.
Tools and materials:
-3D-printer Ender 5 or Ender 5 Pro;
-Filament PLA and ABS;
-Threaded rod M3 x 120 mm;
-Soldering accessories; -File; -Syringe 10 ml; -Multimeter; Step one: accessories and 3D printing
The components that were used in this project are easy to purchase. The biggest expense will be the Ender5 3D printer. It is important that there was this particular printer, and not another, because the “bioextruder mount” was designed specifically for this model.
Files for 3D printing can be downloaded here.
Some parts need to be printed from ABS plastic because they will be in direct contact with the hot end of the printer.
Step two: dismantling the extruder
After the parts are printed, you need to remove the extruder from the 3D printer.
To install the support you will have to disassemble the bearings of the extruder mounting plate, because the “support” will be installed between the bearings and the mounting plate. To do this, you need a hex wrench and a wrench that comes with your 3D printer.
< a href = "https://usamodelkina.ru/uploads/posts/2021-05/1622459182_1-5.jpg" rel = "prettyPhoto"> Step four: assembling the main body of the bioextruder
You will need M3 nuts and bolts to assemble the body. First you need to insert an M3 nut into the center of the “leadscrew gear” *. Then insert the M3 threaded rod. Then assemble the “leadscrew gear”
on the “replistruder core” and screw the “gear plate” on top.
* Names of the parts are indicated by the names of the files to be printed.
Step five: assembling the motor
Install the “NEMA17 GEAR “.
First you need to screw on the bracket. Then screw the motor to the bracket.
Step Five: Installing the Bioextruder on the 3D Printer
Now you need to install the node on the 3D printer. The knot is simply placed on the support and screwed on.
Step Six: Syringe
Now you need to install the syringe.
Then you need to adjust the system. It is necessary to twist the wheel clockwise until the resistance in the syringe. Then turn the sleeve so that the stop moves down. Now, as the motor rotates the shaft, the syringe plunger will eject the contents.
Step seven: connecting the motor
The motor is no longer in the position it was in the original 3D printer. It is located higher, which means the cables are too short. It will be necessary to increase their length. The technician uses jumpers for this.
The motor used is a NEMA17 motor.
There are 4 wires on each side of the motor. You need to find out which stepper motor cables to connect to the built-in controller. We take a multimeter and set it to dial mode. We call the ends of the wires and find the wires from the coils. We also call the controller wires and connect the groups with jumpers.
If, after connecting, the engine rotates in the other direction, then you need to change the pairs of wires.
Step eight: software
Software that will be used for of this project is Cura. This is the most popular software.
The first thing to do is change the start and end G-codes. The printer returns to its original position by default before printing. In this case, the master makes a test print on Petri dishes. When printing, a problem emerged that at the beginning of printing, the tip of the syringe touched the walls of the Petri dish.
With the new code, the printer platform lowers. Then the X and Y axes move the bioextruder to the center and then the platform moves back to its original position. At the same time, the walls are not touched.
The code can be downloaded below.
Next, you need to tweak some parameters.
Stream: This is one of the most important parameters that you need to tweak. This parameter depends on the diameter of the syringe tip. This value should be set between 500% and 1000%.
Speed: 5 mm/s to 30 mm/s
Layer height: 0.1 mm to 0.3 mm
Initial layer width: 120% to 150%
Filling density: this parameter will depend on the form to be printed
Print temperature: 0ºC
Print cooling on: OFF
Retraction on: OFF
The first time the printer was started, it did not start and the LCD said the printer was “preparing”. The reason is a security code that prevents the printer from extruding filament if the end is colder than 80 ° C, so that users do not break the printer due to insufficient heating of the material.
Ender 5 uses a special Marlin firmware. To make changes to the firmware you need to download the latest version. In the Configuration.h file in the Marlin folder, you can find the lines of code that need to be changed.
Custom firmware can be downloaded below.
Step nine: heating
After making sure everything is working correctly, you can move on to the second stage of the project – a heating system that will keep the printed material at a certain temperature. The first step, if they are not ready yet, is to print the “heating_system” details. This is a two-piece model joined by a loop. You also need to print the “clip” part.
The wizard will use a hot-end heater block that includes a temperature sensor, a heating element, and a silicone cover. Watch the video below to see how (1:20 am to 2:00 am and 3:50 am to 5:20 am).
Block the heater will maintain the desired temperature, but another metal piece is needed to distribute heat throughout the syringe. For these purposes, the master uses a copper tube cut lengthwise.
Then we connect the heating system to the bioprinter (see video).
The heating system can be controlled directly from the printer's LCD screen. Note, however, that if you want to maintain the temperature of your printing material, for example, at 30ºC, this does not mean that you need to set the same extruder temperature. The system has a heat loss percentage of about 60%. To hold the hydrogel at 30ºC, the print temperature must be set to about 85ºC.
You can then start printing.
Below are some of the printed samples. When printing, the artist tried different types of hydrogel-like materials that are easy to find in any store, such as aloe vera, hand creams and toothpaste.