Some friends always complain about Guokr Lab: Your tutorials always have a “use a 3D printer to print parts”! I can’t do it! It’s unfair! Well, today, let’s invite our friends from DFRobot to teach you how to DIY a desktop 3D printer that belongs to you!

The shell of this 3D printer is made of acrylic cut into shape, operated by three 35-step stepper motors with a 0.9-degree step angle, and the printing volume is 100x100x80mm. This volume is suitable for printing small gifts and ornaments, but what can you do with 100mm? Alright, without further ado, let’s look at the photos!

First, when you see its photo, you might think it looks like a tinyboy (open-source mini 3D printer)? But it’s not! Its shell was redesigned by creators abroad based on the tinyboy proportions, and the improvements and upgrades are significant. I only have a CAD drawing of the shell; what about the other parts? Let’s find them on Taobao!

2. 12864 LCD offline control screen, this screen does not need to connect an adapter plug; it can be directly connected to the mainboard.

3. A4988 stepper motor driver module, when installing, the adjustable resistor should face to the right. When powered by 12V, the adjustable resistor on the back of the 4988 is in the middle position, and the output current is about 1A. The stepper motor current used this time is relatively small, so it can be adjusted to a lower output current (clockwise rotation increases, counterclockwise rotation decreases).

4. 35-step stepper motor, thickness 20mm.

5. 12V power adapter 48W, current is 4A, and the current for each stepper motor is 0.58A, so this power supply is more than enough.

1. The screw rod needs to be cut according to height; the optical shaft should be purchased with the required dimensions cut by the seller. Other components are as follows.

2. Cut the acrylic shell according to the CAD drawing, and choose 3mm (2.8mm) thickness as the most suitable. At first, I chose a thickness of 5mm, and as a result, it couldn’t be installed.

3. The remote extruder has a 42-step stepper motor, and the remote extruder head nozzle is 0.3mm.

Some auxiliary components:

1. First, install the Y-axis frame, using M3x12mm screws for installation. Tighten the screws moderately to prevent the acrylic from cracking.

2. Install the extruder head moving bracket and linear bearings; here, use nylon bolts to fix the bearings.

3. Install the remote extruder head.

4. Install the Y-axis stepper motor.

5. Insert the extruder head moving bracket and optical shaft into the Y-axis frame.

6. Install the synchronous belt pulley bearing with stops, toothed synchronous belt, and screw rod lifting nut.

7. Install the Z-axis lifting linear bearings.

8. Install the Y-axis moving limit switch.

9. Remove the original screw from the X-axis stepper motor, and use a long screw with two bearings to fix it. This is mainly to increase the motor gear’s wrapping angle to prevent the synchronous belt from slipping.

10. Install the shell, Z-axis motor, and coupling, X-axis motor, X-axis platform synchronous belt pulley, and X-axis limit switch. (This limit switch was taken from a telephone.)

11. Fix the X-axis linear bearing and X-axis acrylic printing platform components with bolts, and paste the platform with masking tape.

12. Use the 3D printer to print the base.

13. Insert the printed base, install the X-axis printing platform, and insert the optical shaft and synchronous belt.

14. Install the remote extruder into the back panel.

15. Connect the stepper motor extension cable and insulate it with heat shrink tubing.

16. Organize the wires of each part with the winding protection sleeve.

1. Main control board wiring

A1, A3 connect to the positive of 12V or 24V.

A2, A4 connect to the negative of 12V or 24V.

A1, A2, A3, A4 must not be connected incorrectly, of which A3 and A4 are responsible for the power supply of the mainboard, motors, and extrusion, while A1 and A2 are responsible for the power supply of the heated bed.

B1, B2 connect to the heated bed power supply.

C1, C2 connect to the controllable fan.

D1, D2 connect to the heating power supply of the extruder head.

E1, E2 connect to the temperature sensor of the extruder head, generally using a 100K NTC B3950. During testing, if this temperature sensor is not connected, the system will enter a protection state, and the motor will not turn.

F1, F2 connect to the temperature sensor of the heated bed, generally using a 100K NTC B3950.

G1, G2 connect to the second extruder temperature sensor, generally using a 100K NTC B3950.

H1, H2 are used to connect the display screen.

M1, M2, M3, M4, M5 connect to the X, Y, Z, E0, E1 motors respectively, among which the indicated 1A1B is a set of coils, and 2A2B is another set of coils. If the motor direction is incorrect, you can swap 1A1B to change the motor direction.

L1, L2, L3 connect to the limit switches of the X, Y, Z motors, for machines like Mendel i3 that return to the origin negatively, connect to the two terminals marked X, while for Delta machines that return to the origin positively, connect to the terminals marked with a triangle.

Notably, for dual Z-axis machines, do not connect to M3. Please connect the two Z-axis motors to M5 and M6 separately, and they will automatically run in sync.

J1, J2, K1, K2 are used for outputting two sets of power supplies, connecting to the fans, with the voltage equal to the main power supply voltage.

P1 is the power selection jumper, which can choose to power the chip through USB or external power supply (marked as 12V, actually connecting to 24V means it is 24V) for the mainboard. The distinction is as follows: when the jumper is on USB, the USB cable must be connected for the mainboard to work properly. When the jumper is on 12V, 12V must be connected for the mainboard to work properly. Generally, the jumper is on 12V for offline printing. S1, S2 are two serial port interfaces, S1 is serial port 1, which is the serial port converted from USB and cannot be used simultaneously with the USB cable, while S2 is serial port 2, which is independent.

R1 is the automatic reset jumper, which should generally have a shorting cap inserted.

2. Initially, I wanted to install the mainboard on the base, but due to the raised stepper motor on the base, it couldn’t be installed. Additionally, the installation position of the control display screen was quite strict. All of this was caused by the fact that this 3D printer is too small, leaving no space for hardware installation. So I had to compromise by using a box from an Apple phone to hold the mainboard and control display screen~

3. Install the control mainboard and display screen into the already drilled box, considering the heat dissipation issue, add a 5V cooling fan.

4. Modify the printing volume in the Configuration.h source file, run Arduino 1.0.2 IDE, click “File” and then click to open the Marlin.ino guide file in the source code, select the board as Arduino Mega 2560, and upload the firmware to the control board (note: this Chinese version firmware can only be uploaded using Arduino version 1.0.2, other versions will result in errors!).

5. Secure the control box to the back panel of the printer with screws, and power on to test whether the X-axis, Y-axis, and Z-axis run normally. During the printing test, if the motor overheats or vibrates and cannot operate, use a multimeter to test the current size of the motor driver module and adjust the current of each motor as needed. (Note: The motor’s drive current is not better when it is larger; it just needs to be sufficient. If the current is too small, it will not be able to move, and if the current is too large, it will also lose steps, causing excessive vibration of the motor.)

Great job!!! What? You say it looks ugly? Don’t mind these details, haha!!! The shell CAD drawing and the Chinese version source code are welcome to click Read the Original to download yourself.

This article has been authorized by DFRobot, and reprinting is prohibited.

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