Máy in 3D mini tự chế từ linh kiện cũ

NOTE: This project is still in development. 3D models may still change slightly. Once finalized, CAD file will be released. The description and documentation are currently incomplete and will be finished later.

Introduction

The goal of the project was to create a mini 3D printer that could be assembled only from "things at home". Specifically from:

• 3D printed components
• Commonly available fasteners
• Parts salvaged from old CD-ROM drives
• Components from old PC accessories
• Parts from older Creality printers (see section below)

Required Components

From Creality Printers

Some of the first cheap 3D printers to gain wide popularity were models from Creality, particularly the legendary Ender 3.

However, the stock version of the Ender 3 had several problems that 3D printing enthusiasts often upgraded. The most frequently upgraded components were: mainboard with noisy A4988 drivers, print head, and single-drive extruder. These are exactly the components needed for my mini 3D printer:

• Creality motherboard (V1.1.4)
• NEMA 17 + single-drive extruder
• Print head:
  • nozzle
  • heat block
  • heat break
  • heatsink
  • Creality heater cartridge
  • Creality nozzle thermistor
  • 40x10 fan
  • PTFE tube

As mentioned above, these are used, problematic components. Therefore, you can’t expect high print quality or reliability from the printer. Especially not in combination with stepper motors salvaged from CD-ROM drives, which don’t provide enough torque and will be used for movement in the x, y, z axes.

From CD-ROM Drives

You’ll need to disassemble three old CD-ROM for the mini 3D printer. From each one, you’ll need:

• stepper motor with a lead screw
• spring
• smooth 3 mm guide rods

From PC Mouse

From a computer mouse, only three switches are needed:

• Omron D2FC type

Additional Accessories

Additional accessories required:

• metal plate
• wiring cables
• power supply
• (control computer)

Metal Plate

This can be cut from any flat sheet metal, such as a CD-ROM drive cover or computer case panel.

Wiring

For all wiring to switches and motors, I use standard stranded UTP cable. In general, any insulated stranded wire will work just fine.
1 m of UTP cable is more than enough for the entire printer.
It’s also nice to have connectors for crimping, though this can be avoided by soldering directly to the control board.

Power Supply

A PC power supply capable of delivering 24V can be used.

However, for greater compactness, I opted to power it via USB-C using a PD module:

Control Computer

A computer is not necessary for operating the printer.
However, since I want to use Klipper firmware, one is needed.
Practically any (old) computer that can run Linux will work — possibly even an old rooted smartphone.

Again, for compactness, I chose a Raspberry Pi 4 mini computer:
 

And printed this case for it:

https://www.printables.com/model/84680-raspberry-pi-4-case-pimesh4

Fasteners

Under construction.

Printed Parts

All parts are printed from PETG, except for the hotend_mount part. That one should ideally be printed from a more heat-resistant material like ABS (or ASA).

The parts are designed for FDM 3D printing and require no post-processing, except for the carriage part. To achieve a precise and consistent diameter of the guide rod hole, it should be drilled with a 3.2 mm drill bit:

Assembly

Switches

Solder wires to the switches, as shown in the image:
 

Insert the switches into the printed parts and push the cable into its channel using a blunt object:
 

Before screwing the switch in with an M2 screw, it's a good idea to cover it with heat-shrink tubing to prevent accidental shorting of the switch pins:
 

Stepper Motors

First, prepare the stepper motors. If possible, desolder their original connector. Otherwise, carefully snip it off with pliers.
Then solder the individual wires:
 

Crimp the necessary connector on the other end and attach the motor using M2 nuts.

Frame and Other Parts

First, place all nuts into the holes in the printed parts. Then screw all parts together according to the 3D model.

Finally, adjust the endstop screw so that the switch is pressed when the carriage is in its end position:
 

Wiring

Connect the mainboard according to its specification.

Firmware

For my mini 3D printer, I chose Klipper firmware in combination with Mainsail OS.

Under construction.