Designing and building own 3D printer

printer

printer first test

printer motors

printer head

I've started to design and build my own 3D printer from scratch. It is a very good exercise as it covers a very large number of fields:

Computer Aided Design (CAD)

This is almost a mandatory step nowadays to optimize the space usage, detect assembly problems, quickly test concepts and answer some specific questions such as how big will it be and what will be the print volume.

It is also an excellent tool to generate drawings that are sometimes required by suppliers. All the aluminum plates for instance are 5 mm laser cut aluminum sheets that required drawings to be sent to the supplier.

I used Design Spark Mechanical 2.0 (free version of Space Claim) and FreeCAD as these are freewares. If I had a licence, I would have used Catia, PTC Creo or Solidworks but I must admit that Design Spark Mechanical has impressive features for a free software.

Simulation tools

To answer certain questions, there are only two ways. Experimenting or simulating.

For the heat bed, I wanted to know in advance how aluminum would compare to glass in terms of temperature distribution, deformation under heat and heat up time. Most 3D printers have either glass heatbeds or PCB heatbeds. When printing advanced materials with higher temperatures, glass heatbeds are usually preferred. I didn't find many printers with aluminum heatbeds. This made me wonder as to me, aluminum would definitely be a more appropriate material, but perhaps the deformation was too high when heated compared to glass?

I used Code Aster which unfortunately only runs under Linux but is an incredible multi-physics simulation engine.

Mechatronics

Designing mechanical parts is one thing, but having mechanisms actuated by motors is a whole different field.

The motors must be dimensioned properly (torque, speed, precision...), the electronics must be compatible (voltage, power, precision, cooling...) and the whole system must be programmed.

Here is the components I used:

- Nema 17 Stepper Motor 45Ncm 2A 4-wire

- DRV8825 Stepper Motor Driver Module 2.5A

- Arduino Due R3 SAM3X8E 32-bit ARM Cortex-M

- Pololu Shield Ramps-fd Controller Control Board

- Repetier firmware + software

I was able to move the print head in all directions but I was still struggling a little with the speed. The motion wasn't as smooth and quick as expected and I am suspecting the DRV8825 stepper driver to be the issue. I haven't had time to trouble shoot it though.

Electronics

When building a 3D printer, electronics are an essential part of it. Even without building the circuit boards from scratch, it is important to understand the schematics of the board, find the proper connections by referring to the pin and wiring diagrams and perform some troubleshooting and tuning on some of the components. Such a project is an excellent way to understand how electronic circuits are designed and to reinforce the theoretical knowledge about electronics and electricity acquired at school.

Programming

Even though there are firmwares available for most electronics, it is necessary to at least understand the code and even make some adjustments to it. The Arduinos boards run on C++ and the machine code is G-code. Some custom routines need to be programmed specific for the printer such as the homing routine or calibration routine.

Woodworking

It helps to have a carpenter in the family. This unique printer deserves a unique style. The covers hiding the electronics and the columns for the opening mechanism are made out of massive cherry wood.

Make or Buy decisions

Theoretically, everything can be self-made, but what is the added value? This question is important, as self made requires a lot of time compared to buying the item. The price, availability, complexity and quality have all to be taken into consideration in order to make the right choice.

I decided to buy the precision rods, all the electronics, the motors, the print head and contracted someone to laser-cut some aluminum parts according to my drawings. The rest is pretty much made from scratch.