A 3D Printer is a CNC (Computer numerical control) device that uses an additive manufacturing process to create parts with a variety of functions. There are many different types of 3D printing technology. The first task for starting this project was to choose the type of 3D printer to build. The most common forms of 3D Printing found are SLS, SLA, DLP, and FDM. deciding between them I had to figure out what I wanted out of the 3d printer. I knew I wanted fast prototyping and something simpler to make so I settled on FDM, the most common form of 3d printing among hobbyists.
Beginning my project:
To start my project I had to research the main parts of a 3d printer and figure out how to source the parts. I knew I wanted to build this 3d printer as cheap as possible so my first steps were to see what I could recycle/ salvage. To design around this I had to pick a printer style that would allow for the most modularity. Below is a list of parts I knew I had to design around.
This part was the easiest to decide on and source. Almost all 3D printers use the same motors either NEMA 17 or NEMA 14. At first, I had looked at taking apart some broken laser printer and salvaging their stepper motors but after taking apart 5 old printer I soon found that only old printers have stepper motors and all new ones have a special dc motor with a custom driver board build onto the motor that allows it to maintain constant RPM no matter the load. Although these motors are cool and I’m looking forward to finding a project for them they won’t work for a 3D printer.
Again like stepper motors in the DIY 3d printing world controller boards are pretty standardized. Typically these boards are designed around the ATmega2560 chip and many are shields for the Arduino Mega. I chose the most common and cheapest DIY board called the Ramps board. This board is an Arduino mega shield that has pins for a power supply, up to two extruders, a heated bead, fans, 6 stepper motors, and a display with an sd card. I was able to buy it cheap from china at the beginning of my build and it came in around the same time as the rest of the parts after sorting them out a month later.
Build space and build plate material was one of the most important factors in deciding the type of 3D printer. Some criteria I set was the ability to have a heated bed while also allowing for a large print space. Below are some designs i considers with these buildplate criteria:
3D printing robotic arm
Pro: large print space, compact, transportable, cool
Cons: less stable so lower quality prints, no ability for heated bed
Hanging 3D printer
Pro: large print space, transportable, cool
Cons: no ability for heated bed, large profile when set up
Delta 3D printer
Pro: less stepper motors, quicker print speed, taller prints, allows for headset bed
Cons: tall profile, small X and Y profile, hoarder to get good quality
Cartesian 3D printer
Pro: most common type so lots of resources on build, sturdy, allows for headset bed
Cons: kind boring looking
So after some time of racking my brain to find a reason to make a cooler printer I decided to go with the most practical option for my first printer, a cartesian printer. While taking apart the laser printers I had salvaged a piece of glass from a scanner and instantly knew it would be my print bead. Although I don’t think it will withstand being heated, it’s at least a size I feel satisfied with and can get a better piece of glass cut at a later date.
There are many forms of motion. First thing was to decide on the use of linear motion, circular motion, or both. Although 3d printers that use some form of circular motion typically print faster I knew it was more challenging then what I wanted to take on for my first 3d print so I chose linear motion. With linear motion the most common forms are using either smooth rod or linear railing in combination with belts and/or threaded rod. I chose to go with a smooth rod which although is considered lower quality would be cheapest and I had expected to salvage enough smooth rod from the laser printers I disassembled but because of the varying sizes I ended up just buying some. After completing the printer though if i could go back i would have chosen to use a linear rail system like the Creality line of printers since it is both cheap and stable and i ran into problems with the linear railing not being strate enough or having too much friction as i decided to use 3D printed Linear bearings.
The extruder can be one of the most expensive parts. Because of this I had just chosen to base my design on a free extruder assembly I was able to get from my high school that was broken but only needed a new nozzle. The extruder was to an up mini and used a magnetic clip mechanism to make the print head detachable for mantaines. I hope to use this clip for exchanging print heads. Using this print head however did present some problems.
The up mini uses custom filament from the company that melts at a lower temperature. Using normal filament on this extruder meant that the cooling fans were not adequate and the assembly would start to melt its housing. To mitigate this I had to mount better fans on the housing and later will probably need to design a whole new assembly.
Another problem this print head presented was that the thermistor built into the hot end. The up mini uses the PT100 thermistor which is a high quality sensor that can measure temperatures up to 500c with great accuracy. The only problem was that this thermistor uses RTD (Resistance Temperature Detector) sensing and most 3D printer boards including my Ramps board use NTC (negative temperature coefficient) sensing since it is cheaper. This meant I needed to buy an amplifier board which I found being sold by E3D.
After mitigating these major problems the print head was working and I was able to design a mount for the extruder and wire it to the microcontroller board. The wire I used was from a surplus store and worked out nice other than being a bit too short. I was able to buy a connector that matched the one on the extruder and combined some downloaded models for extruder mounts to get the Up Mini extruder the mount to my Prusa based Y-axis railing.
For the 3d printer design i decided to go with a typical box type of 3d printer. To go with this I decided to make the control board separate such as in the Creality CR-10.
At this point in time the 3d printer is in a prototype stage. The z-axis system is duct taped to the frame, the y-axis is too short so a foam spacer is placed between the heated plate and the glass build plate. The extruder is also currently jammed in the cold end of the extruder due to overheating which may be the end of the extruder. I was however able to make a handful of prints with varying success before braking the extruder.
After fixing some small details on the printer such as adding z-axis mounts and y-axis spacers the majority of the mods I plan on doing revolve around the extruder. I plan on experimenting with sending a serial connection to the extruder which would allow for less wires and a larger range of extruder types. I may give up on 3d printing with this machine as I now own an ender 3. I currently plan on playing with different machine heads such as:
pick and place
chocolate 3D printing
Silicone 3D printing