3D printing

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Currently I (Dan) have two printers that come and go from the space. One, the MendelMax, usually stays at home, the other, Mendel Prusa i2 stays at the space and goes to things like artwalk. The i2 will be rebuilt into a Rostock model soon (after onespark), and I hope to update this wiki with the steps that come with building one. We have three other members that are currently constructing theirs being Travis with a Wallace, Ronnie with a Mendel i2 and Wyatt with a RostockMax.

Here are Dan's two current printers: i2 on left, max on right

These type of printers are known as 'additive' printers as they add material to build the structure. They print in primarily ABS or PLA plastics but can also print in nylon, wood, and other materials.

Models

3D printers range from the ready-to-print but expensive, to the open-source but (relatively) cheap. They can print a wide range of objects in many materials, but rely on only the science of plastics and the precision of engineering. You can go big and expensive or small and cheap to suit your needs. Personally I enjoy the RepRap project and the fruits it has bared. Various reprap models can be found here.

Plastics

ABS Thermoplastic:

Acrylonitrile butadiene styrene, this plastic is a natural gas and petroleum derived material. This is the plastic I've always used, more information about it at wikipedia

  • Pros: it is known for its durability, relative flexibility (compared to PLA) and is a good material to work with. This plastic dissolves with acetone, so you can use acetone to clean the bed surface but you can also as a bonus do something called 'acetone smoothing' where you heat (very carefully, acetone is EXTREMELY flammable) an acetone bath to steam, then dip the print into the steam for several seconds, pull it out and let it sit. You will then (if you have done it right) have a nice glossy print that you can show off.
  • Cons: you have to print with a heated bed, it has a tendency to curl up off the bed on larger prints, and releases somewhat toxic fumes so should be printed in a fairly well vented or large air space else you may get a headache.


PLA Thermoplastic:

Poly(lactic) acid, this plastic is an organic plastic generally derived from corn starch (in the US) but can be made from various organic materials. I have not tried this plastic, but have seen good results from others and may try it in the future. More information about it on wikipedia

  • Pros: you do not have to have a heated bed, curling is generally not an issue, you print at a lower temperature so its safer, the fumes are non-toxic and smell like fries (so I'm told)
  • Cons: less durable, more rigid compared to ABS, because of its less tolerance to heat, down here in Florida it will melt in your car during the summer.


There are many other pros and cons, but those are the ones that seem to stick out to me the most. If you would like to read more about the differences of these thermoplastics there is a good article here


Obtaining plastic

You can obtain plastics through many different vendors, the quality of some like ultimaker and lulzbot is impeccable, but the quality of others like monoprice can be down right unusable. You can also create your own plastic filament from plastic pellets at a fraction of the cost (~$8 vs ~$50) by using something like the Filastruder and using pellets from Open Source Printing, however there is a high starting cost associated with going that way.


Software

There are four levels of software you need to know about and/or use (from lowest level to highest):

  • Firmware: This is the software that goes on the arduino (on the printer) and is the base control software, after setup and calibration, it need not be touched again. The one I use is Sprinter
  • Printer interface: This is the software that is on the PC controlling the printer, it is used to interface with the firmware and send data to it (gcode of the thing your printing). The one I use is pronterface which is part of the Printrun toolkit. Printrun also contains a slicer which I do not use.
  • Slicer software: This software takes a .stl file (created by the 3d model software) and 'slices' it. It contains all the values (such as heat, layer height, speed, ect) that the printer will use to print and embeds this into a 'gcode' file which is then handed off to the printer interface. The ones I've used and that work well are Cura which contains a printer interface as well (which is extremely simplistic so I do not use that), and Slic3r which works very well and I would recommend it highly as you can configure a lot with it and yet it has a easy to use intuitive interface.
  • 3D model software: This is software that actually creates the 3D model and can export it as an STL file to give to the slicer software. The ones I've seen used to create very nice designs have been Blender which is an open source 3D modeler you can download for free, and SolidWorks that is closed source and you have to purchase but is easier to use.


Electronics

There are various electrical components that make 3d printers. (this is not a build list) In the MendelMax and Prusa i2 they are:

  • Motors: NEMA 17 Steppers - these move the axis' and push the filament into the hot-end
  • Heat bed: MK1 Heatbed - This is required for ABS, can be used for PLA at a lower temp
  • Endstop Switches: Endstop - These are required for homing or allowing the printer software to know where the end or home of the axis is
  • Hot End: BudaSchnozzle - By far one of the most varied parts in 3d printing, this is the device that melts the plastic for extrusion. I find that the lulzbot BudaSchnozzle works quite well on both my printers.
  • Power Supply: Encased PSU - This can come in various forms, from PC power supplies to specialized DC PSUs but, the one linked is nice but a little more expensive.
  • Arduino: Mega 2560 - This is the control board of the entire printer, the brains so to say. Can be official arduino or knockoff (lulzbot sells a tosduino version), both work equally well, I have both Arduino and knockoff.
  • RAMPS: RAMPS board - This is what is known as a 'shield' for the arduino, it sits on top of the arduino and controls the power flow within the printer. The motor controllers sit on top of this and receive power from the RAMPS and instructions from the aruduino through the RAMPS board
  • Motor Controller: pololu motor controller - The motor controller is the device that powers and controls the motors, one per motor or motor set is necessary. Pololu is a great brand of electronics and I encourage you to use them for not only this but other electronics projects.
  • Thermistor: Epcos probe - Thermistors are basically resistive temperature probes. Two temperatures your software needs to keep track of are the heated bed and the hotend so it can control the temprature of them. These probes must be able to handle high heat (in the case of ABS, 240+C for the hot end, 110C for the bed)


Hardware

Hardware on a RepRap style printer comes down to only a few parts:

  • Printed parts: Anything complex is generally printed, the custom parts can either be purchased from a store like lulzbot or printed by someone who owns a printer
  • Nuts/Bolts: Most instructions and printed parts for repraps are designed for Metric, which can be found at places like Ace Hardware. If you want to build the entire printer in SAE you can, but stick with one standard or the other.
  • Linkages: In the i2 threaded rod is used which is cheap and readily available at your local hardware store, in the Max uses extruded aluminum is used which is sturdier and easier to connect to but slightly more expensive (I would go for this option)