3D printing overview, software and hardware

Post date: Jan 13, 2019 7:20:12 PM

With the FTC competition, there are limitations on weight and size of the various components of the robot and, at the same time, the need for strong materials that will bear the weight of the robot (at the beginning and the end of the game in latching on to the lander). To be able to design and build light-weight components that are strong, one device stands out for its capabilities - the 3D printer. Whether it helps us print out last minute objects that are vital to our robot, or prints out life saving human organisms, it is an understatement to say that a 3D printer can do everything. While there might be different models of 3D printers for different uses, they all have the same functions - they intake the material which gets printed out, they heat the material, and layer on the material on a base. For the sake of blog I will focus on household/school 3D printers which could be used to print simple parts such as a phone case.

First let's start with the software. I will describe the process of printing out a custom designed phone case that will be mounted on top of our robot. It has a couple of requirements, such as holes on the back of the phone case to mount it, be able to protect the phone in case another robot collides with ours, not block the camera and be light and movable. The holes in the case need to accomodate a charging port on the bottom of the phone case, and, most importantly, be a snug fit so the phone won’t fall out. To get these specifications, we designed the phone case on PTC. It is extremely important to design what you want to print on PTC before, so you won’t waste materials or time printing out an object that won’t work. Once I finished I imported the design to a 3D model, to be able to put the design on a flash drive and put it in my 3D printer.

I have preloaded environmentally friendly degradable material, since it this is just a prototype. First the machine initializes, what it does during this time is it codes the motion of the dropper and it heats up the dropper to the ideal temperature so it can melt the material. After heating up, the machine begins, it moves in a linear path sketching out the PTC designed phone case layer by layer. After the timer strikes zero the phone case is ready.

Types of 3D printers: There are three types of 3D printers, photopolymerization, granular material binding, and molten polymer deposition. The first type is the photopolymerization uses a light to cure a liquid material into solids of the desired shape.

The Granular material binding uses lasers, hot air, or other energy sources to fuse layers of powder into the desired shape.

And finally the molten polymer deposition, which extrudes molten materials in layers. This is the most common one and can be found in most schools.

Once you are done designing the object it is extremely important to create it into a STL file. When converting to a STL file, it makes your design a 3D model that the printer is able to encode and print out. This is a critical step, or else the printer will be unable to print out your object.

Parts of the 3D printer: The Gantry is the part of the 3D printer that moves the extruder in a linear motion along the x and y axis. The moving bed is an option if the printer doesn’t have a Gantry, instead the bed moves in the x,y, and z direction. The print bed is where the object is printed on. Usually the print bed is made out of glass can withstand extreme heat. The extruder is where the plastic is fed out of the 3D printer, but it is not where it is melted. The hot end is where the plastic is melted, this is on the end of the extruder.

Materials: There are different types of materials, ABS, PLA, PVA, etc. These are the most popular ones. First let's start with the cheapest and the most used one for school printing. It is called Acrylonitrile Butadiene Styrene or ABS for short. This material is typically extruded between 215-230 degrees C(419F-440F). This material is extremely versatile, it can be sanded, it can be glued together to make a glass like material, and it can be mixed with Acetone. But when printing with this material it should be used with caution due to the fact that it releases toxic fumes with can be dangerous. Overall, this material is great for beginners just starting their 3-D printing journey.

Next is polylactide or PLA. This material is biodegradable plastic, so it is environmentally friendly. Believe it or not this material is actually made from corn and potatoes. Because of the biodegradability trait, it extrudes at a lower temperature of 160-220c(320-428f). A fun fact about this material, when it is extruded it smells sweet, a bit like toasted corn. The material characteristics of this material is that it tends to be firmer than ABS. It conclusions this material can also be used with beginners, but it is mainly intended for amateurs.

And the last material is polyvinyl alcohol or PVA. This is a special type of material, it can only be used on 3D printers with multiple extrusions. It is typically extruded at 190 c(374F). An interesting characteristic of this material is that it absorbs water like a sponge. Which makes it a bit hard to use on a humid area, but also gives it some advantages. This material is the most versalite, it can be used to create 3D parts like overhangs. Overall, this material is indeed for commercial 3D printers and advance 3D printers.

In conclusions, these are only the most popular materials for 3D printing. There are also more interesting materials like chocolate and stem cells. With more and more material being able to 3D print the possibilities of what we can design is endless, and the sky's the limit.

Sources: France, Anna Kaziunas, and Brian Jepson. Make: 3D Printing. Maker Media, 2014.