Simmer3D
3D printers have many forms and print many different materials and types of parts. Most entry level printers lay down plastic, but others can do more exotic materials like concrete or skin. They are all part of the same category of additive manufacturing. The focus here is on small plastic parts, the narrow range of 3D printing this blog is about.
The most common type of 3D printer is an FDM printer. FDM stands for Fused Deposition Modeling. The printer melts the material in a hot end and then extrudes a small amount through a nozzle to build the geometry. If you have used a hot glue gun, then you are familiar with melting material and squeezing it through a nozzle. A 3D printer is similar except the movement and the amount of material used is controlled by a computer.
You may think that all you need to do is take a 3D model you found online and send it to the printer…but you would be wrong. The technology may get there some day, but for now there are complications that must be addressed.
The 3D printer can only be instructed in some very basic tasks like move to a location, heat the nozzle or advance the material extruder. The 3D model is a mathematic representation of the geometry. A piece of software called a slicer bridges the gap. You can load the 3D model into the slicer. Parameters about the build are then set. Some of these parameters are material to print, print speed, layer height and the addition of support structures. These parameters will determine the quality of the print and how long it takes to print.
It is important to keep two things in mind. First determine if 3D printing is the best form of manufacturing for your part. The second is how can the design of the part be optimized for 3D printing.
Is 3D printing right for your part?
You will need to know how your part will be used to determine if 3D printing is right for your part. Here are some realities about FDM printing that will help.
Strength is an issue. FDM printers lay down plastic in layers. Adhesion between the layers determines the minimum strength.
Parts created with FDM printers are not water tight. No matter how hard you try, the plastic will not stop moisture from penetrating the surface. This means that you probably shouldn’t use 3D printed parts on food. If you do, they should be used once and thrown away because moisture from food will be a breeding ground for bacteria. If the moisture can get in, then moisture and bacteria can get out.
UV light needs to be considered for parts used outdoors. UV light makes most plastics brittle and fades color. If you want a 3D printed part to be used outdoors, you should consider that the strength will decline with time.