Guide 3D printing Overview

What is 3D printing?​

3D printing is the process of making a physical real world object from a 3d model using additive techniques. This means material is added little by little until the final object or part is made. This is in contrast to subtractive manufacturing techniques such as CNC milling where an object or part is made from a larger stock of material that is removed little by little until the final object is all that remains.

Why use additive manufacturing techniques instead of the CNC milling? There are a lot of reasons to choose one method over the other but a big benefit of 3d printing is you only need the material your final object requires and maybe a little extra for physically supporting the object while it prints. With CNC milling you need to start with more material than your final object and that excess material is wasted. On a 3D printer that extra material is still sitting on the roll or in the bottle and ready to be used on the next object. On the other hand some materials can't be melted easily or don't cure with UV and need to be carved out of their original form. Also 3D printing is fairly slow process compared to CNC milling, often with very large parts even it could be 3D printed it more time effective to just CNC mill it from available stock materials. Additive manufacturing isn't replacing CNC milling any time soon but for your average person there is a lot of objects or parts that don't need to be made of metal or really big and could potentially be printed at home on your own 3D printer.

Types of 3d printing:​

• FFD - Fused Filament Deposition
  
  • 3D objects are made from the bottom up by slicing the 3D model into horizontal layers. The printer works by melting thermoplastics and extruding them on a motion controlled gantry (metal rails that move around to keep the tool in a specific location). This is the most popular form of 3D printing for hobbyists.

Ender 3 - FFD 3D printer - The most popular and ubiqutous 3d printer. Usually retail for $100-$300.

• SLA - StereoLithography Apparatus
  
  • 3D objects are made from the top down using a UV curing resin. LCD or OLED displays can be used to mask the UV exposure to limit curing to the desired areas for each layer. Alternatively a laser can be used to only cure portions of the resin instead of masking this is called DLP (digital light projection) resin printing. Final part must be washed of uncured resin (usually in isopropyl alcohol) and then bathed in UV for a specific amount of time to ensure the resin is fully cured.

Elegoo Saturn - One of the more popular models and brands in Resin 3D Printing due it's low price and functionality. Usually retail for $200-$500

• SLS - Selective Laser Sintering
  
  • 3D objects are made from the bottom up by laser sintering powdered materials including thermoplastics, metals and glass into solid objects. The 3D objects are may by slicing the 3D model into layers and laser sintering one layer at a time. The machine then brushes a thin layer of additional powder over the object and the next layer is sintered to the previous. This process is repeated until the part is complete. Since there is an entire bed of powder material, some sintered into solid object and some not, the parts are supported by the powder around them and do not need any physical support during the printing process. This results in less waste material and a cleaner looking final part. The final part must be excavated from the powder bed when it's complete and the part brought into a another machine to clean it of the excess powder it's was buried in. The excess powders can be recollected and recycled for future prints. The fine powders can be toxic though, regardless of their composition. Just by being a fine powder otherwise harmless materials can be hazardous for our lungs (looking at you wood) so proper protective equipment must be worn during the print cleaning process.

An open source "compact" SLS printer. This printer's unique in being both open source and costs less than $15,000 to make. This is in contrast to commercial units which can easily be $100,000.

Helpful Resources:​

Teaching Tech's 3D Printer Calibration Guide and Wizard - This thing is an amazing resource for dialing in your FFD 3D printer. It can generate Gcode files for your specific printer to help with calibrating and adjusting your settings to get those perfect prints every time.