Previously, I introduced two main methods for making prototype, cnc machining and vacuum casting. Today, I will introduce the 3rd main method for making prototype.

3D printing （SLA,FDM,PBF ）

1) stereolithography or SLA

  This was the very first additive manufacturing process and it's still improving all the time.To use SLA, first you take your 3D CAD model and add supports to it, you then slice that data into thousands of very thin layers.

  Using a UV scanning laser. Then you draw out each layer one on top of another, curing the resin into a solid plastic.

  3D prototype SLA is fast and versatile and there are many resins to choose from. That offer different cosmetic and mechanical properties these are usually divided into different grades, such as prototyping resins, engineering resins and medical and dental resins. You can even add glass fiber or aluminium powder to get greater strength.

  The surface finish is excellent but remember that after printing
  parts still need to be washed and then post cured to achieve maximum strength and stability.

2)Fuse Deposition Modeling or FDM

  This is the 3D printing system most people are familiar with. Nowadays it uses filaments of common plastics like PLA or ABS
or engineering resins like PEEK and ULTEM.

  The filament is extruded through a heated nozzle where it's melted and this melt is then deposited layer upon layer to form the part kind of like Silly String.

  FDM is one of the least expensive additive manufacturing methods and it's very popular with home enthusiasts and small

  3d printing bureaus for someone needing a prototype, but be aware that the resolution is not particularly good, so your parts will likely need some post build sizing or finishing work.

3) Powder Bed Fusion

  There are two main types of powder bed fusion, selective laser sintering SLS and multi jet fusion MJF. They both use a sealed chamber filled with a powdered substrate, where a roller is used to lay down material and smooth and compress the top surface

  Both systems mostly use nylon, SLS fuses the nylon with a laser whereas, MJF fuses the nylon with a somewhat complex system of chemical agents and infrared energy at the end of the day.

  Both systems will give you a robust and moderately accurate prototype for functional testing. MJF tends to be lower cost as the quantity goes up and is therefore somewhat better suited than SLS as a low volume production process.

  There are several advantages to powder bed fusion

  First, parts are self supporting,so additional structures are not needed.

  Second, the entire build volume of the chamber can be used for maximum efficiency.