Plan: Manufacturing Custom Plastic Parts

Types of Manufacturing Processes

• 
  3D Printing
  
• 
  CNC Machining
  
• 
  Polymer Casting
  
• 
  Rotational Molding
  
• 
  Vacuum Forming
  
• 
  Injection Molding
  
• 
  Extrusion
  
• 
  Blow Molding
  

3D Printing

3D printers create three-dimensional parts directly from CAD models by building material layer by layer until a complete physical part is formed.

Manufacturing Process

1. 
   Print setup: Print preparation software is used for orienting and laying out models within a printer’s build volume, adding support structures (if needed), and slicing the supported model into layers.
   
2. 
   Printing: The printing process depends on the type of 3D printing technology: fused deposition modeling (FDM) melts a plastic filament, stereolithography (SLA) cures liquid resin, and selective laser sintering (SLS) fuses powdered plastic.
   
3. 
   Post-processing: When printing is complete, parts are removed from the printer, cleaned or washed, post-cured (depending on the technology), and the support structures removed (if applicable).
   

As 3D printers require no tooling and minimal setup time for a new design, the cost of producing a custom part is negligible in comparison with traditional manufacturing processes.
3D printing processes are generally slower and more labor-intensive than manufacturing processes used for mass production.
As 3D printing technologies improve, cost per part continues to fall, opening up a wider range of low- to mid-volume applications.
Manufacturing Process
Job setup: CNC machines require an intermediary step of generating and validating toolpaths (CAD to CAM). Toolpaths control where the cutting tools move, at what speeds, and any tool changeovers.
Machining: The toolpaths are sent to the machine where the given subtractive process begins. Depending on the desired shape of the final product, the workpiece may need to be set in a new position so that the tool head can reach new areas.
Post-processing: After manufacture, the part is cleaned and deburred, trimmed.
Machining is ideal for low volume plastic part applications that require tight tolerances and geometries that are difficult to mold. Typical applications include prototyping and end-use parts like pulleys, gears, and bushings.
CNC machining has low to moderate setup costs, and can produce high-quality plastic components with short lead times from a wide range of materials.
Machining processes have more part geometry restrictions than 3D printing. With machining, cost per part increases with part complexity. Undercuts, pass throughs, and features on multiple part faces all contribute to increased part cost.
Machining processes require allowances for tool access and certain geometries, like curved internal channels, are difficult or impossible to produce with conventional subtractive methods.