Fused Deposition Modeling â€" better known as FDM â€" is the most widely used additive manufacturing process in the world. From desktop hobbyist printers to industrial machines, the core principle is the same: melt a thermoplastic filament and deposit it layer by layer to build a three-dimensional part.
How FDM Works
An FDM printer has four core systems:
- The extruder â€" feeds filament into the hotend
- The hotend â€" heats filament above its glass transition temperature
- The motion system â€" moves the nozzle in X, Y, and Z axes
- The build plate â€" the surface where the part is deposited
Key insight: Layer adhesion is the weakest point in FDM parts. Parts are typically 20-30% weaker in the Z axis than in X or Y.
Material Selection
| Material | Temp (C) | Strength | Best For |
|---|---|---|---|
| PLA | 190-220 | Moderate | Prototypes, visual models |
| PETG | 230-250 | Good | Functional parts |
| ABS | 220-250 | Good | Heat resistance |
| Nylon | 240-270 | Excellent | Load-bearing parts |
| TPU | 220-240 | Flexible | Gaskets, grips |
Critical Print Settings
- Layer Height â€" 0.2mm is the best all-around balance
- Infill â€" 40-60% for functional parts
- Wall Count â€" minimum 3-4 walls for strength
- Print Speed â€" start at 50mm/s
Common Problems and Fixes
| Problem | Likely Cause | Fix |
|---|---|---|
| Layer separation | Temp too low | Increase by 5C |
| Stringing | Retraction too low | Increase retraction |
| Warping | Poor bed adhesion | Clean bed, use brim |
| Under-extrusion | Partial clog | Cold pull nozzle |
Have a project using FDM? Submit it to AppliedAM