This Instructable is to help with understanding the basics of 3D Printing and how to troubleshoot the most common problems with FDM 3D printers. These images were taken from a slideshow that I created to help people with 3D printing.
What is a 3D Printer?
• A robot that can make 3D objects from electronic data, also called Additive Manufacturing
• Popular Types of 3D printers
–Fused Deposition Modeling (FDM)
• Extrudes molten plastic layer by layer
–Selective Laser Sintering (SLS)
• Laser melts plastic powder layer by layer
• UV light hardens liquid layer by layer
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Step 1: 3D Printing Workflow
Why FDM printing?
• FDM 3D printing is popular because it is the lowest cost method for creating prototypes and refining designs at home
• FDM – Thicker parts, rougher surface finish
• Lowest Cost, fast prints
• Large parts can warp without a heated bed
• Support structures required
• Usually within 11” X 6” X 6”
• Usually weaker PLA material is used
• Walls thinner than .060” can get messy
Step 2: FDM Print Fail Issues
• Nozzle Clogging or Missing Layers
• Parts Warp or Don’t Stick to Bed
• Hole Inner Diameter (ID) is Smaller than Anticipated
• Bridges and Supports
• Multi-zone Temperature control is critical!
Zone 1 (~200 for PLA)
Filament melts and is pushed out from cool filament above
Zone 2 (~Room Temp Fan)
Filament guided in and pushes out molten plastic.
Filament buckles if too hot.
Zone 3 (~Room Temp Fan)
Filament cools to harden fast
Step 3: Nozzle Clogging
• Verify temperature zones are working within 10%
• Make sure no crust in feeder gear
• Nozzle seems to clog more when filament is low – Moisture may be absorbed toward the center of the spool
• Brand new filament, or a full roll, seems to solve this problem
• Preheat nozzle and manually push filament through to feel it go through easily, resistance should be minimal
• Measure the diameter of the output and it should be close to the nozzle diameter
• .15mm or higher layer thickness yields best results, possibly due to self-cleaning
• Output should be close to nozzle diameter. Thinner output means nozzle is still clogged
Step 4: Warping, Holes Closing Up, and Supports
Warping or Not Sticking to Bed
• Bed level is critical for first layer! – First layer should be a smear like a gluestick – Nozzle can jam if it’s too close to the bed
• Heated bed (~60°C for PLA) or painter’s tape helps
• Rafts help with sticking, but not warping
• Consider ribs for the bottom of large surfaces
• Print vertically instead of horizontally if possible
Small Holes Closing Up
• Rotation around a hole creates tension and pulls filament toward the center like a rope
• Hole ID is affected more because there is less support material underneath to stick to
• If support is insufficient, like an aggressive undercut, filament can fall off the edge
• Bridges spanning less than an inch long need no support
• Gradual radius arches or hallow shapes print fine without supports
• Simple conical supports for suspended features peel off easily
• Support material not required for all suspended geometry
Step 5: Going in to Production and Other Resources
• Mold injected version is more precise, so FDM specific geometry like hole size will not translate over
• Not all 3D printed parts can be mold injected – Draft angles, wall thickness, parting lines required for mold injection – CAD software and online service like Protomold can detect issues
Where Can I 3D Print Something?
at a shop with 3D printers
–Laserbird.org (Hackerspace, no time limits, FDM Printers)
–ADX (Must reserve time, FDM printers)
• Online Services
–Solidconcepts (SLS, Injection Molding, Machining, etc.)
–Makexyz (Find 3D printers in your area)
• Purchase a Desktop 3D Printer
–Low-end 3D printers still cost over a thousand dollars
–Only a few Low-end printers on the market are good (Purchase carefully)