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

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?

• Membership
at a shop with 3D printers

–Laserbird.org (Hackerspace, no time limits, FDM Printers)

–ADX (Must reserve time, FDM printers)

• Online Services

–Shapeways (SLS)

–i.materialise (SLS)

–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)

<p>Any chance you could wrap this up into a single document that could be read offline on a dead tree? This appears to be a slideshow, so maybe you could make a PDF?</p>
<p>some nice summarys for all kinds of trouble for FDM-printers. Thanks for the overview! :)</p>

About This Instructable




Bio: We are a new 10,000 sq. ft. makerspace in Portland, OR at 7600 N. Interstate Ave with a wood shop, craft lab, hackerspace, tiny ... More »
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