About Myself

• BS, MS, and PhD in Mechanical Engineering
• Professor of Engineering at ASU for 10 Years
• Moved to Petaluma in January, starting a consulting/mentoring/education business

Workshop Overview

Agenda

• About Myself
• Overview of 3D Printing
• Overview of Computer Aided Design (CAD)
• Practical Example of CAD Usage
• Slicing and Printing Example

Point of this Workshop

I see many people who have access to a 3D printer

Want to:

• Make their own parts
• Enable a second hobby
• Make things for others
• $$ Replacement Parts

Don't:

• Customize Print Settings
• Optimize Designs for Printing
• Design Parts --> Thingiverse

Library Specific

This tutorial is

• Targeted for library printer
• Discusses library Processes

Some things may be different for your printer, but most of this will apply to you.

Items Needed

• Laptop
• Several Programs
  • CAD -- OnShape (web-based), OpenSCAD, FreeCAD, Solidworks, Autodesk Fusion
  • Slicer -- PrusaSlicer, Cura, Slic3r, Bambu Studio, ...
• Access to 3D Printer
• Calipers (or Ruler)
• Library Wifi

Detailed Instructions

Web-based version of this presentation can be found here:

3D printing

Quick Show of Hands

Raise your hand if:

• You have a 3D Printer at Home
• You have used the Library's 3D Printer
• You have ever used a 3D Printer
• You hope to do one of the above

What is a 3d printer?

Library's 3D Printer

Specs

• 250x210x220 mm print
• Filament diameter: 1.75mm
• Layer height 0.05-0.30 mm
• Supported materials PLA, PETG, Flex, PVA, PC, PP, CPE, PVB and when using the Original Prusa Enclosure with filtration add-on ABS, ASA, HIPS, PA

Categories of 3D Printing

3D printing is an example of additive manufacturing.

• Powder Bed Fusion
• Laser Sintering
• Resin Bed: Stereolithography, DLP, etc
• FDM: Fused Deposition Manufacturing
• Printing / Jetting / Polyjet

3D Printer Hardware

Print head

Time Lapse

Materials

• Common filaments: PLA, ABS, PETG
• High-end printers support
  • Flexible materials (TPU)
  • Fiber reinforced
  • CF thread.
• Material properties (strength, flexibility, temperature resistance)
• Trade-offs and selection criteria
• LIBRARY-SPECIFIC: What's available?

PLA is cheap, easy to work with, reduces wear and tear and is compostable

Note: Not Food Safe

Digital Workflow

• 3D model sources (download vs. design)
• File formats (STL, 3MF recommended for library)
• Slicing process using software like Cura or PrusaSlicer
• Generating G-code and what it represents

Print Setup and Operation

• Bed leveling and calibration
• Loading filament
• Starting and monitoring a print
• Basic parameter adjustments (layer height, infill, temperature, speed)

Design for 3D Printing

• Key constraints: overhangs, supports, tolerances, anisotropy
• Orientation and its impact on strength and surface quality
• Common design mistakes and how to avoid them

Geometry Constraints

• Overhangs: unsupported material fails beyond a critical angle (~45° heuristic)
• Bridging: limited span where material can stretch before sagging
• Minimum feature size: tied to nozzle diameter and layer height

Overhang

Bridge

How to deal with Overhangs / Bridges

• Orient in your slicer
• Use Dry / High Quality Material
• Adjust temp / cooling (expert)
• Use Supports

Support

Orientation as a Design Variable

• Strength aligns with filament direction
• Surface quality varies by face orientation
• Trade-off: strength vs. support material vs. print time

Structural Considerations

Structural Considerations

• Anisotropy: weakest axis is typically Z (layer stacking direction)
• Stress alignment: orient parts so loads run along continuous extrusions
• Infill vs. shell: strength of a part is often dominated by outer walls, not internal fill

Infill Patterns

Infill Percentage

Tolerancing and Fit

• Clearance is required due to extrusion width and variability
• Holes print undersized; external features print oversized
• Design intent must account for manufacturing process

Post-Processing

• Removing supports
• Drilling / Reaming
• Tapping / Adding inserts
• Sanding, finishing, and assembly
• Optional treatments (painting, acetone smoothing for ABS)

Troubleshooting

• Common print failures (warping, stringing, clogging)
• Diagnostic approach: isolating variables
• Preventative practices

Deal with Failures

• Nothing too long and skinny (in any orientation)
• Check temperature / cooling
• Print speeds
• Use high-quality material
• Dry your filament
• Check/Clean/Replace your print head
• Check/Clean the bed

Dealing with Failures

• https://www.additive-x.com/blog/how-to-overcome-the-most-common-3d-printing-failures/
• https://www.makeuseof.com/3d-print-failures-common-causes-and-solutions/

Safety and Best Practices

• Temperature hazards (hotend, bed)
• Ventilation considerations (especially with ABS/resins)
• Watch your Part -- easy to waste material
• Clean your 3d Printer

Split the Class

In this phase we split into two 15-minute sessions, one here, one with the librarians.

CAD

What is CAD?

Computer
Aided
Design

CAD Tools

• Autodesk Fusion
• Solidworks
• Onshape
• FreeCAD
• OpenSCAD
• ...

Let's Use Onshape

Sketch

Dimensioning

Extruding

Other advanced things

• Fillet / Chamfer
• Loft
• Revolve

Export

• STL, 3MF (for library)
• Just use defaults
• This goes to Slicing

Slicing Exercise

We should all be back in the same room

What is a slicer

• 3D Shape --> machine instructions
• CNC (computer numerical control)

Slicers

• Prusa Slicer
• Cura
• Slic3r

Import Part

Orienting Part

Machine Parameters

• Print Height
• Temperature
• Infill
• Infill Pattern
• Support
• Support Pattern

Show Output

Show Estimates

Show Impact of Changing Variables

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