Printing Considerations
When to 3D Print
Complex Geometries
- Internal geometries
- Organic geometries
- Areas where milling can’t be achieved
Rapid Prototyping
- Parts needed fast and at a lower cost, as opposed to sending to manufacturing
- Parts that don’t require heavy loads
CAD Variations
- Testing different models or tolerances
- Scaling for visualization
- Iteration
When to consider methods other than 3DP
Simple Geometries
- Rods can’t be printed vertically and lose shape when printed horizontally.
- Boxes – best made on the laser cutter, and are expensive to print.
- Plates/Disks – cheaper, and more easily made on the laser cutter or other subtractive methods
Size
- Restricted to build volume
- Longer print times = higher risks of failure
- When parts or part features are smaller than printer specifications
How 3D Printing is different from other fabrication methods
Injection Molding
A common way to manufacture plastic parts with complex features, smooth surface finish, and at low cost (in high volume). 3D printing also offers complex features but produces rougher (sometimes porous) surfaces at low cost in low volume.
Thermoforming
Thermoforming is a good option for making thin-walled hollow parts but requires mold.
Subtractive Processes (Mill/Laser)
Often faster or cheaper to cut(subtract) from plastic or other stock to create the desired part. For example, laser cutting parts with features only in the x, y-axis or milling parts with features in the x,y, and z-axis. Using plastic that is not 3D printed offers a wider variety of plastic options like Delrin and HDPE.
Notes on "Food Safe" 3D printing materials
Plastics like PLA (corn-derived) aren’t inherently toxic, but “Food Safe” has specific regulatory meanings, particularly from the FDA. The Design Innovation Lab cannot ensure 3D printed parts are Food Safe. Users must make their own safety decisions for any items made there.
Key Concerns
- Toxicity: Not all plastics are food-safe. While PLA can be, additives in many filaments might not be. Filaments marketed as FDA-approved may lack proper documentation. Brass nozzles in FDM printers might have impurities like lead, which could affect safety. Stainless steel nozzles are a safer alternative.
- Regulation: Food-safe claims likely require FDA approval and adherence to industry standards.
- Practicality: FDM prints are porous and difficult to clean, increasing the risk of bacterial growth. They are often not dishwasher-safe, making repeated use less practical.
Conclusion
Marketing FDM printing as food-safe involves complex factors. While plastics can be food-safe, ensuring this within the Design Innovation Lab is not feasible.
