cost out consulting for easier/cheaper manufacturing #sketchyengineering
11 Tips for Injection Molding Design 1. Keep Walls Uniform 🧱 Even wall thickness prevents warping and keeps your part from looking like a Picasso painting. 2. Avoid Sharp Corners 🌀 Sharp corners cause stress—just like in life. Add generous radii for strength and flow. 3. Think About Draft Angles 📐 Parts need to eject from the mold smoothly. No draft angle? Hello, stuck parts! I like to think about my draft angles as some of the first features that I build into my part ... draft can be easy to add at the beginning and difficult to add later. if you want a heavy texture on your part, choose a steeper draft angle. if you know you're going with a glossy part, you can get away with a lower draft angle. I've seen 4-in long parts with a 0.2 degrees of draft but they were SPI-A1/A2 high gloss finish. And I've seen rough textured parts that are pretty shallow, and they have 3-5 degrees of draft in order to get them to release. 4. Respect Shrinkage 📏 All materials shrink a little as they cool. Don’t let your design suffer from denial. This also relates to warp. Large flat faces like to warp no matter how long they're held in the mold. if you can add a slight curve on the surface the tension of the material will help it hold its shape better. I call this 'pillowing' the surface. Add in a 800-1000mm radius on a surface and it will still look mostly flat but it will hold its shape better than a perfectly flat surface. 5. Think About Gate Placement 🚪 Where the plastic flows in matters. Poor placement can lead to ugly weld lines or weak spots. 6. Boss Up Correctly 🛞 Bosses should be reinforced and not too tall or thin. Wobbly bosses are nobody’s favorite. 7. Ribs Over Walls 🍖 Need strength? Add ribs instead of thickening walls. It’s efficient and keeps cooling consistent. 8. Avoid Overhangs or Undercuts 🪜 These complicate mold design and make things tricky for everyone. Be kind to your mold-maker. 9. Plan for Venting 💨 Trapped air equals defects. A well-vented design ensures the molten plastic flows like it should. 10. Test and Iterate 🔄 Prototypes reveal what CAD doesn’t. Test early, test often, and let your design evolve. 11. Know the rules so you can break the rules 😎 If you know the basics about design for injection molding, then you will know when part of your design is breaking those rules. Talk to your vendors about these problem areas, and see what they can come up with. you might be surprised how creative some molders can be. But when none of your part conforms to basic molding design and every surface requires a side action or a cam or a slider or a pick-out, they are much less willing to with your design. Design for Injection molding is as much about balance as it is about innovation. Follow these, and your design will be smooth sailing—or at least smooth molding! #dfm #engineering #design