Vacuum casting can definitely be a practical stepping stone before diving into injection molds, especially if you're still tweaking ergonomics. I've found it pretty cost-effective for initial iterations—say, two or three variations. But yeah, costs can start creeping up if you're planning multiple rounds of adjustments. The silicone molds used in vacuum casting degrade after a certain number of pulls (usually around 15-25 parts), so if you're making lots of small tweaks and need fresh molds each time, it can add up quicker than you'd expect.
One way to keep costs manageable is to group your design changes strategically. Instead of making incremental tweaks one at a time, batch your adjustments into fewer iterations. That way, you maximize each mold's lifespan and get more bang for your buck. Also, consider using vacuum casting primarily for ergonomic validation and initial user feedback—then move to injection molding once you're confident in the design. It's all about balancing your prototyping goals with budget realities...
That's a solid breakdown of vacuum casting's pros and cons. I've personally found vacuum casting pretty helpful when I was prototyping some custom handles for my DIY cabinetry project. It allowed me to test out different grip shapes without committing to expensive tooling right away. But you're right, the silicone molds definitely have their limits—after about 20 pulls, mine started losing detail and accuracy.
One thing I'd add from experience is that vacuum casting can also be great for testing different materials or finishes early on. For instance, I experimented with a few different resin types to see how they felt in hand and how durable they were under daily use. That helped me narrow down exactly what I wanted before moving onto injection molding.
On the other hand, injection molding really shines when you're ready to scale up production or need consistent quality across hundreds or thousands of parts. The upfront cost is steep, but once that's covered, the per-unit cost drops significantly. Plus, you get more material options and better durability overall.
I'm curious though—has anyone here tried using 3D printing as an intermediate step between vacuum casting and injection molding? I've heard mixed things about its practicality for ergonomic testing, especially regarding surface finish and strength. Would love to hear if anyone has firsthand experience with that approach...
