TWS Earphone Charging Case Prototypes: 20 Sets of Replication Parts, Cost Reduced by 60%, Delivery Time Halved

Customer Background

A consumer electronics brand is developing a new TWS true wireless earphone and needs to produce 20 sets of charging case prototypes before the product launch for KOL reviews, product photography, and crowdfunding page display.

Challenges

Quantity Dilemma: If using CNC machining, the cost per unit is too high (about 600 RMB per set); the cycle time for injection molds is too long (over 30 days)
Surface Finish: The casing requires a rubber coating (touch paint) to achieve a skin-friendly, fingerprint-resistant effect, and needs screen printing of the brand logo
Internal Structure: The charging case needs to be assembled with PCB, magnets, and a hinge, requiring high dimensional consistency

Solution

Process Selection: Vacuum replication. The master model is machined with CNC ABS (precision ±0.05mm), and two silicone molds are made simultaneously for casting
Material: PU resin simulates ABS, with color matching according to Pantone color codes
Post-processing: After grinding the parting line, spray black rubber paint (touch paint) and screen print white logo. Adhesion test passed with 3M tape. The internal magnet slot is precise, allowing the customer to assemble directly

Results

Delivered 20 complete charging case shells (including top and bottom covers and hinges) on day 6
The unit cost was reduced to 240 RMB, saving 60% compared to CNC machining
The customer used these prototypes for product photography, KOL testing, and Indiegogo crowdfunding, eventually raising over $500,000
The customer later added 30 more sets for the second round of testing

"Vacuum replication is extremely cost-effective. The quality is completely comparable to injection molding, and the delivery time is fast. For small batches in the future, we will definitely choose Yiruida."