TPU
- Tougher and more resistant to tearing at the pin holes
- Resists abrasion and oils well
- Feels firmer and less soft on the wrist
Industry
Injection Molding for Wearables
A wearable is looked at from a few inches away, worn through workouts and showers, and rubbed with sunscreen and lotion. Few plastic parts are seen so closely or treated so casually.
Daily life
What people put on their wearables
None of it is on the spec sheet. All of it touches the plastic.
| Exposure | What it can do | What helps |
|---|---|---|
| Sunscreen and insect repellent | Stress cracking in polycarbonate and some blends | Chemical resistant grades, lower molded in stress |
| Sweat | Salt and oils that dull finishes and stain light colors | Darker colors or textured surfaces on contact areas |
| Lotion and perfume | Softening or tackiness on some soft materials | TPU and TPE grades tested against the product's use |
| Showers and swimming | Water finding its way past seams and buttons | Overmolded seals and tight parting lines |
| Desks, walls, and door frames | Scuffs on edges and glossy faces | Textured finishes, raised bezels around the screen |
Close up
Color and finish at arm's length
Wearables are fashion as well as electronics. Buyers notice a slightly different gray between band and case.
- A hard case and a soft band are different resins, so matching their colors takes separate color work for each
- Gloss hides nothing on a small part. Flow lines and gate marks have to go where the band or strap covers them
- Fine textures hide fingerprints and scuffs better than a high gloss
- Logos and markings are usually laser marked or pad printed, since there is little room for a label
Bands
Molded TPU band or molded TPE band
Silicone bands come from a different process. For injection molded bands the choice is usually between these two.
TPE
- Softer, closer to the feel of silicone
- Bonds well when overmolded onto a hard clasp or case
- Some grades pick up dust and stains more easily
FAQ
Questions from wearable teams
Who confirms a material is suitable for long skin contact?
The brand does, as part of testing the finished product. Name the resin grade on the drawing and it is run unchanged on every order.
Can a soft seal be molded onto the case?
Yes. Overmolding a soft layer onto the case or button area puts the seal in the part itself, so there is no loose gasket to lose during assembly.
Can we get small launch quantities?
Yes. There is no minimum order quantity, so a first batch can match a launch or a crowdfunding campaign, and later orders run from the same tool.
Have you molded a wearable before?
Yes. Our wearable enclosure case study walks through an overmolded housing project.
Keep reading
Related guides
Small cases, soft bands, and finishes seen up close.
Wearable enclosures
Cases for trackers and devices.
Wearable enclosuresWatch cases
Small, visible, and sealed.
Watch casesEarbud housings
Tiny shells and charging cases.
Earbud housingsWearable case study
An overmolded enclosure project.
Wearable case studyTPU vs TPE
Choosing a band material.
TPU vs TPEConsumer electronics
Phones, speakers, and accessories.
Consumer electronicsIndustries hub
Every sector page in one index.
Industries hubNext step
Send the case, the band, and the color target
Upload CAD for the case and band together, with the color and finish targets. DFM checks gate marks on visible faces and the bond between hard and soft parts. NetProto manufacturing is ISO 9001 certified.