"UHF Solutions" is a company that develops radio frequency electronics based on RFID, BLE, LoRa, and UWB technologies, managing projects from chip design through to serial production.

The team approached PRM.DEV for an enclosure for a new device: a wrist-worn UHF tag reader designed for identification, inventory tracking, and payment applications. The wearable form factor imposed strict constraints: the entire enclosure had to fit within dimensions of 18×50×60 mm, mount on a wristband, and provide IP67 protection.

The industrial design had been approved by the client in advance, which meant the external lines could not be revised during development. Serviceability was a separate requirement: the design had to withstand repeated disassembly and reassembly so that the battery and electronics could be replaced without replacing the enclosure itself.

Given the compact dimensions, the enclosure had to seal all external openings — buttons, power connectors, LED windows, and wristband attachment points — and each sealed assembly had to maintain its properties through repeated disassembly cycles.

The design also had to be developed not only as a functional prototype, but with future serial production in mind. The solutions for part geometry, sealing, and assembly had to remain manufacturable when transitioning from small batches to production tooling at scale.

The joint between the enclosure body and the cover is sealed by a silicone cord seated in a groove. The groove runs around the fastener holes so that water cannot enter through the screws. The cord was formed to match the groove profile, and the cover features a ridge that creates a compression fit. The seal does not depend on how evenly the screws are tightened during assembly.

The cover is held in place by threaded brass inserts molded directly into the plastic during the injection molding process. The threads remain in metal, so the enclosure can be opened repeatedly without stripping the thread engagement.

The button was sealed using two-shot molding: the rigid functional part and the soft seal are produced as a single component, with no gaskets or adhesive joints.

Power is routed through a sealed USB-C connector: the seal is integrated into the connector itself and activates when the connector seats into the enclosure opening. Retention stops were added on the back side to provide the required clamping force.

There is no display on the front panel; status indication is provided by LEDs. To avoid drilling holes for LED output and to maintain enclosure integrity, the wall was locally thinned at the illumination points. Light passes through the thin plastic while the exterior of the enclosure remains solid and unbroken. Baffles were installed between the LEDs to prevent adjacent indicators from cross-illuminating each other.

The wristband attaches via standard pins in the enclosure lugs, allowing it to be replaced without redesigning the enclosure.

The enclosure design was developed with subsequent production scaling in mind. Connector, seal, fastener, and plastic geometry solutions were selected so that they could be reproduced in serial production tooling without fundamental redesign of the enclosure.

PRM.DEV developed a compact, serviceable enclosure for the wrist-worn UHF reader, preserving the specified dimensions of 18×50×60 mm and the approved industrial design. The design combines IP67 protection, access to the electronics and battery for servicing, a sealed USB-C connector, LED status indication without additional openings, and a replaceable wristband attachment.

The device has already been produced in several small batches. As the product has evolved, the client has updated the electronics and revised the PCB, and PRM.DEV has adapted the enclosure to each new modification.

The design developed is now being used as the foundation for the transition to larger-scale serial production.

In addition, we prepared several sets of engineering documentation for different manufacturing technologies and batch sizes: for 3D printing, silicone casting, and injection molding.