Client Background & Product Requirements

An international client required a high-reliability numeric keypad for their terminal devices. As a critical human-machine interface (HMI), the client set stringent requirements for the outer casing and internal structural components:

• Wear Resistance & Non-fading: Font edges must remain sharp, with the font structure integrated into the keycap to ensure the same lifespan as the product itself, preventing peeling or fading over long-term use.
• Backlight Support: The design must support translucent effects for night use, ensuring uniform brightness and optical diffusion.
• Tactile Consistency: Keycap dimensions must be highly uniform with stable assembly gaps to ensure consistent tactile feedback during high-frequency operation.

Manufacturing Challenges

During this project, the client faced several critical manufacturing difficulties:

• Traditional surface-level printing or laser-engraved fonts are susceptible to wear and fading caused by friction, sweat, or cleaning agents.
• The keypad body utilizes a composite structure requiring the integration of multiple materials (such as ABS/PC and translucent materials), posing dual challenges in structural precision and aesthetic quality.
• Mass production required the strict reduction of assembly tolerances to prevent quality fluctuations from impacting the tactile responsiveness of the keys.

Foreshot’s Solutions

Foreshot provided an integrated solution, introducing Design for Manufacturing (DFM) assessments from the earliest stages of development:

1. Double-Shot Injection Molding Technology

Utilizing a "one-step molding" process, the rigid engineering plastic substrate is perfectly combined with translucent material for the font. This integrated structure completely eliminates the wear issues associated with traditional printing. Furthermore, the integrated design effectively reduces subsequent assembly steps and minimizes tolerance risks inherent in secondary assembly.

2. Mold Optimization and Process Control

Through DFM and Moldflow simulation analysis, we predicted and optimized gate positions and runner designs, effectively mitigating weld lines and sink mark risks while ensuring sharp font edges. In critical structural areas, Foreshot successfully stabilized molding tolerances at the 0.03mm – 0.05mm level.

3. Material and Optical Tuning

Material formulations (e.g., PC, ABS, PBT) were adjusted based on backlight requirements to precisely control light transmittance and surface micro-textures, balancing premium product aesthetics with an ergonomic tactile feel.

Project Results & Value