Injection Molding Case Study: Decision Process for ABS vs. PC in Waterproof Control Box Design

LVMA undertook a production task for an outdoor electrical waterproof control box. The control box is a key component of the outdoor power distribution system and requires precise dimensional stability, excellent weather resistance, and reliable sealing performance to protect sensitive electrical components from harsh environmental conditions.

Initial Material Selection Challenge

At the beginning of product design, the customer used Standard ABS material to design the control box because the material is cost-effective and easy to process. Our engineers conducted strict tests based on the customer's requirements. After a long period of UV testing, temperature testing, and humidity testing, the ABS components showed yellowing, aging, and cracking.

The customer's engineering team realized that to achieve optimal performance for their outdoor application, they needed a material solution that could withstand more demanding environmental conditions while maintaining the precise tolerances required for proper sealing integrity.

Material Testing and Evaluation Process

Recognizing that material performance was the customer's primary concern, our engineering team initiated a comprehensive material comparison study using prototype tooling to test different thermoplastic options, enabling the design engineers to quickly and effectively evaluate performance characteristics.

High-Impact ABS: We tested a modified high-impact ABS formulation with enhanced weather resistance additives. Although this provided improvements over standard ABS, the UV degradation and temperature performance were still not meeting the stringent requirements for a 10-year outdoor service life.

Polycarbonate (PC): Our engineering team then recommended testing Polycarbonate (PC). This engineering thermoplastic offers exceptional impact strength across a wide temperature range, superior UV stability, and excellent dimensional stability. PC's inherent toughness and clarity retention made it ideal for applications requiring long-term outdoor durability.

The key advantages of PC that made it the winning choice included:

• ● Outstanding impact resistance from -40℃ to +120℃
• ● Excellent UV resistance with minimal color change over time
• ● Superior dimensional stability ensuring consistent sealing performance
• ● PC has excellent flame retardant properties, matching electrical application scenarios
• ● Excellent electrical insulation properties

Performance Validation and Results

The customer conducted extensive durability testing on our PC injection-molded control boxes, including accelerated weathering tests, thermal cycling, and impact resistance evaluations. The results exceeded expectations:

• ● UV Resistance: Less than 2% color change after 2000 hours of accelerated weathering
• ● Impact Performance: No cracking at -30℃ impact testing
• ● Dimensional Stability: Less than 0.1% dimensional change over temperature range
• ● Sealing integrity: With the sealing rubber ring, the IP67 level is maintained in all environmental tests

From the perspective of initial cost control and processability, ABS material meets the requirements. However, under harsh outdoor conditions, PC material characteristics are more in line with customer needs. The product samples in this case were inspected by the customer, who was very satisfied with the material selection of the samples, making the subsequent cooperation very smooth.

If you’re looking for a partner to help you make complex material selection decisions, or to help you fully realize your design vision through advanced injection molding technology, let us help you move your project forward. Contact our engineering team today to get started on your next project.