Injection Molding Part Color and Material Selection Scheme
Material and color selection of injection molded parts acts as a core link in product development, directly determining structural strength, weather resistance, appearance texture and mass production yield. Defects such as yellowing, color difference, floating fiber, fading, cracking and deformation in post-production mostly arise from mismatched materials and colors selected in the early stage. Scientific selection combines service conditions, stress demands, appearance standards, process difficulty and cost budget to balance qualified performance, ideal appearance, stable production and controllable cost.
I. Select plastic materials based on service conditions
ABS, PP and GPPS general-purpose plastics are prioritized for indoor normal-temperature common appearance parts. Featuring good fluidity, uniform coloring and stable molding, they support diverse appearance effects including pure white, colored, pearlescent and matte finishes with high process tolerance and low cost, suitable for home appliance shells and consumer electronic appearance components.
Reinforced materials such as PC, ABS+GF, PA66 and PBT+GF are adopted for stressed structural parts, internal frames and load-bearing buckles. Glass fiber filled materials deliver high rigidity, deformation resistance and stable dimensions, yet their surfaces are prone to floating fiber and mottling, making them unsuitable for exposed appearance surfaces and only applicable to internal functional structures.
High-temperature engineering plastics including PPS, PEI, PPSU and flame-retardant PA are used for high-temperature, flame-retardant electrical products. These materials possess excellent heat resistance, flame retardancy and dimensional stability, but their ultra-high molding temperature easily decomposes color powder and imposes strict limitations on color matching.
Transparent materials PMMA, PC and PPSU are chosen for light-transmitting products such as lamp shades and display windows, only compatible with low-saturation transparent, translucent and light smoke color matching; heavy solid colors reduce light transmittance and generate atomization defects.
Outdoor products must adopt ASA, weather-resistant PC and UV-modified PP. Ordinary ABS and PP lack anti-ultraviolet capacity and turn yellow, brittle and faded after short-term sunlight exposure.
II. Select product colors based on process stability
Pure black is the most stable color system for mass production, with strong covering power to perfectly hide flow lines, weld lines, floating fiber and sink marks. It features minimal color difference fluctuation, anti-aging performance and the lowest rework rate, compatible with all materials and ideal for mass industrial products.
Gray series deliver advanced texture and stable process performance, insensitive to fluctuations in temperature and injection speed, balancing appearance and yield as the universal preferred color for home appliances and equipment housings.
White and light color series carry high production risks and only fit unfilled pure raw materials. Light colors are highly susceptible to yellowing caused by temperature, drying and raw material batch differences; floating fiber and mottling are inevitable when glass fiber filled materials are matched with light colors, which is a forbidden selection combination.
Colored, pearlescent and metallic textures serve as high-end appearance colors with attractive visual effects yet high process sensitivity. Slight parameter fluctuations trigger color difference and flow lines, leading to high mass production control difficulty and cost, only used for high-end unfilled appearance parts.
III. Core taboos of material and color matching
Glass fiber filled materials shall not be matched with light, bright or colored finishes; light and bright color matching is prohibited for high-temperature engineering plastics; ordinary ABS with light colors cannot be used for outdoor products; heavy dyeing is forbidden for transparent parts. Avoiding forbidden combinations eliminates over eighty percent of mass appearance defects.
IV. Comprehensive principles for selection implementation
Exposed appearance parts prioritize unfilled materials matched with black, gray and low-saturation colors; structural and high-temperature parts adopt dark color systems; outdoor products require weather-resistant materials and dedicated weather-resistant color masterbatch; color masterbatch concentration is strictly controlled for transparent optical parts. All selections follow the principles of matched performance, stable process, compatible appearance and controllable cost.
Summary
Material and color selection of injection molded parts is not a simple appearance choice, but comprehensive matching of performance, process, environment and cost. Proper selection fundamentally avoids defects including color difference, yellowing, floating fiber, aging and cracking, greatly improving product quality and mass production stability while cutting costs of post mold modification, rework and rejection.
