Charging pile housings work outdoors for a long time, enduring ultraviolet radiation, alternating temperature, rain erosion, sand abrasion and salt spray in coastal areas. These products need to meet strict standards of flame retardancy, electrical insulation and impact resistance. Material selection includes two core parts: weather-resistant plastic for molded parts and matching mold steel. Reasonable material matching can stabilize product performance and extend mold service life.
1. Weather-resistant Plastic Selection for Charging Pile HousingsCharging piles are divided into outdoor exposed type, semi-outdoor type and indoor type, with different requirements on weather resistance. Outdoor main shells demand high UV resistance and flame retardancy, while auxiliary parts can adopt economical modified materials.
1.1 Flame-retardant Weather-resistant ASA: First Choice for Outdoor Main HousingsASA is the most widely used material for outdoor charging pile housings. Different from ordinary ABS, ASA has no molecular double bonds vulnerable to ultraviolet rays, presenting excellent natural anti-aging, anti-yellowing and anti-chalking performance. Flame-retardant modified ASA reaches UL94 V0 flame retardant grade to satisfy electrical safety regulations. It features good fluidity and high surface gloss, supporting direct molding without spraying, painting and film coating processes. ASA is suitable for mass production of multi-cavity molds and widely used for AC charging piles and wall-mounted outdoor charging piles. Ordinary ABS with outdoor anti-weather coating can be used for semi-outdoor and indoor products, but not recommended for long-term outdoor exposure.
1.2 Weather-resistant Flame-retardant PC/ABS Alloy: Optimal for Severe Working Conditions
High-power DC charging piles and products used in cold regions prefer weather-resistant flame-retardant PC/ABS alloy. This material combines the high impact resistance and wide temperature adaptability of PC with the good moldability of ABS, working stably at -40℃ to 120℃. Long-acting light stabilizers and antioxidants are added to inhibit aging, yellowing and brittle fracture. Moderate melt viscosity ensures smooth filling of large-size cavities and reduces molding defects such as weld lines and sink marks.
1.3 Economical Auxiliary Materials: Weather-resistant Modified PP and Glass-filled PBTWeather-resistant modified PP has low cost, good water resistance and chemical corrosion resistance, which is applied to side cover plates, access doors and bottom protective shells. It has general rigidity and surface texture, so it cannot be used as main load-bearing housings. Glass-filled PBT has outstanding heat resistance, moisture resistance and dimensional stability, mainly for internal high-pressure isolation covers and terminal protective parts. Glass fiber will aggravate mold abrasion, so high wear-resistant mold steel must be matched. Recycled materials are strictly forbidden for all outdoor plastic parts.
2. Weather-resistant Matching Selection of Plastic Mold Steel for Charging PilesCharging pile molds are mostly large-size molds for long-term mass production. Flame retardants and modified additives will produce slight corrosive gas under high temperature. Combined with humid workshop environment, molds are prone to rust, pitting and polishing failure. Mold steel selection shall comprehensively consider corrosion resistance, wear resistance, polishing performance and fatigue resistance.
2.1 High Appearance and Corrosion-resistant Molds: S136H, STAVAXS136H and STAVAX mirror stainless steel are preferred for molds producing ASA and PC/ABS housings with high appearance requirements. These steels have high purity, excellent acid resistance and rust resistance, capable of resisting corrosive gas and salt spray. They have superior polishing performance to form mirror surface, keeping high gloss of products during long-term production, which is the standard steel for high-end outdoor charging pile molds.
2.2 General Molds for Medium and Large Batch Production: 718H, P20
718H and P20 pre-hardened plastic mold steel are adopted for molds with ordinary appearance and textured surface. They have good machinability, uniform hardness and cost performance, suitable for large mold bases and cavities. Their corrosion resistance is average. Regular maintenance, polishing and rust prevention are required when producing flame-retardant plastics.
2.3 High Wear-resistant Molds for Glass-filled Materials: NAK80, 8407Glass-filled PP and PBT will cause severe scouring on mold cavities. NAK80 and 8407 high-hardness wear-resistant steel have strong scouring resistance and fatigue resistance, applicable to mass production over one million shots. Nitriding and TD coating treatment can further improve surface hardness and wear resistance.
3. Supporting Process and Application Notes for Material SelectionThe weather resistance of plastic parts depends on modified raw materials, while mold stability relies on steel grade and surface protection. Select qualified weather-resistant materials according to regional UV duration and salt spray level. Classify mold steel according to material corrosion and wear degree. Carry out daily rust prevention, dirt removal and vent groove cleaning for molds to avoid converting corrosion points into product appearance defects.
4. ConclusionMaterial selection for charging pile housings is a systematic project combining plastic formula and mold steel matching. Reasonable material collocation solves outdoor aging problems of products and reduces mold failure caused by corrosion and wear, so as to improve the overall quality and service life of charging piles.
