In the field of non-standard precision OEM parts processing, aluminum alloys, stainless steel, copper, and engineering plastics are the four core raw materials for manufacturing CNC Turned Parts and irregularly shaped milled structural parts. Different materials exhibit significant differences in cutting difficulty, load-bearing strength, corrosion resistance, and processing costs. Furthermore, the surface treatment processes suitable for each material are completely distinct. Incorrect material selection can easily lead to production problems such as insufficient part strength, rust susceptibility, appearance defects, and budget overruns. Shengpeng Precision, relying on its mature and stable Metal Milling Service with full-category milling capabilities, and complemented by Aluminum Die Casting blank forming and 3D Printing Service for rapid prototyping, comprehensively analyzes the four mainstream materials from four dimensions: material properties, processing characteristics, suitable surface treatments, and applicable working conditions, facilitating rapid material selection for R&D engineers and foreign trade procurement.
一、Detailed Explanation of Core Processing Characteristics of Four Materials
1. Aluminum Alloy (6061/6063/7075)
Processing Characteristics: Lightweight, low cutting resistance, extremely low tool wear, capable of high-speed machining, high production efficiency; 7075 aerospace aluminum has high tensile strength, suitable for heavy-duty structural components; short plates are relatively soft, easily deformed during thin-wall machining, and prone to scratches during daily use.
Supporting Blank Solutions: For large-volume lightweight housings, die casting followed by precision milling is preferred, significantly reducing material loss and processing time.
Suitable Surface Treatments: Ordinary decorative anodizing, hard anodizing, sandblasting, wire drawing, mirror polishing; electroplating cannot be relied upon for long-term corrosion protection.
Applicable Applications: New energy battery housings, lightweight brackets for automated equipment, instrument exterior panels, and shells for portable testing equipment.
2. Stainless Steel (304/316L)
Processing Characteristics: High material viscosity, prone to tool sticking during cutting, resulting in severe tool wear, longer processing time, and higher unit processing cost; top-tier tensile strength and resistance to acid, alkali, and salt spray corrosion; 316L is suitable for seawater and humid chemical environments.
Suitable Surface Treatments: Electrolytic polishing, chemical passivation, nickel plating, wire drawing, sandblasting; no anodizing process.
Applicable Applications: Food processing equipment, minimally invasive medical surgical accessories, outdoor corrosion-resistant hardware, sealing parts for seawater environments, and cleanroom equipment housings.
3. Copper (Brass, Copper)
Processing Characteristics: Excellent plasticity, smooth cutting and forming; electrical and thermal conductivity far exceeds other metals; soft material, easily deformed in ultra-thin and slender parts; raw material procurement price is higher than carbon steel and aluminum.
Suitable Surface Treatments: Nickel plating, gold plating, silver plating, passivation, mirror polishing, enhancing oxidation resistance and electrical conductivity.
Applicable Applications: Electronic connectors, RF conductive terminals, high-power heat dissipation modules, electromagnetic shielding precision hardware.
4. Engineering Plastics (POM, ABS, PEEK, Nylon)
Processing Characteristics: No tool wear, lowest basic processing cost, lightest weight; high temperature resistance, rigidity varies depending on grade; prone to softening and warping during high-speed cutting.
Molding Support: Small batches of R&D samples are CNC milled; large batches of standardized plastic parts can be injection molded.
Suitable Surface Treatments: UV spraying, rubber oil spraying, sandblasting, bonding treatment; does not support metal oxidation or electroplating processes.
Applicable Applications: Insulating and isolating accessories, wear-resistant bushings, small insulating instrument housings, non-magnetic medical auxiliary parts.
二、Comparison of Advantages and Disadvantages of Surface Treatment Processes for Various Materials
Aluminum Alloy Anodizing: The film layer is integrated with the substrate and never peels off; wear-resistant and weather-resistant; can be colored; disadvantage: only suitable for aluminum; insulating but not conductive.
Stainless Steel Passivation/Electropolishing: Improves cleanliness and rust prevention; extremely thin film layer does not affect tolerances; no decorative color, average wear resistance.
Copper Gold/Silver Plating: Excellent conductivity and oxidation resistance, suitable for precision electronic components; high plating cost, easily worn off upon impact.
Plastic Spray Painting/Sandblasting: Rich appearance and feel, moderate cost-effectiveness; poor surface wear resistance, prone to aging and yellowing with long-term outdoor use.
三、Core Advantages of Material Selection
Aluminum Alloy: Lightweight, fast processing speed, rich appearance finishes, balancing quality and mass production costs;
Stainless Steel: Dual advantages of corrosion resistance and cleanliness, irreplaceable in medical and harsh outdoor environments;
Copper: Top-tier conductivity and thermal conductivity, the only preferred choice for electronic and heat dissipation components;
Engineering Plastics: Insulation, lightweight, low cost, highest cost-effectiveness for small indoor insulation structural components.
四、Material Selection Shortcomings and Avoidance Points
Aluminum alloys have low hardness, making them unsuitable for high-friction and high-intensity wear conditions; anodizing provides insulation, but prohibits their use in conductive parts.
Stainless steel is difficult to process and expensive, making it unnecessary for ordinary low-cost indoor structural components.
Copper raw materials are expensive; for applications without conductivity or heat dissipation requirements, aluminum can significantly control costs.
Engineering plastics have poor high-temperature resistance and cannot replace metals in high-temperature and heavy-duty applications.
五、OEM One-Stop Customization Services
Shengpeng Precision can recommend the optimal material based on the customer's product usage environment, load standards, export testing requirements, and budget, and match suitable surface treatment processes to avoid rework losses caused by material mismatch. Integrating milling, turning, die casting, 3D printing, sheet metal, and full-category surface treatment capabilities, we provide one-stop service for drawing review, blank forming, precision machining, appearance protection, and finished product testing and delivery, balancing small-batch R&D prototyping with stable mass production for large-scale export.
