① Batch requirements: The minimum batch size can support 10 pieces/batch (small batch customization). For batches ≥100 pieces, cost benefits can be enjoyed. For large batches (≥1000 pieces), process optimization can be implemented to reduce the unit price. ② Delivery cycle: Sample making (including mold making) takes 7~15 days, small batches (10~100 pieces) take 15~25 days, and large batches (≥1000 pieces) take 25~40 days (adjusted according to the complexity of the casting). ③ Customization: We fully support the customization of irregular-shaped parts, complex internal cavity parts, and non-standard sizes. Simply provide CAD drawings (or samples), and we can complete mold design, process optimization, and casting production in a one-stop service. We can adapt to customization needs in various industries such as medical, aviation, machinery, and electrical.

Common surface treatment methods and applicable scenarios: ① Acid pickling and passivation: removes the surface oxide layer, enhances corrosion resistance, suitable for pretreatment of subsequent spraying and electroplating, or industrial parts with low appearance requirements; ② Electroplating (nickel plating, chromium plating): enhances surface hardness, wear resistance, and aesthetics, suitable for precision instruments, decorative parts; ③ Chemical plating: no electroplated layer, strong bonding force, suitable for surface protection of complex internal cavities and irregular parts; ④ Spraying (fluorocarbon, epoxy): enhances corrosion resistance and anti-aging properties, suitable for castings in outdoor or chemical corrosion environments; ⑤ Polishing: enhances surface smoothness (Ra≤0.8μm), suitable for high-precision assembly parts and appearance parts.

Copper alloys differ significantly in their tolerance ranges and are suitable for various working conditions: ① Brass: Long-term operating temperature ≤200℃, withstandable pressure ≤10MPa, suitable for medium and low temperature, medium and low pressure conditions (such as ordinary pipelines, atmospheric pressure valves); ② Aluminum bronze: Long-term operating temperature ≤300℃, withstandable pressure ≤25MPa, wear-resistant and high temperature resistant, suitable for medium and high temperature, medium and high pressure mechanical components; ③ Tin bronze: Long-term operating temperature ≤250℃, withstandable pressure ≤15MPa, suitable for medium working conditions with wear resistance and impact resistance. If higher temperature (≤400℃) and higher pressure (≤30MPa) requirements are needed, special formulated copper alloys (such as beryllium bronze) can be selected, and casting processes can be optimized to enhance density.

To address core defects, precise control is required from the process side: ① Porosity: Select high-purity copper alloy raw materials (with impurity content ≤0.5%), adopt vacuum degassing or inert gas protection during melting, design reasonable exhaust channels in the mold to avoid insufficient permeability of the shell; ② Shrinkage/porosity: Optimize the pouring system (use bottom pouring or stepped pouring), control the pouring temperature (1080~1150℃ for brass, 1100~1180℃ for bronze), set up risers reasonably to achieve sequential solidification; ③ Cracks: Avoid excessive wall thickness difference in the casting (the maximum wall thickness difference should not exceed 3:1), slow down the cooling after pouring (use slow cooling pits or insulation covers), reduce thermal stress, and strictly control the shell baking temperature (800~950℃) to avoid uneven expansion of the shell and resulting stress.

① Brass (such as H62, H65): good fluidity, excellent casting performance, moderate cost, strong corrosion resistance, suitable for manufacturing civil and industrial general-purpose parts such as valves, pipe fittings, and hardware accessories; ② Bronze (such as tin bronze ZCuSn10Pb1, aluminum bronze ZCuAl10Fe3): wear-resistant, impact-resistant, high temperature resistant, suitable for manufacturing mechanical wear-resistant parts (sleeve, worm gear), chemical equipment accessories; ③ Copper (T2, T3): excellent electrical and thermal conductivity, high purity, suitable for manufacturing electrical components, heat dissipation parts, but casting difficulty is slightly higher, process parameters need to be strictly controlled to avoid porosity.

The dimensional accuracy can stably reach CT5-CT7 levels as specified in the GB/T 6414-2017 standard (adjusted according to the complexity of the casting structure), with linear tolerances controlled within ±0.05~±0.15mm per 100mm; the surface roughness Ra is ≤1.6~3.2μm, meeting most assembly and appearance requirements without additional polishing.

Supplementary note: For complex internal cavities and thin-walled castings (with a minimum thickness of 1.5mm), there may be slight deviations in dimensional accuracy (CT7-CT8 level). However, the surface roughness can be improved to Ra≤0.8μm through subsequent polishing, meeting the requirements of high-precision equipment components.