# Customization Process of Castings in Dalian As a major industrial hub and port city in Northeast China, Dalian boasts a profound foundation in the foundry industry. It holds distinct technological and supply chain advantages in the production of customized castings for sectors including shipbuilding, equipment manufacturing, and construction machinery. Below is the complete process for customized casting production in Dalian, covering the entire chain from demand communication to after-sales service: ## I. Demand Communication & Feasibility Assessment The customization process begins with the accurate transmission of customer requirements. Customers shall provide core information to the foundry manufacturer: - **Product parameters**: material (cast iron, cast steel, aluminum alloy, stainless steel, etc.), dimensional specifications (including tolerance requirements), weight, and appearance requirements (e.g., surface roughness); - **Performance indicators**: mechanical properties (strength, hardness, toughness), corrosion resistance, high-temperature resistance, etc. (application scenarios must be specified; for instance, marine parts require seawater corrosion resistance); - **Order information**: batch size (single piece, small batch, or mass production), delivery lead time, and budget range. If customers do not have complete drawings, most foundry enterprises in Dalian offer reverse engineering or design optimization services: 3D scanning of existing parts or generating CAD/3D models based on customer needs, with the technical scheme finalized upon mutual confirmation. The manufacturer’s technical team will simultaneously assess feasibility — for example, if the required dimensional accuracy exceeds the capability of conventional sand casting (e.g., ±0.1 mm), investment casting (lost-wax process) or die casting will be recommended; for high-alloy steel materials, the smelting equipment’s ability to meet composition control requirements will be verified. ## II. Process Scheme Design & Quotation Based on the demand assessment, the manufacturer develops a detailed process scheme: - **Process selection**: choose sand casting (low cost, suitable for large parts), precision casting (high precision, suitable for complex structures), die casting (high efficiency, suitable for small light-alloy parts), etc., according to batch and precision requirements; - **Mold scheme**: wooden molds or resin molds for small-batch orders, and steel molds (high durability) for mass production; - **Auxiliary processes**: heat treatment (quenching and tempering to improve strength), surface treatment (painting, galvanizing for rust prevention), non-destructive testing (UT/RT inspection), etc. Subsequently, the manufacturer calculates costs (raw materials, mold fees, labor, equipment depreciation, inspection fees, logistics costs, etc.) and issues a detailed quotation. Upon customer confirmation of the quotation, a formal contract is signed, specifying quality standards (e.g., GB/T 11352 *Carbon Steel Castings for General Engineering Purposes*), delivery date, payment terms (usually 30% advance payment, balance settled upon quality inspection report), and liability for breach of contract. ## III. Mold Development & Sample Verification After the contract takes effect, mold manufacturing commences: - **Mold processing**: CNC machining or manual fabrication of molds per drawings, with strict control over parting surfaces and gate/riser positions to avoid casting defects; - **Trial production**: trial casting of a small number of samples using the mold, followed by dimensional inspection (coordinate measuring machine), appearance inspection (free of blowholes and sand holes), and performance testing (hardness, tensile test). If samples fail to meet requirements, the manufacturer shall adjust the mold (e.g., correct dimensional deviations) or optimize process parameters (e.g., adjust smelting temperature and pouring speed) until samples are approved by the customer. This step is critical to ensuring mass production quality and requires both parties to sign and confirm the sample standard. ## IV. Mass Production & In-Process Quality Control Mass production starts after sample approval, with core procedures as follows: 1. **Batching & smelting**: mix raw materials per material formula (e.g., pig iron, scrap steel, and inoculant for cast iron), smelt in medium-frequency furnaces or electric arc furnaces, and monitor chemical composition in real time via spectrometers to ensure compliance; 2. **Pouring & forming**: inject molten metal into molds per process requirements, controlling pouring temperature (approx. 1500°C for cast steel) and speed to prevent cold shuts, shrinkage cavities, and other defects; 3. **Cooling & demolding**: demold castings after cooling to room temperature, remove gates, risers, and flash; 4. **Post-treatment**: conduct heat treatment (e.g., quenching and tempering for cast steel parts), surface grinding (roughness ≤ Ra12.5μm), and rust prevention treatment (e.g., electrophoretic coating, plastic spraying) as required; 5. **In-process quality inspection**: sample each batch for non-destructive testing (ultrasonic inspection for internal defects) and mechanical property tests, with all data recorded and archived for quality traceability. ## V. Finished Product Inspection, Packaging & Shipment Upon completion of mass production, finished product inspection is performed: - **Full inspection items**: dimensional tolerances, appearance quality, performance indicators (e.g., hardness ≥ HB200), and chemical composition; - **Certificate issuance**: provide quality inspection reports (including third-party inspection reports if requested by the customer). Qualified products are packaged per customer requirements: large parts in wooden cases filled with shockproof foam, small parts on pallets with stretch film, marked with product model, quantity, and batch number. Leveraging Dalian’s port advantages, manufacturers can directly connect with freight forwarders for export orders and ship via Dalian Port, shortening logistics cycles. ## VI. After-Sales Service & Technical Support After shipment, the manufacturer provides: - **Logistics tracking**: real-time feedback on cargo transportation status; - **Installation guidance**: dispatch technicians to assist with installation and commissioning if required by the customer; - **Quality assurance**: responsible for replacement, return, or repair in case of non-human-induced quality defects (e.g., cracks, blowholes); - **Long-term cooperation**: establish product archives for customers and offer process optimization suggestions for subsequent orders. Centered on customer needs, Dalian’s casting customization process achieves full-process controllability from design to delivery, supported by a mature industrial system and port logistics advantages. It meets the high-precision and high-performance casting demands of various industries, whether for single-piece customization or mass production.
