一, Core process and cycle composition of mold development
The development of electronic injection molds is a system engineering that integrates design, processing, assembly, and debugging. Its cycle can be divided into the following four stages:
1. Pre planning and design phase (5-20 days)
Requirement analysis and scheme demonstration: After the customer proposes the mold requirement, it is necessary to clarify the product purpose, material characteristics, production batch and other parameters. For example, the TWS earphone case needs to consider IPX7 waterproof requirements, while the smart watch frame needs to balance lightweight and structural strength. At this stage, the feasibility of the design is verified through CAE simulation (such as Moldflow analysis). Simple molds can be completed within 3 days, while complex molds (such as multi slide die-casting molds) may take more than 7 days.
Detailed design and drawing output: CAD/CAM software (such as UG, Pro/E) is used for 3D modeling and engineering drawing. Taking a moderately complex injection mold as an example, which includes hundreds of components such as cavity, core, pouring system, cooling system, etc., the design needs to take into account structural strength, cooling efficiency, and processing technology. If it involves multi station progressive molds (such as terminal stamping molds), the step spacing accuracy between stations (± 0.01mm) needs to be considered, and the design cycle can be extended to 10-15 days.
2. Processing and manufacturing stage (20-60 days)
Material preparation and rough machining: Mold materials need to be selected according to the usage scenario, such as H13 hot work mold steel for high temperature environments, and S136 corrosion-resistant plastic mold steel for transparent parts. The material needs to undergo pre-treatment such as forging and annealing. Steel forging for large molds (such as car bumper molds) may take more than 5 days, while material cutting for small precision molds can be completed in 2-3 days. Rough machining removes most of the blank residue through processes such as CNC milling and wire EDM (slow wire cutting). For example, rough machining of the cavity of a TV casing injection mold requires the use of a Φ 50mm end mill with a feed rate of 5000mm/min, which takes about 8 days.
Semi precision machining and precision machining: Semi precision machining is used to correct rough machining errors, while precision machining achieves dimensional accuracy and surface quality. Precision molds (such as optical lens molds) require a five axis linkage machining center to mill with a cutting depth of 0.01mm, and the precision machining of a single cavity may take up to 15 days. Electric discharge machining (EDM) is used for complex cavities (such as deep and narrow grooves in engine cylinder molds), with a processing speed of about 0.5-2mm ³/min. A cavity with a depth of 200mm takes more than 7 days.
Special processing and surface treatment: For micro molds (such as MEMS sensor molds), special processes such as laser processing and electron beam processing are required. The processing of a single microstructure (diameter ≤ 0.1mm) takes several hours, and the special processing of the entire mold may take 5 days. Surface treatment (such as nitriding and coating) can improve the lifespan of molds. Ion nitriding process requires insulation for 20-30 hours, and testing after cooling takes 2-3 days.
3. Assembly and debugging phase (10-25 days)
Component assembly: Assemble the processed parts into a mold assembly, and strictly control the assembly accuracy. For example, the fitting gap of the parting surface of the injection mold should be ≤ 0.02mm, and the clearance between the inclined guide column and the slider of the multi slider mold should be controlled within 0.01-0.03mm. Manual grinding and adjustment may take more than 7 days.
Trial molding and optimization: Problems such as flash, shrinkage, and size deviation often occur during the first trial molding. Taking the automotive dashboard mold as an example, the first trial mold may require adjusting the injection pressure (from 80MPa to 120MPa), cooling time (from 30s to 20s), and repairing or polishing the mold cavity. The single optimization cycle is about 5 days, and complex molds require 3-5 trial molds, with a total time of up to 15 days.
4. Other influencing factors
Customer confirmation and changes: Design scheme or process adjustments may result in a 10-20 day extension of the cycle, for example, if the customer temporarily requests that the mold be compatible with multiple materials, the flow channel system needs to be redesigned.
Supply chain collaboration: The delivery time of externally purchased parts (such as standard mold frames and hot runner systems) may affect the schedule. The delivery time of imported hot runner systems can be as long as 4-6 weeks, while domestic parts can be shortened to 1-2 weeks.
Equipment failure and scheduling: The downtime of a five axis machining center may be delayed by 3-5 days due to a malfunction, and tight equipment scheduling when multiple projects are running in parallel can result in a 20% -30% extension of processing time.
二, Comparison of development cycles for different types of molds
Mold type design stage, processing stage, assembly and debugging stage, total cycle
Simple molds (such as injection molds for daily necessities) take 5-7 days, 15-25 days, 7-10 days, and 30-45 days
Medium complexity molds (such as automotive interior parts molds) take 10-15 days, 30-50 days, 15-20 days, and 60-90 days
High complexity molds (such as aerospace structural component molds) take 20-30 days, 60-100 days, 25-40 days, and 120-180 days
Typical case:
The injection mold for the washing machine inner tube of a certain household appliance enterprise (medium complexity): design takes 12 days, processing takes 45 days, debugging takes 18 days, and the total cycle is 75 days.
The hot forming mold (high complexity) for the door anti-collision beam of a certain automobile OEM factory: designed for 28 days, processed for 90 days, debugged for 35 days, with a total cycle of 153 days.
三, Key strategies for shortening the mold development cycle
1. Technological innovation drives efficiency improvement
Digital design and simulation: using AI assisted design (such as generative design) to automatically optimize mold structure, combined with virtual trial molding technology (Virtual Tryout) to predict defects in advance and reduce design rework. After a certain enterprise introduced AI design, the mold design cycle was shortened by 40%.
High speed machining and additive manufacturing: using high-speed milling (HSM) technology to increase cutting speed to 3-5 times that of traditional machining; 3D printing (such as SLM metal printing) is used to manufacture conformal cooling channels, which increases cooling efficiency by 50% and shortens processing cycles by more than 20 days.
2. Process optimization and collaborative management
Concurrent Engineering: During the design phase, material procurement and process planning are carried out simultaneously. For example, when 60% of the 3D modeling is completed, ordering long-term materials (such as imported steel) can be initiated, which can shorten the waiting time by 7-10 days.
Intelligent production scheduling: Real time monitoring of equipment load through MES system, dynamic adjustment of processing sequence, and avoidance of equipment idle. After a certain mold factory introduced intelligent scheduling, the equipment utilization rate increased from 65% to 85%, and the processing cycle was shortened by 25%.
3. Supply chain integration and standardization
Standardized mold components: using standard mold frames and accessories from brands such as LKM and DME to reduce customized processing. For example, using a standard hot runner system can save 7 days of design and processing time.
Localized supply chain layout: Establish close cooperation with surrounding heat treatment plants and surface treatment suppliers to shorten the heat treatment cycle from 10 days outsourced to 5 days.
