Depth analysis of injection mold opening cycle -- complexity and collaboration are key variables

2025-03-29 17:53:24

First, the main factors affecting the mold opening time

Die complexity

Simple mold (single cavity, simple structure) : such as daily necessities shell, may only take 4-6 weeks.

Complex molds (multi-cavity, precision structure, core-pulling/sliders) : such as automotive parts or medical precision parts, may take 8-16 weeks.

Special process requirements (such as two-color mold, laminated mold) : the time may be extended by 20%-50%.

Mold material

Ordinary steel (such as P20, 718) : short processing cycle, suitable for low life requirements.

High hardness steel (such as H13, S136) : Heat treatment and finishing time increased by 1-2 weeks.

Aluminum mold (rapid prototyping) : can be shortened to 2-4 weeks, but only hundreds to thousands of times of life.

Design and validation

3D design, DFM analysis, customer feedback modification: Repeated communication may add 1-3 weeks.

Key point: Product design flaws (such as uneven wall thickness) can result in multiple reworks, significantly extending cycle times.

Plant scheduling and equipment

Peak season schedules may be delayed by 2-4 weeks.

High-precision equipment (five-axis machining, mirror discharge) can shorten the processing time, but the queue needs to be queued when resources are tight.

Second, mold opening process and time decomposition

Product Design and DFM Analysis (1-3 weeks)

Customers provide 3D drawings → mold factory manufacturability analysis (DFM), feedback modification suggestions.

Common delays: The customer repeatedly adjusts the product design (such as adding a back-off structure).

Mold design (1-2 weeks)

Parting surface design, cooling system layout, ejection mechanism planning.

Complex molds require multiple simulation verification (Moldflow analysis).

Manufacturing (3-8 weeks)

Roughing: CNC milling for large cavities, about 1-2 weeks.

Finishing: EDM discharge machining details texture, precision parts processing takes 2-3 weeks.

Heat treatment: hardening/tempering of steel increases by 3-5 days.

Surface treatment: nitriding, chrome plating, etc., increased by 1 week.

Mold testing and debugging (1-4 weeks)

First test (T0) : Test the basic form, usually 1-3 days.

Problem correction (such as shrinkage, flash) : each round of modification takes 3-7 days, complex problems may take multiple rounds.

Switching of mold materials (e.g. from PP to PC) may increase the test time.

Mass production acceptance (1 week)

Continuously produce 500-1000 pieces, verify stability, and sign PPAP documents.

3. Feasible plan for accelerating mold opening

Parallel engineering: Simultaneous preparation of injection molding machine parameters during mold processing, saving 1-2 weeks.

Modular design: Use standard die frames (such as LKM) to reduce processing.

Rapid prototyping technology:

3D printing soft mold (silicone mold) : sample within 72 hours, suitable for small batch verification.

Aluminum mold + high-speed processing: 30%-50% faster than steel mold, suitable for small and medium-sized batches.