When you press mute button of a high-end mobile phone and feel precise touch of "click", have you ever thought: metallic luster and frosted touch of this button actually come from a precise "rotational ballet" in mold?
Rotary mold, this "space magic" that allows mold core to rotate and translate during injection molding process, is reshaping boundaries of modern manufacturing with millimeter-level precision.

Definition: Rotary Mold is a mold system that completes multi-material injection and multi-process processing in a single molding cycle through rotation/translation of mold core or template. It integrates multiple functions like a Swiss Army Knife, and its core value lies in:
Process integration: two-color injection molding, in-mold assembly in one step;
Efficiency doubled: multiple composite structure products are produced in a single cycle;
Zero interface defects: no seams or glue marks on material bonding surface
Classic application scenarios
�� Game handle: seamless combination of hard skeleton (ABS) and non-slip soft rubber (TPU);
�� Car gear lever: transparent logo (PMMA) and leather texture (PVC) are integrated;
�� Medicine bottle safety cap: inner antibacterial PP and outer non-slip TPE are injected simultaneously.

1. Say goodbye to "multi-layer cake" production
Traditional process: injection molding of part A → cooling and removal → putting into another mold to inject part B → manual assembly;
Rotary mold: Parts A and B are continuously molded in mold through a rotating station, which takes only 1/3 of time of traditional process.
2. Micron-level combination accuracy
Mold core rotation positioning accuracy can reach ±0.01mm (equivalent to 1/5 of a hair);
Case: A folding screen mobile phone hinge kit achieves a 0.03mm shaft core-gear gap through a rotating mold.
3. No restricted areas for material mix and match
"Hard and soft" combination of hard plastic (PC/PA) and soft plastic (TPU/LSR);
"Cross-border marriage" of conductive plastic (POM+carbon fiber) and insulating material (PEI).

1. Horizontal rotation (turntable mold)
Process:
1️⃣ Station A: Inject first material (such as hard plastic base);
2️⃣ Turntable rotates 180°;
3️⃣ Station B: Inject second material (such as soft plastic handle);
Advantage: Simple structure, suitable for small and medium-sized parts.
2. Vertical flip type (flip mold)
Process:
1️⃣ Upper mold injection molding A surface;
2️⃣ Mold core flips 180° as a whole;
3️⃣ Lower mold injection molding B surface;
Advantage: Suitable for large parts (such as automotive interior panels).
3. Servo motor drive system
Torque ≥ 500N·m, speed 0.1-10rpm steplessly adjustable;
Repeat positioning accuracy ±0.005mm, life span over 1 million times.

 

Case 1: Foldable mobile phone hinge
Pain point: Traditional hinges require 30 parts to assemble, thickness > 3mm;
Rotary mold solution:
Hard stainless steel skeleton and self-lubricating plastic gears are injected synchronously;
Flexible circuit board embedded in mold;
Results: Thickness compressed to 1.2mm, opening and closing life over 400,000 times.
Case 2: Medical three-way valve
Requirement: Transparent valve body (PC) and blue identification ring (ABS) zero pollution combination;
Technical breakthrough:
Integrated sterile gas protection system in two-color rotary mold;
Joint surface shear strength ≥ 45MPa (3 times that of super adhesive process);
Benefit: Yield rate is increased from 82% to 99.9%.

1. "Invisible killer" of thermal expansion
Thermal expansion coefficient of steel is ≈11.7μm/(m·K), and a mold temperature fluctuation of 1℃ will cause a 300mm mold core to move 3.5μm;
Countermeasures:
Use Invar alloy (thermal expansion coefficient <1.5μm/(m·K)) to manufacture key components;
Real-time infrared temperature measurement + dynamic compensation algorithm.
2. Paradox of lubrication and sealing
Rotating mechanism needs lubrication, but lubricating oil may contaminate cavity;
Breakthrough:
Solid lubricating coating (molybdenum disulfide/graphene);
Magnetic fluid sealing technology to achieve zero leakage.

AI dynamic parameter adjustment:
Automatically correct rotation angle according to material shrinkage rate;
Self-sensing mold core:
Embedded thin film pressure sensor to monitor state of joint surface in real time;
Metamaterial application:
Shape memory alloy mold core to achieve adaptive deformation of mold
Every rotation of rotary mold is a symphony of precision machinery, material science and control algorithms. It allows manufacturing industry to move from "two-dimensional thinking" to "three-dimensional thinking" and reconstruct production logic in a small space. Perhaps one day in the future, we will be able to see another kind of poetry of industrial civilization in rotation of mold.