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The innovative design and intelligent development trend of injection molds

• 2025-07-09

The innovative design and intelligent development trend of injection molds

    Injection molding, as one of the most widely used processing technologies in modern manufacturing, the technical level of its core carrier, the injection mold, directly determines the quality of the product, production efficiency and manufacturing cost. With the continuous emergence of new materials, new processes and new technologies, the injection mold industry is undergoing a critical period of transformation from traditional manufacturing to intelligent, precise and green manufacturing. This article will systematically explore the cutting-edge technologies and practical breakthroughs in the field of injection molds from aspects such as innovative design of mold structure, application of new materials, intelligent manufacturing technology, green production concepts, and future development trends, providing new ideas and references for the industry's development.

Automobile radiator crossbeam accessories Manufacturer in China (jfmoulds.com)

I. Breakthrough Directions for Innovative Design of Injection Mold Structures

    The structural design of injection molds is the core factor determining the molding quality. Traditional mold structures often encounter problems such as low efficiency and poor stability when dealing with complex geometric shapes, high-precision requirements, or the molding of special materials. In recent years, the industry has witnessed the emergence of numerous breakthrough technologies in structural innovation, effectively addressing the pain points of traditional design.

1. Conformal cooling water channel design and additive manufacturing application

    The cooling water channels of traditional molds are mostly straight or simple curved structures, which are difficult to match with the complex shapes of plastic parts, resulting in problems such as uneven cooling, long molding cycles, and warping and deformation of plastic parts. The conformal cooling water channel design simulates the temperature field distribution of the plastic part through computer-aided engineering. It adopts a three-dimensional curved water channel structure parallel to the surface contour of the plastic part, enabling the cooling medium to flow evenly through all areas of the plastic part and significantly improving the cooling efficiency.

    The maturity of additive manufacturing technology provides feasibility for the processing of conformal cooling water channels. By adopting selective laser melting technology, the core and cavity of the mold can be directly sintered, integrating the complex conformal waterways inside the mold without the need for splicing or drilling processes in traditional processing. The practice of a certain auto parts enterprise shows that the adoption of conformal cooling for bumper molds has reduced the cooling time from the original 60 seconds to 35 seconds, increasing production efficiency by 40%. At the same time, the warpage of plastic parts is controlled within 0.1mm, and the scrap rate has decreased by 60%.

2. Modular and quick-change mold structure design

    In response to the production demands of multiple varieties and small batches, modular mold design enables rapid switching between different plastic parts by decomposing the mold into standardized modules such as basic mold bases, replaceable cavities/cores, and core-pulling mechanisms. The modules are connected by high-precision positioning pins and locking devices to ensure the assembly accuracy after mold changing. After a certain home appliance enterprise adopted modular molds for its washing machine panel production line, the mold changing time was shortened from the traditional 2 hours to 15 minutes, and the equipment utilization rate increased by 25%.

    Rapid mold changing technology also includes hydraulic/pneumatic driven automatic mold changing systems. Through the linkage of sensors and control systems, it realizes the automatic identification, positioning and clamping of molds. Installing robot-assisted devices between the injection molding machine and the mold can further reduce manual intervention and enable the mold changing process to be fully automated.

3. Innovation in mold parting and core-pulling mechanisms for complex cavities

    For plastic parts with complex structures such as deep cavities, upside-down holes, and side holes, traditional core-pulling mechanisms often have problems such as complex structures, motion interference, or insufficient core-pulling force. In recent years, the industry has developed a variety of innovative core-pulling solutions:

    Laminated core-pulling mechanism: Through a multi-layer nested core design, it realizes the layered core-pulling of deep cavity plastic parts, avoiding the damage to the plastic parts caused by a single core-pulling action. The outer shell mold of a certain medical device enterprise's infusion set adopts three-layer stacked core-pulling, successfully solving the core-pulling problem of a tubular structure with a depth of up to 120mm.

    The inclined top and rotary core-pulling composite mechanism: It combines the linear motion of the inclined top with the circular motion of the rotary core-pulling, and is suitable for plastic parts with helical grooves or complex side depressions. The threaded interface forming of the mobile phone charger shell often adopts this structure to ensure that the thread accuracy reaches ISO 4H grade.

    Flexible core-pulling system: It adopts a multi-degree-of-freedom mechanical arm driven by a servo motor as the core-pulling actuator. By controlling the core-pulling path through a program, it can adapt to the minute structural changes of different batches of plastic parts and is particularly suitable for customized production.

4. Runner optimization for multi-material co-injection molds

    Multi-material co-injection molding can achieve the integrated molding of plastic parts of different materials, colors or properties in the same mold, reducing subsequent assembly processes. The core of its mold structure lies in the design of the runner system, which requires precise control of the filling sequence, flow ratio and interface integration of various materials.

    The innovative "dynamic switching runner" controls the injection timing of different materials through solenoid valves, and in combination with the gradient gate design, it enables the two materials to form a uniform layered structure in the cavity. The smartwatch case of a certain electronic enterprise is made by co-injection molding of ABS and TPU. Through the optimization of the flow channel, the bonding strength of the two materials has been increased to 25MPa, far exceeding the 15MPa of the traditional structure. In addition, for the rotary molds of multi-color molding, high-precision dividing plates are used to control the rotation Angle of the cavity, ensuring clear boundaries of the colorants and avoiding color mixing defects.

Tray mold Manufacturer in China (jfmoulds.com)

Ii. Application Progress of New Mold Materials and Surface Treatment Technologies

    The performance of mold materials directly affects the service life, forming accuracy and manufacturing cost of molds. With the increasing demand for forming special materials such as high temperature, high corrosiveness and high filling rate, traditional die steel has become difficult to meet the requirements. The application of new materials and surface treatment technologies has become an important direction for the development of the industry.

Research and application of high-performance die steel

    Traditional die steels such as Cr12 and S136 have the problem of outstanding individual performance in terms of hardness, wear resistance or corrosion resistance, but insufficient overall performance. In recent years, domestic and foreign steel enterprises have developed a variety of high-performance alloy die steels. Through composition optimization and improvement of heat treatment processes, they have achieved breakthroughs in comprehensive performance.

    Powder metallurgy high-speed steel: ASP-60 die steel produced by powder metallurgy process, with alloy elements such as tungsten, molybdenum and vanadium content reaching over 15%. After heat treatment, its hardness can reach HRC 65-67, and its wear resistance is three times that of traditional Cr12 steel. It is suitable for processing reinforced plastics with added glass fibers. After a certain car engine hood mold adopted this material, its service life was increased from 500,000 cycles to 1.5 million cycles.

    Corrosion-resistant martensitic stainless steel: such as 718H steel, by increasing the content of chromium and nickel elements and applying ultra-fine treatment, it can maintain a hardness of HRC 50-52 while achieving salt spray corrosion resistance of over 5000 hours, making it suitable for the molding of corrosive materials like PVC and POM.

Low-temperature tempered high-strength steel: After deep cryogenic treatment, the content of residual austenite inside STAVAX ESR steel is reduced to below 5%. At room temperature, its tensile strength reaches 1800MPa, and it can still maintain stable mechanical properties in a low-temperature environment of -50℃. It is suitable for engineering plastic molds formed at low temperatures.

2. Innovative application of non-metallic mold materials

    In the field of small-batch production or prototype manufacturing, non-metallic material molds have been widely applied due to their advantages of low cost and short cycle. In recent years, the performance of composite material and engineering plastic molds has been continuously improving, gradually penetrating into the medium-batch production field:

    Carbon fiber reinforced epoxy resin mold: Formed by the composite molding of carbon fiber and epoxy resin, the mold weight is only 1/5 of that of traditional steel molds. The thermal conductivity can be adjusted to 15-20 W/(m·K) by adding graphene, making it suitable for low-pressure molding of thermosetting plastics. The outer shell mold of a certain aerospace enterprise's unmanned aerial vehicle adopts this material, reducing the manufacturing cost by 60% and shortening the production cycle from 45 days to 15 days.

    Peek-based engineering plastic molds: PEEK (polyetheretherketone) features high-temperature resistance and chemical corrosion resistance. By adding glass microspheres, the coefficient of linear expansion can be controlled below 8×10^-6/℃, making it suitable for injection molding of small plastic parts. The disposable syringe molds of a certain medical equipment enterprise are made of PEEK material. The cost of a single set of molds is only 1/10 of that of steel molds, and it can meet the production demand of 10,000 to 50,000 molds.

3. Advanced surface treatment technology enhances the performance of molds

    Surface treatment technology can significantly enhance the wear resistance, corrosion resistance, demolding property and other properties of molds by forming special coatings or modified layers on the surface of molds, while reducing production costs. In recent years, innovations in the field of surface treatment in the industry have focused on the following aspects:

    Physical vapor deposition (PVD) super-hard coating: By using multi-arc ion plating technology to deposit coatings such as TiAlN and CrN on the mold surface, the thickness is controlled at 3-5μm, the hardness can reach HV 2500-3000, and the coefficient of friction is reduced to below 0.2. After a certain bottle cap mold enterprise applied the TiAlN coating, the demolding force of the mold was reduced from the original 80N to 35N, eliminating the need for mold release agents and avoiding surface contamination of plastic parts.

    Chemical vapor deposition (CVD) diamond coating: Polycrystalline diamond coatings are deposited on the mold surface through hot wire CVD technology, with a hardness as high as HV 10000 and a thermal conductivity of 800 W/(m·K), making it suitable for processing reinforced plastics with high filling rates (glass fiber content above 50%). Experimental data show that the service life of molds coated with diamond is 10 to 15 times that of uncoated molds.

    Laser surface texturing treatment: By using femtosecond laser to process micron-level (5-50μm) pits or stripe structures on the surface of the mold cavity, a "micro-oil storage tank" or "gas film layer" is formed, which can reduce the friction coefficient by more than 50%. For the molding of high-viscosity materials such as PC (polycarbonate), texturing treatment can reduce the injection pressure by 15% to 20% and decrease the internal stress of the plastic part.

    Sol-gel ceramic coating: A SiO2-Al2O3 composite ceramic coating is formed on the mold surface through the sol-gel method, with a thickness of 1-2μm. It has excellent corrosion resistance and non-stickiness, and is suitable for the molding of easily decomposable materials such as PVC and POM. After the PVC drainage pipe molds of a certain pipe fitting enterprise adopted this coating, the mold cleaning cycle was extended from 15 days to 60 days, and the production stability was significantly improved.

Garbage can mold Manufacturer in China (jfmoulds.com)

Iii. Intelligent Manufacturing and Digital Management of Injection Molds

    The in-depth advancement of the concepts of Industry 4.0 and intelligent manufacturing has driven the injection mold industry to transform from the traditional "experience-driven" model to a "data-driven" one. Intelligent manufacturing technology integrates technologies such as sensors, the Internet of Things, and big data analysis with the entire process of mold design, processing, and usage, achieving high-precision, high-efficiency, and high-reliability production of molds.

Mold design and simulation based on digital twins

    Digital twin technology achieves dynamic simulation and optimization of the entire process from design, processing, mold testing to production by building a virtual digital transformation of molds. During the design stage, 3D modeling software is used to construct the geometric model of the mold, and CAE simulation tools are combined to simulate and analyze processes such as filling, holding pressure, cooling, and warping.

    Filling process simulation: By simulating the flow path, pressure distribution and temperature changes of the molten material in the cavity, the position and number of gates are optimized. The mold for the refrigerator drawer of a certain home appliance enterprise reduced the number of gates from 4 to 2 through simulation, eliminating the defect of weld marks.

    Cooling system simulation: Calculate the temperature field distribution of the mold based on the heat conduction equation, optimize the diameter, spacing and flow rate of the water channels, and control the temperature difference of the mold within ±2℃.

    Warpage prediction and compensation: Based on the material shrinkage rate data, the reverse compensation amount is preset during mold design to counteract the warpage deformation of the plastic part after molding.

    The digital twin model can also be connected with the real-time data of production equipment. During the mold trial stage, process parameters can be optimized through virtual debugging, reducing the number of physical mold trials. The practice of a certain auto parts enterprise shows that after adopting digital twin technology, the number of mold trials has been reduced from the traditional 5 to 8 times to 2 to 3 times, shortening the development cycle by 30%.

2. Integration of intelligent processing equipment and techniques

    The high-precision processing of mold parts relies on the coordination of intelligent processing equipment and techniques. In recent years, the intelligence level of five-axis linkage machining centers, high-speed milling, electrical discharge forming and other equipment has significantly improved. Combined with adaptive control technology, real-time adjustment of the processing process has been achieved.

    Five-axis linkage machining center: It adopts closed-loop control of grating rulers and thermal error compensation technology, and can complete the milling, drilling, tapping and other processes of complex cavities in one clamping. When a certain precision mold enterprise processes the curved cavity of the mobile phone shell mold, the surface roughness is controlled within Ra 0.05μm, meeting the requirements of mirror effect.

    High-speed milling technology: High-speed milling machines with spindle speeds ranging from 40,000 to 60,000 r/min, in combination with ultra-fine-grained cemented carbide tools, can achieve high-speed cutting of die steel, with a material removal rate of up to 500cm³/min, and the processing efficiency is three times that of traditional milling.

    Adaptive control of electrical discharge forming: By using sensors to monitor the discharge gap and current changes in real time, the pulse parameters are automatically adjusted to avoid dimensional errors caused by uneven electrode wear. For the deep and narrow groove structure in the mold, the processing accuracy can reach ±0.002mm.

    In addition, the integration of the automated loading and unloading system with processing equipment has enabled 24-hour continuous production, reducing the processing cycle of mold parts by more than 40%.

3. Mold condition monitoring and predictive maintenance

    During the use of molds, by installing sensors to monitor their operating status in real time and combining big data analysis to achieve predictive maintenance, the downtime caused by sudden failures can be significantly reduced. Commonly used monitoring techniques include:

    Temperature monitoring: Thermocouples or infrared temperature sensors are embedded in the mold cavity and core to collect temperature data in real time. An alarm is issued when the temperature exceeds the set range to prevent defects in plastic parts due to overheating or overcooling.

    Pressure monitoring: Install pressure sensors inside the cavity to monitor the changes in the injection pressure and holding pressure of the molten material, and promptly detect problems such as blockage at the feed port or mold leakage.

    Vibration monitoring: By collecting the vibration signals during the opening and closing of the mold through an acceleration sensor, analyzing the changes in vibration frequency and amplitude, and determining the wear status of the guide pins and guide sleeves.

    Wear monitoring: A laser displacement sensor is used to scan the surface of the cavity, and the wear amount is calculated by comparing it with the initial size. When the wear amount exceeds 0.01mm, a warning is issued to prevent the mass production of substandard plastic parts.

    The data acquisition system transmits sensor signals to the cloud platform and builds a fault prediction model through machine learning algorithms to predict potential faults 3 to 5 days in advance and generate maintenance suggestions. After a certain automotive mold enterprise applied this technology, the downtime due to mold failures was reduced by 60%, and the maintenance cost was lowered by 35%.

Iv. Future Development Trends and Challenges of the Injection Mold Industry

1. Deep integration of intelligence and automation

    In the future, injection molds will develop towards full-process intelligence: artificial intelligence (AI) will be used in the design stage to automatically generate mold solutions; During the processing stage, intelligent scheduling and adaptive processing of equipment, cutting tools and fixtures are achieved. During the production stage, the Internet of Things (iot) is utilized to enable the collaborative work of molds, injection molding machines, and robots, thereby building an unmanned intelligent production line.

2. Adaptation of new materials to new forming processes

    With the wide application of bio-based plastics, high-performance composite materials and functional materials, molds need to adapt to the special properties of the materials: in view of the high water absorption of bio-based plastics, anti-corrosion molds should be developed; In response to the high filling rate of composite materials, the wear resistance of molds is enhanced. To meet the precision forming requirements of functional materials, achieve micron-level precision control.

3. The balance between globalization and personalized customization

    Under the background of global division of labor, mold enterprises need to establish cross-regional collaborative design and manufacturing networks, and achieve design data sharing and remote debugging through cloud platforms. At the same time, in the face of the growth of consumers' personalized demands, molds need to have the ability to respond quickly and achieve small-batch customized production through modular and parametric design.