Practical experience with new technologies in the mold industry
Under the wave of transformation and upgrading of the manufacturing industry, molds, as the "mother of industry", are accelerating iterations in the direction of high precision, high efficiency, long life and intelligence. Traditional mold production relies on trial and error experience, cumbersome processing procedures, long delivery cycles, high operation and maintenance costs and other pain points, which are being solved one by one by a series of new technologies. Combining many years of practical experience in front-line production, technology research and development, and project implementation, this article deeply dissects the application scenarios, practical key points, and pitfall avoidance guidelines of the four core new technologies in the current mold industry, providing industry colleagues with practical reference that can be directly reused.
CAE full-process simulation technology: bid farewell to experience trial and error and realize pre-design prediction
Traditional mold design relies entirely on the experience of engineers. Injection Molds are prone to weld marks, warping deformation and uneven filling.Stamping molds frequently suffer from wrinkles, cracks, excessive springback and other problems. They often require repeated mold trials and repairs. This not only wastes raw materials, but also significantly lengthens the research and development cycle. The cost of mold trial for small and medium-sized enterprises even accounts for more than 30% of the total research and development costs.
In the research and development of automotive panel and precision injection molds , we fully implement the full-process CAE and Moldflow simulation technology of cold stamping to achieve full-process simulation from product structure, mold structure to molding process. In the design stage, molding defect prediction, process parameter optimization and structural plan iteration are completed. The core practical process is divided into three steps:
- （1）Modeling and accurate parameter assignment:The simulation model is built strictly according to the actual production material characteristics, Injection Molding/stamping pressure, temperature, speed and other parameters, eliminating idealized setting of parameters to ensure that the simulation results are consistent with on-site production;
- （2） Comparative iteration of multiple plans: Design 2-3 sets of alternative plans for complex cavities, flow channels and cooling systems, and compare the molding effect, stress distribution, and cooling efficiency through simulation to select the optimal plan;
- （3）Closed loop of simulation and field data: record the actual data of the mold test, reversely correct the simulation parameter library and continuously improve the defect prediction accuracy. After iterative optimization, the defect prediction accuracy can reach more than 90%.
For a new energy vehicle battery case mold project, through CAE simulation optimization, the original number of mold trials was reduced from 12 to 3, the research and development cycle was shortened by 40%, and the product size qualification rate was increased from 85% to 99.2%; for a precision connector injection mold, the runner and gate design were optimized through simulation, completely solving the problem of uneven filling of multiple mold cavities, and the product weight fluctuation was controlled within ±0.01g.
Simulation technology isn’t "one-click results". It must be combined with on-site production experience to correct parameters to avoid over-reliance on simulation and ignoring actual processing and assembly errors. Small and medium-sized enterprises can start with single product simulation and gradually build exclusive parameter libraries, without blindly pursuing full category coverage.
3D printing additive manufacturing: breaking through the limitations of traditional processes and overcoming complex mold problems
Traditional machining can't process mold cavity conformal cooling water channels, complex special-shaped cavities and integrated structures, resulting in uneven mold cooling, product deformation and long production cycles, especially in precision injection molding and die-casting molds. The application of 3D printing (metal additive manufacturing) technology has completely broken the geometric limitations of mold structure design and has become the core breakthrough in complex Mold Manufacturing.
Practical application implementation：We focus on applying 3D printing technology to three major scenarios: conformal cooling water channel molds, special-shaped cavity inserts, and mold repair and reconstruction:
- Conformal cooling waterway design: abandon the traditional linear waterway and design a 3D conformal waterway that fits the contour of the product cavity. The cooling uniformity is increased by 60%, the injection molding cycle is shortened by 25%-40%, and the problems of product warping and sink marks are effectively solved;
- Integrated printing of complex cavities: For mold inserts with multi-curved surfaces, deep cavities and thin rib structures, direct 3D printing is performed without splicing processing, which avoids flash and burr problems caused by assembly gaps and the processing accuracy is improved to ±0.005mm;
- Rapid mold repair: Laser cladding 3D printing technology is used to partially repair worn and chipped mold cavities. After repair, the mold performance reaches standard, the cost is only 30% of that of a new mold, and the repair cycle is shortened by 70%.
After the introduction of 3D printing conformal water channels in a precision home appliance shell injection mold, the cooling time of the product was reduced from 28 seconds to 15 seconds, the daily production capacity increased by 35%, and the product deformation was controlled within 0.02mm; the edge of the scrapped automobile stamping mold was repaired by laser cladding, and its service life was restored to the level of the new mold, saving more than 20,000 yuan in cost for a single set of molds.
Choose metal printing materials suitable for mold working conditions, giving priority to mold steel powder with up to standard hardness and wear resistance; aging treatment, fine grinding and polishing must be carried out after printing to eliminate internal stress and ensure the dimensional accuracy and surface quality of the mold; small and medium-sized enterprises can use the combination model of "printed inserts + traditional mold bases" to reduce technology application costs.
Five-axis linkage precision machining + flexible automation: improve processing accuracy and achieve efficient mass production
Traditional three-axis machining centers process complex curved surface molds, which require multiple clamping and tool changes. The processing accuracy is poor and the efficiency is low, and complex profiles can't be formed in one go. The five-axis linkage machining center is paired with a flexible automated production line to realize one-time clamping and full-process processing of complex mold shapes, while promoting the transformation of mold production from single-machine processing to automated mass production.
- （1）Five-axis machining process optimization: For the complex curved surfaces of mold cavities and cores, five-axis linkage milling is used to optimize tool paths and cutting parameters to avoid tool interference. The surface roughness can reach Ra0.02μm without manual polishing, which directly meets high-precision production requirements. For new energy vehicles and medical device molds, the processing accuracy is stably controlled at ±0.003mm, breaking through the accuracy bottleneck of high-end molds;
- （2）Implementation of the flexible automated production line: Integrate the five-axis machining center, EDM, wire cutting, and manipulators to build a flexible mold steel processing production line to achieve automatic loading and unloading of workpieces, automatic flow of processes, and networked monitoring of equipment. The equipment utilization rate is increased from 60% to more than 90%, and labor costs are reduced by 50%;
- （3）Process integration and simplification: Integrate rough machining, finishing, corner cleaning, chamfering and other processes to reduce process turnover and shorten the processing cycle of a single set of complex molds by 30%.
High-end medical parts multi-cavity molds are processed through five-axis precision. The cavity size consistency error is ≤0.005mm. The product does not require subsequent trimming, and the yield rate reaches 99.5%. After the mold flexible production line is put into use, the batch mold order delivery cycle is shortened by an average of 20%, and the response speed to small batches and multi-variety orders is greatly improved.
Five-axis machining requires tool selection and fixture design in advance to avoid vibration and tool failure during processing; automated production lines need to establish standardized processing procedures and equipment operation and maintenance systems, and provide employee skills training in advance to avoid equipment failures affecting production efficiency; there is no need to blindly transform the entire line, and five-axis equipment can be introduced from the core process first to gradually realize automation upgrades.
Mold surface strengthening technology: extend service life and reduce operation and maintenance costs
Mold cavity wear, corrosion and edge chipping are common problems in the industry, especially for stamping and die-casting molds. Frequent mold repairs and mold changes lead to production interruptions and high operation and maintenance costs. Surface strengthening technologies such as laser quenching, plasma nitriding, and laser cladding can greatly extend the service life and maintenance cycle of the mold by improving the surface hardness, wear resistance and corrosion resistance of the mold.
Practical application implementation- Laser quenching: Laser partial quenching is used for the cutting edge of the stamping mold and the cavity of the injection mold to form a hardened layer of 0.1-0.3mm thick and HRC58-62. The mold deformation is extremely small and no subsequent grinding is required. After laser quenching of a certain automotive sheet metal stamping mold, the maintenance cycle was extended from 80,000 pieces to 300,000 pieces;
- （2）. Plasma nitriding: suitable for small and medium-sized precision molds. After surface nitriding, the wear resistance is increased by 3 times and the corrosion resistance is significantly enhanced. It is suitable for molds that produce acidic and corrosive plastic products for a long time;
- （3）. Nano-coating: Plating TiN and DLC nano-coating on the surface of the mold to reduce the friction coefficient, reduce product sticking and strain problems, make demoulding smoother, and increase the service life of the mold by 2-3 times.
After the precision die-casting mold is treated with plasma nitriding + nano-coating, the cavity wear rate is reduced by 80%, and more than 150,000 molds can be produced continuously after a single mold repair. After the plastic packaging mold is laser quenched, the surface finish of the product is greatly improved, and the scrap rate is reduced to less than 0.5%.
Select the corresponding strengthening process according to the mold material and operating conditions to avoid blind processing that will lead to a decrease in the toughness of the mold and easy cracking; surface strengthening must be carried out after the mold is finished, to avoid damage to the surface performance after the strengthening process.
Practical summary and future prospects for the implementation of new technologies in the mold industry
The core of the implementation of new mold technology isn’t to blindly pursue new technologies, but to fit the company's own product positioning and production scale to achieve the integration and optimization of "traditional technology + new technology". Judging from practical experience, companies can follow the path of "first simulation to reduce costs, then precision to improve efficiency, and then intelligent upgrade" when implementing new technologies. First, they can quickly reduce costs and increase efficiency through CAE simulation and surface enhancement technology, and then gradually introduce 3D printing, five-axis machining, and flexible automation technology to achieve technological iteration.
In the future, the mold industry will develop in depth towards digital twins, AI intelligent mold adjustment, and unmanned production. Digital management of the entire mold life cycle, real-time monitoring and adaptive adjustment of the production process will become a new trend in the industry. As a mold practitioner, only by continuing to learn new technologies, accumulating practical experience, and deeply integrating technological innovation with actual production can we seize the opportunity in the wave of manufacturing upgrades and create high-precision, high-efficiency, and cost-effective mold core competitiveness.
The iteration of mold technology ultimately focuses on improving quality, reducing costs and increasing efficiency. The above practical experience comes from the implementation of front-line projects. Different companies can optimize and adjust based on their own actual conditions.