In combination with the current market environment, the mold manufacturing characteristics of 3C products and the problems to be solved, with the direction of intelligent manufacturing technology, improve the processing precision and surface quality of the mold.
China is a big consumer of 3C (computer, communication, electronics) products, with a demand market of 1.3 billion people. Mobile phones and computers of well-known brands such as Apple and Huawei have become the target of young people. At the same time, China is also a big manufacturing country. Two-thirds of the world's electronic products are manufactured and assembled in China. Domestic 3C manufacturing companies are large, but most of them are some processing companies that do not master high-end products and core technologies. Millions of employees earn meager profits on busy production lines. Nowadays, 3C products are developing towards diversification and individualization. Under the fierce market competition, the speed of upgrading is getting faster and faster, and the variety of shape design brings new opportunities to the mold manufacturing industry. As a CNC process technician, the author combines his own work experience to talk about the wisdom manufacturing technology and development direction of 3C mold.
1.3C mold manufacturing characteristics
The mold is a molding tool specially designed and manufactured according to the product structure requirements, and its working nature is the mother machine of the batch product. The shape and size of the raw material can be directly changed to make it a qualified part, and the manufacturing cost can be minimized. The various components manufactured by the mold (see Figure 1) account for more than 70% of the 3C products, from the outer casing structure to the integrated circuit board, which is widely used (see Figure 2). Compared with other manufacturing methods, it has the dual advantages of high efficiency and low cost. The mold is also a "quality amplifier", which plays a decisive role in product quality. If a set of molds has defects, the thousands of products produced by them will have the same defects, resulting in batches of non-conforming products, which is also the source of some "cottage" electronic products.
Analysis on the Development and Future of 3C Mould Technology
The 3C mold with complex shape puts high demands on structural strength and manufacturing precision. The forming surface of the product does not allow any flaws. For this reason, sophisticated processing equipment and measuring devices are often used. Some molds have different working surfaces and matrix requirements. It is difficult to meet all the requirements with the same material. Generally, welding and surface treatment methods are adopted. Special parts such as inserts, surfacing, spraying and nitriding are used in important parts of the mold. Process to enhance its local performance.
The 3C mold is unique in its manufacturing process and covers the essence of electromechanical processing and manual operation. In the 1980s, the processing of small household appliances was mainly manual, and the quality of the molds depended on the skill level of the skilled craftsmen. In particular, the mold fitters performed the best, and many teachers practiced their skills. In the late 1990s, mold processing began with CNC machine tools and special equipment. The popularization and application of machining centers and wire cutting solved many problems in the technical field. Electrolytic, laser and ultrasonic technologies used in special processing can be further in-depth. The cavity and dead angle of the mold fill the gaps that conventional cutting tools cannot achieve.
2.3C mold problem to be solved
The manufacturing precision of 3C mold is strict. If the conventional equipment and processing method are used (see Figure 3), the accuracy error of the parts is controlled within a reasonable range, but the accumulated error after assembly will cause the working part of the mold to produce corresponding Misalignment and offset directly affect the size and appearance quality of the formed product. According to the traditional manufacturing process, the operator will use the remedy of grinding and matching, to learn from each other's strengths, and to make up for it. Although it is barely able to meet the acceptance requirements of the mold after rework, it leaves a hidden danger for the normal use in the future.
During mold cutting, mold deformation and machining errors due to tool wear and cutting force changes cause great difficulties for subsequent assembly. Some irregular mold surfaces, the cutting point of the tool and the workpiece change continuously with the slope of the curved surface of the machining part, forming an uneven cutting step. Due to the limitation of the cutting edge arc and the feed angle, the surface of the mold after CNC fine cutting will leave a slight knife mark (see Figure 4). Under the premise of taking into account the production efficiency, the operator often uses the method of grinding and polishing, and uses the power tool to quickly remove the processing marks. Although the specified surface roughness is met, excessive polishing will destroy the curved surface and the linear structure of the mold. The results of CNC machining have been abandoned.
In recent years, the booming 3C products have presented severe challenges to Chinese mold companies, and the shortcomings of mold production efficiency and quality instability have gradually emerged. To solve the technical problems in these processing fields, we can only use more advanced intelligent technology to reduce random errors and manual interference during the processing, avoid the rework and repair, and complete all the processing parts in one step. Fundamentally improve mold quality and production efficiency.
3.3C mold's intellectual advantage
Zhizhi Technology is a perfect combination of computer software and high-end CNC equipment. It integrates design, processing, testing and testing functions. It can carry out intelligent modeling and finite element analysis in the design stage of the mold, and pre-complete the forming process and simulation test of the mold. Optimize and improve possible defects. After decades of upgrading, CNC machine tools have a man-machine dialogue function, which can automatically select the best tool path according to the machining characteristics of the mold and the logical thinking of the programmer. Technology provides a powerful hardware foundation. The coordinate measuring machine and the optical projector are commonly used measuring devices in the mold manufacturing. They can perform all-round random detection on the processing part of the online mold, and the detection data is synchronously fed back to the execution unit of the computer software to assist the numerical control system to complete the precise guidance function of the machine tool. The secondary part is trimmed in an unsuitable part, and the processing size can be as precise as several micrometers. The entire contents of the processing part can be completed in one setup, ensuring the accuracy requirements of the mold.
The intelligent CNC machine tool has the cutting parameter optimization and tool path compensation function, which can effectively control the deformation amount and machining error of the mold. During the die cutting process, the rigidity and cutting force of the various parts of the machined surface are different, and the force deformation and feed resistance are different. The cutting parameter optimization function uses the intelligent process calculation method of the numerical control system to control the spindle speed and the amount of the tool. The feed rate is dynamically adjusted to keep the tool in the best cutting state. While ensuring the surface quality and reducing the amount of deformation, the production efficiency is improved; the tool path compensation function is based on the tool compensation of the numerical control machine tool, and the finite element analysis is used to preprocess the mold deformation amount and the tool wear value to make the tool An equivalent compensation motion is added to the original path to eliminate residual errors caused by machining deformation and tool wear, thereby achieving high precision, high efficiency and high quality machining. The five-axis linkage small machining center (see Figure 5) is the main processing equipment for 3C molds, with good positioning accuracy and vibration resistance. It is suitable for free surface interpolation of mold cavity, which can realize the precision machining of nano level and achieve the effect of milling and grinding. The workpiece error is controlled at 0.01mm, which not only saves time-consuming and laborious machining and grinding and polishing processes, but also facilitates automation of the machining process and improves the development speed of the mold.
The intelligent special equipment integrates the manufacturing methods of different principles such as electromechanical, chemical, ultrasonic and 3D printing, and can be processed in close proximity, which has significant advantages in the processing of super-hard materials and difficult molds. Ultrasonic vibration cutting is a new processing technology for hard and brittle materials, suitable for quenched billets and carbide molds. With the help of the frequency of the ultrasonic waves, even the hardest mold can be vibrated with a lower contact force and a higher feed speed. The minimum machining hole diameter is 0.3 mm, and a high-quality mold surface can be obtained. Laser machining centers are used for micro-cavity and hole machining of molds, as well as precision cutting of thin and tubular parts. High-precision 5-axis micromachining is achieved through a computer-controlled digital servo system. The included programming software pre-sets the angle and depth of the cavity sidewalls for perfect layered cutting.
CAD/CAE/CAM software is the foundation of Zhizhi technology. The UG and Pro-based mold software is powerful. By simple line arrangement, complex cavity and external structure can be designed, which has an irreplaceable role. The molds of 3C products are mainly injection molds and metal molds, and generally rely on professional modeling and programming software. For the same or a similar set of processing features, just make a module and you can use the geometric transformation functions such as array and scaling to make several others. Correct modeling is the first step in making molds. The practice tells us that the programming ideas of mold surfaces are basically the same as the modeling methods. The curves and features used in modeling determine the tool path during programming. The finishing strategy in the mold creation requires less empty path, fast execution speed, clear and smooth cutting trajectory, no approximation error and pause in the middle. It is as smooth as a highway. Even if you take several overpasses, you should avoid sharp turns and Crossroads. The programming skill of the mold is the smooth transition and seamless connection between the machined surfaces. For complex mold surfaces composed of multiple curved surfaces, continuous processing should be carried out in one process as much as possible to reduce the clamping and alignment. The cutter error. Among the commonly used surface machining paths, the most effective are the streamline cutter and the three-dimensional spiral cutter. These two cutters can generate a continuous smooth cutting path with little lifting, without cutting speed and feed direction. Sudden change. Even if the tool moves a small distance, it must be coherent, forward and backward. The surface of the mold made by such wisdom has no inward and backward retracting knives and cut-and-cut marks, and is smooth and round, with sharp edges and corners, achieving a perfect mirror effect.
4. Conclusion
The traditional cutting process, its manufacturing precision and surface quality have replaced the mold improvement technology, which will lead to another industrial revolution in the field of mold manufacturing. Talent is the soul of the mold, and the mold is inseparable from the excellent designers and skilled operators. Ten years of hard work, thousands of molds to train a senior mechanic. We usually learn more about the typical mold production cases, learn from the wisdom and skills, take the wisdom of technology as the direction, establish their own quality and brand advantages, and provide first-class molds and services for domestic 3C products.