Oct.2023 10
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The development of advanced mold manufacturing technology
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High-Speed Milling In conventional milling, low feed rates and large cutting parameters are used, while high-speed milling employs high feed rates and small cutting parameters. High-speed milling has the following characteristics compared to conventional milling: a. Efficiency: The spindle speed in high-speed milling is generally between 15,000 to 40,000 RPM, with some machines reaching up to 100,000 RPM. When cutting steel, the cutting speed is approximately 400m/min, which is 5 to 10 times higher than traditional milling. When machining mold cavities, its efficiency is 4 to 5 times higher compared to traditional methods (such as conventional milling and electrical discharge machining). b. High Precision: High-speed milling achieves a precision of about 10μm or even higher. c. High Surface Quality: Due to the minimal workpiece temperature rise (approximately 3°C) during high-speed milling, there is no surface layer alteration or microcracking. Thermal deformation is also minimal. The best surface roughness (Ra) is less than 1μm, reducing the workload for subsequent grinding and polishing. d. Machining of Hard Materials: High-speed milling can machine steels with hardness ranging from 50 to 54 HRC, and the highest hardness that can be milled is up to 60 HRC. Given the advantages mentioned above, high-speed machining is widely applied in mold manufacturing, gradually replacing some grinding and electrical discharge machining processes.

Electrical Discharge Milling Electrical discharge milling, also known as EDM milling or spark machining, represents a significant development in electrical discharge machining technology. It is a new technique for machining mold cavities without the need for complex and expensive shaping electrodes. Similar to CNC milling, EDM milling uses a high-speed rotating rod-shaped electrode to machine two-dimensional or three-dimensional profiles on workpieces, eliminating the need for intricate shaping electrodes. Machines like Mitsubishi's EDSCAN8E EDM milling machine, equipped with electrode wear compensation systems, CAD/CAM integration, online automatic measurement systems, and dynamic simulation systems, showcase the current level of EDM milling technology.

Wire EDM Cutting The development of CNC wire EDM technology(WEDM) has reached a high level with excellent functionality and a high degree of automation, allowing for unmanned operation. The maximum cutting speed has reached 300mm²/min, with machining precision reaching ±1.5μm and surface roughness of Ra0.1-0.2μm. The development of fine wire cutting technology with diameters of 0.03-0.1mm enables one-pass cutting of complex molds, including narrow slots as small as 0.04mm and radii as small as 0.02mm. Taper cutting technology can achieve precision machining with angles exceeding 30°.

Grinding and Polishing Technology Grinding and polishing are widely used in precision mold manufacturing due to their high precision, excellent surface quality, and low surface roughness values. Precision mold manufacturing often utilizes advanced equipment and technologies such as CNC contour grinding machines, CNC optical profile grinding machines, CNC continuous-path coordinate grinding machines, and automatic polishing machines.

CNC Measurement The complexity of product structures inevitably leads to complex shapes of mold components. Traditional geometric measurement methods are no longer suitable for mold production. Modern mold manufacturing extensively employs coordinate measuring machines (CMMs) to measure the geometric dimensions of mold components. Inspection methods during the mold machining process have also made significant progress. CMMs not only provide high-precision data for complex surfaces but also feature excellent temperature compensation, reliable vibration protection, effective dust control, and simplified operating procedures, enabling on-site automated inspections.

The application of advanced mold manufacturing technology has transformed traditional mold-making techniques, shifting the focus from reliance on human factors and uncontrollable variables to a reliance on physical factors that are easier to control. This has resulted in overall better mold quality and enhanced repeatability.