Machining Methods

The Conditions For Machine Tools Can High-Speed Cutting

The Conditions For Machine Tools Can High-Speed CuttingThe Conditions For Machine Tools Can High-Speed Cutting

Using high-speed machining technology to process molds, in addition to the high quality of the processed products, can also significantly reduce or even eliminate inefficient grinding and manual post-machining man-hours, and shorten the overall mold manufacturing cycle.

In order to adapt to market demands, the schedule for the development of new products is becoming shorter and shorter, and only the rapid introduction of products to the market can seize the opportunities (business opportunities). For example, the delivery period of mobile phone molds has traditionally been compressed from 45 days to 30 days, or even 14 days, from the entire process of market demand, design and development, manufacturing and machining, trial testing, and product launch. In this case, from R & D, manufacturing to delivery, traditional manufacturing and machining technologies have been unable to meet market demand. In other words, in the 21st century, “speed” and “quality” will determine who is the winner of the market. Therefore, production equipment, peripheral equipment, production technology, machining tools, CAD / CAM / CAE software must all develop towards high speed, high precision and efficiency.

How can the machine tool meet high-speed cutting can be roughly divided into the following requirements:

1. The mechanism design is suitable for high-speed operation

Machine tools operating at high speeds first require high rigidity of the mechanism, which can absorb high-frequency vibrations and high inertia G values to ensure high-speed cutting precision and stability. The spindle speed can now reach a very high level, which requires high-speed spindles to have a good lubrication and cooling system and to meet the principle of small, thin and light. As one of the high-speed machining execution mechanisms, the high-speed feed mechanism is required to meet the high feed acceleration and deceleration, and at the same time must achieve high precision. Therefore, the actual transmission of the servo motor and the ball screw without backlash and LOSSMOTION phenomenon can show the effect in high feed cutting; the design of the ball screw mechanism should also ensure the positioning accuracy and prevent thermal displacement errors; The Z axis requires light weight, because the Z axis up and down reactions must be sensitive and there will be no interference and jitter, and a special electronic control circuit design is required, so that the Z axis will not fall even in the event of an instantaneous power failure, causing the tool The insert is damaged. The mold machining is generally a long-term machining, so the heat of the spindle inverter running at high speed for a long time increases, it is easy to cause aging of electronic parts, so the electric control box needs to use a closed air conditioning system to ensure the life and stability of parts in the box And prevent oil from entering.

2. Excellent CNC control system

The CNC system is a unit that issues position commands. The commands are required to be transmitted accurately and quickly. After machining, the position commands are issued to each coordinate axis. The servo system must quickly drive the tool or the table to move accurately according to the commands. It requires to be able to process blocks quickly, to control its machining errors to a minimum, and so on. In the field of high-speed machining applications, Siemens 840D and Fanuc18iMB are the most representative.

3. Tool holders and tools suitable for high-speed operation

Tools for high-speed cutting, especially high-speed rotating tools, require better quality and performance of tools and tool holders from the perspective of ensuring machining accuracy and operating safety. For the cutter, the slenderness ratio is less than 10 times or less. There are tungsten carbide tools, CBN tools and titanium-coated tungsten carbide tools. For the tool holder, it is required that the dynamic balance is less than 2.5G. HSK, BBT (BTF-B) and some special tool holders can meet the above requirements well.

4. Professional CAD / CAM software

Specialized CAD / CAM software requires precise path calculation methods, which can not only accurately meet the accuracy requirements of 3DProfile, but also reduce discharge processes, and even meet the surface quality requirements without polishing. It must be able to produce a good cutting path, make the cutting amount stable, not only improve the machining efficiency, but also extend the tool life and save tool costs. Between the diversification of design software, it needs to have good transcoding compatibility with other software, can easily transfer the graphics files of other software without distortion, even if there are small holes or gaps, it can be built in Quickly fix in 2D and 3DCAD to help users grasp the loophole and master the timeliness.

In terms of practicability, professional CAD / CAM software needs to have the function of self-curved CAD, understand the characteristics and focus of the workpiece before NC machining, and optimize the function of simulated cutting. At the same time, it can also simulate the cutting situation and change the tool path and data to achieve the most suitable state. Such as empty cutting removal, automatic knife height change, corner deceleration, heavy cutting deceleration, arc transformation, etc. In particular, the tool length measurement can detect the shortest tool clamping length before machining, so that the machining safety and stability reach the best state.

In addition to a complete protection lock device, the protection software will not be stolen, followed by a built-in tool library and machining methods for high-speed machining machine tools, cumulatively retaining company tools and machining KNOW-HOW, reducing the impact of personnel turnover on the company .

In terms of safety performance, the CNC program must be completely verified by the entity to produce an optimized program to completely solve the problems of overcutting, knife collision, and interference. At the same time, the unprocessed area can be inspected more comprehensively through physical comparison. Can have 3D three-dimensional advancing and retracting tool function, cutting meets the best mold quality and prolongs the maximum tool life, and has the fewest tool surface marks. At the same time, it is required to achieve the same amount, equal load and equal direction cutting, which not only protects the life of the spindle, saves more than half of the tool cost, but also enhances the efficiency of servo machining and shortens its machining time. According to existing customer feedback, the company introduced high-speed After machining, the machining and grinding time is reduced by 2/3 compared with the original machining time. Finally, it is required to provide complete physical simulation functions, such as optimization of tool lifting, tool handle, tool interference inspection, corner machining, etc. In addition to the safety of cutting, it can also remove empty cutting.

5. Environmental protection requirements

(1) Fully enclosed shield to prevent air pollution caused by oil vapor flying during machining.

(2) Machining oil and gas chip blowing devices to reduce the generation of large amounts of oil vapor during machining.

Based on the above requirements, Dongtai Seiki has launched a series of new high-speed mold milling models such as the MDV-508HSC high-speed vertical machining machine, which can not only help customers reduce the machining process, shorten the delivery time, can achieve high-quality surface accuracy, reduce The polishing time can directly mill high-hardness materials above HRC58, and the small-diameter angle-clearing (Min. Up to R0.1) machining is almost close to the mirror surface finish, which can reduce the time of many electrical discharge machining and subsequent manual polishing, which not only greatly improves the production capacity It also improves the quality of the mold and meets the needs of customers.

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