The hottest needle is five axis synchronous hard m

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Five axis synchronous hard milling for mold and forming manufacturing

nowadays, enterprises must cope with the increasing competitive pressure through fast and flexible processing technology. In most cases, the reduction of processing time is often achieved through the optimization of upstream or intermediate processes, such as hardening, rather than relying on modern equipment and milling cutter technology. Upstream or intermediate processes may take up a lot of time and logistics resources, so it will unnecessarily prolong the time of the manufacturing process

hard milling can provide great improvement potential in the conventional tool manufacturing production chain, and in some cases, it can even replace the traditional production links. However, the principle of hard milling is that not all "operable" occasions are economical. When processing special materials with extremely hard, extremely fine, extremely small and extremely complex shapes, the available process still has its limitations

with appropriate process design, only one rough machining process is required to perform stepless hollowing of the hot runner of the workpiece; This can significantly reduce the cost of primary and fine grinding and stripping of residual materials

hard coating can improve productivity

the rapid development of hard material coating technology is an important factor to tap the potential of high-efficiency processing of hard milling, which can realize the processing of materials with hardness of 50~67hrc. Today, in this regard, the typical TiAlN PVD coating has been applied, and this material has been further optimized by changing the coating structure and adding other alloy elements. In addition, CAM technology and equipment technology have made their respective contributions to improving the efficiency and ability of the process flow. In particular, five axis synchronous machining has a series of advantages, so it has become the goal of many machining centers

as early as the early 1990s, people understood and described the processing of mold cavities with five synchronous control shafts. Also belonging to this technology category are larger row width, shorter and more stable milling cutter, arbitrary machinability to mold shape, more stable and tool protective process, etc

overall processing of compressor rotor with better comprehensive performance

as long as you look at the edge of the disc, you can find an interesting phenomenon: at present, the development of processing technology for turbine blades, especially the so-called BL speed 50r/minisks (blade integrated disc) and the overall processing of compressor rotor, often have similar edge conditions. In particular, the materials used in this occasion (titanium based and nickel based alloys) will put forward higher requirements for processing technology similar to hard processing

when designing the trajectory of five axis hard machining of typical workpiece, the cutting graduation can be different from that under the condition of three-axis machining edge. In that case, because the cutting condition will be affected by the other two axes, another kind of tool is also used. In this way, most of the materials can be cut off during rough machining, and it can be very close to the outline of the workpiece. This greatly improves the process conditions of subsequent processes, such as rough grinding and fine grinding. This can greatly shorten the time required for rough grinding, reduce tool wear, and improve the safety of the process. When finishing, the tool with wide row spacing can be used through the flexibility obtained in directional operation, so that the number of finishing tracks can be greatly reduced. This means that under the premise of ensuring the same surface quality, the production time can be changed from hours to minutes

today, as long as we look at the situation of tool manufacturing industry, we can find that five axis synchronous processing is really used on few occasions. Although in most cases, the equipment can be equipped as required, usually only three axes are used, or at most an adjustable fourth or fifth axis is carried for processing. Why? The actual situation is that the programming work of five axis machining is time-consuming, and due to the lack of technical know-how, the substantial improvement of the overall economic benefits is hindered; Therefore, in this limited situation, the three-axis machining method is more practical. In addition, the cam software that can meet the special requirements for process guidance and residual material identification has not been matched yet. These special requirements just need to appear from hard milling. This is of great significance for rough milling and rough grinding where constant tool depth and load conditions are required

the fluctuation of trajectory operation increases the load of the blade

the trembling trajectory movement of the tool tip or the axis of the tool will cause the load of the tool and the blade to increase. It is very beneficial to keep the narrow limit value of the hard machining process window to explore the dynamic load performance of NC program and machine tool equipment in detail. Once the process window breaks away from this narrow value due to uneven trajectory guidance and increased axle load, it will lead to serious tool wear and contour chipping

in order to realize NC data analysis and optimal adjustment by using dynamic and control models, Fraunhofer IPT developed NC profiler software (Figure 1). This software can identify the dangerous area of the tool travel, and the user can synchronously observe the NC program block, axis curve and 3D tool path, so as to quickly understand the information of the damaged area in the tool path. Different NC profiler software functions can be used to realize partial automatic or manual optimal adjustment and confirmation of new tools

Figure 1 NC profiler software for NC data analysis and optimal adjustment

track information is not affected by equipment type

when designing tracks on cam system, track information is basically not restricted by equipment type. Therefore, the dynamics of the machine tool and its impact on the subsequent process guidance can be temporarily ignored. In conventional three-axis machining occasions, the influence of equipment and its control system is small in most cases, because it is not directly related to the workpiece. In five axis machining, the situation is different. If five axes need to run at the same time, the movement must be carried out synchronously, otherwise serious contour deviation may be caused. According to different processing methods (end milling or side milling), the directional axis has more or less influence. For example, in side milling, if the directional motion is uneven, traces will appear directly on the workpiece. In addition, the tool will also be subjected to a great load, and even there will be a danger of tool breakage

therefore, a penetrating technical scheme should be adopted from the trajectory design, post-processing program, synchronous operation scheme of cam system to the control system and machine tool equipment. The recent research on the application of the through synchronization link (integrated into Unigraphics nx5) is supported by the German Research Association DFG within the framework agreement of "integrated production technology in high wage countries" (ICD b2.2)

the goal of the current research work is to study the five axis synchronous machining in the tool manufacturing industry, so as to reduce the cost of programming and realize the good benefits of hot runner mold processing. This is also one of the goals of a two-year hard precision machining research project sponsored by the European Commission, which is jointly implemented by Fraunhofer IPT and 11 other partners. This cooperation involves scientific research institutions, equipment manufacturers in different fields in the tool and mold manufacturing industry all over Europe, and cam suppliers, tool and coating manufacturers, measuring units, fixture manufacturers and end users who can make powders, liquids, particles and other situations. In addition to the new type of machine tools and equipment with hydrostatic bearings, the overall process of hard milling was also observed to achieve the set goals

realize unified fine grinding allowance through rough machining

an example of five axis synchronous hard machining is the machining of molds used for precision deep drawing of white iron cans. The mold has extremely high requirements for material, surface quality and accuracy, because the workpiece made by deep drawing process must meet the stringent requirements of sealing and reproducibility of each component. In order to quickly process various shapes from a unified blank, starting from simple rough drilling, the hardened blank is used as the basis of milling. When designing the rough machining and rough grinding process, the focus is on how to achieve a unified machining allowance through the best use of the milling machine in a very short time, so that the final fine grinding process can improve the accuracy and surface quality

the best rough machining process reduces the cost of fine grinding

with an ideal process design, the stepless reaming of the hot runner cavity can be realized through a rough machining program. This can significantly reduce the cost of fine grinding, which can not only save the overall processing time, but also save the programming cost of stripping the remaining materials during the three-axis rough machining. The processing strategy of five axis synchronous rough machining is shown in Figure 2

Figure 2 processing curve of stepless milling of mold hot runner cavity using five axis synchronous rough machining technology

during the processing process, on the one hand, the tool needs to gradually adapt to the transition from drilling round holes from the center of the workpiece to the final rectangular shape that can enhance the research and development of enterprises, especially domestic enterprises, to produce better products. On the other hand, it also needs to tilt on the vertical plane, so that in the last step, The inclined inner contour of the workpiece can be processed through the roll milling process. When using three-axis operation guidance, the cutting edge can often only achieve a very shallow cutting depth, so only part of the cutting edge can be used. The machining strategy introduced here can make full use of the cutting edge. Therefore, when using spiral tools, a relatively stable process flow and a relatively uniform wear distribution on the cutting edge can be achieved

the evaluation of the processing strategy shows that although the overall hard processing is adopted, the similar processing time achieved by conventional or composite soft, hard and EDM processing can also be achieved. In view of the obvious reduction of logistics costs and processing time, five axis hard machining still has significant advantages

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