Introduciton of Machining

Introduciton of Machining

  Have a shape as a processing method, all machining process for the production of the most commonly used and most important method. Cnc machining Machining process is a process generated shape, in this process, Drivers device on the workpiece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete.

  Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. Cnc machining  In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining. 

 Strict precision and good surface finish, Machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Cnc machining Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing

China's mold industry

China's mold industry

  Due to historical reasons for the formation of closed, "big and complete" enterprise features, most enterprises in China are equipped with mold workshop, in factory matching status since the late 70s have a mold the concept of industrialization and specialization of production.  Production efficiency is not high, poor economic returns. 

Mold production industry is small Precision stamping parts and scattered, cross-industry, capital-intensive, professional, commercial and technical management level are relatively low

 According to incomplete statistics, there are now specialized in manufacturing mold, the product supporting mold factory workshop (factory) near 17 000, about 600 000 employees, annual output value reached 20 billion yuan mold.  However, the existing capacity of the mold and die industry can only meet the demand of 60%, still can not meet the needs of national economic development.  At present, the domestic needs of large, sophisticated, complex and long life of the mold also rely mainly on imports.  According to customs statistics, in 1997 630 million U.S. dollars worth of imports mold, not including the import of mold together with the equipment; in 1997 only 78 million U.S. dollars export mold.  At present the technological level of China Die & Mould Industry and manufacturing capacity, China's national economy in the weak links and bottlenecks constraining sustainable economic development

 Research on the Structure of industrial products mold

    In accordance with the division of China Mould Industry Association, China mold is divided into 10 basic categories, which, stamping die and plastic molding two categories accounted for the main part.  Calculated by output, present, China accounts for about 50% die stamping, plastic molding die about 20%, Wire Drawing Die (Tool) about 10% of the Precision stamping parts world's advanced industrial countries and regions, the proportion of plastic forming die die general of the total output value 40%

 Most of our stamping die mold for the simple, single-process mode and meet the molds, precision die, precision multi-position progressive die is also one of the few, die less than 100 million times the average life of the mold reached 100 million times the maximum life of more than accuracy 3 ~ 5um, more than 50 progressive station, and the international life of the die 600 million times the highest average life of the die 50 million times compared to the mid 80s at the international advanced level.

 China's plastic molding mold design, production technology started relatively late, the overall level of low.  Currently a single cavity, a simple mold cavity 70%, and still dominant. A sophisticated multi-cavity mold plastic injection mold, plastic injection mold has been able to multi-color preliminary design and manufacturing.

 Mould is about 80 million times the average life span is about, the main difference is the large deformation of mold components, excess burr side of a large, poor surface quality, erosion and corrosion serious mold cavity,Precision stamping parts the mold cavity exhaust poor and vulnerable such as, injection mold 5um accuracy has reached below the highest life expectancy has exceeded 20 million times, the number has more than 100 chamber cavity, reaching the mid 80s to early 90s the international advanced level.

 mold Present Status of Technology   

 Technical level of China's mold industry currently uneven, with wide disparities.  Generally speaking, with the developed industrial countries, Hong Kong and Taiwan advanced level, there is a large gap. 

   The use of CAD / CAM / CAE / CAPP and other technical design and manufacture molds, both wide application, or technical level, there is a big gap between both.  In the application of CAD technology design molds, only about 10% of the mold used in the design of CAD, aside from drawing board still has a long way to go; in the application of CAE design and analysis of mold calculation, it was just started, most of the game is still in trial stages and animation; in the application of CAM technology manufacturing molds, first, the lack of advanced manufacturing equipment, and second, the existing process equipment (including the last 10 years

 the introduction of advanced equipment) or computer standard (IBM PC and compatibles, HP workstations, etc.) different, or because of differences in bytes, processing speed differences, differences in resistance to electromagnetic interference, networking is low, only about 5% of the mold manufacturing equipment of recent work in this task; in the application process planning CAPP technology, basically a blank state, based on the need for a lot of standardization work; in the mold common technology, such as mold rapid prototyping technology, polishing, electroforming technologies, surface treatment technology aspects of CAD / CAM technology in China has just started.  Computer-aided technology, software development, is still at low level, the accumulation of knowledge and experience required.  

Most of our mold factory, mold processing equipment shop old, long in the length of civilian service, accuracy, low efficiency, still use the ordinary forging, turning, milling, planing, drilling, grinding and processing equipment, mold, heat treatment is still in use salt bath, box-type furnace, operating with the experience of workers, poorly equipped, high energy consumption.  Renewal of equipment is slow, technological innovation, technological progress is not much intensity.  Although in recent years introduced many advanced mold processing equipment, but are too scattered, or not complete, only about 25% utilization, equipment, some of the advanced functions are not given full play.

    Lack of technology of high-quality mold design, manufacturing technology and skilled workers, especially the lack of knowledge and breadth, knowledge structure, high levels of compound talents.  China's mold industry and technical personnel, only 8% of employees 12%, and the technical personnel and skilled workers and lower the overall skill level.  Before 1980, practitioners of technical personnel and skilled workers, the aging of knowledge, knowledge structure can not meet the current needs; and staff employed after 80 years, expertise, experience lack of hands-on ability, not ease, do not want to learn technology.  In recent years, the brain drain caused by personnel not only decrease the quantity and quality levels, and personnel structure of the emergence of new faults, lean, make mold design, manufacturing difficult to raise the technical level.

Precision stamping parts

Standard model method

Standard model method 

 According to the drawing wedm in advance in processing a standard model or the qualified stamping parts, to adjust the assembly put it in

between convex, concave die, upper and lower die relative motion can be reasonable degree when appropriate.

 Measurement method

  Measuring method of the measuring tool have feeler. Precision stamping parts A feeler method after the adjustment convex, concave die clearance good uniformity, it is the commonly used method. Assembly, the punch in the concave die in the hole, convex, concave die according to the size of the clearance choose different specifications of the feeler insert convex, concave die  clearance, inspection concave die around the blade gap everywhere, and according to the measured results adjustment. If the adjustment of the punch fixed board knock until adjust good so far. 

 Adjustment method of repair match means

 Die in use after period of time, because the convex, concave die normal wear and tear. To working parts inspection, if products produce burr, convex, Precision stamping parts concave die dull and collapse the blade factors, it is because of the convex, concave die clearance for wear changed, namely bigger or not even. To make the convex, concave die restored to the original gap value out of parts can use the following method to qualified for repair match means.

Convex, concave die clearance greaten repair match means method 

 General dies in use after period of time, because normal wear will make convex, concave die gap increase gradually, thus to make the work and so on a series of problems produced burr. This kind of circumstance, can use first thickness is equal to one of the KuaiGui insert gap between the convex, concave die, if convex, concave die clearance does not too big, the grinding work part of the blade continue to use, can improve the quality of stamping. When gap value too big when, the recoverable high temperature heat of local forging the modification methods female die size make it restored to the original gap value. Workpiece cooling followed by the pressure seal the law to file to trim gap value, and with the flame hardening method to improve the blade surface hardness. 

 Convex, concave die clearance does not even repair match means method 

Dies after a period of using, clearance does not even can make blunt a local produce burr or the blade was edge chewed. In normal wear punching die, because after wearing precision guide device that reduce convex, concave die happen relatively migration, respectively in the guide pin and a guide to cover on the plating chromium layer the restored to its original size, Precision stamping partsagain through the pressure seal the law will remove file high. If it is due to the pins loosening lose positioning function and cause different convex, concave die heart, and cause convex, concave die clearance does not even. Should first will convex, concave die gap adjusting well, to match for taper pin.

Technology Repair measures

Technology Repair measures 

 The main technological measures to adjust the gap between two kinds of the mould method:

 1. Size method 

 Processing of the punch, will the punch front-end appropriate lengthen, extended period of section size and sunken model hole processing to the same size. Assembly, Precision stamping parts make the punch into female model hole, natural form the cutting clearance, and then to the punch with fixed together with the punch mould seat on board with the pin for fixed and will last longer period of the punch front can remove form even clearance. 

2. Positioning hole method

  Process positioning hole method and the inside of the progressive die principle about. Processing, the punch in fixed board and concave die on the same position processing two positioning hole, can will locate hole and the mold cavity a cut out. Assembly, in the positioning hole insert pins to ensure that gap.

Standard model method  

According to the drawing wedm in advance in processing a standard model or the qualified stamping parts, to adjust the assembly put it in between convex,Precision stamping partsconcave die, upper and lower die relative motion can be reasonable degree when appropriate.  

 Measurement method  

Measuring method of the measuring tool have feeler. A feeler method after the adjustment convex, concave die clearance good uniformity, it is the commonly used method. Assembly, the punch in the concave die in the hole, convex, concave die according to the size of the clearance choose different specifications of the feeler insert convex, concave die clearance, Precision stamping partsinspection concave die around the blade gap everywhere, and according to the measured results adjustment. If the adjustment of the punch fixed board knock until adjust good so far.

Convex, concave die gap between the control and adjustment of the method

Convex, concave die gap between the control and adjustment of the method

  Convex, concave die clearance control, should according to die structure, Precision stamping parts clearance size, blanking pieces of quality and practical assembly condition to selected. Convex, concave die gap between the control and adjustment method have the following kinds.

  （1）Pervious to light method 

 Will convex, concave die after molmerged, shone a light on the underside, observe the convex, concave die around through light and distribution to judge the size of the clearance and uniformity. If not even, to adjust to evenly between fixed again, this method is suitable for small gap plate stamping die. 

（2）Feeler method

  Will convex, concave die after molmerged, convex, concave die into the thickness of unilateral clearance feeler convex, concave die gaps in each direction. Precisionstamping parts  Then tighten the screw on mode. Finally put paper to stamping and will last mould seat and fixed on board with drilling, reaming positioning pin hole, and at a pin location.

 （3）Gaskets DiaoZhengFa

  Gasket adjustment method is simple, convenient, clearance is used widely. As shown in figure 1 shows, the mat with good contour mat iron, will gaskets wrapped in the punch to the punch into the concave mould, observe the convex, concave die clearance condition. If clearance does not even, with striking the protruding models of fixed plate method clearance adjustment, then tighten the screw on mode. Finally put paper to stamping, observation on paper cutting around burr and even rate to judge whether clearance convex, concave die even, to adjust the gap until cutting burr uniform so far. Finally the mould seat and the plate with drilling, reaming positioning pin hole, and enter the pin location. This method widely used cutting materials focusing thick large clearance and bending stamping, deep drawing mould clearance control.

  (4) Chemical method

  When the convex, concave die complex shape, the use of the above several methods more difficult to adjust the gap, the chemical method can be used to control the gap, the plating method is used. Plating method is the punch in the work surface coated with copper or zinc instead of washers. The plating thickness and unilateral gap is same, Precisionstamping parts blade people concave die hole, and check the move without block phenomenon can assembly tighten. Coating in use process will die fall off naturally, need not removed. This uniform coating, can improve the uniformity of assembling clearance.

Cold die clearances between control and adjusting  method

  Cold stamping mould convex, concave die size and distribution of the clearance degree directly affect the quality of the blanking pieces and the length of the service life of the die. Precision stamping partsIn guarantee blanking pieces space is mould manufacturing assembly very important link, and assembly quality will directly influence the convex, concave die if the clearance between the uniform. Such as the process of convex, concave die size precision although already meet the requirements, but in assembling if adjustment is bad, can cause clearance does not even, rushed out of the spare parts of the raw edges. Even rushed out of unqualified parts. The mold assembly is key to control convex, concave die of relative positions, in order to ensure that the convex, concave die, uniform and the clearance between the right to rush out of qualified parts.

 Die before assembly the problems that should be paid attention

   Convex, concave die and mould parts itself is clearance of the precision, and the assembly of the assembly process is reasonable. In order to ensure that the position of the convex, concave die correctly and gaps even, mould design, processing to assembly from the whole link should pay attention to the following questions：

   （1）Convex, concave die design and manufacture of the right

  Design should be based on the above all when die cutting the section of a quality, service life of die factors such as the reasonable selection of convex, concave die clearance. And to consider the mould in the process of using that gap wear increases, Precision stamping parts general in the design the least reasonable clearance when mould. And in the manufacturing process can ensure the parts processing precision and quality, in the assembly process ensure convex, concave die gap even, this for processing complex shape is very key parts.

 （2）Assembly method the choice should be reasonable 

   Die assembly method include roughly assembly method and direct with assembly method. Before the assembly must be carefully study mold assembly drawing, full consideration and analysis of the structure characteristics of punching die, Precision stamping partsdie parts processing technology and processing accuracy etc, in order to choose convenient, accurate and reliable assembly method to ensure the quality of blanking pieces

Renoho Precision Machinery Technology Co.,Ltd: Cold die clearances between control and adjusting ...

Renoho Precision Machinery Technology Co.,Ltd: Cold die clearances between control and adjusting ...: Cold die clearances between control and adjusting method  Cold stamping mould convex, concave die size and distribution of the clearance ...