China Shenzhen Perfect Precision Product Co., Ltd. company news

What are the factors that affect the machining accuracy in precision parts machining In the field of precision parts processing, a complete system consisting of machine tools, fixtures, workpieces and tools is called a process system. In the process of machining, the relative position of the workpiece and the tool determines the size, shape and position of the part. Therefore, the problem of machining accuracy also involves the accuracy of the entire process system. Various errors of the process system will be reflected as geometric errors of the processing system in different ways and programs under different conditions during the processing. According to the nature of the process system error, it can be summarized as the geometric error of the process system, the error caused by the force deformation of the process system and the error caused by the internal stress of the workpiece. In the field of precision parts processing, the geometric errors of the process system include the principle error of the processing method, the geometric error of the machine tool, the adjustment error, the manufacturing error of the tool and fixture, the clamping error of the workpiece and the error caused by the wear of the process system.

What is the application method of CMM in precision parts processing CMM is an efficient, new and modern large-scale precision instrument in precision parts processing. The CMM comprehensively applies advanced technologies such as electronic technology, computer technology, precision measurement technology and laser interference technology, mainly including measurement system, control system, coordinate display system and data output system. Therefore, the operation and use of the CMM requires a certain degree of basic professional technical knowledge. Grasp the application method of measuring function in measuring CMM, not only can you check the size, shape and mutual position of parts and components, such as box, guide rail, turbine and blade, cylinder, cam, gear, space surface measurement, but also can be used for scribing, centering space, photolithography integrated circuit, etc., can scan continuous surfaces and prepare the processing program of CNC machine tools, can be connected with flexible manufacturing system, Therefore, it is called the modern "measurement center". Therefore, the measurement function of CMM should be flexibly applied in the field of precision parts processing.

The Composition System and Structure Characteristics of CMM in Precision Parts Processing In the field of precision parts processing, CMM is composed of mainframe, measuring head and electrical system. The mainframe includes frame structure, ruler system, guide rail, driving device, balancing device and turntable accessories; The electrical system includes electrical control system, computer hardware, measurement and software, printing and drawing devices, etc. Therefore, the use of CMM requires familiarity with the basic components of the equipment and basic skills to conduct measurement operations. The structure of CMM can be divided into mobile bridge type, fixed bridge type, gantry type, cantilever type, horizontal arm type, column type, horizontal boring type and instrument table type. When using, pay attention to the structural characteristics and application scope of the instruments used. For example, the mobile bridge type is the most widely used structural form in CMM at present, which has simple, compact structure, good stiffness and relatively open space. The workpiece is installed on a fixed worktable with strong bearing capacity, and the workpiece quality has no influence on the dynamic performance of the measuring machine. In the field of precision parts processing, small and medium-sized CMMs often use this form.

What is End Milling in Precision Parts Processing In the field of precision parts processing, end milling refers to milling with the end tooth edge of a milling cutter. When milling the plane, the tool tip distributed on the end face of the milling cutter is used to form the plane. The plane milled by the end face washing method also has a series of knife lines. The thickness of the knife lines (that is, the size of the surface roughness value) is also related to many factors such as the feed speed of the workpiece and the speed of the milling cutter. In the process of precision parts processing, a plane is milled by end milling. The flatness mainly depends on the perpendicularity of the spindle axis and the feed direction of the milling machine. If the spindle is perpendicular to the feed direction, the path of the tool tip when rotating is a circle parallel to the feed direction, which cuts a plane. In fact, the tip of the milling cutter will mill a net pattern on the surface of the workpiece. If the spindle of the milling machine is not perpendicular to the feed direction, it is equivalent to cutting a concave surface on the workpiece surface with an inclined ring. At this time, the cutter tip will mill a unidirectional arc pattern on the workpiece surface.

Development Trend of Tool Materials in Precision Parts Processing In the field of precision parts processing, with the development of modern technology, there are more kinds of tools and more complete specifications. In the rapidly changing parts processing industry, people have increasingly high requirements for tool performance, and the old tool materials can no longer meet the needs of the processing industry. The call for new materials is getting stronger and stronger, and new alloy materials, such as ultra-fine grain alloy and titanium based cemented carbide, have sprung up. Ultra-fine grain alloy ultra-fine grain alloy is a kind of hard alloy with high hardness, high strength and sharp edge. its grain size is less than um, most of which is less than 0.5 um. It is suitable for low-speed machining of all kinds of difficult to machine materials, such as stainless steel, heat-resistant steel, chilled cast iron, titanium alloy and aluminum alloy, and especially suitable for manufacturing all kinds of small-sized solid carbide tools. Carbon, titanium nitride based cemented carbides Carbon and titanium nitride based cemented carbides are sintered with TiC and TiN as the main components, and other carbides are added, with nickel and molybdenum as the binder. Its main advantages are high hardness, good oxidation performance, small friction coefficient, difficult chip bonding, good abrasion resistance against crescent pits, and low relative density. It is called "cermet" and is suitable for high-speed finishing and semi finishing of steel parts. At present, it is suitable for milling and manufacturing of integral milling cutter in the field of precision parts processing.

How to reduce errors in turning milling combined machining under limited conditions In the process of turning milling compound machining, the reduction of clamping quantity avoids the error accumulation caused by positioning datum conversion. At the same time, most of the current turning milling compound processing equipment has the online detection function, which can realize the in-situ detection and precision control of key data in the manufacturing process, thus improving the processing accuracy of products; High strength integrated bed design improves the difficulty of gravity machining ability of cutting materials. When turning and milling, the cutter conducts intermittent cutting, which can obtain relatively short cutting for workpieces formed of any material, and is easy to automatically remove chips. In addition, chip breaking can allow the tool to have enough time to cool, reduce the thermal deformation of the workpiece, and improve the service life of the tool. Compared with the traditional CNC machine tools, the turning speed of turning milling composite processing is higher, the product quality of turning milling composite processing in Dongguan is better, the cutting force is reduced, the machining accuracy of thin-walled bars and slender bars is improved, and the workpiece forming quality is improved. High. Because the cutting speed can be divided into the rotational speed of the workpiece and the rotational speed of the tool, according to the mechanical characteristics, increasing the rotational speed of the tool and reducing the rotational speed can achieve the same processing effect of the workpiece speed. The blank processing is particularly effective because the reduction of the blank speed of forgings can eliminate the vibration caused by the eccentric workpiece or the periodic change of the radial cutting force, thus ensuring the smooth cutting of the workpiece and reducing the error. When the small turning milling compound machine tool is used to process the workpiece, the low speed of the workpiece can effectively reduce the centrifugal force of the workpiece, avoid the deformation of the workpiece, and help to improve the machining accuracy of the part. In the process of turning and milling, large longitudinal feed can also be used to obtain cutting, and the surface roughness can also be effectively guaranteed. It can also clamp the workpiece at one time to complete the multi-faceted processing task, ensuring the turning milling compound processing accuracy in Dongguan.

Four advantages of turning milling combined processing Turning milling compound machining can realize the machining of all or most of the typical aviation parts through one clamping, thus providing a new way for the precision machining of complex aviation parts. Its application advantages are mainly reflected in the following aspects (1) Significantly reduce the number of clamping, improve processing efficiency, and eliminate errors caused by changes in machine tools and clamping methods. (2) The process is more centralized, which can significantly shorten the processing process chain, reduce the waiting time and machine non working time. (3) The machining process of turning, milling, drilling and other machining methods can be realized without changing the positioning state, reducing the number of fixtures and ensuring the consistency of dimensional accuracy. (4) At present, turning milling composite machining mostly has the online measurement function, which can measure the processing results in the process and between processes in situ, so as to achieve the accuracy control process of the whole processing. It can be seen that these advantages of turning milling compound processing equipment can effectively make up for the shortcomings of the current complex aerospace parts manufacturing process, and can significantly improve the precision and efficiency of turning milling compound processing in Dongguan.

What are the characteristics of titanium based alloy and ceramic cutting tools in precision parts processing With the continuous development of the modern machining industry, the performance of ordinary tools in the process of precision parts processing is increasingly unable to meet the actual needs, so a batch of new tools with new materials have been born, making the tools have higher strength, hardness and wear resistance. Among them, titanium based alloys and ceramic materials are the best. Carbon and titanium nitride based cemented carbides are mainly composed of TiC, TiN, and other carbides or oxides, with nickel and molybdenum as binders. Its main advantages are high hardness, good oxidation resistance, small friction coefficient, difficult chip bonding, good abrasion resistance against crescent pits, and low relative density. It is called "cermet" abroad, and is suitable for high-speed finishing and semi finishing of steel parts. At present, it is suitable for milling and manufacturing of integral milling cutter. Ceramic materials have higher hardness and heat resistance than cemented carbide. They can still be cut at 1200 ° C, with good wear resistance and chemical inertness, small friction coefficient, and strong resistance to adhesion and diffusion wear. Therefore, they can be cut at a higher speed in precision parts processing. Ceramic materials are stronger than cemented carbide materials. In order to make up for the shortcomings of ceramic materials such as low bending strength, brittleness and poor stamping resistance, the ceramic cutting edge often grinds a 20 ° negative chamfer, and the thickness and tip arc of the blade are slightly larger than those of cemented carbide inserts of the same size.

Quality problems easily occurred in multi head worm powerful cutting in precision parts machining In the process of machining precision parts, the main reason for the phenomenon of tool binding in turning is that the workpiece moves due to insecure clamping, resulting in an increase in cutting amount. In addition, poor elasticity of turning tool shank, excessive selection of cutting parameters, too large longitudinal rake angle of worm turning tool, improper selection of cutting fluid or work hardening affecting cutting due to blunt cutting edge of turning tool may also cause tool binding. In case of tool binding, it may damage the turning tool and scrap the workpiece, or it may damage the machine tool, so it should be prevented as much as possible. Incorrect tooth profile In the processing of precision parts, the incorrect tooth profile is mainly due to the grinding and installation of turning tools. For example, the sharp angle of turning tool is not corrected; Unequal height between turning tool tip and workpiece center; The tool tip angle bisector is not perpendicular to the workpiece axis; The cutter is not installed correctly according to the worm form and requirements during fine turning. In addition, the wear of the turning tool will also affect the correctness of the tooth profile. Vibration caused by poor surface quality and insufficient rigidity of cutter bar; The turning tool is blunt or damaged; Poor rigidity of workpiece and improper selection of cutting parameters; During rough machining, the borrowing amount is too large to be corrected; Insufficient margin in finishing stage; Improper selection of cutting fluid; The surface quality of worm tooth will be degraded if there is chip buildup or chip roughening in turning.

What are the difficulties in turning and milling composite materials Turning milling composite processing is a highly precise processing technology with strong automation technology production and processing. It means that all the production processes of workpieces are under the control of CNC machine tools, and some very different composite materials can be produced and processed. Today's composite materials are widely used in all aspects of our lives, especially in aerospace and some ultrahigh precision machinery manufacturing industries. 1、 Types of composite materials for CNC machining centers Composite materials can be divided into metal materials and metal composites, non-metallic materials and metal composites, non-metallic and non-metallic composites according to their composition. According to its structural characteristics, it can be divided into: 1. Chemical fiber composite material. A variety of chemical fiber boosters are placed in the base material and combined. Such as chemical fiber elastomer materials, chemical fiber reinforced alloys, etc. 2. The interlayer is made of composite material. It is composed of surface raw materials and core plates with different characteristics. Generally, the base material is of high hardness and thin; The core material is light and has low compressive strength, but has certain strength and thickness. It is divided into solid core skirt wall and honeycomb partition. 3. Sand composite materials. Hard sands are jointly distributed in the foundation, such as diffusely reinforced aluminum alloy, cermet, etc. 4. Doped composite materials. It is composed of two or more types of enhanced phase raw materials doped in one base material phase raw material. Compared with ordinary single phase composite materials, its impact compressive strength, fatigue limit and impact toughness are significantly improved, and it has unique thermal deformation characteristics. It is divided into intralayer doping, solid layer doping, sandwich hybrid, intralayer/solid layer doping and super hybrid composite materials. 2、 Problems that should be paid attention to when turning and milling composite materials 1. The carbon fiber composite solid layer has low compressive strength and is easy to be layered under the effect of cutting speed, so the axial force should be reduced when drilling or trimming. High speed rotation and small tool path are specified for drilling. The rotating speed ratio of the CNC machining center is generally 3000~6000r/min, and the cutting speed is 0.01~0.04mm/r. It is good to use a three point two edge or two point two edge fried dough twist drill. The sharp tip can first cut off the carbon fiber material layer, and the two edges have a repairing effect on the surface layer. The diamond inlaid fried dough twist drill is sharp and wear-resistant. The drilling of the composite material and titanium metal interlayer is a difficult point. Generally, the overall cemented carbide drill is selected, and the milling is carried out according to the main cutting parameters of titanium metal. The drilling starts from the titanium metal side until the drilling is completed. The lubricating fluid is added during the milling to reduce the scald of the composite material. Boeing Company of the United States has developed a PCD fried dough twist drill to drill holes in the interlayer. 2. The actual drilling effect of three types of new overall carbide tool composite material production turning tools is stronger. They all have some common characteristics: high stiffness, small helix angle, even 0 °. The specially designed herringbone edge can reasonably reduce the radial cutting speed of the CNC machining center, reduce the hierarchical, and their work efficiency and actual effect are very good. 3. The composite material is cut into powder, which is harmful to human health. A powerful vacuum cleaner should be used for dust collection. Water cooling and heat dissipation can also reasonably reduce smoke pollution. 4. Carbon fiber composite prefabricated components are generally large in size, complicated in appearance and structure, high in strength and hardness, and belong to raw materials that are difficult to produce and process. In the process of drilling, the cutting speed is relatively high, the drilling heat is not easy to transmit, the epoxy resin will be burnt or the resin will become soft when it is relatively serious, and the CNC blade is seriously damaged. Therefore, the CNC blade is important for carbon fiber processing, and its drilling principle is closer to cutting rather than cutting. Therefore, the drilling angular speed of turning milling composite processing usually exceeds 500m/min, so the high-speed rotating small tool path strategy is selected. Generally, the overall carbide tool extruding tap turning tool, electroplating process diamond particle sand wheel blade, diamond inlaid turning tool, copper fund steel particle woodworking saw blade are used for edge cutting production and processing of CNC blades.