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

What is steel? Steel is a broad term for iron and carbon alloys. The carbon content (0.05% - 2% by weight) and the addition of other elements determine the specific alloy of steel and its material properties. Other alloying elements include manganese, silicon, phosphorus, sulfur and oxygen. Carbon increases the hardness and strength of steel, while other elements can be added to improve corrosion resistance or machinability. The manganese content is also generally high (at least 0.30% to 1.5%) to reduce the brittleness of the steel and improve its strength. The strength and hardness of steel is one of its most popular properties. It is they that make steel suitable for construction and transportation applications because this material can be used for a long time under heavy and repeated loads. Some steel alloys, i.e. stainless steel varieties, are corrosion resistant, which makes them the best choice for parts working in extreme environments. However, this strength and hardness will also prolong machining time and increase tool wear. Steel is a high density material, which makes it too heavy in some applications. However, steel has a high strength to weight ratio, which is why it is one of the most commonly used metals in manufacturing. Type of steel Let's talk about many types of steel. As steel, carbon must be added to iron. However, the content of carbon will be different, resulting in great changes in its performance. Carbon steel generally refers to steel other than stainless steel and is identified by the 4-digit grade of steel. More broadly, it is low carbon steel, medium carbon steel or high carbon steel. Low carbon steel: carbon content less than 0.30% (by weight) Medium carbon steel: 0.3 – 0.5% carbon content High carbon steel: 0.6% and above The main alloying elements of steel are represented by the first digit of the four digit grade. For example, any 1xxx steel, such as 1018, will use carbon as the main alloying element. 1018 steel contains 0.14 – 0.20% carbon and a small amount of phosphorus, sulfur and manganese. This universal alloy is commonly used to machine gaskets, shafts, gears and pins. Easy to process carbon steel is re phosphated and re phosphated to break the chips into smaller pieces. This prevents long or large chips from getting entangled with the tool during cutting. Easy to machine steel can speed up processing time, but may reduce ductility and impact resistance. stainless steel Stainless steel contains carbon, but it also contains about 11% chromium, which increases the corrosion resistance of the material. More chromium means less rust! The addition of nickel can also improve the rust resistance and tensile strength. In addition, stainless steel has good heat resistance and is suitable for aerospace and other applications in extreme environments. According to the crystal structure of metal, stainless steel can be divided into five types. These five types are austenite, ferrite, martensite, duplex and precipitation hardening. Stainless steel grades are identified by three digits instead of four digits. The first number represents the crystal structure and major alloying elements. For example, 300 series stainless steel is austenitic chromium nickel alloy. 304 stainless steel is the most common grade, also known as 18 / 8, because it has 18% chromium and 8% nickel. 303 stainless steel is a free machining version of 304 stainless steel. The addition of sulfur reduces its corrosion resistance, so type 303 stainless steel is more likely to rust than type 304 stainless steel. Stainless steel can be used in a wide range of industries. Type 316 stainless steel can be used for valve components in medical equipment such as machines and pipelines after proper processing. 316 stainless steel is also used for processing nuts and bolts, many of which are used in the aerospace and automotive industries. 303 stainless steel is used for gears, shafts and other parts necessary for aircraft and automobiles. chisel tool steel Tool steel is used to manufacture tools for various manufacturing processes, including die casting, injection molding, stamping and cutting. There are many different tool steel alloys available for different applications, but they are all known for their hardness. Each of them can withstand the wear of multiple uses (the steel mold used for injection molding can withstand a million times or more of materials) and has high temperature resistance. A common application of tool steel is injection molding, which is processed by hardened steel CNC to produce the highest quality production parts. H13 steel is usually selected because of its good thermal fatigue performance - its strength and hardness can withstand long-term exposure to extreme temperatures. H13 mold is very suitable for advanced injection molding materials with high melting temperature, because it provides longer mold life than other steels – 500000 to 1 million times. At the same time, S136 is stainless steel, and the die life exceeds one million times. This material can be polished to the highest level and used for special applications of parts requiring high optical clarity. Steel treatment Some of the most useful properties of steel come from additional processing and machining steps. These methods can be carried out before processing to change the properties of the steel and make the steel easier to process. Please remember that hardening materials before machining will prolong machining time and increase tool wear, but steel can be processed after machining to increase the strength or hardness of the finished product. That is to say, it is important to anticipate any planned treatment that you need to apply to achieve the necessary properties for your parts. heat treatment Heat treatment refers to several different processes involving manipulating the temperature of steel to change its material properties. An example is annealing, which is used to reduce hardness and increase ductility, making steel easier to process. The annealing process slowly heats the steel to the desired temperature and holds it for a period of time. The time and temperature required depend on the specific alloy and decrease with increasing carbon content. Finally, the metal is slowly cooled in the furnace or surrounded by insulating material. Normalizing heat treatment can eliminate the internal stress in the steel while maintaining higher strength and hardness than annealed steel. During normalizing, the steel is heated to a high temperature and then air cooled to obtain higher hardness. Quenched steel is another heat treatment process. You guessed it, it hardens steel. It also increases strength, but also makes the material more brittle. The hardening process consists of slowly heating the steel, soaking it at high temperature, and then rapidly cooling the steel in water, oil or brine solution. Finally, tempering heat treatment process is adopted to reduce the brittleness of quenched steel. Tempered steel is almost identical to normalizing: slowly heat it to a selected temperature, and then air cool the steel. The difference is that the tempering temperature is lower than other processes, which reduces the brittleness and hardness of tempered steel. Precipitation hardening Precipitation hardening improves the yield strength of steel. Some grades of stainless steel may contain pH values in their names, which means that they have precipitation hardening characteristics. The main difference between precipitation hardening steels is that they contain additional elements: copper, aluminum, phosphorus or titanium. There are many different alloys. In order to activate the precipitation hardening property, the steel is formed into the final shape and then subjected to age hardening treatment. The aging hardening process heats the material for a long time to precipitate the added elements and form solid particles with different sizes, thus improving the strength of the material. 17-4PH (also known as 630 steel) is a common example of stainless steel precipitation hardening grades. The alloy contains 17% chromium and 4% nickel, and 4% copper, which contributes to precipitation hardening. Due to increased hardness, strength and high corrosion resistance, 17-4PH is used for HELIDECK platforms, turbine blades and nuclear waste drums. Cold working The properties of the steel can also be changed without applying a large amount of heat. For example, cold worked steel is made stronger by a work hardening process. Work hardening occurs when the metal is plastically deformed. This can be achieved by hammering, rolling or drawing the metal. During machining, if the tool or workpiece is overheated, work hardening may also occur accidentally. Cold working can also improve the machinability of steel. Low carbon steel is very suitable for cold working. Precautions for steel structure design When designing steel parts, it is important to remember the unique characteristics of the material. Making it well suited to the characteristics of your application may require additional consideration of manufacturing design (DFM). Due to the hardness of the material, it takes longer to process steel than other softer materials such as aluminum or brass. You need to use the correct machine settings to optimize machining quality and minimize tool wear. In fact, this means slower spindle speed and feed speed to protect your parts and molds. Even if you don't do the processing itself, you should still evaluate the steel type suitable for your project, not only the hardness and strength, but also the difference in machinability. For example, the processing time of stainless steel is about twice that of carbon steel. When deciding on different grades, you should also consider which properties are the highest priority and which steel alloys are easy to obtain. Commonly used grades, such as 304 or 316 stainless steel, have a wider range of stock sizes to choose from and require less time to find and purchase.

We have encountered many problems about the best way to fasten different 3D printing components. For example, when prototyping a hardware product, it is usually necessary to make an assembly structure that is more complex than a single 3D printing component, such as an electronic shell or a robot component. Sometimes, you may need to print components of the building package of a 3D printer that is too large, so you need to consider ways to assemble the printing parts permanently or intermittently. One way to assemble 3D parts is to use snap fit components, but another good method is to use threads. There are many different methods to implement threads in 3D printing parts, so we will introduce the advantages and disadvantages of the most commonly used methods and the specific installation steps to help you get started. Threaded insert Our preferred method, and our most frequently recommended method, is to use threaded inserts because they are easy to install and feel good. Advantages: fast, simple and clean; Unlimited assembly / disassembly; Production quality Disadvantages: more expensive; The wall thickness needs to be increased Materials and tools: brass inserts; Soldering iron; Precision knife Installation steps: 1. Place the insert into the relevant hole to be pushed in 2. With a heated soldering iron, place it in the middle of the insert and apply a small amount of pressure. 3. When the insert starts to heat up, you will see it sink into the hole 4. Once the blade appears flush with the part surface, please use your precision blade to check and trim any excess material Self tapping screw Another method of threaded inserts is to use self tapping screws. If you want fast but dirty things, this is the simplest and cheapest way. So if this is your first prototype, or if you are using low resolution materials, such as PLA, self tapping screws are a good choice. Advantages: easy installation; Minimum design requirements; cheap Disadvantages: brittle materials may break; Limited assembly / disassembly; Low strength; Materials and tools; Self tapping screw Installation steps: 1. It's as simple as a screwdriver and a screw... Just screw it Design thread into 3D model When designing parts that require very large threads, the best way is to design the threads into the 3D model itself. Advantages: Custom thread can be designed; Good when the insert is not available (i.e. M50 thread); Suitable for brittle materials Disadvantages: the thread will wear with time; It is difficult to model accurately; High resolution printing is required; Materials and tools None (CAD only) Installation steps: 1. Ensure the accuracy of thread modeling 2. Print components using high-resolution materials 3. For internal threads, use a tap to "finish" the thread. If you do not have a tap available, try using a machine screw. 4. For external thread, please use a steel nut that matches your thread size and use it to complete the thread on the part. 5. Ensure that the through hole of the part is completely tapped - this will ensure that excess material is removed from the tapping feature and the part is ready for fastening. 6. For blind holes, ensure that the tapping depth is sufficient for assembly and ensure that any excess material is cleaned (attempting to screw fasteners into parts with debris may damage your function). When using this method to add a thread to a printed part, make sure that it is vertically aligned with the thread feature; Special attention should be paid to avoid cross threading, which may cause permanent damage to the parts. Cut the thread with a tap This is the most traditional method of using threads. In reduced material manufacturing, once the CNC places the hole at the position where the thread will pass through, a drill tap is used to create the required thread in each hole. When prototyping with 3D printing, you can create threads in a plastic prototype using the same method as a hand drill tap. Advantages: better assembly / disassembly than self tapping screws; Disadvantages: low strength; The plastic wire wears away with time; Time intensive Materials and tools: drilling and tapping; Screw; Installation steps: 1. Tap the thread features with the corresponding drill bit to cut the available thread 2. Be careful not to damage components when applying torque Fixed hexagon nut Another common strategy for fastening parts together is to create printed pockets for capturing hex nuts. Advantages: low cost solution; Good clamping force; Easy to install Disadvantages: only applicable to external surface; Additional material is required to fix the nut; Design constraints Materials and tools: hex nuts; screw How to use this method: 1. Measure the size of fasteners - this is a good resource to help you. 2. Add a little tolerance (0.005 – 0.010 inch) to the hole size to accommodate any dimensional error. 3. Before pressing the nut into the bag, apply a little glue on the nut, but stick it to the inner surface of the bag. Otherwise, when torque is applied to the nut, it may be pulled out of the groove Mechanical precautions The following three questions can help you consider which approach is best for your project: 1. Do you need to disassemble and reassemble components? 2. What is your strength requirement or retention? 3. What are the inherent geometric or spatial constraints in part design? In addition, when designing the fastening function, please keep the following three important considerations in mind: 1. Bending along an axis parallel to the printing should generally be avoided, as the components printed in this direction are much weaker in structure. 2. When adding assembly features, please pay attention to the allowable stress and strain of the material. 3. Please carefully check the CAD model before adding fastener features. For example, if you want to add a hex nut, check the height of the hex nut used; If a threaded insert is to be used, check the pitch of the installed insert.

In the face value economy era, refined products are often considered more valuable, and consumers are more willing to pay for them, even if the price is more expensive. The so-called texture is obtained by the appearance and touch of the surface. This feeling, surface treatment is a very key factor. For example, the shell of apple notebook computer is made of a whole piece of aluminum alloy, which is processed by CNC, and then subjected to polishing, high gloss milling, wire drawing and other multiple surface processes, so that its all aluminum metal texture coexists with the sense of fashion and technology. Aluminum alloy is easy to process, with rich surface treatment methods and good visual effects. It is widely used in notebook computers, mobile phones, mobile solid-state drives (PSSD), LED lamps, cameras and other products. It often cooperates with surface treatment processes such as polishing, wire drawing, sandblasting, high gloss cutting and anodizing to make products present different textures. polishing The polishing process mainly reduces the roughness of the metal surface through mechanical polishing or chemical polishing. However, polishing cannot improve the dimensional accuracy or geometric accuracy of parts, but is used to obtain the appearance effect of smooth surface or specular gloss. Mechanical polishing is to use sandpaper or polishing wheel to reduce the roughness and make the metal surface smooth and bright. However, the hardness of aluminum alloy is not high, and deep grinding lines will be left with coarse-grained grinding and polishing materials. If fine grain is used, the surface is fine, but the ability to remove the milling grain is greatly reduced. Chemical polishing is an electrochemical process, which can be considered as reverse plating. It removes a thin layer of material on the metal surface, leaving a smooth and ultra clean surface with uniform luster and no fine lines during physical polishing. In the medical field, chemical polishing can make surgical tools easier to clean and disinfect. In electric appliances such as refrigerators and washing machines, chemical polishing products are used to make parts have longer service life and brighter appearance. The use of chemical polishing on key parts of the aircraft can reduce friction resistance and make it more energy-saving and safe. Sandblasting Many electronic products will adopt sandblasting technology on the surface, so that the product surface presents more subtle matte touch, similar to frosted glass. The matte material is implicit and stable, creating the low-key and durable characteristics of the product. Sand blasting is to use compressed air as power to spray spraying materials, such as copper ore sand, quartz sand, carborundum, iron sand and sea sand, onto the surface of aluminum alloy at high speed, to change the mechanical properties of the surface of aluminum alloy parts, improve the fatigue resistance of parts, and also increase the adhesion between the original surface of parts and the coating, which is more favorable to the durability of the coating film and the leveling and decoration of the coating. The sand blasting surface treatment process is the fastest and most thorough cleaning method. It can be arbitrarily selected among different roughness to form different roughness on the surface of aluminum alloy parts. wire drawing Drawing process is very common in product design, such as notebook and headset in electronic products; Refrigerators and air purifiers in household products; It is also useful in automobile interior decoration. The center console of the brushed panel can also improve the quality of the automobile. Repeatedly scraping lines on the aluminum plate with sandpaper can clearly show each fine trace, make the fine hair shine in the metal matte, and give the product a strong and atmospheric beauty. According to the need of decoration, it can be made into straight lines, random lines and spiral lines. The surface of the microwave oven, which has won the if award, adopts the wire drawing process, which has the beauty of firmness and atmosphere, as well as the sense of fashion and technology. High gloss milling The high gloss milling process is to use the fine engraving machine to cut parts and process local highlight areas on the product surface. The metal shell of some mobile phones is milled with a circle of highlight chamfers, and the metal appearance of some small parts is milled with one or several bright shallow straight grooves to add bright color changes to the product surface, with a strong sense of fashion. In recent years, the metal frame of some high-end TV sets has adopted the high light milling process, and the anodizing and wire drawing process have made the whole TV set full of a sense of fashion and a sharp sense of technology. anodic oxidation In most cases, aluminum parts are not suitable for electroplating, because aluminum parts are easy to form an oxide film on oxygen, which will seriously affect the bonding force of the electrodeposited layer. Generally, anodic oxidation is used. Anodic oxidation refers to the electrochemical oxidation of metals or alloys. Under specific conditions and applied current, a layer of aluminum oxide film is formed on the surface of the parts to improve the surface hardness and surface wear resistance of the parts and enhance the corrosion resistance. In addition, through the adsorption capacity of a large number of micropores in the thin layer of the oxide film, the surface of the parts can be colored into various beautiful colors, enriching the color performance of the parts and increasing the beauty of the products. In addition to the above five surface treatments, the aluminum alloy parts can also be provided with decorative chromium plating, chromium plating, nickel plating, silver plating, gold plating, baking paint, plastic spraying, Teflon spraying, silk screen printing, laser marking and other surface treatment processes to meet the diversified technological requirements of the parts.

In the face value economy era, refined products are often considered more valuable, and consumers are more willing to pay for them, even if the price is more expensive. The so-called texture is obtained by the appearance and touch of the surface. This feeling, surface treatment is a very key factor. For example, the shell of apple notebook computer is made of a whole piece of aluminum alloy, which is processed by CNC, and then subjected to polishing, high gloss milling, wire drawing and other multiple surface processes, so that its all aluminum metal texture coexists with the sense of fashion and technology. Aluminum alloy is easy to process, with rich surface treatment methods and good visual effects. It is widely used in notebook computers, mobile phones, mobile solid-state drives (PSSD), LED lamps, cameras and other products. It often cooperates with surface treatment processes such as polishing, wire drawing, sandblasting, high gloss cutting and anodizing to make products present different textures. polishing The polishing process mainly reduces the roughness of the metal surface through mechanical polishing or chemical polishing. However, polishing cannot improve the dimensional accuracy or geometric accuracy of parts, but is used to obtain the appearance effect of smooth surface or specular gloss. Mechanical polishing is to use sandpaper or polishing wheel to reduce the roughness and make the metal surface smooth and bright. However, the hardness of aluminum alloy is not high, and deep grinding lines will be left with coarse-grained grinding and polishing materials. If fine grain is used, the surface is fine, but the ability to remove the milling grain is greatly reduced. Chemical polishing is an electrochemical process, which can be considered as reverse plating. It removes a thin layer of material on the metal surface, leaving a smooth and ultra clean surface with uniform luster and no fine lines during physical polishing. In the medical field, chemical polishing can make surgical tools easier to clean and disinfect. In electric appliances such as refrigerators and washing machines, chemical polishing products are used to make parts have longer service life and brighter appearance. The use of chemical polishing on key parts of the aircraft can reduce friction resistance and make it more energy-saving and safe. Sandblasting Many electronic products will adopt sandblasting technology on the surface, so that the product surface presents more subtle matte touch, similar to frosted glass. The matte material is implicit and stable, creating the low-key and durable characteristics of the product. Sand blasting is to use compressed air as power to spray spraying materials, such as copper ore sand, quartz sand, carborundum, iron sand and sea sand, onto the surface of aluminum alloy at high speed, to change the mechanical properties of the surface of aluminum alloy parts, improve the fatigue resistance of parts, and also increase the adhesion between the original surface of parts and the coating, which is more favorable to the durability of the coating film and the leveling and decoration of the coating. The sand blasting surface treatment process is the fastest and most thorough cleaning method. It can be arbitrarily selected among different roughness to form different roughness on the surface of aluminum alloy parts. wire drawing Drawing process is very common in product design, such as notebook and headset in electronic products; Refrigerators and air purifiers in household products; It is also useful in automobile interior decoration. The center console of the brushed panel can also improve the quality of the automobile. Repeatedly scraping lines on the aluminum plate with sandpaper can clearly show each fine trace, make the fine hair shine in the metal matte, and give the product a strong and atmospheric beauty. According to the need of decoration, it can be made into straight lines, random lines and spiral lines. The surface of the microwave oven, which has won the if award, adopts the wire drawing process, which has the beauty of firmness and atmosphere, as well as the sense of fashion and technology. High gloss milling The high gloss milling process is to use the fine engraving machine to cut parts and process local highlight areas on the product surface. The metal shell of some mobile phones is milled with a circle of highlight chamfers, and the metal appearance of some small parts is milled with one or several bright shallow straight grooves to add bright color changes to the product surface, with a strong sense of fashion. In recent years, the metal frame of some high-end TV sets has adopted the high light milling process, and the anodizing and wire drawing process have made the whole TV set full of a sense of fashion and a sharp sense of technology. anodic oxidation In most cases, aluminum parts are not suitable for electroplating, because aluminum parts are easy to form an oxide film on oxygen, which will seriously affect the bonding force of the electrodeposited layer. Generally, anodic oxidation is used. Anodic oxidation refers to the electrochemical oxidation of metals or alloys. Under specific conditions and applied current, a layer of aluminum oxide film is formed on the surface of the parts to improve the surface hardness and surface wear resistance of the parts and enhance the corrosion resistance. In addition, through the adsorption capacity of a large number of micropores in the thin layer of the oxide film, the surface of the parts can be colored into various beautiful colors, enriching the color performance of the parts and increasing the beauty of the products. In addition to the above five surface treatments, the aluminum alloy parts can also be provided with decorative chromium plating, chromium plating, nickel plating, silver plating, gold plating, baking paint, plastic spraying, Teflon spraying, silk screen printing, laser marking and other surface treatment processes to meet the diversified technological requirements of the parts.

1. Define goals The main objective of deploying the industrial Internet of things is to reduce costs and improve efficiency (related reading: how to improve production efficiency during tool use), or to achieve remote monitoring of systems and processes. After the target is determined, we can analyze the components according to the existing equipment and data. This process is very important. In most cases, it is impossible to replace all the old equipment, and the cost is too high. Therefore, in practice, machining enterprises tend to integrate communication equipment and protocol conversion software to connect all systems, so as to realize effective use of existing equipment. 2. Device connection The Internet of things is a "network", so it is necessary to realize the connection. Therefore, enterprises must connect the machines and sensors of different manufacturers. For old equipment without communication capability, they can integrate sensors for processing and strategically re arrange a sensor network to meet the requirements of data collection. After the equipment is connected, the communication between the equipment is realized, and how to push the data is also considered. The real power source of industrial Internet of things and cloud computing is data centralization and integration of applications to extract and process information. Many industrial IOT platforms now provide databases with various capabilities such as data storage time processing, equipment supply and reporting. Although they are usually configured for specific applications, many of them are built for simple and rapid implementation. 3. Remove obstacles In the industrial Internet of things, privacy and security are important obstacles to industrial Internet of things investment. When collecting and transmitting sensitive data, it must be protected. Therefore, the industrial Internet of things should take special security measures to ensure that the system can safely collect, monitor, process and store data. However, to ensure security, it is necessary to balance the costs related to time and resources with data protection.  

Now, with the development of science and technology, the machining industry requires higher and higher precision, so non-standard mold parts are more and more widely used in production and processing. A complete set of molds is composed of many non-standard parts, and the mold parts have a great impact on the quality of molds. It can be seen that the accuracy of non-standard parts is important. Therefore, the finishing of non-standard mold parts must be well controlled. In order to control the accuracy of non-standard parts processing, we should consider many aspects of non-standard processing molds: the design of non-standard molds, the materials of non-standard molds, the processing process of non-standard molds and the final quality specifications of non-standard molds. None of these aspects can be ignored, and any further neglect will have a serious impact on the accuracy of non-standard parts. 1、 Rationality of non-standard die design The rationality of mold structure design is the basis for processing non-standard parts. It is related to the production cycle and processing quality of the mold, so we need to pay attention to it. The following aspects should be paid attention to when designing non-standard molds: 1. When designing non-standard molds, we need to find ways to make the production process simple and easy to operate. 2. When designing the non-standard mold, the lower guide post structure is required for the small push rod or the eccentric structure of the mold. For multi rib ventilation windows, pay attention to reserving positions. 3. After the non-standard mold is designed, all data shall be checked until all dimensions are correct, and then the drawings can be officially issued for processing. 2、 Quality control of mould materials Non standard parts are small batches or single pieces in production. They are complicated in the processing process, some have a long manufacturing cycle, and the materials used have a great impact on the finished products. According to the current production situation, mold production needs to control the following aspects. 1. For the selection of suppliers that need to be fixed and have stable quality assurance, the cost should also be considered. 2. Strict inspection is required for material processing: (1) Is the chemical composition of the material correct (2) Whether the surface quality of the material meets the standard, and whether there are obvious cracks, scabs, slag inclusions, etc. (3) Whether it meets the hardness requirements of non-standard parts. (4) The accuracy of datum and parting surface shall be further checked. 3. During the production process, it is necessary to monitor the quality of materials and mold bases at any time. Once there is any problem, it is necessary to give feedback in time. 3、 Monitoring the process of non-standard parts processing 1. First of all, the drawings, process requirements and completion time of non-standard parts need to be very clear. 2. The processing personnel shall strictly follow the requirements of the drawings during the processing process, and conduct self inspection at all times during the processing process. 3. The work requiring cooperation in the processing process shall be negotiated in advance to avoid errors in the cooperation process. 4、 Factory quality requirements for non-standard parts 1. The surface of non-standard parts shall be free of scratches, scratches and other surface defects. 2. The machined threaded surface shall not have black skin, bump, disorderly buckle and burr defects.

In the past processing, grinding, polishing and other processes are often required after the milling process to achieve the required surface quality. If only milling can achieve this effect, the machining efficiency will be greatly improved. Recently, a series of test results of static pressure gas surface induced ultra precision machining carried out at the Federal Institute of technology in Zurich, Switzerland, show that the surface quality of the workpiece obtained by line by line milling can reach the level of RA less than 25 nm, while the surface quality of the workpiece obtained by surface milling can reach the level of RA less than 3 nm. The surface quality of milling processing has been greatly enhanced, even reaching the level of polishing, and many subsequent processing has lost the necessity of existence, which greatly shortens the processing time and avoids the convex surface and corner grinding in grinding and polishing. In this kind of precision milling equipment, the function of tool shank is very important. Wear free clamping precision tool shank Conventional tool holders, such as collet tool holders and heat shrinkable tool holders, are difficult to complete precision milling tasks. Because there are tiny impurities in the clamping surface, problems such as chattering scratches, tool damage, inaccurate workpiece and concentricity error will occur in the processing. But the precision tool handle can effectively solve this problem. For example, XiongKe tribos is a kind of precision tool holder. Its built-in stress locking clamping technology can control the runout and repetition accuracy within 0.003 mm. When the extension length is 2.5 x D and the rotation speed is 25000 rpm, the balance level reaches g 2.5. There is no movable part on the tool handle, so it is not mechanically sensitive, which can prevent fixture wear and material fatigue. In addition, it has excellent vibration damping function and fast tool changing speed. XiongKe tribos series tool handles have different types of interfaces such as hsk-e 25, hsk-e 32 and hsk-f 32, which can meet various processing needs. It has been widely used in micro mold manufacturing industry, optical industry, medical technology industry, coin, watch and jewelry processing and other fields. It plays a pivotal role in improving the fineness of milling processing and protecting the tool life. Reduce chatter and scratches in large cutting In the process of large cutting volume, the tool shank will have a great impact on the surface quality of the workpiece, which is found and confirmed by the research of WBK Institute of production technology in Karlsruhe. This research institute has carried out full groove and half groove milling experiments on several machine tools, and conducted comparative tests on several different tool shanks. The test results fully prove that there are great differences in the surface quality of workpieces with different tool handles. The surface quality of precision tool shank is far ahead of that of ordinary heat shrinkable tool shank, especially when the groove is deeper, this advantage is more obvious. Another advantage of the precision tool shank is the damping characteristic of the hydraulic expansion technology, which can effectively prolong the service life of the tool. Under the same other conditions, higher cutting rate and feed rate can be achieved. In addition, precision tool holders and high-precision five axis machining equipment can form a perfect partnership. The hydraulic tool shank can effectively alleviate the vibration in the machining process, provide strong support for the extension rod, and minimize the contour interference. Moreover, the clamping time and tool changing time required by this set of equipment are very short, only a few seconds; The clamping device requires no maintenance and is not sensitive to impurities.

Many enterprises find it difficult to process titanium metal. On the one hand, it is because of the high hardness of titanium, and on the other hand, it is also because titanium processing is a new process and lacks a model for reference. When workers are used to processing metals with lower requirements such as cast iron, titanium, which is harder than stainless steel, naturally becomes a member of the list of difficult to process materials. In fact, compared with most materials, metallic titanium is also a material that can be directly processed. As long as the workpiece is stable, the clamping is firm, and the processing parameters are correctly selected, the matter is not as complicated as expected. However, there are still some problems that must be paid attention to in the processing of workpieces with complex shapes, which may contain many fine or deep cavities, thin walls, inclined surfaces and thin brackets. Vibration and heat must be considered It is better to equip ISO 50 spindle with short tool overhang for processing metal titanium. However, the current situation is that most machine tools are equipped with IS0 40 spindle. If the strength of the machine tool is too high, it is impossible to maintain the sharpness of the tool for a long time. In addition, how to clamp the parts with complex structure is also a thorny problem. However, the biggest challenge actually comes from vibration and heat. Sometimes the cutting process in titanium metal processing must be used for full groove milling, side cutting or contour milling, which will cause vibration and form poor cutting conditions. Vibration can cause the blade to break, damage the blade and produce many unpredictable results. Therefore, when setting the machine tool, attention must be paid to the principle of improving stability to reduce the occurrence of vibration. One improvement measure is to adopt multi-stage clamping to make the parts closer to the main shaft to help counteract the vibration. A large amount of heat will be generated during the processing of titanium metal, resulting in an increase in temperature. Unfortunately, the high temperature will affect the cutting performance of the tool, but it will not affect the hardness of the workpiece. Titanium metal can still maintain extremely high hardness and strength at high temperature, and even work hardening may occur, which makes processing more difficult and is not conducive to some subsequent cutting processes. Therefore, selecting the best indexable blade grade and groove shape is the key to the success of machining. According to past experience, fine grain uncoated blade grades are very suitable for titanium metal processing; Today, the blade grade with PVD titanium coating has greater advantages in improving cutting performance. Accuracy, conditions and correct cutting parameters The runout accuracy of the tool in the axial and radial directions requires special attention. For example, if the insert is not properly installed in the milling cutter, the surrounding cutting edge can be easily damaged. In addition, the manufacturing tolerance of the tool is wrong, the tool wear, the spindle wear and the defects of the tool shank will also greatly reduce the service life of the tool. In all cases of poor processing performance, the proportion caused by the above factors accounted for 80%. Compared with the positive rake groove tool that most people like, the tool with a slightly negative rake groove can remove material at a higher feed rate, and the feed rate per tooth can reach 0.5 mm. However, this requires that the machine tool is very solid and the clamping is extremely stable. In addition to insert milling, the main deflection angle of 90 ° should be avoided as far as possible, which can improve the cutting stability, especially in the case of shallow cutting depth. In deep cavity milling, it is an ideal way to use a tool with variable length through the tool shank. Its processing effect is better than using a long tool with a single length in the whole process. When milling titanium metal, it is required to accurately calculate the feed rate of each tooth of the tool, so that it is not less than the minimum feed rate - usually 0.1mm. In addition, it is also possible to reduce the spindle speed to achieve the initial feed rate, which is also conducive to improving the tool life. If the minimum feed per tooth is used and the spindle speed is too fast, the impact on the tool life can be as high as 95%. Once the stable working condition is established, the spindle speed and feed rate can be increased accordingly to obtain the best performance.

 Original error The original error is the error existing at the beginning of the milling machine process. The common errors are geometric error, positioning error, machining error caused by stress deformation, machining error caused by thermal deformation, and error caused by the internal stress distribution of the workpiece.  Set error of process system 1. Geometric error of milling machine: the forming movement of the machined tool to the workpiece is completed by the milling machine, so the machining accuracy is inseparable from the accuracy of the milling machine. The manufacturing error of milling machine mainly includes spindle rotation error, guide rail and transmission chain error, as well as the error caused by precision reduction caused by long-time work. 2. Geometric error of cutter: cutter is one of the important parts of milling machine, and the error of cutter has great influence on the forming of workpiece. There are many kinds of influence of tool error on machining accuracy. If it is a fixed size tool, the manufacturing error will directly affect the workpiece. The general tool has little influence on the accuracy of the workpiece. 3. Geometric error of fixture: fixture mainly indicates the correct position of workpiece and tool. Once the fixture has accuracy error, it will have a great impact on the machining accuracy of milling machine. Positioning error 1. Non coincidence error of datum: there is an error between the positioning datum and the design datum. The two do not coincide, and can only be processed by the adjustment method. It will not occur during trial cutting. 2. Inaccuracy of positioning pair manufacturing: the correct position of the workpiece in the fixture is determined by the positioning element. The direction of the reference misalignment error may be different from the direction of the positioning pair manufacturing inaccuracy error. The positioning error may be the vector sum of the reference misalignment error and the positioning pair manufacturing inaccuracy error. Error caused by stress deformation of process system 1. Rigidity of workpiece: the rigidity of workpiece is lower than that of milling machine, cutter and fixture. Under the action of cutting, the workpiece will be deformed due to insufficient rigidity, which has a great impact on the machining accuracy of milling machine. 2. Tool rigidity: the rigidity of the cylindrical turning tool on the normal of the machining surface is very high, and the deformation can be ignored. When milling small-diameter inner holes, the rigidity of the cutter bar is very poor, which will have a certain impact on the accuracy of the holes. 3. Component stiffness of milling machine: each mechanical manufacturing equipment is composed of a variety of components, and the component stiffness has a great impact on the machining accuracy of the milling machine. The main factors affecting the rigidity of milling machine parts are the contact deformation of the joint surface, the influence of friction, the influence of low rigidity parts and the influence of clearance.

1. Surface texture defect detection of machined parts -- detection There are many textures on the surface of mechanical parts, and many textures are defective. If you want to find defects and compensate for defects, it is very helpful to improve the accuracy of parts. The detection in the part surface texture detection system can be carried out through the following aspects: (1) Use some equipment and methods to test the surface principle of mechanical parts (2) Input the detected information into the computer for processing (3) The computer system is programmed with signal processing and spectrum image After these three steps are completed, the routine detection of part surface texture is completed. 2. Detection and analysis of surface texture defects of machined parts There are many time sequences in the process of machining. If there are processing defects in the time sequence, it is easy to cause defects in the surface texture of mechanical parts. However, due to different processing tools and processing methods, various textures in different forms may be produced, which not only affects the beauty but also the accuracy of parts. After analysis, when the frequency domain filter is used to suppress the filtering operation in the region where the energy in the spectrum is relatively concentrated, the texture features in this direction will be more weak. We can reduce the texture features through this method, so as to enhance the strength of the effective texture direction, which makes it easier to distinguish and identify the background texture and the defect texture. 3. Surface texture defect detection of machined parts -- Extraction of texture features The separation of background texture and defect texture is the focus of image recognition, and it is more convenient and effective when the image is effectively filtered. Moreover, after filtering the background image, the texture defect image will be enhanced to a certain extent. So people can better distinguish the defect texture and the background texture. However, in the process of distinguishing, it should be noted that there are many unknown situations in this case. The first is the defective target, and the second is the noise point. It is for these two reasons that necessary treatment and noise reduction should be carried out during use. The texture information of defects is usually expressed in Fourier transform and is isolated. In the filtering processing project, the texture signal will also be automatically saved. Moreover, after image filtering, its background and texture defect characteristics are obviously different.