CNC Technology – Page 65 – CNC Machining & Turning, Milling, Metal parts

Common faults of metal stamping parts

In the progressive die, the shape of the metal stamping part is formed by punching the surplus material around the stamping part. The main reason of turning over and twisting is the influence of blanking force. During blanking, due to the existence of blanking clearance, the material is stretched on one side of the female die (material warps upward), and the side close to the punch is compressed. When the unloading plate is used, the unloading plate is used to compress the material to prevent the material on the die side from warping upward. At this time, the stress state of the material changes correspondingly. With the increase of the pressing force, the material near the punch side is stretched (the compression force tends to decrease), while the material on the die surface is compressed (the tensile force tends to decrease). The overturning of stamping parts is caused by the stretching of the material on the die surface. Therefore, when blanking, pressing and pressing the material is the key to prevent the stamping parts from turning over and twisting. The causes and Countermeasures of turning over and twisting of stamping parts during bending.

It is caused by the burr of the blanking part. It is necessary to study the cutting edge and check whether the blanking clearance is reasonable.

When blanking, the stamping parts have been turned over and twisted, which leads to poor forming after bending, which needs to be solved from the blanking station.

It is caused by the instability of stamping parts during bending. Mainly for U-shaped and V-shaped bending. In order to solve this problem, the key to solve the problem is to carry out the lead position before bending and during the bending process, and to hold down the material during the bending process to prevent the stamping parts from sliding during bending.

Processing characteristics of metal stamping parts

Metal stamping parts used by the die known as stamping die, referred to as the die. Stamping die is a special tool for batch processing materials (metal or nonmetal) into required stamping parts. The stamping die is very important in stamping. If there is no die that meets the requirements, it is difficult to produce in batch; if the technology of stamping die is not improved, the stamping process can not be improved. Stamping process and die, stamping equipment and stamping materials constitute the three elements of stamping process. Only when they are combined with each other can stamping parts be produced.

Compared with other processing forms such as mechanical processing and plastic processing, metal stamping processing has many advantages in terms of technology and economy. The main manifestations are as follows:

(1) Generally, there is no chip and broken material in stamping, the consumption of material is less, and other heating equipment is not needed. Therefore, stamping is a kind of material saving and energy-saving processing method, and the production cost of stamping parts is low.

(2) as like as two peas in the stamping process, the stamping parts are ensured to have the size and shape accuracy, and generally do not damage the surface quality of stamping parts, while the die life is generally longer.

(3) Metal stamping parts can process parts with large size range and complex shape, such as stopwatch of clock and watch, longitudinal beam of automobile and cage cover. In addition, the cold deformation hardening effect of materials during stamping makes the stamping strength and rigidity higher.

(4) The production efficiency of metal stamping parts processing is high, and easy to operate, and easy to realize mechanization and automation. Because stamping depends on the stamping die and stamping equipment to complete the processing, the ordinary press stroke times per minute can reach dozens of times, high-speed pressure can reach hundreds or even more than 1000 times per minute, and each stamping stroke can get one punch, so the production of metal stamping parts can achieve high-efficiency mass production.

Because of the superiority of stamping, metal stamping parts processing is widely used in various fields of national economy. For example, in aerospace, aviation, military industry, machinery, agricultural machinery, electronics, information, railway, post and telecommunications, transportation, chemical industry, medical appliances, daily electrical appliances and light industry, there are stamping processing. Not only is it used by the whole industry, but everyone has direct contact with stamping products: for example, there are many large, medium and small stamping parts on airplanes, trains, automobiles and tractors; the body, frame and rim of cars are all processed by stamping. According to relevant investigation and statistics, 80% of bicycles, sewing machines and watches are stamping parts; 90% of TV sets, tape recorders and cameras are stamping parts; there are also metal food cans, steel precision boilers, enamel pots and bowls and stainless steel tableware. All of them are stamping products, and even the computer hardware can not do without stamping parts.

However, the dies used in metal stamping process are generally special. Sometimes, a complex part needs several sets of dies to process and form. The mold manufacturing precision is high, and the technical requirements are high, which is a technology intensive product. Therefore, only in the case of a large number of stamping parts, the advantages of metal stamping can be fully reflected, so as to obtain better economic benefits.

Cold stamping knowledge of metal stamping parts

The metal stamping parts are light in weight, thin in thickness and good in rigidity. Its dimensional tolerance is guaranteed by the mold, so the quality is stable and can be used without mechanical cutting. The metal structure and mechanical properties of cold metal stamping parts are better than the original blank, and the surface is smooth and beautiful. The tolerance grade and surface state of cold metal stamping parts are better than that of hot metal stamping parts.

Large quantities of small and medium-sized parts are usually produced by compound die or multi station continuous die. With the modern high-speed multi position press as the center, equipped with strip material uncoiling, correction, finished product collection, transportation, mold warehouse and rapid die change device, and using computer program control, it can form a high productivity automatic metal stamping production line. By using new die materials and various surface treatment technologies and improving the die structure, high-precision and long-life metal stamping die can be obtained, so as to improve the quality of metal stamping parts and reduce the manufacturing cost of metal stamping parts.

The technology and equipment of metal stamping production are developing continuously. In addition to the traditional use of press and steel mold to manufacture metal stamping parts, various special metal stamping forming processes, such as hydraulic forming, spinning forming, superplastic forming, explosive forming, electro-hydraulic forming and electromagnetic forming, are also developing rapidly, which improves the technical level of metal stamping to a new height. The stamping process of special hardware is especially suitable for the production of various kinds of small and medium-sized parts (even dozens of pieces). For ordinary metal stamping process, simple mold, low melting point alloy mold, group mold and metal stamping flexible manufacturing system can be used to organize the metal stamping processing of various varieties of small and medium-sized parts.

Overview of metal stamping parts

Hardware: steel or some non-ferrous metal parts, processing means: cold / hot stamping, extrusion, rolling, welding, cutting, and other processes, including a wide range of definitions.

Stamping parts: most used in hardware processing, refers to the steel / non-ferrous metal and other sheet metal dies at room temperature, which are formed to the specified shape by the pressure required for processing by the press.

Metal stamping parts are widely used in various fields of our life, including some electronic devices, auto parts, decorative materials and so on. We usually refer to cold stamping parts. For example, a piece of iron plate, if you want to turn it into a fast food plate, you must first design a set of mold. The working surface of the mold is the shape of the plate. Pressing the iron plate with the mold will become the plate you want. This is cold stamping, that is, stamping the metal materials directly with the mold.

Some key points in the use of aluminum shell

For the purchase of aluminum shell, customers can choose according to the quality of the product, the quality will have a great impact on its service time. At the same time, good quality products in use, the effect is relatively good, can meet the needs of users.

The appearance of aluminum shell provides great convenience for users, especially in the power supply shell. This use is to take advantage of the electrical conductivity of aluminum alloy, which has better conductivity than other metals. Users need to pay attention to some key links when using, mainly including the following aspects.

The power supply shell uses aluminum shell, which makes it stronger and more convenient to use. First of all, for different occasions of the power shell, there will be a certain difference in material requirements. For example, the use of aluminum alloy shell, mainly used in the electronic field, can effectively reduce the probability of accidents.

Secondly, due to the corrosion resistance of aluminum shell, the requirements for working environment are relatively low when it is used. In some chemical enterprises, the power supply shell made of this material can also be used. On the one hand, it can protect the internal components of the power supply, but also provide convenience for users.

Finally, in the use of aluminum shell, once damaged, it can be replaced in time, the damaged products can also be recycled, for resources can play a role in recycling, for the environment also plays a very good protection.

What is the market situation of aluminum shell mold?

The material of the aluminum shell is an aluminum alloy material, which becomes a kind of shell through manufacturing and processing. This device is widely used in the society, and is also involved in the industry. It is mainly used as shell to play a good protective role, or panel, bracket, etc., aluminum shell has a very good protection effect, which has won the favor of consumers.

According to the different uses of aluminum shell, there will be great differences in the design work. Generally speaking, in order to select the appropriate shell, it is necessary to select a professional enterprise for design work.

Aluminum shell is widely used in the society, which makes the sales of this product in the market relatively high. There are many enterprises engaged in the shell production. When customers purchase aluminum shell, they need to refer to certain standards, so as to make the purchase work more smoothly. For the purchase of aluminum shell, customers can choose according to the quality of the product, the quality will have a great impact on its service time. At the same time, good quality products in use, the effect is relatively good, can meet the needs of users.

Aluminum shell mold weight is very light, but also has the properties of aluminum alloy material, with good corrosion resistance. At present, the sales momentum of this kind of mold in the market is relatively good. At the same time, it is also good at making complex parts. It can produce appropriate products according to the needs of customers, and at the same time, it is more favorable in price.

The development of aluminum shell in the market mainly depends on the market demand. China’s aluminum alloy mold started relatively late, so that the market demand for it is relatively large, while its cost is relatively low, better promote the development of mold in the market.

Causes and solutions of surface damage of aluminum shell

Reasons for surface damage of aluminum shell:

① There are impurities or segregation on the surface of ingot. When there are a lot of segregation floating objects on the surface of the ingot, but the ingot is not homogenized or the homogenization effect is not good, there are a certain number of hard metal particles in the ingot. When the metal flows through the working belt during extrusion, these segregation floating objects or hard metal particles adhere to the surface of the working belt or cause damage to the working belt, and finally cause Scratch on the surface of the profile;

② There are impurities in the mold cavity or the working belt, and the hardness of the die working belt is low, so that the surface of the working belt is injured and the profile is scratched during extrusion;

③ There are bare metal or graphite strip on the discharge track or swing bed, and there are hard inclusions in it, which will scratch the profile surface when it contacts with the profile;

④ When the fork bar transfers the profile from the discharge track to the swing bed, the profile is damaged due to the high speed;

Solution to surface damage of aluminum shell:

① Strengthen the quality control of ingot;

② Improve the quality of die repair, regular nitriding and strictly implement the nitriding process;

③ The soft felt is used to isolate the profile from the assistive device to minimize the contact damage between the profile and the accessory;

④ In production, handle with care and avoid dragging or turning the profile at will.

The factors influencing the price change of aluminum profile shell mainly include the following aspects:

1、 Due to the influence of alumina supply, the cost of aluminum melting accounts for 28% – 34% of the production cost of aluminum ingot. Due to the high concentration of the international alumina market, most of the world’s alumina (80% – 90%) are sold through long-term contracts, so there is very little alumina available for sale in the spot market. Take China as an example. Before 1997, China’s alumina gap was mainly purchased from the international spot market without long-term contracts. In 1997, China Nonferrous Metals and Alcoa signed a 30-year long-term supply contract, with 400000 tons per year. The price was set according to a certain proportion of LME’s original aluminum price. In recent years, with the continuous expansion of China’s electrolytic aluminum production scale, the domestic demand for alumina is also growing. At present, about two-thirds of the imported alumina needs to be purchased from the spot market. According to statistics, in 2004, China imported 5.87 million tons of alumina, a year-on-year increase of 4.8%. The average import price was 340 US dollars (the cash cost of foreign alumina production was less than 120 US dollars). According to simple calculation, direct import of alumina in 2004 alone paid more for foreign alumina suppliers The cost is as high as several billion yuan. The rising price of alumina makes the production cost of electrolytic aluminum production enterprises rise sharply, and the economic benefits decline sharply, and most enterprises fall into meager profits or losses.

2、 When the relationship between supply and demand is in a temporary balance, the market price of the commodity will fluctuate in a narrow range; when the relationship between supply and demand is unbalanced, the price will fluctuate greatly. In the aluminum futures market, investors can pay attention to an indicator reflecting the change of aluminum supply and demand – inventory. The inventory of aluminum profile shell is divided into report inventory and non report inventory. The reported inventory is also known as “explicit inventory”, which is the inventory quantity of aluminum in its designated delivery warehouse published by Futures Exchange on a regular basis. The non reported inventory mainly refers to the amount of aluminum held by producers, traders and consumers worldwide. Since there is no special agency for statistics and release of these inventories, these inventories are also known as “hidden inventory”.

3、 At present, the average power consumption per ton of aluminum in aluminum plants at home and abroad is controlled below 15000 kwh / T. The experience of aluminum ingot production in western countries shows that when the electricity charge exceeds 30% of the cost of aluminum production, it is considered as dangerous production.

4、 The influence of economic situation has become an important variety of non-ferrous metals, especially in developed countries or regions, aluminum consumption has been highly related to economic development. When a country or region’s economy develops rapidly, aluminum consumption will also increase synchronously. Similarly, the economic recession will lead to the decline of aluminum consumption in some industries, and then lead to the fluctuation of aluminum price. In addition, the price fluctuation of some metals related to aluminum, the fluctuation of international oil price, and the changes of industrial policies in various countries will have an impact on aluminum price.

5、 The influence of import and export tariff and international exchange rate, the price and settlement of international aluminum 6 trade are generally in US dollars. In recent years, the trend of US dollar has an obvious impact on aluminum price. The influence of import and export tariff on the price of aluminum profile shell is particularly prominent in China.

6、 The influence of the improvement and innovation of aluminum profile shell production process on the aluminum price, the rapid application of computer technology in the aluminum electrolysis industry, led to the in-depth study of the physical field in the electrolysis process and the establishment of the relevant mathematical model, so that the design of the electrolytic cell is more reasonable and the cell capacity is greatly increased

What is the processing technology of aluminum alloy shell?

What is the processing technology of aluminum alloy shell? The following is a brief introduction:

1. Hydroforming technology

In recent years, high pressure forming is a new technology in the world. According to their structural characteristics, various connectors can be formed at one time by internal high pressure forming method, or profiles can be made by general extrusion method, and then the tube blank can be pressed into the die cavity by internal pressure and axial force feeding.

Because of its excellent formability and large design freedom, one hydroforming part can replace the one formed by welding several parts, so it can avoid the distortion and deformation caused by welding, and has high dimensional accuracy and mechanical properties. Its main advantages are: reducing weight and saving materials.

2. Precision die casting technology

The connecting parts of aluminum alloy body frame structure are mostly formed by casting, and some advanced high-precision casting methods, such as semi-solid die-casting, are mainly used. At present, there are two forming processes in semi-solid die casting: rheological forming and thixoforming. In the former, the liquid metal is fed into the specially designed injection molding machine barrel, and the screw device is applied to shear to cool it into semi-solid slurry, and then die-casting is carried out. In the latter, the solid metal particles or chips are fed into the screw injection forming machine, and the metal particles are transformed into slurry under the condition of heating and shearing, and then die-casting is formed.

At present, the semi-solid metal casting used in industry at home and abroad mainly refers to thixotropic casting, which is widely used in body frame structure. Thixotropic casting, as a precision forming method, has high strength after forming and can realize one-time forming of complex shapes. It can be used to mass produce all kinds of parts without cutting or little cutting, and reduce the number of parts.

What should be paid attention to when choosing aluminum profiles?

What should be paid attention to when choosing aluminum profiles? The following is a brief introduction:

1. Check the product factory certificate, pay attention to the date of production, specifications, technical conditions, enterprise name and production license number.

2. Carefully observe the surface condition of the product. The product should have bright color and good luster. There should be no obvious scratch, bubble and other defects on the surface.

3. Pay attention to the wall thickness of the products. The thickness of the door and window materials should not be less than 1.2mm.

4. Pay attention to the thickness of the product surface coating. The film thickness of anodic oxidation product is not less than 10 μ m, the film thickness of electrophoretic coating product is not less than 17 μ m, the coating thickness of powder spraying is not more than 40-120 μ m, and the coating thickness of fluorocarbon paint spraying product should be more than the second coating, not less than 30 μ M.

5. The users in coastal areas should choose electrophoretic coating profiles, powder spraying profiles or fluorocarbon spraying profiles with good corrosion resistance.

6. During routine maintenance, brush and other hard objects should not be used as cleaning tools. Soft cotton yarn and cotton cloth should be selected.

7. Water, detergent and soap can be used for cleaning, but no other organic matter can be used.