Category: Manufacturing Technology knowledge

Alloying treatment of cast iron can be traced back to the 1930s and 1940s. Alloying treatment has made a qualitative leap in the properties of cast iron. At the same time, some special purpose cast iron such as wear resistance, corrosion resistance and heat resistance have also been born. It was also during this period that cast iron was produced by inoculation. In the late 1940s, the cast iron with spherical graphite after inoculation replaced the ordinary sheet graphite cast iron. We call this type of cast iron ductile iron. Classification of spheroidizing and anti spheroidizing elements Spherical elements are…

1. Bending time definition and its constituent items 1.1 Bending man hour refers to the man hour for bending in the workshop. 1.2 Bending man hour consists of preparation man hour, operation man hour and auxiliary loading and unloading man hour. 1.3 Preparation time refers to the time consumed to get familiar with process documents, get materials, adjust the bending machine, etc. 1.4 Operation man hour refers to the time consumed for bending. 1.5 Auxiliary loading and unloading man hours refer to the time consumed for loading and unloading. 2. Calculation regulations for each component item of bending man hour…

The maintenance of the continuous die must be careful and patient, and it must not be blindly carried out. When the die is repaired due to faults, the tape must be attached to facilitate the query of problems. Open the mold, check the mold condition, confirm the cause of the failure, find out the problem, and then clean the mold before removing the mold. The force shall be uniform when removing the mold. For the mold structure where the stripper spring is between the fixed plate and the stripper plate and the stripper spring is directly pushed onto the inner…

Wear is a very common phenomenon in machining process, which may be caused by many factors, such as workpiece material, environment, processing method, etc. Mechanical wear will have adverse effects on the processing quality, precision and efficiency of products. Therefore, for those who are engaged in machining industry, it is very important to do a good job in the prevention of mechanical wear. Common types and characteristics of mechanical wear The common wear types in machining mainly include running in wear, hard grain wear, surface fatigue wear, thermal wear, phase change wear and hydrodynamic wear. Running in wear is the…

The casting grain coarseness refers to the defect that shows the grain structure is too coarse to be suitable for application when the machinist or the fracture inspection is carried out. This kind of coarse grain structure may be distributed throughout the whole casting, or may occur locally. In essence, coarse grain defect is a metallurgical defect. Based on many years of production practice and referring to relevant information, the author talks about the causes of coarse grain defects in castings and preventive measures. 1 Casting structure and process design (1) If the section difference of the casting is too…

1. Corner melting When cutting the corner of the sheet steel at a reduced speed, the laser will melt the corner due to overheating. A small radius is generated at the corner to maintain high speed laser cutting and avoid overheating and melting of steel plates when cutting corners, so as to obtain good cutting quality, reduce cutting time and improve productivity. 2. Part spacing In general, when cutting thick plates and hot plates, the distance between parts should be large, because the heat of thick plate hot plates has a great impact, and when cutting sharp corners and small…

During the processing of stainless steel parts, the deformation of parts caused by welding is often encountered. Part deformation is only a surface phenomenon. Due to the role of welding heat source, it is easy to overheat the weld metal and the welding heat affected area, which often leads to defects in the weld metal and the metal grains in the heat affected area. In addition, in order to prevent and eliminate the adverse effects of welding on parts, it is necessary to control the temperature of parts and wait for parts to cool down for the next weld welding…

1. Incorrect knife tip angle When grinding the turning tool, the tool tip angle is incorrect, that is, the included angle between the projection of the two cutting edges of the turning tool on the base surface is inconsistent with the tooth profile angle of the machined thread, resulting in the incorrect angle of the machined thread. Solution: When grinding the turning tool, an angle ruler or sample plate must be used to detect the correct tooth profile angle. The method is: parallel the sample plate or angle ruler to the front of the turning tool, and then check with…

Special attention shall be paid to the following points during the use of aluminum alloy die casting die: 1. Cleaning the parting surface of the mold is very troublesome and easy to ignore. If the boss has a high starting point and buys a good mold, it will be much easier to work. If the mold quality is not good, there will inevitably be flash or dirt on the parting surface of the mold during production. The operator should often clean these parts and equip a small shovel at any time. If the flash is not removed in time, the…

Screw threads are classified according to the number of spiral grooves on the thread in addition to the section shape. The thread with one spiral groove is called single head thread. Threads with more than two spiral grooves are called multi head threads. The distance between two adjacent spiral grooves on the thread is called pitch. The distance along the spiral groove is called lead. The relationship between lead and pitch can be expressed by the following formula L = t  ×  Where, L - thread lead (mm), N - Number of thread heads, T - thread pitch (mm). When…