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5、 Die grinding 1. Importance of die grinding Regular grinding of die is the guarantee of punching quality consistency. Regular grinding of the die can not only improve the service life of the die, but also improve the service life of the machine. It is necessary to grasp the correct grinding time. 2. The specific characteristics of the die need to be sharpened For the grinding of the die, there is no strict number of blows to determine whether the grinding is needed. It mainly depends on the sharpness of the cutting edge. It is mainly determined by the following…

1、 Information from waste The scrap is essentially the reflection of the formed hole. The opposite position is the same. By checking the scrap, you can judge whether the gap between the upper and lower dies is correct. If the gap is too large, the waste will have rough and undulating fracture surfaces and a narrow bright zone. The larger the gap, the greater the angle between the fracture surface and the bright zone area. If the gap is too small, the waste will show a small angle fracture surface and a wide bright band area. The excessive gap forms…

The positioning accuracy of NC machine tool refers to the position accuracy that can be achieved by the movement of each coordinate axis of the machine tool under the control of NC device. The positioning accuracy of NC machine tool can be understood as the motion accuracy of machine tool. Ordinary machine tools are fed manually, and the positioning accuracy mainly depends on the reading error, while the movement of NC machine tools is realized by digital program instructions, so the positioning accuracy depends on the NC system and mechanical transmission error. The movement of the moving parts of the…

The steel grade consists of numbers, letters and numbers. The letter symbols of non oriented and oriented silicon steel are "W" and "Q" respectively The thickness is placed in the front, the letter symbol is placed in the middle, and the iron loss value is placed in the back, such as 30q113. In oriented silicon steel, the letter symbols "g" and "Q" with high magnetic induction are placed together, such as 30qg113 The number after the letter represents 100 times the iron loss value (w / kg). The letter "g" indicates that it is tested at high frequency; If "g"…

Welding steel includes carbon steel for welding, alloy steel for welding and stainless steel for welding. Its brand is represented by adding the symbol "H" to the head of various welding steel brands. For example: "H08", "h08mn2si", "h1cr18ni9" For high-grade and high-quality welding steel, the symbol "a" is added at the end of the brand. For example: "H08A", "08mn2sia".

Bearing steel is divided into four categories: high carbon chromium bearing steel, carburized bearing steel, high carbon chromium stainless bearing steel and high temperature bearing steel. ① For high carbon chromium bearing steel, the symbol "g" is added at the head of the brand, but the carbon content is not indicated. The chromium content is expressed in thousands, and other alloy elements are expressed according to the alloy content of alloy structural steel. For example, the grade of bearing steel with an average chromium content of 1.50% is expressed as "GCr15". ② Carburized bearing steel adopts the brand representation method…

1. Allowable burr height of punching parts (1) limit value of burr of blanking parts It is not allowed that the burr of blanking parts exceeds a certain height. The limit value of burr height of stamping parts (mm) is shown in the table below.  (2) marking requirements for burrs in design drawings *Burr direction: burr side. *Parts requiring burring: coin or coin continue. Generally, do not press all the burrs on the fracture of the whole structural member, which will increase the cost. Try to use it in the following situations: the fracture exposed to the outside; Sharp edges…

Except that the symbol "SM" is added at the head, the representation method of plastic mold steel is the same as that of high-quality carbon structural steel and alloy tool steel. For example, the grade of carbon plastic die steel with an average carbon content of 0.45% is expressed as "sm45"; Alloy plastic die steel with average carbon content of 0.34%, chromium content of 1.70% and molybdenum content of 0.42% is indicated as "sm3cr2mo".

For non quenched and tempered mechanical structural steel, the symbols "YF" and "F" are respectively added at the head of the brand to represent free cutting non quenched and tempered mechanical structural steel and non quenched and tempered mechanical structural steel for hot forging. Other contents of the brand representation method are the same as those of alloy structural steel. For example: "yf35v", "f45v". Tool steel is divided into carbon tool steel, alloy tool steel and high-speed tool steel. ① Carbon tool steel is represented by standard chemical element symbols, symbols specified in Table 1 and Arabic numerals. Arabic numerals…

Free cutting steel is represented by standard chemical element symbols, symbols specified in Table 1 and Arabic numerals. Arabic numerals indicate the average carbon content (in tens of thousands). ① For sulfur free cutting steel and sulfur and phosphorus free cutting steel, the free cutting element symbol is not added after the symbol "Y" and Arabic numerals. For example, the grade of free cutting steel with an average carbon content of 0.15% is expressed as "Y15" ② For sulfur or sulfur and phosphorus free cutting steel with high manganese content, manganese element symbol shall be added after the symbol "Y"…