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1. Density and relative density Density refers to the mass contained in the unit volume of a substance. The unit is milligram / m3 (mg / m3) or kilogram / m3 (kg / m3) or gram / cm3 (g / cm3). Relative density refers to the ratio of the density of a substance to the density of a reference substance under their respective specified conditions. The symbol is D, dimensionless. The general reference material is air or water: when air is used as the reference material, the density of dry air under the standard state (0 ℃ and 101.325kpa) is…

1、 Concept of surface roughness Surface roughness refers to the roughness of the machined surface with small spacing and small peaks and valleys. The distance (wave distance) between two wave peaks or two wave valleys is very small (below 1mm), which belongs to micro geometric error. Specifically, it refers to the height and spacing (s) of micro peak and valley (z). Generally, it is divided according to s: s ＜ 1mm is the surface roughness; 1 ≤ s ≤ 10mm refers to waviness; S > 10mm is F shape. 2、 Comparison table of vdi3400, RA and Rmax The national standard…

The geometric characteristics of machined surface include surface roughness, surface waviness and surface processing texture. Surface roughness is the basic unit of geometric features of machined surface. When machining the workpiece surface with metal cutting tools, the surface roughness is mainly affected by geometric factors, physical factors and machining process factors. 1. Geometric factors: From the perspective of geometry, the shape and geometric angle of the tool, especially the arc radius of the tool tip, the main deflection angle, the auxiliary deflection angle and the feed rate in the cutting parameters, have a great influence on the surface roughness. 2.…

Abstract: the main valve sleeve hole of shell parts in aviation hydraulic products has the characteristics of large length diameter ratio. This kind of parts are mainly made of high-strength aluminum alloy. The inner hole processing belongs to typical deep hole processing. Its dimensional tolerance, geometric tolerance and other requirements are strict, the surface roughness value is low, and there are many restrictions on the structure of machining tools, which brings great difficulties to the finish machining of parts. By studying the process route arrangement, processing parameters and processing tool selection of shell deep hole processing, and through many tests…

The vibration and vibration of the tool in lathe machining cause chattering lines on the surface of the workpiece, and the rework rate and scrap rate are high. The vibration of machine tool is generally caused by the insufficient rigidity of any or more of the three systems of machine tool, workpiece and tool. Let's first talk about the aspects that need to be investigated when vibration and vibration occur. A. Troubleshooting points for workpieces:  (1) . cylindrical turning of slender shafts; In general, the distance between the cutting point and the clamping point is easy to vibrate if the…

Summary: Extrusion die casting and die forging is a kind of continuous casting and continuous forging technology. This paper introduces the technology and equipment of multi-directional extrusion die casting die forging and the technical realization principle of the invention of die, points out the shortcomings of unidirectional extrusion die casting die forging technology and the problems existing in the die locking resistance mechanism of traditional casting device, and puts forward a recommended scheme for the development of equipment with high forging pressure and high die locking force. The development trend of multi-directional extrusion die casting die forging technology is introduced.…

If the cross hole processing of steel parts is completed by drill, it is a headache for many tool manufacturers and engineers. After research and development, antimar tool has finally solved this problem and provided an optimized process scheme and special drill bit for this kind of processing. In the drilling process of cross holes of steel parts, the impact at the broken hole leads to uneven stress on the bit, and the bit is prone to edge collapse, knife breakage and rapid wear. Therefore, tool users have high cost, low efficiency, and it is difficult to stably control the…

1、 What is jogging? Slow wire is a CNC machine tool that uses continuously moving fine metal wire (called electrode wire, generally copper wire) as electrode to conduct pulse spark discharge on the workpiece, produce a high temperature of more than 6000 degrees, etch the metal and cut the workpiece. The principle of slow wire processing is that there is a gap between the on-line electrode and the workpiece, and the metal is removed by continuous discharge. 2、 Development status of slow wire processing technology: With the continuous improvement of manufacturing accuracy and surface quality requirements of precision, complex and…

Due to the complexity of NC machining (such as different machine tools, different materials, different cutting tools, different cutting methods, different parameter settings, etc.), it must take a long time to engage in NC machining (whether machining or programming) to reach a certain level. This treasure is summarized by engineers in the long-term actual production process, related to the selection of NC machining processes, processes and common tool parameters A summary of some experience in monitoring in the processing process can be used for your reference. Q1: how to divide the processing procedures? Answer: the division of NC machining processes…

In China, Volkswagen has always been regarded as a god car. This is not only because of the skyward sales of Volkswagen cars. The two joint ventures SAIC Volkswagen and FAW Volkswagen have long occupied the top two in the sales ranking of joint venture car enterprises, but also because Volkswagen has too many fans in China. Their praise of Volkswagen's car technology has reached a crazy level, which led to the birth of a large number of folk believers. Speaking of Volkswagen technology, I believe that many people, like the author, think of the letters TSI and DSG at…