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

1. Minimize the number of parts Find ways to assemble parts. For example, many electronics enclosures use movable hinges instead of knuckle hinges. When routing, select a molded guide feature, or use a thermoformed guide (such as an old LazerTag gun). Speaking of minimizing the number of parts 2. Built in fasteners Whenever possible, build assembly features directly into the part instead of using screws. Snap fit is usually equally safe and can be assembled without tools. Sometimes screws are necessary, but the economical use of fasteners may consume up to 50% of the assembly labor. It should be noted that the snap fit may increase the cost of the injection mold, so it is important to design the part as injection friendly. 3. Use rubber roll parts It's great to be a product designer now. Many of our design problems have been solved! Previously, each thread had to be carefully designed, but now hundreds of standard diameters and pitches can be selected. This goes far beyond the basic nuts and bolts. Cots cover most of the functions of spring, pin, motor, microcontroller, sensor and gear design. This not only allows you to focus on unique challenges, but also means that the manufacturing team has the tools and skills to assemble your design. 4. Use the same parts throughout the design and product family Warning on rubber roller parts: it is not enough to use standard screws only. I have designed a robot component, one part of which has M5 x 10 mm socket head cap screws, the other part is M4. Design a 5 x 12 mm hex head screw on the other part. I have to switch between assembly tools frequently; It is easy to confuse which screw will go where, which is a very bad idea. Don't follow my example: Standardize parts not only on each component, but also on the entire product line. Where possible, a single tool should be used for the entire assembly. 5. Use modular design An important application of cots and ordinary parts is modularization, which decomposes the design into smaller sub assemblies and can be used for a variety of products. Think about your first computer: you can put some pre assembled parts together - the motherboard, the hard disk, the video card, it's easy. Another advantage is that modular design is not only good on the assembly line; They also help you extend the use time of the product on site by facilitating maintenance and upgrading.

Effect of surface treatment: 1. Improve the corrosion resistance and wear resistance of the surface, and slow down, eliminate and repair the change and damage of the material surface; 2. Make ordinary materials obtain surfaces with special functions; 3. Save energy, reduce costs and improve the environment. Classification of metal surface treatment processes Classification description of surface treatment process The surface modification technology changes the surface morphology, phase composition, microstructure, defect state and stress state of materials through physical and chemical methods to obtain the surface treatment process with required performance. The chemical composition of the material surface remains unchanged. The surface alloying technology enables the added materials to enter the matrix through physical methods to form an alloying layer to obtain the surface treatment process with required properties. The surface conversion film technology is a surface treatment process that chemically reacts the added materials with the matrix to form a conversion film to obtain the required performance. The surface replica technology is a surface treatment process that enables the added materials to form plating and coating on the substrate surface through physical and chemical methods to obtain the required performance. The matrix does not participate in the formation of the coating It can be divided into four categories: surface modification technology, surface alloying technology, surface conversion film technology and surface coating technology. 1、 Surface modification technology 1. Surface hardening Surface quenching refers to the heat treatment method of strengthening the surface of parts after austenitizing the surface layer with rapid heating without changing the chemical composition and central structure of steel. The main methods of surface quenching include flame quenching and induction heating, and the common heat sources include flame such as oxyacetylene or oxypropane. 2. Laser surface strengthening Laser surface strengthening is to use a focused laser beam to shoot at the workpiece surface, heat the extremely thin material on the workpiece surface to the temperature above the phase change temperature or melting point in a very short time, and then cool it in a very short time to harden the workpiece surface. Laser surface strengthening can be divided into laser transformation strengthening treatment, laser surface alloying treatment and laser cladding treatment. Laser surface hardening has small heat affected zone, small deformation and convenient operation. It is mainly used for locally strengthened parts, such as blanking die, crankshaft, cam, camshaft, spline shaft, precision instrument guide rail, high-speed steel cutter, gear and cylinder liner of internal combustion engine. 3. Shot peening Shot peening is a technology to spray a large number of high-speed moving projectiles onto the surface of parts, just like countless small hammers hitting the metal surface, so that the surface and sub surface of parts will have certain plastic deformation to achieve strengthening. Shot peening can improve the mechanical strength, wear resistance, fatigue resistance and corrosion resistance of parts; Commonly used for surface matting and descaling; Eliminate the residual stress of castings, forgings and weldments. 4. Rolling Rolling is a surface treatment process in which hard rollers or rollers are used to press the surface of a rotating workpiece at room temperature and move along the generatrix direction to plastically deform and harden the workpiece surface to obtain an accurate, smooth and strengthened surface or a specific pattern. It is often used for simple parts such as cylinder, cone and plane. 5. Wire drawing Wire drawing refers to the surface treatment method that makes the metal pass through the die forcibly under the action of external force, the metal cross section area is compressed, and the required shape and size of cross section area are obtained, which is called metal wire drawing process. Drawing can be made into straight lines, random lines, ripples and spiral lines according to the decorative needs. 6. Polishing Polishing is a finishing method to modify the surface of parts. Generally, only smooth surfaces can be obtained, and the original machining accuracy cannot be improved or even maintained. With different pre machining conditions, the Ra value after polishing can reach 1.6~0.008 μ m。 It is generally divided into mechanical polishing and chemical polishing. 2、 Surface alloying technology 1. Chemical surface heat treatment The typical process of surface alloying technology is chemical surface heat treatment, which is a heat treatment process that places the workpiece in a specific medium for heating and insulation, so that the active atoms in the medium penetrate into the workpiece surface to change the chemical composition and structure of the workpiece surface, and then change its performance. Compared with surface quenching, chemical surface heat treatment not only changes the surface structure of steel, but also changes its chemical composition. According to the different elements infiltrated, chemical heat treatment can be divided into carburization, ammoniation, multi-element penetration, penetration of other elements, etc. The chemical heat treatment process includes three basic processes: decomposition, absorption and diffusion. The two main methods of chemical surface heat treatment are carburizing and nitriding. Contrast carburizing and nitriding Objective To improve the surface hardness, wear resistance and fatigue strength of the workpiece, while maintaining good toughness of the heart. Improve the surface hardness, wear resistance, fatigue strength and corrosion resistance of the workpiece. The material contains 0.1-0.25% C low carbon steel. The higher the carbon, the lower the core. It is medium carbon steel containing Cr, Mo, Al, Ti and V. Common methods: gas carburizing, solid carburizing, vacuum carburizing, gas nitriding and ion nitriding Temperature 900~950 ℃ 500~570 ℃ The surface thickness is generally 0.5~2mm, not more than 0.6~0.7mr It is widely used in mechanical parts such as gears, shafts, camshafts, etc. of aircraft, automobiles and tractors. It is used for parts with high wear resistance and precision requirements, as well as heat resistance, wear resistance and corrosion resistance parts. Such as small shaft of instrument, light load gear and important crankshaft. 3、 Surface conversion film technology 1. Blackening and phosphating Blackening: The process of heating steel or steel parts to an appropriate temperature in air water vapor or chemicals to form a blue or black oxide film on their surface. It also becomes bluish. Phosphating: the process of workpiece (steel or aluminum or zinc parts) immersed in phosphating solution (some acid phosphate based solutions) to deposit a layer of water-insoluble crystalline phosphate conversion film on the surface, which is called phosphating. 2. Anodizing It mainly refers to the anodizing of aluminum and aluminum alloys. Anodizing refers to the process of immersing aluminum or aluminum alloy parts in acid electrolyte, acting as anode under the action of external current, and forming an anti-corrosion oxidation film firmly combined with the substrate on the surface of the parts. This oxide film has special characteristics such as protection, decoration, insulation and wear resistance. Before anodizing, polishing, degreasing, cleaning and other pre-treatments shall be carried out, followed by washing, coloring and sealing. Application: It is commonly used for the protective treatment of some special parts of automobiles and airplanes, as well as the decorative treatment of handicrafts and daily hardware products. 4、 Surface coating technology 1. Thermal spraying Thermal spraying is to heat and melt metal or non-metallic materials, and continuously blow and spray them onto the surface of the workpiece by compressed gas to form a coating firmly bonded with the substrate, so as to obtain the required physical and chemical properties from the surface of the workpiece. Thermal spraying technology can improve the wear resistance, corrosion resistance, heat resistance and insulation of materials. It has applications in almost all fields, including aerospace, atomic energy, electronics and other cutting-edge technologies. 2. Vacuum plating Vacuum plating is a surface treatment process for depositing various metal and non-metallic films on metal surfaces by evaporation or sputtering under vacuum conditions. By vacuum plating, a very thin surface coating can be obtained, which has the advantages of fast speed, good adhesion and less pollutants. Principle of Vacuum Sputtering Plating According to different processes, vacuum plating can be divided into vacuum evaporation plating, vacuum sputtering plating and vacuum ion plating. 3. Electroplating Electroplating is an electrochemical and redox process. Take nickel plating as an example: Dip the metal parts in the solution of metal salt (NiSO4) as the cathode, and use the metal nickel plate as the anode. After the DC power is turned on, the metal nickel coating will be deposited on the parts. Electroplating methods are divided into ordinary electroplating and special electroplating. 4. Vapor deposition Vapor deposition technology is a new type of coating technology, in which a vapor phase substance containing deposition elements is deposited on the material surface by physical or chemical methods to form a thin film. According to the different principles of the deposition process, the vapor deposition technology can be divided into physical vapor deposition (PVD) and chemical vapor deposition (CVD). Physical Vapor Deposition (PVD) Physical vapor deposition (PVD) refers to the technology of vaporizing materials into atoms, molecules or ions by physical methods under vacuum conditions, and depositing a thin film on the surface of materials through a vapor process. Physical deposition technology mainly includes vacuum evaporation, sputtering and ion plating. Physical vapor deposition has a wide range of suitable matrix materials and film materials; Simple process, material saving and pollution-free; The obtained film has the advantages of strong adhesion between film and substrate, uniform film thickness, compactness, less pinholes, etc. It is widely used in the fields of machinery, aerospace, electronics, optics and light industry to prepare wear-resistant, corrosion resistant, heat-resistant, conductive, insulating, optical, magnetic, piezoelectric, lubricating, superconducting and other films. Chemical Vapor Deposition (CVD) Chemical vapor deposition (CVD) is a method of forming metal or compound films on the substrate surface by the interaction of mixed gases and the substrate surface at a certain temperature. Because of its good wear resistance, corrosion resistance, heat resistance, electrical and optical properties, CVD films have been widely used in mechanical manufacturing, aerospace, transportation, coal chemical industry and other industrial fields.

Effect of surface treatment: 1. Improve the corrosion resistance and wear resistance of the surface, and slow down, eliminate and repair the change and damage of the material surface; 2. Make ordinary materials obtain surfaces with special functions; 3. Save energy, reduce costs and improve the environment. Classification of metal surface treatment processes Classification description of surface treatment process The surface modification technology changes the surface morphology, phase composition, microstructure, defect state and stress state of materials through physical and chemical methods to obtain the surface treatment process with required performance. The chemical composition of the material surface remains unchanged. The surface alloying technology enables the added materials to enter the matrix through physical methods to form an alloying layer to obtain the surface treatment process with required properties. The surface conversion film technology is a surface treatment process that chemically reacts the added materials with the matrix to form a conversion film to obtain the required performance. The surface replica technology is a surface treatment process that enables the added materials to form plating and coating on the substrate surface through physical and chemical methods to obtain the required performance. The matrix does not participate in the formation of the coating It can be divided into four categories: surface modification technology, surface alloying technology, surface conversion film technology and surface coating technology. 1、 Surface modification technology 1. Surface hardening Surface quenching refers to the heat treatment method of strengthening the surface of parts after austenitizing the surface layer with rapid heating without changing the chemical composition and central structure of steel. The main methods of surface quenching include flame quenching and induction heating, and the common heat sources include flame such as oxyacetylene or oxypropane. 2. Laser surface strengthening Laser surface strengthening is to use a focused laser beam to shoot at the workpiece surface, heat the extremely thin material on the workpiece surface to the temperature above the phase change temperature or melting point in a very short time, and then cool it in a very short time to harden the workpiece surface. Laser surface strengthening can be divided into laser transformation strengthening treatment, laser surface alloying treatment and laser cladding treatment. Laser surface hardening has small heat affected zone, small deformation and convenient operation. It is mainly used for locally strengthened parts, such as blanking die, crankshaft, cam, camshaft, spline shaft, precision instrument guide rail, high-speed steel cutter, gear and cylinder liner of internal combustion engine. 3. Shot peening Shot peening is a technology to spray a large number of high-speed moving projectiles onto the surface of parts, just like countless small hammers hitting the metal surface, so that the surface and sub surface of parts will have certain plastic deformation to achieve strengthening. Shot peening can improve the mechanical strength, wear resistance, fatigue resistance and corrosion resistance of parts; Commonly used for surface matting and descaling; Eliminate the residual stress of castings, forgings and weldments. 4. Rolling Rolling is a surface treatment process in which hard rollers or rollers are used to press the surface of a rotating workpiece at room temperature and move along the generatrix direction to plastically deform and harden the workpiece surface to obtain an accurate, smooth and strengthened surface or a specific pattern. It is often used for simple parts such as cylinder, cone and plane. 5. Wire drawing Wire drawing refers to the surface treatment method that makes the metal pass through the die forcibly under the action of external force, the metal cross section area is compressed, and the required shape and size of cross section area are obtained, which is called metal wire drawing process. Drawing can be made into straight lines, random lines, ripples and spiral lines according to the decorative needs. 6. Polishing Polishing is a finishing method to modify the surface of parts. Generally, only smooth surfaces can be obtained, and the original machining accuracy cannot be improved or even maintained. With different pre machining conditions, the Ra value after polishing can reach 1.6~0.008 μ m。 It is generally divided into mechanical polishing and chemical polishing. 2、 Surface alloying technology 1. Chemical surface heat treatment The typical process of surface alloying technology is chemical surface heat treatment, which is a heat treatment process that places the workpiece in a specific medium for heating and insulation, so that the active atoms in the medium penetrate into the workpiece surface to change the chemical composition and structure of the workpiece surface, and then change its performance. Compared with surface quenching, chemical surface heat treatment not only changes the surface structure of steel, but also changes its chemical composition. According to the different elements infiltrated, chemical heat treatment can be divided into carburization, ammoniation, multi-element penetration, penetration of other elements, etc. The chemical heat treatment process includes three basic processes: decomposition, absorption and diffusion. The two main methods of chemical surface heat treatment are carburizing and nitriding. Contrast carburizing and nitriding Objective To improve the surface hardness, wear resistance and fatigue strength of the workpiece, while maintaining good toughness of the heart. Improve the surface hardness, wear resistance, fatigue strength and corrosion resistance of the workpiece. The material contains 0.1-0.25% C low carbon steel. The higher the carbon, the lower the core. It is medium carbon steel containing Cr, Mo, Al, Ti and V. Common methods: gas carburizing, solid carburizing, vacuum carburizing, gas nitriding and ion nitriding Temperature 900~950 ℃ 500~570 ℃ The surface thickness is generally 0.5~2mm, not more than 0.6~0.7mr It is widely used in mechanical parts such as gears, shafts, camshafts, etc. of aircraft, automobiles and tractors. It is used for parts with high wear resistance and precision requirements, as well as heat resistance, wear resistance and corrosion resistance parts. Such as small shaft of instrument, light load gear and important crankshaft. 3、 Surface conversion film technology 1. Blackening and phosphating Blackening: The process of heating steel or steel parts to an appropriate temperature in air water vapor or chemicals to form a blue or black oxide film on their surface. It also becomes bluish. Phosphating: the process of workpiece (steel or aluminum or zinc parts) immersed in phosphating solution (some acid phosphate based solutions) to deposit a layer of water-insoluble crystalline phosphate conversion film on the surface, which is called phosphating. 2. Anodizing It mainly refers to the anodizing of aluminum and aluminum alloys. Anodizing refers to the process of immersing aluminum or aluminum alloy parts in acid electrolyte, acting as anode under the action of external current, and forming an anti-corrosion oxidation film firmly combined with the substrate on the surface of the parts. This oxide film has special characteristics such as protection, decoration, insulation and wear resistance. Before anodizing, polishing, degreasing, cleaning and other pre-treatments shall be carried out, followed by washing, coloring and sealing. Application: It is commonly used for the protective treatment of some special parts of automobiles and airplanes, as well as the decorative treatment of handicrafts and daily hardware products. 4、 Surface coating technology 1. Thermal spraying Thermal spraying is to heat and melt metal or non-metallic materials, and continuously blow and spray them onto the surface of the workpiece by compressed gas to form a coating firmly bonded with the substrate, so as to obtain the required physical and chemical properties from the surface of the workpiece. Thermal spraying technology can improve the wear resistance, corrosion resistance, heat resistance and insulation of materials. It has applications in almost all fields, including aerospace, atomic energy, electronics and other cutting-edge technologies. 2. Vacuum plating Vacuum plating is a surface treatment process for depositing various metal and non-metallic films on metal surfaces by evaporation or sputtering under vacuum conditions. By vacuum plating, a very thin surface coating can be obtained, which has the advantages of fast speed, good adhesion and less pollutants. Principle of Vacuum Sputtering Plating According to different processes, vacuum plating can be divided into vacuum evaporation plating, vacuum sputtering plating and vacuum ion plating. 3. Electroplating Electroplating is an electrochemical and redox process. Take nickel plating as an example: Dip the metal parts in the solution of metal salt (NiSO4) as the cathode, and use the metal nickel plate as the anode. After the DC power is turned on, the metal nickel coating will be deposited on the parts. Electroplating methods are divided into ordinary electroplating and special electroplating. 4. Vapor deposition Vapor deposition technology is a new type of coating technology, in which a vapor phase substance containing deposition elements is deposited on the material surface by physical or chemical methods to form a thin film. According to the different principles of the deposition process, the vapor deposition technology can be divided into physical vapor deposition (PVD) and chemical vapor deposition (CVD). Physical Vapor Deposition (PVD) Physical vapor deposition (PVD) refers to the technology of vaporizing materials into atoms, molecules or ions by physical methods under vacuum conditions, and depositing a thin film on the surface of materials through a vapor process. Physical deposition technology mainly includes vacuum evaporation, sputtering and ion plating. Physical vapor deposition has a wide range of suitable matrix materials and film materials; Simple process, material saving and pollution-free; The obtained film has the advantages of strong adhesion between film and substrate, uniform film thickness, compactness, less pinholes, etc. It is widely used in the fields of machinery, aerospace, electronics, optics and light industry to prepare wear-resistant, corrosion resistant, heat-resistant, conductive, insulating, optical, magnetic, piezoelectric, lubricating, superconducting and other films. Chemical Vapor Deposition (CVD) Chemical vapor deposition (CVD) is a method of forming metal or compound films on the substrate surface by the interaction of mixed gases and the substrate surface at a certain temperature. Because of its good wear resistance, corrosion resistance, heat resistance, electrical and optical properties, CVD films have been widely used in mechanical manufacturing, aerospace, transportation, coal chemical industry and other industrial fields.

The main function of shaft parts is to support other rotating parts to rotate and transmit torque, and at the same time, it is connected with the machine frame through bearings. It is one of the important parts of the machine. Shaft parts are rotary parts, whose length is greater than the diameter, and are usually composed of cylindrical surface, conical surface, internal hole, thread and corresponding end face. The shaft often has splines, keyways, transverse holes, grooves, etc. According to functions and structural shapes, shafts have many types, such as smooth shaft, hollow shaft, half shaft, stepped shaft, spline shaft, crankshaft, camshaft, etc., which play a supporting, guiding and isolating role. 1. View representation 1) Shaft parts are mainly revolving bodies, which are generally processed on lathes and grinders. They are usually expressed in a basic view. The axis is horizontally placed, and the small head is placed on the right for easy viewing during processing. 2) It is better to draw a full shape with the single key groove on the shaft facing forward. 3) For the structure of shaft holes, keyways, etc., it is generally represented by partial sectional view or sectional drawing. The removed profile in the profile can not only clearly express the structure shape, but also conveniently mark the dimensional tolerance and geometric tolerance of the relevant structure. 4) Small structures such as undercuts and fillets are represented by local enlarged drawings. 2. Dimension ① The main datum in the length direction is the main end face (shoulder) installed. The two ends of the shaft are generally used as the measurement datum, and the axis is generally used as the radial datum. ② The main dimensions shall be indicated first, and the length dimensions of other multi segments shall be indicated according to the turning sequence. Most of the local structures on the shaft are located near the shaft shoulder. ③ In order to make the marked dimensions clear and easy to see the drawing, the internal and external dimensions on the sectional view should be marked separately, and the dimensions of different processes such as turning, milling and drilling should be marked separately. ④ The chamfer, chamfer, undercut, grinding wheel overtravel groove, keyway, central hole and other structures on the shaft shall be marked after referring to the dimensions of relevant technical data. 3. Materials of shaft parts ① The common materials for shaft parts are 35, 45 and 50 high-quality carbon structural steel, among which 45 steel is the most widely used, and is generally subject to quenching and tempering treatment, with hardness of 230~260HBS. ② Q255, Q275 and other carbon structural steels can be used for shafts that are not very important or have small load. ③ Shafts with large force and high strength requirements can be quenched and tempered with 40Cr steel, with hardness of 230~240HBS or hardened to 35~42HRC. ④ For shaft parts working under high-speed and heavy load conditions, 20Cr, 20CrMnTi, 20Mn2B and other alloy structural steels or 38CrMoAIA high-quality alloy structural steels shall be selected. After carburizing and quenching or nitriding treatment, these steels not only have high surface hardness, but also greatly improve their central strength, with good wear resistance, impact toughness and fatigue strength. ⑤ Nodular cast iron and high-strength cast iron are often used to manufacture shafts with complex shape and structure due to their good casting performance and vibration reduction performance. Especially, the RE Mg ductile iron in our country has good impact resistance and toughness, as well as the advantages of antifriction and vibration absorption, and low sensitivity to stress concentration. It has been applied to important shaft parts in automobiles, tractors, and machine tools. ⑥ 45 and 50 medium carbon steels with tensile strength no less than 600MPa are generally used to obtain high hardness lead screws without final heat treatment. The lead screw of precision machine tool can be made of carbon tool steel T10 and T12. The screw rod with high hardness obtained through the final heat treatment can guarantee the hardness of 50-56HRC when it is made of CrWMn or CrMn steel. 4. Technical requirements for shaft parts ① Dimensional accuracy The dimension accuracy of main journal diameter is generally IT6~IT9, and the precision is IT5. For each step length of stepped shaft, the tolerance shall be given according to the use requirements, or the tolerance shall be allocated according to the requirements of the assembly dimension chain. ② Geometric accuracy The shaft is usually supported on the bearing by two journals, which are the assembly datum of the shaft. The geometric accuracy (roundness, cylindricity) of the supporting journal shall be generally required. The geometrical form tolerance of journal with general accuracy shall be limited to the diameter tolerance range, that is, E shall be marked after the diameter tolerance according to the tolerance requirements, and if the requirements are higher, the allowable tolerance value shall be marked (that is, the shape tolerance value shall be marked with a frame in addition to E after the dimensional tolerance). ③ Mutual position accuracy The coaxiality of mating journals (journals for assembling transmission parts) in shaft parts relative to the supporting journals is a general requirement for their mutual position accuracy. Because of the convenience of measurement, it is usually represented by radial circular runout. The radial circular runout of the common fitting precision shaft to the supporting journal is generally 0.01~0.03mm, and that of the high-precision shaft is 0.001~0.005 mm. In addition, there are requirements for perpendicularity between axial positioning end face and axis line. ④ Surface roughness Generally, the surface roughness of the supporting journal is Ra0.16~0.63um, and the surface roughness of the matching journal is Ra0.63~2.5um. For general parts and typical parts, there are generally corresponding tables and data available for the above items.

Concentrated solar power (CSP) is distinguished from other renewable energy sources by using thermal energy storage (TES) and conventional heat engines to dispatch energy on demand. However, in order to achieve a competitive levelized cost of energy (LCOE), CSP system costs must be reduced.   Recent studies of several triple periodic minimum surfaces (TPMS) and periodic nodal surfaces as heat exchangers have shown that Schwarz-D TPMS surfaces have excellent heat transfer properties. group IV-VI transition metal carbides, borides and composites are the most common ultra-high temperature ceramic (UHTC) materials. Prior to the introduction of additive manufacturing, TPMS devices were difficult to fabricate. Compared to previous methods of manufacturing ceramic TPMS structures, adhesive jet additive manufacturing is developing as a promising and scalable method of forming ceramics. Adhesive jet printing has been used to fabricate UHTC heat exchanger plates in combination with reactive infiltration, but has not been used to fabricate UHTC TPMS structures sintered to high relative densities. Lessons learned from sintering nanomaterials suggest that low raw density during molding is not always an issue and that achieving good uniformity is more important.   In this study, the authors demonstrated the feasibility of adhesive spray additive manufacturing of UHTC-TPMS structures by sintering and printing empty candidates. Components with at least 92% theoretical relative density were created, which are also part of the TPMS. ​ The target density represents the transition from the intermediate to the final stage of sintering, which is necessary to sinter complex near-net forms to full density and suppress gas permeation using the sintering HIP technique. The purpose of the demonstration TPMS part was to see if the printing and sintering parameters obtained from the test specimens were applicable to the complex geometry that would be used for the heat exchanger design. The team printed 9 cm 3 cubic TPMS pieces and sintered them without distorting or breaking them. Design topologies, materials and fabrication advances are presented to achieve best-in-class performance in molten chloride salts in CSP heat exchangers.   The researchers discuss the use of a combination of binder jet additive manufacturing and sintering to build ZrB2-MoSi2-based UHTC-TPMS cells. Because of its good processing characteristics and quality, ZrB2-MoSi2 was intentionally chosen as an invalid candidate to demonstrate the feasibility of a UHTC-TPMS heat exchanger until the best UHTC material for this application could be determined.   It was shown that adhesive spray additive manufacturing can be used to print and sinter UHTC-TPMS structures. In order to effectively limit distortion, it was found that a space-limiting strategy was needed. It was able to use conventional powder feedstock with a d50 of approximately 2-3 m, the same size used in conventional UHTC processing. These materials are sintered to a theoretical relative density of 92-98%, which is sufficient to prevent heat exchanger fluids from passing through the walls, separating the two regions and allowing for thermal isostatic pressure when higher densities are required. ​

There are many common failures of rotating machinery, including steam excitation, mechanical loosening, rotor blade breakage and shedding, friction, shaft cracking, mechanical deviation and electrical deviation, etc.     Steam Excitation There are usually two reasons for steam excitation, one is due to the opening sequence of the regulating valve, the high pressure steam produces a force that lifts the rotor upward, thus reducing the bearing specific pressure and thus destabilizing the bearing; the second is due to the uneven radial clearance at the top of the lobe, which produces a tangential component force, as well as the tangential component force generated by the gas flow in the end shaft seal, causing the rotor to produce self-excited vibration. Steam excitation generally occurs in the high-pressure rotor of high-power turbines, when steam oscillation occurs, the main characteristic of vibration is that the vibration is very sensitive to the load, and the frequency of vibration coincides with the first-order critical rotor speed frequency. In the vast majority of cases (steam excitation is not too serious) vibration frequency to half-frequency components. In the event of steam oscillation, sometimes it is useless to change the bearing design, only to improve the design of the through-flow part of the steam seal, adjust the installation gap, significantly reduce the load or change the main steam into the steam regulating valve opening sequence in order to solve the problem. Mechanical loosening There are usually three types of mechanical loosening. The first type of loosening refers to the presence of structural looseness in the base, table and foundation of the machine, or poor cement grouting and deformation of the structure or foundation. The second type of loosening is mainly caused by the loosening of the machine base fixing bolts or cracks in the bearing seat. The third type of loosening is caused by the unsuitable fit between the parts, when the loosening is usually the loosening of the bearing tile pillow in the bearing cover, excessive bearing clearance or the existence of loosening of the impeller on the rotating shaft. The vibration phase of this loosening is very unstable and varies greatly. The vibration when loose has a directional nature, in the direction of loosening, due to the decline in binding force, will cause the vibration amplitude to increase. Rotor broken blade and shedding Rotor broken blade, parts or scale layer off the failure mechanism and dynamic balance failure is the same. Its characteristics are as follows. ① vibration of the through-frequency amplitude in the instant sudden increase. ② the characteristic frequency of vibration is the rotor's operating frequency. ③The phase of the working frequency vibration will also change abruptly. Friction When the rotating parts of rotating machinery and fixed parts come into contact, radial friction or axial friction of moving and static parts will occur. This is a serious failure, it may lead to the entire machine damage. There are usually two cases when friction occurs. The first is partial friction, when the rotor only accidentally touches the stationary part, while maintaining contact only in a fractional part of the rotor into the moving whole cycle, which is usually relatively less destructive and dangerous for the machine as a whole. The second, especially for the destructive effect and danger of the machine is the more serious case, which is the full circumferential ring friction, sometimes called "full friction" or "dry friction", they are mostly generated in the seal. When circumferential ring friction occurs, the rotor maintains continuous contact with the seal, and the friction generated at the point of contact can lead to a dramatic change in the direction of rotor motion, from a forward positive motion to a backward negative motion. Friction is so harmful that even a short period of friction between the rotor shaft and the shaft shank can have serious consequences. Shaft Cracking The cause of rotor cracks is mostly fatigue damage. Rotating machinery rotor if improperly designed (including improper material selection or unreasonable structure) or improper processing methods, or an old unit with long operating time, due to stress corrosion, fatigue, creep, etc., will produce micro-cracks at the location of the original rotor inciting point, coupled with the continuous action of the larger and changing torque and radial load, micro-cracks gradually expand and eventually develop into macro-cracks. The original initiation points are usually found in areas of high stress and material defects, such as stress concentrations on the shaft, tool marks and scratches left during machining, and areas with minor material defects (e.g., slagging). At the initial stage of cracking in the rotor, the expansion rate is relatively slow and the growth of radial vibration amplitude is relatively small. But the crack expansion speed will accelerate with the deepening of the crack, the corresponding will appear amplitude rapidly increased phenomenon. In particular, the rapid rise of the diphthong amplitude and its phase change can often provide diagnostic information of cracks, so the trend of diphthong amplitude and phase change can be used to diagnose rotor cracks. Mechanical and electrical deviations The reason for the mechanical and electrical deviations in the vibration signal is determined by the operating principle of the non-contact eddy current sensor. Cutting imperfectly machined shaft surfaces (elliptical or different shafts) produce an indication of sinusoidal dynamic motion with a frequency that coincides with the rotational frequency of the rotating part. The cause of imperfectly machined cutting surfaces is usually generated by worn bearings in the machine tool where the final machining took place, dulled tools, too fast feeds or other defects in the machine tool, or by the wear of the lathe thimbles. Unsmooth or other defects on the journal surface, such as scratches, pits, burrs, rust scars, etc. will also produce deviation output. The easiest way to check this error condition is to check the runout value of the journal with a percentage meter. The fluctuation value of the percentage meter will confirm the presence of error on the measured surface as observed by the non-contact eddy current sensor. The measured surface of the journal should be protected as carefully as the journal surface of a plain bearing. When lifting, the cable used should avoid the area of the surface measured by the sensor, and the support frame for storing the rotor should ensure that it does not cause scratches, dents, etc. on the journal surface. In general, eddy current sensors work satisfactorily in the magnetic field present as long as the field is uniform or symmetrical. If one surface area on the shaft has a high magnetic field while the rest of the surface is non-magnetic or only has a low magnetic field, this can cause electrical deviations. This is due to the change in sensor sensitivity caused by the magnetic field from the eddy current sensor acting on such journal surfaces. In addition, uneven plating, uneven rotor material, etc. can also cause electrical deviations which cannot be measured and confirmed with a percentage meter.  

In machinery and equipment, sliding bearings are used more frequently, but they are prone to wear. In the actual application process, the composition of the oil sample can be monitored and analyzed using iron spectrum analysis, so that abnormalities can be found in time to facilitate timely troubleshooting by machinery maintenance personnel. Although vibration analysis can also effectively detect the situation of mechanical operation failure, but wear failure is more difficult to troubleshoot, and the sliding bearing wear at the beginning, its working condition is still in the normal state, and wear will not affect the normal operation of other parts, so that the overall mechanical vibration parameters may be in the normal parameter range, and thus can not effectively predict the obstacles. Different from the vibration analysis method, the iron spectrum analysis method can effectively detect a large number of abrasive particles, so as to provide a scientific basis for early troubleshooting. However, in practical application, since ferro-spectroscopy is mainly sensitive to ferromagnetic substances, but is slow to respond to non-magnetic substances, it may fail if the amount of non-magnetic nature substances is not large. This shows that the application of iron spectrum analysis to predict the wear failure of sliding bearings is difficult. In this regard, enterprises should actively strengthen the research on failure prediction technology, carefully study the causes of main exhaust sliding bearing wear, accumulate experience, and propose effective treatment measures to prevent the occurrence of failure, so as to reduce the event of sliding bearing failure, reduce the economic loss due to failure, and improve the economic efficiency of enterprises.

Nowadays, mechanization and automation have become the mainstream of industry development. Machine and equipment composed of various parts are prone to problems in the application process due to the lack of coordination or cooperation of certain parts. Raw material specifications, properties, material use, machine vibration, clamping pressure or looseness, elastic deformation process system, worker operation, testing methods, and inspector errors all have an impact on the quality of processed products. When we talk about the quality of working prototypes, it is not difficult to think of the following 5 main factors. I. , operator As cnc machine functions become more and more complex, the level of programming and operator varies greatly . Combining superior human skills with computer information technology allows for maximum utilization of the machine. To do this, the machine operator must be familiar with the equipment performance. If the operator does not know enough about the performance of the equipment, he or she may operate it incorrectly, thus accelerating the wear and tear of machine components or even causing damage to the machine. Therefore, this will require a lot of maintenance costs and longer maintenance time. cnc machine tool operators in order to restore the original accuracy of the equipment, must understand and master the machine manual and its operating precautions to achieve civilized production and safe processing. To strengthen the skills training of the whole staff of processing production, reasonable arrangement of primary and secondary processing positions, improve the quality awareness of personnel and sense of work responsibility. II. Machine A complete cnc machining system consists of machine tools, workpieces, fixtures and tools. The machining accuracy is related to the accuracy of the whole process system. Various errors of the process system will be reflected in different forms as machining tolerances under different circumstances.  cnc machine accuracy is an important factor affecting the quality of prototype parts. When the machine accuracy is poor, some parts are damaged or the clearance of each part is not adjusted properly, various defects will appear in the prototype during cnc machining. Therefore, we must not only choose the right turning angle, the right cutting volume and cnc machining method, but also understand the impact of machine accuracy on the quality of cnc machining. The maintenance of the machine directly affects the processing quality and productivity of the prototype. In order to ensure the working accuracy and extend its working life, all machines must be properly maintained. Usually after 500 hours of machine operation, a level of maintenance is required. Three, cnc machining methods There are many kinds of cnc machining methods, and cutting machining is one of the most common ones. In the cutting process, the workpiece is subjected to changes in force and heat, and the physical and mechanical properties of the metal material are slightly hardened, so the choice of the tool plays an important role. In general, the material used to make the tool should be selected according to the material of the workpiece to be machined. Otherwise, the surface of the workpiece will form spurs related to the tool, which will easily increase the roughness of the workpiece and at the same time reduce the surface quality. In addition to the tool factor, the cutting environment and cutting processing conditions, such as cutting volume, cutting lubrication, etc. also have an impact on the machining quality. In the cnc machining process, the machining system is the overall commander of the entire cutting process. All the cnc machining process is executed according to the system, so the accuracy and rigidity of the machining system is also one of the main factors affecting the machining quality. There are two principles of machining process arrangement. Machining decentralization: manufacturing complex parts with multiple processes, broken down into multiple machine processing. Machining concentration: compound machine functions, such as cnc turning and milling, laser ultrasonic vibration processing, grinding, five-axis linkage, etc. All processes are completed by one machine. According to the structural analysis of the workpiece, the use of different processing methods is also an important factor affecting the quality of machining. IV. Materials Machined materials are generally divided into plastic and metal. Each material has its own characteristics. It is also important to choose the right material according to the requirements of the workpiece and the application during machining. The consistency of the material should be good, otherwise the quality of the same part may be different. With the right material hardness, try to ensure that the material is not deformed. These are important prerequisites for assessing quality.   V. Inspection After the machine has finished machining the workpiece, inspection is the last key step before delivery to the customer. Machining inspection generally requires attention to two aspects. 1. inspection procedures - the inspection process, including the inspection process, as well as relevant regulations, systems, standards, etc.. In general, the inspection process is the inspection in the production process and the way to intervene, including the first inspection, self-inspection, mutual inspection and full-time inspection. 2. Inspection methods - refers to how to test and inspection standards. The inspection of machined parts is generally based on mechanical drawings, through inspection instruments and gauges for product inspection. Traditional machining inspection and more modern machining inspection Traditional machining inspection instruments include micrometers, percentages, vernier cards, planes, rulers, levels, and a variety of plug gauges, ring gauges, etc.. More modern machining inspection instruments are optical collimator, projector, three-dimensional measuring instrument, latitude and longitude meter, laser detector, etc. Qualified mechanical product inspector must master the knowledge of inspection instruments and gauges related to the unit product. In the process of cnc machining, to control the quality of processing, it is necessary to understand and analyze the various factors affecting the quality of processing does not meet the requirements, while taking effective technical measures to overcome. With the continuous improvement of modern production levels, the requirements for the quality of machined products are becoming higher and higher. Only by taking comprehensive measures for quality control can we ultimately achieve the purpose of improving the service life of the equipment and increasing the service life of the equipment, taking into account the economic benefits and energy saving in the processing process. At the same time, to ensure the quality of machining, in order to promote the long-term stable development of the machining industry.

CNC machining became the industry standard in the late 1960's and has since been widely chosen to produce a wide variety of high precision parts. Using the best CNC machines or computer numerical control machines, it is possible to create many types of complex parts and assemblies that would otherwise be difficult to do with traditional machining processes. When it comes to precision machining services, many customers have this question in mind, which materials are suitable for machining? There is a wide range of materials that are compatible with CNC technology. This article here lists some of them.   Popular materials chosen by precision machining service providers   High-precision CNC precision machining of parts can be made from a variety of materials, as listed below. Aluminum. Considered exotic in manufacturing, aluminum is probably the most widely used material for CNC milling. The ability to machine faster than other materials makes aluminum a more useful material for CNC machining. Because it is lightweight, non-magnetic, corrosion resistant and inexpensive, aluminum is widely used in the production of aircraft components, automotive parts, bicycle frames and food containers.   Stainless Steel. Stainless steel alloys are unaffected by most stains and rusts. The material is prized for its strength and corrosion resistance and can be used for anything from surgical equipment to electronic hardware. Stainless steel is a very versatile material that is relatively light and durable, expanding its use in a variety of industries.   Carbon steels. Carbon steel is also one of the popular materials to consider for CNC machining. It is available in a variety of formulations from which you can choose according to the requirements of your application. This material is mainly used for CNC machining due to its durability, safety, long shelf life, affordability and environmental friendly nature. Brass. Widely considered one of the simplest and most cost-effective materials for precision machining services, brass is selected for the manufacture of complex parts requiring sophisticated functionality. Easy to machine, smooth and with a clean surface, brass is used in the manufacture of medical devices, consumer products, electronic hardware and contacts, accessories, commercial products and more.   Titanium. Titanium is resistant to heat and corrosion, making it a viable choice for many industrial applications. Titanium is unaffected by salt and water and is widely used in the manufacture of medical implants, aircraft components and jewelry, among others.   Magnesium. Magnesium is the lightest structural metal widely used by precision machining service providers. Magnesium has excellent machinability, strength and robustness making it well suited for multiple industrial applications.   Monel. There is an unprecedented demand for CNC machined Monel alloy parts. It is primarily used in applications that are exposed to corrosive environments and require higher strength. There are very few CNC machining shops that specialize in Monel alloys because of the difficulty of machining and the high level of experience required.   Inconel. It is a nickel-based high-temperature alloy that has gained popularity in recent years due to its many beneficial properties. Inconel parts are suitable for environments where they may suffer from water corrosion or oxidation. It is also well suited for applications where parts may be subjected to extreme pressure and heat.   In addition to the materials listed above, there are several other materials that are compatible with precision CNC machining processes. These include cemented carbide, tungsten, palladium, Inva alloy, nickel, niobium, alloy steel, beryllium, cobalt, iridium and molybdenum. It is important to select the right material after considering the application areas it will be used in, other machining activities, etc. Choosing the right material from multiple options is critical, as it determines the success of the application.

Since the damage of materials is divided into two forms of brittle fracture and yielding according to their physical nature, the strength theories are divided into two categories accordingly, and the following are the four strength theories commonly used at present.   1, the maximum tensile stress theory (the first strength theory that is the maximum principal stress) This theory is also known as the first strength theory. This theory that the main cause of damage is the maximum tensile stress. Regardless of the complex, simple stress state, as long as the first main stress reaches the strength limit of the one-way stretch, that is, fracture.   Damage form: fracture.   Damage condition: σ1 = σb   Strength condition: σ1 ≤ [σ]   Experiments have proved that this strength theory better explains the phenomenon of fracture of brittle materials such as stone and cast iron along the cross section where the maximum tensile stress is located; it is not suitable for cases without tensile stresses such as one-way compression or three-way compression.   Disadvantage: The other two main stresses are not considered.   Use range: Applicable to brittle materials under tension. Such as cast iron tensile, torsion. 2、Maximum elongation line strain theory (second strength theory i.e. maximum principal strain) This theory is also called the second strength theory. This theory believes that the main cause of damage is the maximum elongation line strain. Regardless of the complex, simple stress state, as long as the first main strain reaches the limit value of one-way stretching, that is, fracture. Damage assumption: The maximum elongation strain reaches the limit in simple tension (it is assumed that until fracture occurs it can still be calculated using Hooke's law).   Damage form: fracture.   Brittle fracture damage condition: ε1= εu=σb/E   ε1=1/E[σ1-μ(σ2+σ3)]   Damage condition: σ1-μ(σ2+σ3) = σb   Strength condition: σ1-μ(σ2+σ3) ≤ [σ]   It is proved that this strength theory better explains the phenomenon of fracture along the cross section of brittle materials such as stone and concrete when they are subjected to axial tension. However, its experimental results only agree with few materials, so it has been rarely used.   Disadvantage: It cannot widely explain the general law of brittle fracture damage.   Scope of use: Suitable for stone and concrete axially compressed. 3, maximum shear stress theory (the third strength theory that Tresca strength) This theory is also known as the third strength theory. This theory that the main cause of damage is the maximum shear stress Regardless of the complex, simple stress state, as long as the maximum shear stress reaches the ultimate shear stress value in one-way stretching, that is, yielding. Damage assumption: complex stress state danger sign maximum shear stress reaches the limit of the material simple tensile, compressive shear stress.   Damage form: yielding.   Damage factor: maximum shear stress.   τmax = τu = σs / 2   Yield damage conditions: τmax=1/2(σ1-σ3 )   Damage condition: σ1-σ3 = σs   Strength condition: σ1-σ3 ≤ [σ]   Experimentally, it is proved that this theory can better explain the phenomenon of plastic deformation in plastic materials. However, the members designed according to this theory are on the safe side because the influence of 2σ is not considered.   Disadvantage: No 2σ effect.   Scope of use: Suitable for the general case of plastic materials. The form is simple, the concept is clear, and the machinery is widely used. However, the theoretical result is safer than the actual one. 4, shape change specific energy theory (the fourth strength theory that von mises strength) This theory is also known as the fourth strength theory. This theory that: no matter what stress state the material is in, the material mechanics of the material yielded because the shape change ratio (du) reached a certain limit value. This can be established as follows   Damage condition: 1/2(σ1-σ2)2+2(σ2-σ3)2+(σ3-σ1)2=σs   Strength condition: σr4= 1/2(σ1-σ2)2+ (σ2-σ3)2 + (σ3-σ1)2≤ [σ]   Based on test data for thin tubes of several materials (steel, copper, aluminum), it is shown that the shape change specific energy theory is more consistent with the experimental results than the third strength theory.   The unified form of the four strength theories: so that the equivalent stress σrn, has the unified expression for the strength condition   σrn≤[σ].   Expression for equivalent stress.   σr1=σ 1≤[σ]   σr2=σ1-μ(σ2+σ3)≤[σ]   σr 3= σ1-σ3≤ [σ]   σr4= 1/2(σ1-σ2)2+(σ2-σ3)2+(σ3-σ1)2≤ [σ]