July 2019 – Page 29 – CNC Machining & Turning, Milling, Metal parts

The structure and operation of the pipe bending machine

(1) wheel model (BENDING DIE)
Install: A, take the wheel die retaining nut in reverse clockwise direction (FIG-7 (1)). B, put the wheel die, and then lock the nut to lock the nut.
(2) clamping die (CLAMP DIE)
Installation: A, pull out clamping die fixing centering shaft (FIG-7 (2)). B. Put the clamping die in, and then insert the fixed mandrel.
Adjust: A, fix the clamping seat (FIG-7 (3) to relax, and then put the control panel in manual mode, press the pinch button (FIG-7 (3) to the end of the clamping line. ” At this time, there should be clearance between the clamping die of the wheel die, and the adjusting screw can be clamped by the mold base (FIG-7 (4) to adjust).
B, adjust the clamping screw adjustment screw (FIG-7 (4), so that the clamping die and wheel mold are fully sealed.
C, press the back button (FIG-4 (6)) to back the clamping die, then rotate the clamping adjusting screw (FIG-7 (4)) in clockwise direction about 1/2-1/4 circle.
D, then fix the clamping nut (FIG-7 (3)).
(3) guide mode (PRESSURE DIE)
Installation: A, remove the guide screw (FIG-7 (8)), and then insert the guided die.
B, lock the guide screw.
Adjustment: A, the guide die seat fixed nut (FIG-7 (5) relaxation, and then the control panel in manual mode, press the pinch button (3) to the guide die end end (at this time between the wheel and guide die between the gap, can be adjusted by the guide die screw (FIG-7 (6) to adjust.
B, adjust the guide adjusting screw (FIG-7 (6), make the guide die and wheel die fully closed.
C, press or withdraw button (FIG-4 (6), then adjust the guide screw (FIG-7 (6) in clockwise direction about 1/2-1/4 circle.
D, then fix the guide pin screw (FIG-7 (6)).
(4) mandrel
Installation: A, put the mandrel clockwise into the heart stick.
B, then fix the mandrel fixing screw (FIG-7 (8)).
(Note that the mandrel must match the bending direction of the elbow)
Tubular regularization
When designing and piping, avoid excessive arcs, arbitrary curves, composite bending and arcs greater than 180 degrees. Too large arc not only makes the tooling heavy, but also restricted by the size of the machine tool. The design of arbitrary curve and compound bend is very unreasonable, which greatly hinders the mechanization and automation of production and makes it difficult for the operator to get rid of the heavy manual labor; the circular arc is more than 180 degrees so that the bending machine can not unload the mold.
Standardization of bending radius
The bending radius should be realized as “one tube, one mold” and “multi tube one mode”. For a pipe, no matter how many bending or bending angles, the bending radius can only have one, because the bending machine does not change the module during the bending process, this is “one tube and one mold”. And “multi tube one mode”, that is, the same diameter pipe should be the same kind of bending radius, that is to use the same set of modules to bend the shape of different shapes, which is beneficial to reduce the number of modules.
Bending radius
The size of the bending radius determines the resistance of the pipe during bending. Generally speaking, the diameter of the pipe is small, and the inner wrinkle and skidding are easy to appear when bending. The bending quality is difficult to guarantee, so the R value of the bending die is 2-3 times as good as the pipe diameter.
Bending speed
The main influence of the bending forming speed on the forming quality is that the speed is too fast to cause the flat of the bend part of the catheter, and the roundness can not reach the requirement, which causes the pulling and breaking of the catheter; it is too slow to cause the wrinkling of the catheter and the slipping of the pressing block, and the pipe of the large pipe is easily formed into the sink of the pipe bending part. In view of the large number of tests on the two CNC bender, it is advisable to determine the bending speed of the pipe as 20%-40% of the maximum bending speed of the machine.
Mandrel and its position
In the course of bending, mandrel plays the role of supporting the inner wall of the bending radius of the pipe to prevent its deformation. If the domestic pipe is bent on the machine tool, the quality of the pipe can hardly be guaranteed without using the mandrel. There are many kinds of mandrel, such as column mandrel, universal single, double, three or four ball mandrel, directional single and multi ball mandrel. In addition, the position of the mandrel has a certain influence on the bending of the pipe. In theory, its tangent line should be flat with the tangent of the bend die. But after a large number of experiments, it has been proved that 1 to 2mm is better in advance, and the quality of the pipe is ideal at this time. Of course, too much advance can cause the appearance of the “goose head” on the outer wall of the curved part.

How to keep the screw bright and not rusty

A hardware company in Dongguan is a professional manufacturer of stainless steel fittings. Recently, the company has produced a batch of stainless steel 303 material and six angle screw fittings. It needs stainless steel passivation to prevent the surface of the workpiece from rust and the salt fog for 48 hours.
Stainless steel 303 is an austenitic type of easy to cut stainless steel and wear resistant acid steel, and it contains 0.15% sulfur, so it is easy to cut. After receiving the workpiece, caymeng technician, according to the stainless steel passivation process, first needs to use caymeng brand fast cleaning agent to clean the workpiece surface first, and caymeng brand fast cleaning agent can effectively improve the gloss of the workpiece surface. And quickly remove the oil contamination on the surface of the workpiece to achieve the cleaning effect.
After cleaning, the 303 material of stainless steel needs to be treated with sulfur removal. It is necessary to use the caymeng disulfide removal agent to remove sulfur and soak the water for 5 minutes at normal temperature to remove the feeling of cleaning. Then, according to the requirements of the stainless steel 303 and the salt mist for 48 hours, the technician adopts the caymeng brand unrust iron passivation solution ID3000. This product is suitable for the passivation of austenitic stainless steel and duplex stainless steel, which can greatly improve the anti rust ability of the material. The passivation film produced by the micro chemical reaction of stainless steel passivating liquid with the metal element on the stainless steel surface only takes place in the molecular structure change, and therefore uses Kay. The stainless steel passivation solution treated by ID3000 has the characteristics of no change in color and size, and the test performance of neutral salt mist can improve the perfect effect of 5-20 times. After washing – stainless steel passivation, the workpiece also needs to be closed by caymeng sealant to improve the anti rust ability of the product, heat the sealing agent to 45 degrees, and then put six corners of the screw into the container for 5 minutes, remove the workpiece, blow dry, and do not need further water treatment.
The most important and critical time after a series of processes is to see the effect of salt fog, put in the salt mist machine 48 hours after the six corners of the screw, drops of water, bright a new, the perfect clearance of the sample.

Electroplating process of belt buckle

The hardware BUCKLE needs strong and durable features, so special folding and stamping equipment is needed when molding. How can all kinds of belt buckles be shaped so that each detail can be evenly plated? The understanding of Dongguan bright belt is the plating process of belt buckle.
First of all, we divide the types of electroplating into: rolling and hanging.
1, rolling electricity in the hardware BUCKLE product appearance requirement is not high, its electroplated hardware products will not be very bright, there will be flower marks, of course the electroplating cost is also low. Three pieces of corn, bump, nail, button and bottom button are usually rolling. Hanging up electricity is used on the products which require high appearance of hardware buttons, such as alloy button, Hardware needle button and hardware chain.
If the belt buckle is safe and environmental friendly, it can be divided into nickel plating and nickel free plating.
2, electroplating is to turn color into film by chemical treatment and attach to the surface of the product. If the element of nickel is infiltrated during the electroplating process, it will not conform to the national environmental protection standard, for nickel plating; for electroplating, no nickel is permeated in the electroplating process, that is, nickel free electroplating. Of course, nickel-free plating of hardware products also requires raw materials, such as raw materials itself contains “nickel” that can not be nickel-free plating.
Tips: Hardware accessories commonly used electroplating colors are: bronze, black bronze, red bronze, nickel, dumb nickel, black nickel, light black nickel, dark black nickel, etc. Two. Spray paint (injection). In addition to the deployment of any color, the brightness of the fuel can be distinguished from gloss, semi gloss and dummy oil. Spray transparent oil, commonly known as jet oil, is mainly used for acid protection or surface protection. Wipe the oil and then wipe the surface bulge after spraying.

Five elements of selection of metal hose

1. The nominal diameter of the size hose, the choice of joint type (mainly flange connection, threaded connection, quick connection) and metal hose size, hose length.
2, the pressure according to the actual working pressure of the hose, then query the nominal diameter of the corrugated metal hose and the pressure gauge, decide whether to use a stainless steel tube type of metal hose.
3. The chemical properties of the medium conveyed in the medium hose are determined according to the corrosion resistance parameter table of the material of the hose.
4. The working temperature and range of the medium in the temperature hose; the ambient temperature when the hose works. At high temperature, according to the working pressure temperature correction coefficient of metal hose at high temperature, the pressure after temperature correction should be determined to determine the correct pressure level.
5. According to the state when the hose is used, the optimum length of the correct use and installation of the metal hose and the hose in the settlement compensation, the length calculation of various motion states of the hose, the minimum bending times and the minimum bending radius of the hose, and the correct selection of the length of the soft tube, and the correct installation of the tube.

Surface treatment technology for stainless steel parts

There are many kinds of surface treatment processes for stainless steel, such as electroplating, anodizing, sandblasting, painting, passivation, pickling, degreasing, rust removal and so on. This paper mainly introduces three common surface treatment processes of stainless steel, i.e. passivation, pickling and degreasing.

1. Passivation of stainless steel
The recommended surface of this process must be iron free. The presence of stainless steel particles on the surface of any iron, cast iron, low carbon steel, medium carbon steel or low alloy steel will promote pitting corrosion of “free” iron and stainless steel on its surface. This is a very serious problem, so passivation is used only for stainless steel and stainless steel. The main purpose of stainless steel passivation is to prevent oxidation and corrosion of stainless steel surface.

2. Stainless steel pickling.
The purpose of pickling of stainless steel is to remove the oxide coating on the surface of stainless steel after high temperature welding, heat treatment or hot working. At the same time, steel or iron or steel particulate pollutants corroded by red rust can also be eliminated. Please note that if there is no acid solution to clean the surface after pickling, the surface will soon begin to rust and corrode. The corrosion resistance of the steel surface layer is reduced.
Stainless steel pickling process can be applied to all 200, 300, 400 series of stainless steel surface treatment. All pickling operations result in the removal of impurities from the metal surface with a slight change in size, so the result is a degree of extinction of visual brightness that may also be a significant reduction in size.
Heat treatment in vacuum or a good controlled atmosphere, such as bright annealing, eliminates the need for pickling, which usually results in a better finish for stainless steel.

3. Degreasing and degreasing of stainless steel detergent.
Before any surface treatment of stainless steel, grease, cutting fluid, drawing compounds and other lubricants must be removed before surface heat treatment of stainless steel parts or final passivation treatment. Stainless steel parts must also be further welded before degreasing to prevent carbon from pickup at high temperatures.
Usually, stainless steel cleaning agent is selected. It only needs room temperature soaking for 1-8 minutes to remove any oil stains. It is easy to operate and has low labor intensity. It can be reused repeatedly and the cost of production can be reduced effectively. In cleaning operations with other metals, cleanliness can be increased through the use of brushing, spraying or stirring operations.

Working principle of pulse dust collector in gas box

The dust gas is from the inlet of the dust collector into the air inlet of the bellows (32 series from the ash bucket) into the clapboard to turn to the ash bucket. At the same time, the velocity of the air flow is slow. Because of the inertia effect, the coarse particle dust in the gas falls into the ash bucket, and the fine dust particles enter the filter chamber with the air flow, and the dust is attached to the exterior of the filter bag and the gas after purification. Through the filter bag, we enter the upper cleaning room, which is collected by the cleaning rooms and drained out by the main fan of the dust collecting system and discharged into the atmosphere.
With the continuous filtration process, dust on the surface of the filter bag is increasing and the resistance of airflow is increasing. When a certain resistance value is passed (example 1770Pa), it can be manually operated according to the need, and can also be controlled by an electronic control instrument of the fixed or timing cleaning program, automatically controlling the lifting valve of the first division of the starting dust collector, cutting off the air flow through the filter chamber, and opening the high pressure compressed air released by the electromagnetic pulse valve, and in the first chamber gas box. All filter bags are pulsing and blowing ash (stopping air cleaning) to make every filter bag swollen suddenly, so that the dust accumulated in the bag table will be recovered to the beginning of use, and the dust sink is not applied to the ash bucket. Then the program control instrument opens the lifting valve at the prescribed interval to restore the filter in the first room, and then starts the second room. The lifting valve, closing the filtration air in the second room, opening the electromagnetic pulse valve of the second division room to release the high pressure compressed air, and blowing the dust on all the filter bags in the second compartment box, and clearing the dust on the second chamber filter bag, then the program control instrument opens the second compartment lift valve to restore the filtering of the second division chamber. Since then, according to the pre specified electronic control procedures, the third compartment and the third compartment… The filter bag was stopped by air blowing and ash cleaning until the last compartment cleaned up, and the electric control device was closed, and the dust collector was resumed for official filtration and dust collection. The time interval between the filter and the air blows and the blowing time, the interval between the compartments and the cleaning period are controlled by the program-controlled instrument, and the time is adjustable.

Sintering of powder metallurgy machine parts manufacturing

The sintering process in the production and processing of powder metallurgical machinery parts is one of the most basic processes of powder metallurgy, which plays a decisive role in the physical and mechanical properties of powder metallurgy parts.
Sintering is a kind of high temperature heat treatment, which involves the knowledge of sintering furnace, sintering atmosphere, selection and control of sintering conditions. Therefore, sintering is a very complicated process. At the same time, sintering is a special process of high energy consumption, high equipment investment, and the quality characteristics of the product can not be fully measured. So it is one of the most important links to influence the quality and cost of powder metallurgy parts. The sintering process is very critical and must be strictly controlled to ensure the quality of sintered parts. Therefore, the operators need special skills training to fully understand and master the basic principles of sintering, the process of sintering (such as materials, temperature and time, sintering atmosphere, environment, etc.), the effect of sintering atmosphere, and the factors affecting the quality of the sintered products, so as to master the sintering skills and the skills of sintering skillfully. Improve the ability to analyze problems.
How do the press billets of powder metallurgy be sintered? Sintering is heat treatment of powders or compacts at temperatures below the melting point of major components. The purpose is to make metallurgical bonding between powder particles, even though the powder particles are transformed from mechanical agglutination to grain boundary bonding between atoms.
The purpose of sintering of powder metallurgy parts is that the blank of pressing has the shape and size of the mechanical parts, but its strength is very low, so it can not meet the requirements of use. Before sintering, the blank is only a mixture of powder particle interface, rather than a true atomic binding material. Therefore, sintering must be made to make the billet become metallurgical material and endow the powder metallurgy parts with mechanical and physical properties. The strength and elongation of the iron powder press after sintering are greatly improved. For example, the tensile strength can be increased from zero to 200MPa, and the elongation increase from zero to 8%, if the temperature is 1200 C.
The requirements for pressing and sintering of powder metallurgy machinery parts.
1. precision requirements for size and shape. The size and shape accuracy of sintered parts, including surface roughness, should meet the design requirements. Sintering will cause the sinter to shrink or expand, and the sinter will be deformed because of the uneven distribution of the density of the press and the uneven temperature of the furnace, so the size and shape of the sintered product will change. This requires strict control of sintering conditions to ensure the size and shape accuracy of sintered products.
2. density requirements. In sintering, the density, porosity, porosity and shape of the sintered products change with the sintering of powder particles and the shrinkage or expansion of the sintered products. Relative density and porosity characterize the density of powder metallurgy parts. As a self-lubricating powder metallurgy oil bearing, there is also a requirement for connecting voids.
3. the requirements of the organization. Powder metallurgy parts, like other materials, depend on the structure of the structure, which represent the structure factors of the powder parts: grain size, phase structure, distribution of phase, distribution of alloy components, porosity, pore size and pore shape. The formation and change of the microstructure of powder metallurgy parts mainly occurs in the sintering process.
4. the requirements of mechanical and physical properties. The final sintered parts need to achieve the required mechanical and physical properties. Mechanical properties include strength, hardness, elongation and impact toughness. Physical properties include density, conductivity, thermal conductivity and magnetism.
Sintering of powder metallurgy parts is divided into solid phase sintering and liquid phase sintering. Solid phase sintering is simply a metallurgical bonding between powder metallurgy particles. Liquid phase sintering is the sintering of certain molecular particles in powder metallurgy which produces liquid at higher melting point temperatures. The sintering process of powder metallurgy parts can be divided into pre sintering, grease removal, high temperature sintering and cooling.

Sheet metal processing technology

sheet metal
A kind of processing technology, sheet metal has not yet had a complete definition up to now. According to a definition in a foreign professional journal, it can be defined as: sheet metal is a comprehensive cold processing technology for sheet metal (usually below 6mm), including shearing, punching / cutting / compounding, folding, riveting, splicing, forming (such as car body). The notable feature is the same thickness of the same parts.

Process characteristics
Sheet metal has the characteristics of light weight, high strength, electrical conductivity (able to be used for electromagnetic shielding), low cost, and good mass production performance. It has been widely used in electronic and electrical, communications, automobile industry, medical equipment and other fields. For example, in computer chassis, mobile phone, MP3, sheet metal is an essential part. With the application of sheet metal more and more widely, the design of sheet metal parts becomes a very important part of the process of product development. The mechanical engineers must master the design skills of sheet metal parts skillfully, so that the design of sheet metal not only meets the requirements of the product’s function and appearance, but also makes the stamping die manufacturing simple and low cost.

Main uses
Sheet metal materials suitable for stamping are very numerous. Sheet metal materials widely used in electronic and electrical industry include:

The ordinary cold rolled sheet SPCC SPCC refers to the continuous rolling of steel ingots through the cold rolling mill to make steel sheet or sheet material with required thickness. There is no protection on the surface of the SPCC. The exposure to the air is very easy to be oxidized, especially in the wet environment, the speed of oxidation is accelerated, the dark red rust appears, and the surface should be painted, electroplated, or other protective surfaces.

The bottom material of SECC SECC galvanized steel sheet is a general cold rolled steel coil, which becomes galvanized after the continuous galvanizing line is degreased, pickled, electroplating and various post-processing processes. SECC not only has the mechanical properties and approximate machinability of cold-rolled steel sheets, but also has superior corrosion resistance and decorative appearance. It has great competitiveness and substitution in the market of electronic products, household appliances and furniture. For example, the common use of computer boxes is SECC.

Hot dipped galvanized steel SGCC hot dip galvanized steel coil refers to the semi-finished products of hot rolled or cold rolled, after cleaning and annealing, immersed in the melting zinc groove of about 460 C, and coating the steel sheet with zinc layer, and then made by quenching and tempering and chemical treatment. The SGCC material is harder than the SECC material and has poor ductility (avoiding deep drawing design). The zinc layer is thick and the electric welder is poor.

The SUS301 Cr (chromium) content of stainless steel is lower than that of SUS304, and the corrosion resistance is poor, but after cold processing, it can get good tensile and hardness, good elasticity, more used for spring spring and anti EMI.

Stainless steel SUS304 is one of the most widely used stainless steel, because the steel containing Ni (nickel) is more corrosion resistant and heat-resistant than the steel containing Cr (chromium). It has very good mechanical properties, no heat treatment hardening and no elasticity.

Sheet metal process
In general, the basic equipment includes the Shear Machine, the CNC Punching Machine / laser, the plasma, the water jet cutting machine (Cutting Machine), the bending machine (Bending Machine), the drilling machine and all kinds of auxiliary equipment, such as the uncoiler, the leveler, the deburring machine, the spot welder and so on.

In general, the four most important steps in sheet metal process are scissors, blanking / cutting / folding / rolling, welding, surface treatment, etc.

The sheet metal is sometimes made of gold, which is derived from the English platemetal. In general, some metal sheets are made by hand or die stamping to produce plastic deformation, forming the desired shape and size, and further forming more complex parts by welding or a small amount of mechanical processing, such as the chimneys commonly used in the family, iron. The skin furnace and the shell of the car are all sheet metal parts.

Sheet metal processing is called sheet metal processing. For example, making use of plate to make chimneys, iron buckets, oil tank oil pot, ventilation pipe, big head of elbow, round place, funnel shape and so on. The main working procedure is cutting, bending and buckle edge, bending forming, welding, riveting and so on. It needs certain geometric knowledge.

Sheet metal parts are sheet metal parts, that is, parts that can be processed by stamping, bending, drawing and so on. A general definition is that of parts with constant thickness in the process of processing. The relative is casting, forging, mechanical parts, etc., for example, the iron shell outside the car is a sheet metal piece, no rust. Some of the cabinet made of steel are also sheet metal.

The modern sheet metal process includes: filament power winding, laser cutting, heavy processing, metal bonding, metal drawing, plasma cutting, precision welding, roll forming, sheet metal bending, die forging, water jet cutting, precision welding and so on.

The surface treatment of sheet metal parts is also a very important part of sheet metal processing, because it has the function of preventing parts from rusting and beautifying the appearance of products. The surface pretreatment of sheet metal parts is mainly to remove oil pollution, oxide skin, rust and so on. It is prepared for the surface treatment, and then the treatment is mainly spray (roast) paint, spray and rust proof layer and so on.

Advantages and disadvantages of injection molding

The injection is also a machine made shoe, and the help face is ligation on the last of the last. Generally, it is directly injected into the PVC, TPR and other materials by the turntable machine to form the sole, and now there is a PU (chemical name polyurethane) injection molding (machine and mold are not the same as the usual injection).
Advantages: because the machine is made, the output is large, so the price is low.
Disadvantages: if there are many styles, it is more troublesome to change moulds, and the shoe is difficult to set, and it is not cold and sticky.

Material used for forging

Forged materials, in addition to the usual materials, such as carbon and alloy steels of various components, and the next of aluminum, magnesium, copper, titanium and their alloys, are also made by forging or rolling, which are also made by forging or rolling, only because of their relatively narrow plastic zones. So forging difficulty is relatively large, heating temperature of different materials, forging temperature and final forging temperature are strictly required