Technology

Metal Forming

Powder metallurgy is a processing method that uses metal powder as raw material and presses and sinters it to make various products. The powder metallurgy process consists of three main steps. First, the main component materials are decomposed into powders composed of many fine particles; then, the powder is loaded into the mold cavity and a certain amount of pressure is aplied to form the required part shape and shape. size of the compact; finally, the compact is sintered. The essential advantages of the powder metallurgy parts production process are the final forming capabilities of the parts and high material utilization.

Sintering

The operation of heating green pressed parts to an apropriate temperature to increase their mechanical strength and hardness is called sintering. During the sintering process, the grain interface is first formed, which in turn causes the recrystallization of the grains. The high temperature improves the plasticity of the metal surface and establishes a layer of liquid network structure, which can improve the mechanical interlocking properties between each other. In addition, Dissolved gases in metal can also be driven out at high temperatures. As for the sintering temperature, it is usually below the melting point of the main component metal, and the sintering time is about 20-40 minutes. In addition, during the sintering process, in order to avoid oxidation of the powder in contact with the atmosphere, reduction can be used Use neutral gas or nitrogen to prevent the formation of harmful oxide layers during high heat. In addition, after sintering, the size of green pressed parts may increase or decrease slightly due to factors such as product shape, particle size and distribution, chemical composition, sintering operation conditions, pressure levels, etc.

Hot Pressing

The hot pressing method is a processing method that simultaneously completes the pressing and sintering of powder in a mold. It is often used in the manufacture of tungsten carbide tool materials. This method has the advantages of improving the strength, hardness, and precision of the product, but because heating is performed while pressurizing, the mold used must be of heat-resistant material, and the heating time and the duration of the heating are difficult to control; in addition, during When processing high-temperature alloys, graphite molds must be used. However, due to the very low strength of the graphite mold, it can only be used once and consumes a lot of money.

Heat Treatment

Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common aplication is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching. Although the term heat treatment aplies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.

Vacuum melting

Vacuum induction melting (VIM) is a metal process that uses the principle of electromagnetic induction heating to smelt metal under vacuum conditions. During the electromagnetic induction process, eddy currents are generated, causing the metal to melt. This process can be used to refine high-purity metals and alloys.

Vacuum arc remelting (often abbreviated as VAR) is a process for producing metal ingots that are highly homogeneous in both mechanical and chemical properties. The vacuum arc remelting process can be used to refine special steels or materials required for harsh aplication environments such as biomedicine and aerospace.

Casting

Casting is a process in which metal is smelted into a liquid that meets certain requirements and poured into a mold. After cooling, solidification, and cleaning, a casting with a predetermined shape, size, and performance is obtained. Because the casting blank is almost in shape, it eliminates the need for mechanical processing or a small amount of processing, reduces costs and reduces production time to a certain extent. Casting is one of the basic processes in the modern device manufacturing industry.

Metal Powder Injection Molding Technology (MIM) is a new powder metallurgy near-net-form molding technology formed by introducing modern plastic injection molding technology into the field of powder metallurgy.

Deformation processing

Forging

Metal forging is the process in which metals are formed and shaped using compressive forces. The forces are delivered using hammering, pressing, or rolling.

There are a number of forging processes – cold forging, warm forging, and hot forging – which are classified by the temperature of the metal being worked with. Forging is one of the more pivotal metalworking processes in the metal manufacturing industry. It’s especially vital in the iron and steel industries and is viewed as a tremendous source of productivity. Here are some of the more common methods used:

• Closed die forging
• Open die forging
• Cold forging
• Roll forging

Sheet rolling

In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness, to make the thickness uniform, and/or to impart a desired mechanical property. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is known as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is known as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes.

There are many types of rolling processes, including ring rolling, roll bending, roll forming, profile rolling, and controlled rolling.

Swaging

Swaging is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.

As a general manufacturing process swaging may be broken up into two categories:

The first category of swaging involves extrusion of the workpiece, forcing it through a confining die to reduce its diameter, similar to the process of drawing wire. This may also be referred to as "tube swaging".

The second category involves two or more dies used to hammer a round workpiece into a smaller diameter. This process is usually called "rotary swaging" or "radial forging".

Wire drawing

Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die(s). There are many aplications for wire drawing, including electrical wiring, cables, tension-loaded structural components, springs, paper clips, spokes for wheels, and stringed musical instruments. Although similar in process, drawing is different from extrusion, because in drawing the wire is pulled, rather than pushed, through the die. Drawing is usually performed at room temperature, thus classified as a cold working process, but it may be performed at elevated temperatures for large wires to reduce forces.

Tube Rolling

Roll forming is a simple yet efficient metal forming process, ideal for even the most complex shapes. The process involves a roll forming mill and starts at the coil feeder, where material – typically coiled steel – enters the line. Some aplications require a pre-piercing operation prior to being roll-formed. Subsequently, the strip of sheet metal is passed through a set of forming rolls. Each forming roll only bends small parts of the bend until the final shape is obtained. This progressively shaping method prevents springback from occurring.

Tube rolling is the process of trying out a number of tubes in the same spot in an amplifier and selecting the one that sounds best to you. This can be very helpful in optimizing the tone of the amplifier. CAUTION: Tube amplifiers run on dangerous high-voltages and the tubes get very hot during operation.

Deep Processing

Lathe

A lathe is a tool that rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation, facing, turning, with tools that are aplied to the workpiece to create an object with symmetry about an axis of rotation.

Computer numerical control (CNC) is a manufacturing method that automates the control, movement and precision of machine tools through the use of preprogrammed computer software, which is embedded inside the tools. CNC is commonly used in manufacturing for machining metal and plastic parts.

Milling is a process where a milling tool cuts away the material in a rotary motion. As with drilling, this is possible with a wide array of different tools with different diameters and different hardness's. Because the mill is moving, the rotational speed must be high in order to get a clean finish of the milled hole.

Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal fabrication process whereby a desired shape is obtained by using electrical discharges (sparks). Material is removed from the work piece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the tool or electrode, while the other is called the workpiece-electrode, or work piece. The process depends upon the tool and work piece not making physical contact. Extremely hard materials like carbides, ceramics, titanium alloys and heat treated tool steels that are very difficult to machine using conventional machining can be precisely machined by EDM.

Laser cutting is a technology that uses a laser to vaporize materials, resulting in a cut edge. While typically used for industrial manufacturing aplications, it is now used by schools, small businesses, architecture, and hobbyists. Laser cutting works by directing the output of a high-power laser most commonly through optics. The laser optics and CNC (computer numerical control) are used to direct the laser beam to the material. A commercial laser for cutting materials uses a motion control system to follow a CNC or G-code of the pattern to be cut onto the material. The focused laser beam is directed at the material, which then either melts, burns, vaporizes away, or is blown away by a jet of gas,[1] leaving an edge with a high-quality surface finish.

A water jet cutter, also known as a water jet or waterjet, is an industrial tool capable of cutting a wide variety of materials using an extremely high-pressure jet of water, or a mixture of water and an abrasive substance. The term abrasive jet refers specifically to the use of a mixture of water and an abrasive to cut hard materials such as metal, stone or glass, while the terms pure waterjet and water-only cutting refer to waterjet cutting without the use of added abrasives, often used for softer materials such as wood or rubber.[1]

Waterjet cutting is often used during the fabrication of machine parts. It is the preferred method when the materials being cut are sensitive to the high temperatures generated by other methods; examples of such materials include plastic and aluminum. Waterjet cutting is used in various industries, including mining and aerospace, for cutting, shaping, and reaming.

Surface treatment

Surface grinding is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or nonmetallic materials to give them a more refined look by removing the oxide layer and impurities on work piece surfaces. This will also attain a desired surface for a functional purpose.

Polishing is the process of creating a smooth and shiny surface by rubbing it or by aplying a chemical treatment, leaving a clean surface with a significant specular reflection (still limited by the index of refraction of the material according to the Fresnel equations).

Chemical cleaning is a method to derive surfaces and walls of equipment, pipelines, vessels, kettles and heat exchangers of unwanted contaminants. Chemical cleaning also means the purification, conditioning, treatment or disinfection of water.，Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurised fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material (often called the media).

Forming of Ceramics

Zirconia and alumina ceramic processing steps:

There are three main molding processes for ceramic processing. One is slip injection molding, which is mainly completed through physical dehydration and chemical condensation to increase ionic strength. It is mainly suitable for the production of large ceramic parts with complex shapes. The second is hot injection molding. Ceramic powder is mixed with a binder at high temperature, injected into the mold under the action of compressed air to cool and form, and then dewaxed under the protection of inert powder, and then fired into ceramics with dimensions. Precision and high production efficiency. The third is tape casting, which has the characteristics of high flexibility.

Step 2: Degreasing and degluing.

In addition to dry pressing molding, the plasticizer added must be removed after the product is molded, otherwise it will affect the quality of the product. It is usually removed by degreasing and degluing.

Step 3: Sintering.

The purpose of sintering when processing zirconia ceramics is to fix its chemical and physical properties and to achieve the desired effect on the surface. There are mainly pressureless sintering, hot press sintering, static pressure sintering, microwave sintering, plasma sintering, etc.

Production of silicon nitride ceramics

1. Normal pressure sintering

Nowadays, many times when people make silicon nitride ceramics, they use normal pressure sintering, which mainly has certain requirements in terms of decomposition temperature. Generally, the temperature is between 1,700 and 2,000 degrees Celsius. Therefore, the ceramics produced in this way also have very outstanding performance in terms of strength.

2. Reaction sintering

The so-called reaction sintering, as the name suggests, is a process in which silicon nitride ceramics are made through certain physical and chemical reactions. It mainly presses silicon powder into a green body of the required shape, and then puts it into a nitriding furnace for reaction. This method can save a certain amount of cost to a large extent, but it still costs a lot of time, so it should generally be considered carefully.

3. Air pressure sintering

In the past two years, people have paid great attention to air pressure sintering, and have invested a lot of manpower and material resources in it. Silicon nitride ceramics that have been sintered by air pressure generally have the characteristics of high toughness, high strength and good wear resistance. Various complex shaped products close to the final shape can be directly produced, thus greatly reducing production costs and processing costs. , so it is more suitable for some large-scale production.

Forming of aluminum nitride ceramic substrates

Casting method has also become an important part of the electronics industry

The main molding process using aluminum nitride ceramic substrates.

1 ball mill pulping

In the preparation of aluminum nitride slurry, organic mixed solvents such as dispersants, binders, plasticizers, etc. are usually added to obtain slurry characteristics that are easy to be cast and molded. In addition, Y203 is generally added to act as a sintering aid under normal pressure sintering conditions. The viscosity of the slurry has an important impact on the performance of the substrate.

2. Tape casting

Tape casting has high production efficiency and is easy to achieve continuous and automated production, reduce costs, and achieve mass production. The thickness of the substrate produced can be as thin as less than 10μm and as thick as more than 1mm.

Three glue discharge

Since the substrate blank produced by the tape casting method contains a large amount of organic matter, its internal porosity is large and its strength is low. In order to prevent the above defects from occurring, it is pre-sintered in a nitrogen atmosphere furnace at 1100°C. Sintering can improve the strength of the blank, reduce the porosity, and obtain AIN substrate materials with high flatness and good performance.

Four sintering

After debinding, the aluminum nitride substrate will be sintered at high temperature. The key points of the sintering process of high thermal conductivity aluminum nitride substrate include sintering method, addition of sintering additives, control of sintering atmosphere, etc. There are generally five commonly used sintering processes for AlN substrates, namely hot press sintering, pressureless sintering, microwave sintering, discharge plasma sintering and self-propagating sintering. Among them, hot pressing sintering is currently the main process for preparing high thermal conductivity densified AIN ceramics.

Boron nitride ceramic production process

The sintering methods of H-BN ceramics mainly include: pressureless sintering, hot press sintering, hot isostatic pressing sintering and discharge plasma sintering. Among them, pressure-free sintering is a conventional sintering method that is simple to operate and easy to control the temperature. However, due to its high porosity, it can only be used in situations where mechanical strength is not required; hot isostatic pressing sintering can produce high-density products. However, the disadvantage is that the body is not easy to package, the equipment cost is high, and the operation is complicated. Spark plasma sintering is a new and efficient sintering technology that can ensure better mechanical properties, but its implementation suffers from complex equipment, high energy consumption, and high cost. limited.

Compared with other sintering methods, hot-pressing sintering to prepare h-BN ceramics is generally considered an ideal sintering method. It refers to filling dry powder into a special graphite mold and using double or unidirectional pressure to carry out single-step sintering. A sintering method that axially compresses the mold and at the same time heats it to a certain temperature range to carry out molding and sintering. During the hot-pressing sintering process, the blank is also affected by heating pressure. This additional driving force can destroy the suport structure of the flake h-BN card and promote the rearrangement of the h-BN grain size. At the same time, It can effectively reduce the sintering temperature and shorten the sintering time, and finally obtain ceramic products with high density, uniform grain size and good mechanical properties. The purity of ceramic products can be achieved without adding sintering aids or forming aids.

Powder Preparation

Water Atomizing Process

Water atomization process involves usage of high-pressure fluid jets to break up a molten metal stream into very fine droplets, then solidify into fine particles. After dehydration, drying, sieving, raw powder reduction, powdery cake crushing, screening and blending, finally get the metal powder. We are capable of producing spherical and nonspherical powders with D50 <10µm to >500µm. Edgetech is producing a range of powders for PM, filter aplication and other industry sectors.

Powder properties of water atomization:

-Powder with low impurity content

-Good compressibility

-Good formability

-Won't produce segregation during the process of transit and blend

-Powder particle size distribution can customize according to customer's requirements

Gas atomization process

Gas atomization uses nitrogen or argon jets impinging on a molten stream of metal to form tiny droplets. These droplets can form higher sphericity metal powder.

Powder properties of gas atomization:

-Powder with surface luster, spherical particle and good flowability

-High tap density

-High purity

-Powder particle size distribution can customize according to customer's requirements

Plasma Rotating Electrode Process (REP)

The plasma rotary atomization method is one of the more ideal ways to prepare high-purity and clean solid spherical powder materials. Its mechanism can be simply described as: plasma beam is used as heat source, metal or alloy is used as consumable electrode, and the electrode end is coaxial Plasma melts and obtains spherical powder under the action of its own high-speed centrifugal force and surface tension.

Features of plasma rotary atomization powder making:

-The powder has a narrow particle size distribution and a more concentrated particle size

The particle size of alloy powder prepared by gas atomization method is mainly concentrated in the range of 10-150μm;

The particle size of alloy powder prepared by plasma rotary atomization method is mainly concentrated in 25-120μm.

-There is basically no hollow powder and satellite powder in the powder

-Powder ceramic has less inclusions and higher cleanliness

-Low powder oxygen increase

-Alloy-free smelting process;

-No high-speed inert gas flow to break the liquid flow;

-The oxygen increase of the gas atomized powder is above 100pm, and the oxygen increase of the plasma rotary atomized powder can be controlled below 50pm.

We can provide spherical titanium alloy powder, tantalum powder, niobium powder and others produced by rotating electrode process technology.

Spheroidizing Technology - Laser plasma atomization

We provide spherical pure titanium metal powder produced by spheroidizing technology.

Irregular shape powder is fed into a high temperature zone (10e4℃) plasma field which melts the fed powder and after quick-cooling can form spherical metal powders.

Powder properties of spheroidizing technology:

1、Spheroidization rate is nearly 100%

2、Powder with low impurity content

3、Powder with good flowability and high tap density

4、Powder particle size distribution can customize according to customer's requirements