Material manufacturing technology refers to the processes and techniques used to create various materials, products, and components from raw materials. It encompasses a wide range of industries, including metals, polymers, ceramics, composites, and more. The goal of material manufacturing technology is to efficiently produce materials with desired properties, such as strength, durability, conductivity, and appearance.
Material manufacturing technology is continually evolving with advancements in materials science, engineering, and automation. The choice of manufacturing method depends on factors like material type, desired properties, complexity of the design, production volume, and cost considerations.
Material Manufacturing Technology
A. Material forming
Forging: forging, machine pressing, casting
(1) Forging: commonly known as “strike iron”.
(2) Machine pressing: stamping, spinning, extrusion.
- Stamping: Use pressure machinery and match corresponding molds to manufacture the required product process, which is divided into several processes such as cutting, blanking, forming, flashing, and stretching. Load shearing, blanking, and flashing are a process for separating materials. Forming, stretching is a process that uses the elongation properties of materials to change the structure of products. In stamping products, it often occurs that the above two processes need to be used repeatedly to achieve the required product effect. In the stamping process, both the material and the mold affect the quality of the product, including: the extensibility of the material, the hardness of the material, the defects of the material itself, the hardness of the mold, the clamping gap of the mold, and the rationality of the mold structure. This process is widely used in the manufacture of automobiles, computers, electrical appliances, lamps and other industries, such as iron ceiling lamps.
- Spinning: Utilizing the extensibility of the material, the spinning machine is equipped with the corresponding mold and the technical support of the workers to achieve the production process of the lighting spun parts. This process can replace the stretched products with difficult shapes. The lighting Parts industry is mainly used for Production of aluminum cups. Extrusion: Utilizing the extensibility of materials, through extrusion machinery and equipped with linear molds, the process of pressing into the products we need. This process is widely used in the manufacture of aluminum profiles, steel pipes, and plastic pipe fittings, as well as guide rails and grille light panels in the lighting industry.
(3) Casting: negative pressure casting, casting, die casting
Negative pressure casting
It is used for low requirements on product density, and the production process of some products is used in the manufacture of large machine tools. Casting: Commonly known as “sand turning” process.
Die-casting machinery and molds are used to manufacture the required products, which are widely used for products with complex structures and high three-dimensional degrees. The process has high precision and good surface leveling, and is widely used in industries such as automobiles, weapons, and lamps, but the manufacturing cost is high. Divided into hot chamber die casting and cold chamber die casting.
- Hot chamber die-casting: high degree of automation, high efficiency, poor high temperature resistance, short cooling time, used for zinc alloy die-casting (zinc alloy melting point 380 ° C, density 6.75KG/CM3, used in the manufacture of ceiling lamps and spotlights) .
- Cold chamber die-casting: There are many manual operation procedures, low efficiency, high product defect rate, good high temperature resistance, and long cooling time. Used for aluminum alloy die-casting (melting point of aluminum alloy is about 780°C, density 2.55KG/CM3, used in the manufacture of ceiling lamps and spotlights).
Processing procedure: Clamping—Clamping—Feeding—Cooling—Demoulding—Discharging Among them, the feeding and discharging of hot die-casting are all automatic operations, while the feeding and discharging of cold chamber die-casting require manual operation. The die-casting process has high requirements on mechanical equipment, product mold requirements and raw material quality.
This process is the same as the die-casting process, only differing in the mold process and processing temperature. It has higher precision, higher requirements on the mold, and higher product cost. It is used in the production and manufacture of transformer shell bases.
B. Surface Treatment
The role of surface treatment: Surface anti-corrosion, plating (decoration) effect.
The evolution of surface treatment:
Human beings entered the Bronze Age from the Stone Age, and the need for surface treatment technology arose along with it. Archaeological excavations have shown:
- Copper was discovered 6,000 years ago
- Copper artifacts appeared in the Neolithic Age 5,000 years ago
- Bronze artifacts appeared 4,000 years ago
- In the Shang Dynasty more than 3,000 years ago, hot-dip tinning appeared, and meteorite iron began to be used
- Iron smelting began in the Spring and Autumn Period, and surface treatment processes such as baking orchid anti-rust were introduced in the Warring States Period
- There are records of rusting in the Tang Dynasty, quenching in the Warring States period, and the application of chemical heat treatment (carburizing) and blue burning (thermal oxidation) and gilt in the Southern and Northern Dynasties.
The development of aqueous solution electroplating
The development of electroplating starts from the discovery and application of primary batteries, which are applied to aqueous solution electroplating.
- In 1837, Bird discovered that a slag-like shell was deposited on a platinum electrode.
- With the discovery of the Volta (volta) stack, that is, the primary battery, Faraday (Faraday) published the famous electrolytic law in 1833 and 1834, clarifying the physical and chemical basis of the electroplating process.
- In 1840, Shore applied for and a commercial patent.
- 1854 mentioned Bunsen Bunsen) (deposition Geuther (Jejin) announced in 1856 that the chromium layer was plated with chromic anhydride solution. In 1869-1870, commercial nickel plating (ie stainless steel color) appeared
- After the 1880s, the development of DC civilian motors promoted the development of electroplating gold. In 1916, Watt (Watt) schlotter’s (bright nickel) began to be commercialized. ideal effect.
In 1949, Blum and Hogaboom published what is considered a classic or landmark treatise that brought electroplating into the orbit of science and engineering. The proposal of Gibbs (Gibbs) thermodynamics and Nernst (Nernst) equation made a leap forward in the development of chemistry and electrochemistry. Electroplating is an application of the electrolytic process.
After the 1940s, dppymknh (Frumkin), Bockris (Boklis) and Conway (Conway) introduced a new concept of electrode process kinetics. The mechanical, physical and chemical properties of the electroplating layer and many engineering properties, as well as the basic relationship between the coating and the changes in hardness, anti-corrosion, friction, etc., lead to the mechanism and influence of side effects such as surface stress, fatigue, hydrogen embrittlement, and melting embrittlement. my country’s electroplating industry began in the 1950s after liberation. The Soviet Union aided in the construction of 156 key projects, which made the electroplating process develop unprecedentedly.
Classification of surface treatment process
- Heat treatment mainly applies to the application of the wear-resisting and hardening toughness of mechanical appliances to undergo qualitative changes through heating.
- Rolling, mechanical grinding, polishing
- Coating (painting is divided into oil spraying and powder spraying)
a) Electroplating method with external current
Insert electrodes into the electrolyte and pass current.
b) Electroplating method without external current
Materials with different potentials are used to contact the plated parts, and deposition can also be carried out through the generated internal current. Oxidation or reduction processes that occur when electrons are lost or captured by surface transformations are also commonly used to form protective layers on surfaces. According to the type of deposition, it can be divided into barrel plating, vacuum plating, vapor phase plating, electroless plating, aqueous solution ion plating and metal electrophoresis, oxidation, coloring, etc. Aqueous solution ion plating is divided into single metal plating, composite plating and electroforming, special material plating, etc.
Process flow of rolling, mechanical grinding and polishing
It is a way to use a motor (rh/900~1400) to drive a 6-corner or 8-corner drum to treat the ridges, burrs and rust remaining on the surface of the machined product.
Processing object: small accessories
Advantages: fast processing time, clean, able to decontaminate the surface of the workpiece. Suitable for surface shaping treatment of small parts Disadvantages: easy to deform the process, unable to deal with large workpieces and large ridges
Main raw material: tea powder. Red alum, mukang, iron sand, etc. For barrel plating small parts, organic solvents such as trioxyethylene, soap oil, tea powder, etc. are added to water and directly electroplated after barrel treatment
Driven by a motor (rh/1400-2800 rpm), a process method in which the grinding wheel shapes the surface of the workpiece
Processing objects: parting line of die-casting parts, water lines and surface of forging parts. (General workpieces treated before painting)
Advantages: It is easy to handle, and has a good effect on leveling the surface of the workpiece and fine processing.
Disadvantages: physical and technical labor, which has a certain impact on human health, requires dust removal facilities and consumes labor insurance supplies
Main raw materials: emery (180# 200# 240# 260# 280# 320#) corundum sand (180# 190# 200# 220# 240#) and a small amount of red paste and grinding wheel (250 300 350m) and bovine rubber beads
Use a motor (rh/1400~2800 rpm) to drive the grinding wheel. Hemp wheel, cloth wheel, a process for shaping the surface of the workpiece
Processing objects: Die-casting parts, the surface of steel parts (mainly for the decoration of electroplating parts)
Advantages: It can obtain a very detailed and smooth effect on the surface of the workpiece
Cons: same as grinding
Main raw materials: same as grinding, white wax, purple wax and polishing paste are also required
Main ingredients: Green paste (chromium oxide, alumina) Red paste (iron oxide, alumina) White paste (calcium oxide, magnesium oxide, diatomaceous earth, etc.)
Coating process (removal of oil and wax) (removal of rust and compounding) (film treatment) (drying) (baking) (dusting and wiping) With the development of science and the improvement of people’s living standards, the coating process uses color masterbatches to formulate a variety of colors that meet the needs of human consumption, which not only achieves the effect of anticorrosion, but also meets the requirements of decoration.
Treatment before electroplating
Electroplating is an atomic-level deposition process, which is essentially different from macroscopic coverage such as atomization melting and painting. In order to achieve better bonding (adhesion) and decorative effects, consideration should be given to:
- The nature of the basic material, the variety of the base material, the structure, and the forming method are hot rolling or cold rolling through casting and forging.
- The cleanliness of the surface. There are processing debris on the surface of processed and formed parts, and oily impurities will also include wax, thick oil seal oil layer, thin anti-rust oil film, corrosion inhibitor, etc. Different methods need different methods to deal with.
- Corrodibility, size, quantity and precision of parts materials, some materials are susceptible to corrosion, such as aluminum, magnesium, zinc, etc. Some will dissolve in anodizing, such as chromium, tin, etc.
- The structure and state of the surface and the surface structure of the material to be plated will directly affect the structure and characteristics of the coating.
As far as the production equipment for electroplating is concerned, in terms of the relative arrangement of the plated parts, anodes, plating solutions, and plating tanks, and different operating methods, the most commonly used ones are fixed plating tanks, but various alternative methods are also used and developed. . Movement of parts (such as swinging, stirring, continuous electroplating wire and plate, automatic machine, etc.), movement of plating tank (barrel plating), movement of plating solution (spray, rapid plating, electrolytic polishing, etc.)
- Fixed plating tank: The electroplating solution is contained in the fixed plating tank, the plated parts are immersed and face the anode, and electricity is supplied by means of conductive and fixed racks. (This method is traditional and the most extensive) Advantages: less investment in equipment, unlimited shape, size and quantity of plated parts, easy to monitor and maintain.
- High-speed electroplating: (mainly used for electroplating small pieces of precious metals) through the movement of parts and the use of forced convection or jetting to make the plating solution flow at high speed to carry a strong current of up to hundreds of amperes per square decimeter to achieve a very high plating speed .
- Barrel plating: suitable for the processing of a large number of small parts. Advantages: It can polish the plated parts, and the difference in the thickness of the coating between parts is small, but it is difficult to perform partial electroplating, and it is also difficult to apply high-speed plating.
- Brush plating: wrap the surface of the anode with a soft porous material that can contain the electroplating solution, such as cotton cloth or other fiber products, pass an electric current and rub on the surface to be plated, and the plated layer can also be plated on the rubbed surface area. This method has been used to repair local coating defects.
- Plates and wires with continuous electroplating.
- Special process: gypsum, glass, plastic, electroplating combined with electroless plating and aqueous solution.
Materials And Manufacturing
- Commonly used materials for manufacturing lamps are: steel plates, aluminum alloy castings, profiles, plastic materials, zinc alloy castings, packing and sealing materials (rubber, foam, resin, etc.) glass, light control materials, (high-purity aluminum, stainless steel, polished glass, etc.).
- Steel plate Application: It can be used for lamp beading, small lamp body, lamp cover, embedded lamp box, control panel, base and projector. Grade and characteristics: Low carbon steel has good mechanical strength and ductility, but is not corrosion resistant. It is available in the form of coil, sheet or plate, with a thickness of 0.45~1.2MM. For indoor use places that do not pay much attention to aesthetics, the surface of the selected steel plate is preferably coated with a layer of zinc, but it must be painted for most use places.
- Pre-coated materials Processing: Cutting, drilling, punching, bending and pressing processes.
- Manual operation: cut out the shape first, and then punch the bent plate or flywheel.
- Semi-automatic operation: CNC controlled, cnc machining lighting part movement is done by the operator.
- Automatic Cold Roll Forming: Slabs are usually processed in this way.
- Rolling machine Automatic production control of sheet metal: For the manufacture of large box-type recessed lamps and ceiling lamps, European equipment manufacturers have fully realized automatic mechanization.
- Stamping: For some smaller round lamps, it is usually directly stamped with deep-drawn low-carbon steel plates.
- Attached steel parts: Uncoated steel materials can be spot welded or continuous welded before painting. However uncoated materials must be joined with rivets, nuts and bolts, self-tapping screws or adhesives.
- Coating: powder coating process is usually adopted. Compared with the traditional wet coating layer, it can obtain a thicker coating film, typically up to 50~100um thickness, while the traditional method can only reach 25um. This is very beneficial in devices that require highly reflective properties, such as device boxes.
- There are two treatment processes: degreasing process and pretreatment (usually phosphating), followed by electrostatic spraying process and subsequent drying process. Electroplating is rarely used, usually only for decoration, or for some small parts that require a protective layer, such as screws, bolts and nuts. Chromium and nickel are typical for decorative plating, while zinc is generally used for plating for protective purposes. Coating a layer of metallized plastic film on the surface of the steel plate can be used as a reflective layer.
Aluminum alloy castings Applications
Luminaire housings for floodlighting, street lighting, small indoor spotlights. Grades and Properties: LM6 aluminum silicon alloy (12% Si) with eutectic composition is the most commonly used alloy material because of its short solidification time, good flow and low shrinkage, making it suitable for gravity casting and die casting. In addition, it also has good corrosion resistance, and does not need to be coated with a protective layer when it is used outdoors (unless there are aesthetic requirements).
The copper-aluminum alloys LM2 and LM24, which contain slightly less silicon, are also economical and have high strength, good castability, but poor corrosion resistance compared to LM6. In some places, such as airport lighting, higher strength and corrosion resistant alloys such as LM25 are required. These alloys are calcined at high temperatures to ensure sufficient strength. Aluminum is used in most applications because of its important properties, namely its heat resistance.
Since aluminum is a relatively low-grade metal, it will undergo electrolysis when it comes into contact with other metals such as steel, stainless steel and copper. Therefore, it is necessary to coat the surface of these metals with intermediate performance metal materials (zinc or cadmium), or use grease and plastic gaskets to act as barrier barriers. Aluminum casting process: There are two main processes, both of which are to inject molten metal into a mold with holes. Whereas in gravity casting the pressure comes from the molten metal itself above the cavity, in die casting the molten metal is forced into a steel mold that produces thinner components. Coating of aluminum castings: Prior to coating, they are trimmed or tumbled to remove surface flash or debris. Using related processes such as LM25 is suitable for anodizing process. In these processes, when aluminum is exposed to air, a thin and tough oxide layer is artificially formed on its surface instantaneously, about 10um thick. Before the oxide layer is permanently sealed, immerse The surface color can be obtained in the dye.
Application: reflectors and grilles
Properties and Grades: For satisfactory results reflectors must contain at least 99.8% aluminum, best results are obtained when using 99.99% ultra-pure material. Most reflectors form a thin oxide film through the anodization process, and the oxide film is brittle, so many fine textures will be produced on the surface of the oxide film when it is bent at a small angle. The same effect can be produced due to the difference in expansion after heating over 100°C. Another characteristic of the oxide film is that it can produce a rainbow effect, which is especially obvious under trichromatic lamps.
Process: The reflector material is divided into two main parts: one is a coil or sheet with a thickness of 0.4~1.2mm; the other is a symmetrical reflector produced by spinning a thicker sheet. Coil or sheet material is first unloaded—cut into shape—manually or semi-automatically stamped, and the bending can be completed by coil machining.
The assembly of the grid and the crosspieces is a labor-intensive production process; the spinning process is generally used to produce large parabolic or axisymmetric reflectors, mainly for spotlights. Manual or semi-automatic operation—lathing—processing with various steel formers—plastic forming of rotating flat plates around a punch—surface polished and chemically treated to shine. Coating: For reflectors, this process is mainly anodic oxidation, which thickens the oxide layer by a few microns and becomes a natural oxide layer, which makes aluminum have better corrosion resistance. In electrochemical processes, an oxide layer can grow on the base metal, which must be preceded by a manual or chemical polishing process.
The thicker the film layer, the lower the reflectivity. There are new developments in the method of enhancing the performance of the reflective surface: a thin oxide layer (such as Ti) is evaporated to the anodized surface, and its reflection performance is consistent with that of aluminized glass. This material More expensive but less iridescent and less likely to develop microcracks.
Other metal materials
- (1) The development of filament materials: natural fiber – spinneret – carbon – osmium – titanium – tungsten The main advantages of tungsten: u High melting point of 3420 ℃ makes it work at a higher temperature than other metals, and it is the same under all conditions In most cases, higher temperature means higher lumen efficiency. Its vapor pressure u is the lowest among all conductive materials. On this basis, very high filament temperature and minimum evaporation (bulb blackening) can be obtained. u Tungsten is a spectrally selective emitter with higher emissivity in the visible spectrum than in the infrared region, which contributes significantly to the efficiency at any given temperature.
- (2) Other uses Tungsten is often used as a manufacturing material for filaments and electrodes. u Pure aluminum and brass are commonly used in the manufacture of lamp caps. Brass is often nickel-plated for high corrosion resistance. Aluminum is gradually becoming the manufacturing material for low-cost u lamps (such as incandescent lamps). Soldering or brazing is often used for the electrical connection between the lamp cap and the filament, and in some u-lamp models the traditional weld between the lamp cap and the guide wire is being replaced by a mechanical crimp. Another important use of aluminum u is as a vapor deposit on reflective coatings in spot and reflector lamps, mainly due to its low melting point of 660°C. In incandescent lamps, the filament holder is made of molybdenum (halogen-free) and tungsten (halogen-containing). The bracket used to place the discharge lamp or the incandescent lamp in the jacket part is generally made of stainless steel wire spot welded into the required shape. u Nickel, iron, and copper alloys are widely used in fuses, glass-sealing alloys, bimetals, and guide wires, and metal laser cutting lighting parts that bend under heat control are introduced into some high-pressure sodium u lamps as starting devices. To generate the radiation bands in the discharge lamp spectrum, a large number of metals are used in the vapor state, such as dysprosium, gallium, holmium, indium, mercury, scandium, sodium, thallium, thorium, thulium and tin. u
- (3) Electrode The electrode conducts electrical energy into the discharge lamp and provides electrons to maintain the current. Due to the requirement to work at high temperatures (up to 2000°C), the materials used in the electrodes must have low vapor pressure, not only to ensure their own life, but also to prevent excessive contamination of the lamp itself (blackening of the ends). In addition, these materials must have sufficient Mechanical strength, impact resistance and, if necessary, sufficient ductility to allow fabrication of complex electrode geometries. Tungsten has by far the most important commercial use, although tantalum, nickel and iron are also used, eg the electrodes (cold cathodes) of neon lamps are made of pure iron. Tungsten is an abundant electron emitter at temperatures in excess of 2000°C, but such high temperatures are unacceptable in many long-life discharge lamps, so a way must be found to enhance electron emission. One solution is to make electrodes out of thoriated tungsten, in which thorium oxide particles provide a source of thorium that diffuses to the hottest point on the electrode surface, usually the tip of the electrode, where its work function is reduced and Increase electron emission rate. Thorium-containing electrodes are used in some metal halide lamps. Both use emissive materials to significantly enhance electron emission, usually in the form of some kind of oxide coated on the electrode or placed in the electrode during assembly. In high-pressure sodium lamps, the electrodes of the complex helix are impregnated with a composite oxide based on calcium, barium and tungsten, usually called BCT emitter material, and an optional emitter material is ytterbium oxide, which is used in low-pressure sodium lamps and fluorescent lamps. Emissive materials based on oxides of calcium, barium and strontium.
Pros: Versatility and design flexibility.
Disadvantages: Reduced high temperature resistance, chemical corrosion resistance, strength and UV stability are not ideal. Properties and Grades: Two main types: Thermoplastics (remeltable and recyclable), Thermosets (not reversible in the process). Accessories such as lamp holders that traditionally use thermosets have been replaced by thermoplastic materials, especially polycarbonate. Plastic can withstand a high temperature of about 200°C, but at higher temperatures, it will harden, become brittle, and change color. It is more expensive and has good flame retardancy.
Applications: Luminaire bodies, diffusers, refractors, reflectors, end caps, sockets, bushings, terminal blocks and turnbuckles.
- 1) Ultra-high temperature plastic (160°C~200°C): Polyphenylene sulfide (polyphenylene sulfide) is an opaque material, and the surface layer can be plated with aluminum. It is often used in the main body and reflector of small lamps, and has good flame retardancy. Polyetherimide (polyetherimide) is often used in environments up to 180°C. It is a translucent material, and the surface can be coated with a cold light film, so that it can transmit infrared rays and reflect visible light (also known as cold beams). In this temperature range, there are some other materials. Applicable, such as polyethersulfone. (polyethersulfone), good flame retardancy, but as the temperature increases, the hardness decreases, and the appearance is light yellow, so it cannot be used for refractors and reflectors.
- 2) High-temperature materials (130°C~160°C) Glass-reinforced polyester (GRP) thermosetting plastics are used in most street lighting fixtures and floodlighting fixtures. Comparable to aluminum and can be formed into sheet molding compositions (SMC) or dough molding compositions (DMC). Inexpensive, high chemical strength, but easy to wear and poor resistance to UV radiation, used in tropical environments, the surface becomes dull in a short time. Not inherently flame retardant, but this property can be achieved through additives. Polybenzothiazole (polybutylene terephthalate)
(PBT) Thermoplastics, equivalent to SMC and DMC, have almost the same temperature resistance. It is used in the lamp caps of most fluorescent lamps and has a sheath. It is also used to make lamps for spotlights and interior decorative lamps. It has good flame retardancy and satisfactory UV radiation resistance. Compared with SMC and DMC, it has better processability. The maximum operating temperature of transparent refraction materials is between 140°C and 160°C. In the past, stability against UV radiation was an issue, but now polyestercarbonate is used to provide a satisfactory performance in street lighting bowl shades.
3) Medium temperature materials (100°C~130°C)
Polycarbonate (polycarbonate) In this temperature range, it is the main variety, with strong impact resistance, usually made of transparent or colored forms to make lamp bodies, diffusers, refractors, reflectors and flame retardancy as a prerequisite accessories, such as lamp holders. When applied to reflectors, this material will be aluminized. Compared to stamped and spun reflectors, these reflectors are more economical and more complex reflectors can be produced. The tendency of polycarbonates to yellow under UV radiation in hot climates remains a problem, a condition usually implicated in high power mercury discharge lamps. In the case of strong ultraviolet radiation, the working temperature of the material should be limited to 15 ℃ ~ 20 ℃. Polycarbonate has been successfully blended with acrylonitrile-butadiene-styrene terpolymer (ABS) to form a glossy synthetic material for decorative lampshades and lamp bodies.