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The surface treatment of hardware is the core process in the manufacturing of custom cases, hardware shells, sheet metal parts and mechanical components. Through professional surface treatment techniques, the corrosion and wear resistance of metal workpieces can be effectively enhanced, the appearance texture and structural stability can be optimized, and the products can better meet industrial usage standards and be suitable for the usage scenarios.
ШИДЗЕ, as a professional custom hardware enclosure processing factory, usually selects different surface treatment methods based on the specific usage scenarios of the hardware enclosures. For hardware processing factories, choosing the appropriate surface treatment process directly determines the product quality and service life.
ШИДЗЕ will systematically introduce 6 mainstream hardware surface treatment processes from aspects such as processing procedures, applicable scenarios, core technical points, and professional equipment configuration requirements, providing professional reference for procurement selection and factory production processing.
Sandblasting Surface Treatment
Sandblasting is a classic physical surface treatment process. It uses high-pressure air to drive abrasive particles to impact the surface of metal workpieces, and is widely used in the preliminary pre-treatment and matte texture finishing of custom hardware cases and metal enclosures. It is a highly versatile basic process for hardware processing.
Processing Procedure
First, clean the hardware workpiece thoroughly to remove oil stains, пыль, oxide scales, and impurities from the surface. According to the hardness and surface texture requirements of the workpiece material, select corresponding abrasives, such as glass beads, quartz sand, and stainless steel beads. Place the workpiece in a sealed sandblasting chamber and adjust the air pressure and spraying distance.
Through the abrasive’s uniform impact, complete surface grinding, deburring, and leveling treatment. Finally, remove dust and conduct secondary cleaning to ensure no abrasive residue on the workpiece surface, and proceed to subsequent anti-rust and painting processes.
Applicable Scenarios
Suitable for aluminum alloy cases, stainless steel hardware enclosureс, and various sheet metal parts. It mainly processes products with matte, anti-glare, and uniform sanding textures. It can be used as a pre-treatment process for anodizing and painting, significantly enhancing the coating adhesion. Widely applied in the surface treatment of electronic equipment enclosures, mechanical hardware accessories, outdoor communication cases, and ordinary industrial structural components. It is also the preferred process for removing metal surface tool marks and burrs after CNC processing, suitable for the majority of non-ultra-high precision hardware workpieces.
Technical Points
The abrasive must be strictly matched with the substrate: for aluminum and thin-walled hardware, glass beads are preferred to avoid surface scratches; for thick-walled steel and heavy-duty hardware, stainless steel beads are used to enhance surface density. The processing air pressure should be stabilized at 0.4–0.8 MPa to prevent uneven sandblasting and deformation of the workpiece surface.
The spraying distance is fixed at 10–15 cm, and the gun head moves at a constant speed to ensure uniform surface roughness, with a standard roughness Ra controlled at 1.2–6.3 μm. Excessive sandblasting is strictly prohibited to avoid thinning of the workpiece wall thickness and a decrease in structural strength, affecting the stability of the product.
Equipment Points
The core processing equipment includes fully automatic sealed sandblasting machines, high-pressure air compressors, abrasive recovery systems, and dust purification equipment. Industrial-grade sandblasting equipment must support stepless air pressure adjustment and uniform spraying coverage throughout the area. It must adopt a sealed chamber design to comply with environmental protection emission standards and eliminate dust pollution.
The equipment is equipped with automatic abrasive screening and recycling systems to reduce material loss and production costs. For standardized batch workpieces such as cases and enclosures, it is recommended to equip a line-type automatic sandblasting equipment to significantly improve batch processing efficiency.
Metal Texturing Treatment
Metal texturing is a mechanical texture processing technology that can form continuous and regular texturing on the metal surface, balancing decorative and anti-scuffing and anti-abrasion performance. It is the mainstream appearance level process for high-end custom hardware enclosures and precision sheet metal parts.
Processing Procedure
First, perform deburring and leveling treatment on the workpiece surface to eliminate unevenness, defects, and processing marks. According to the required texture fineness of the product, select sanding belts of different mesh sizes, ranging from 180# к 800#. Use professional texturing equipment for uniform grinding, achieving different texture effects such as straight-line texturing, random texturing, and cross texturing. After texturing, clean the surface grinding dust and promptly perform oil sealing for oxidation prevention and protection film application to avoid oxidation discoloration and staining on the workpiece surface.
Applicable Scenarios
It is mainly applicable to hardware components made of stainless steel, алюминиевый сплав, and cold-rolled steel. It is widely used in high-end electronic device casings, instrument and meter enclosures, home appliance hardware accessories, communication equipment shells, и т. д., as well as high-end industrial products. It is suitable for products that require a natural metallic texture, anti-fingerprint, and anti-abrasion and wear resistance, effectively enhancing the product’s grade. It is not applicable to complex curved surfaces or ultra-thin wall structure components, as it is prone to causing component deformation and uneven textures.
Technical Key Points
Select the abrasive belt according to the product positioning: 180#–320# coarse grit abrasive belts are used for industrial hardware rough texture processing, while 400#–800# fine grit abrasive belts are used for high-precision decorative shell fine processing. Strictly control the grinding speed and pressure to ensure uniform texture depth and no local over-grinding or missed grinding. Aluminum alloy components need to avoid excessive grinding to prevent surface high-temperature oxidation and blackening.
The direction of the brushed texture should be uniform, matching the aesthetic requirements of product assembly, and ensuring overall texture coordination. After the brushing process, the anti-oxidation post-treatment must be completed within 2 hours to prevent rusting, color change, and loss of gloss.
Equipment Key Points
The core equipment includes flat brushing machines, rotating brushing machines, and fully automatic abrasive belt grinding machines. High-precision models are equipped with constant pressure control systems, maintaining stable grinding pressure throughout the process and eliminating texture color differences and uneven depths. The equipment supports speed adjustment and rapid replacement of abrasive belts, capable of adapting to various texture processing needs.
Batch production equipment is equipped with an automatic loading and unloading system to reduce human intervention errors and improve product consistency. Standardized professional dust removal devices are provided to purify the workshop environment and comply with industrial production environmental protection norms.
Aluminum Oxidation Treatment
Aluminum oxidation is an exclusive electrochemical surface treatment process for aluminum alloys, and it is the most mainstream anti-corrosion and decorative process for aluminum chassis and hardware enclosures. Through electrolytic reactions, a dense and hard oxide film is formed on the metal surface, fundamentally enhancing the protective performance and appearance texture of the aluminum material.
Processing Flow
The pre-processing steps include degreasing, alkaline washing, acid washing, and pure water cleaning, thoroughly removing oil stains, natural oxide layers, and impurities from the workpiece surface to ensure the cleanliness of the substrate. The cleaned aluminum alloy workpiece is placed as the anode in the electrolytic tank and subjected to electrolytic oxidation treatment with direct current. An even oxide film layer is formed on the aluminum surface. After the oxidation process, according to the requirements, coloring, sealing treatment can be carried out, and finally, it is cleaned and dried to complete the overall processing, effectively locking in the color of the film layer and enhancing the corrosion resistance.
Applicable Scenarios
It is only applicable to aluminum alloy and aluminum profile hardware components. It is the core processing technology for aluminum chassis, equipment enclosures, new energy accessories, and precision sheet metal parts.
It is widely used in outdoor communication equipment, industrial control chassis, medical equipment enclosures, consumer electronic accessories, и т. д., for products requiring anti-corrosion, anti-oxidation, and appearance texture. It can be made in natural matte or colored decorative surfaces, balancing practicality and aesthetics. It is not suitable for steel, нержавеющая сталь, and other non-aluminum material components.
Technical Key Points
The pre-processing must be thorough, with residual oil stains and oxide layers causing uneven oxide films, pinholes, and delamination. Strictly control the electrolytic voltage, current, and oxidation time. The thickness of the conventional hard aluminum oxide film is controlled at 5–25 μm, and the thickness of the ordinary decorative oxide film is 3–10 μm.
The coloring process needs to control temperature, concentration, and duration to ensure uniform color without color differences and easy color retention. The sealing treatment is crucial, effectively closing the micro-pores of the oxide film, significantly enhancing the anti-corrosion and anti-pollution ability of the component, and avoiding whitening and dirt accumulation later.
Equipment Key Points
The entire equipment includes pre-processing cleaning tanks, electrolytic oxidation tanks, coloring tanks, sealing tanks, constant temperature control systems, DC stabilized power supplies, and drying equipment. Industrial production lines need to be equipped with precise temperature control systems to ensure the constant temperature of the electrolyte solution and avoid fluctuations in membrane layer quality.
The power equipment must support precise adjustment of current and voltage to adapt to different membrane layer processing requirements. Batch production requires the configuration of a fully automated assembly line to achieve automatic loading and unloading, as well as slot body switching, ensuring uniform product quality for each batch and reducing the defect rate.
Электростатическое распыление / Painting Treatment
Electrostatic spraying includes two processes: powder spraying and painting. It uses the principle of electrostatic adsorption to evenly attach the coating to the surface of the hardware, which is the most versatile, balanced in protection and decorative effects, and suitable for most metal materials.
Processing Flow
First, the workpiece undergoes degreasing, rust removal, and sanding/pre-treatment to enhance surface adhesion. Using an electrostatic spraying equipment, the powder coating or paint is atomized and evenly covered on the workpiece surface through electrostatic adsorption. After spraying, the workpiece is sent to a constant-temperature oven for high-temperature curing.
The curing temperature for powder spraying is 180–220℃, while for liquid painting, it is low-temperature leveling curing. After cooling, the surface flatness and adhesion are checked, and any defects are repaired before completion.
Applicable Scenarios
It is suitable for most hardware materials such as steel plates, cold-rolled steel, нержавеющая сталь, and aluminum alloys. It has strong versatility and is widely used in industrial cases, cabinet shells, equipment sheet metal, outdoor hardware brackets, and household hardware accessories. It is suitable for workpieces that require pure color decoration, dust prevention, rust prevention, and weather resistance, and can be customized with any color, matte, glossy, or frosted texture. It is the most cost-effective batch surface treatment process.
Technical Points
Pre-treatment is the core to prevent paint peeling and cracking. The surface must be free of oil stains, oxide scales, and have an appropriate roughness. Controlling the electrostatic voltage and spraying thickness, avoiding thin paint layers showing through, thick paint layers running, and powder accumulation. The curing temperature and duration must be strictly matched with the coating parameters.
Insufficient temperature will result in poor adhesion and easy detachment, while excessive temperature will cause the paint surface to turn yellow and crack. Outdoor products need to use weather-resistant coatings to effectively resist ultraviolet rays and rain erosion, preventing fading and powdering over time.
Equipment Points
The core equipment includes electrostatic spraying machines, electrostatic spray guns, constant-temperature curing ovens, dust-free spraying rooms, and powder recovery systems. The production environment must be dust-free and dry to avoid impurities adhering to the surface and causing particle flaws. Fully automatic spraying equipment supports uniform spraying from multiple angles, suitable for complex-structured workpieces without blind spots for coating.
The powder spraying equipment is equipped with a recovery system to increase coating utilization and save costs. Batch processing should preferentially use line spraying equipment, suitable for standardized production of large quantities of cases and shells.
Electrophoretic Surface Treatment
Electrophoretic coating is a precise coating process that uses the effect of an electric field to evenly deposit the coating on the metal surface. The film layer is uniform, has strong adhesion, and excellent corrosion resistance, suitable for complex precision hardware workpieces.
Processing Flow
The workpiece undergoes degreasing, water washing, phosphating, and pure water rinsing to thoroughly clean the base material surface. The workpiece is placed as an electrode in the electrophoretic tank, and after power-on, the coating particles are uniformly adsorbed and deposited on the workpiece surface, forming a uniform film. After electrophoretic coating, the workpiece is taken out, and the surface is washed multiple times to remove floating paint, and finally dried and cured at a constant temperature to form a dense, smooth protective coating.
Applicable Scenarios
It is suitable for hardware materials such as steel, алюминиевый сплав, and galvanized plates, especially for complex-structured cases and shells with irregular shapes, grooves, edges, and hollows. It is widely used in precision electronic hardware, communication equipment accessories, automotive hardware parts, and high-end industrial cases. The film layer is thin and uniform, not affecting the assembly accuracy of the workpiece, suitable for products with strict size tolerance, high corrosion resistance, and high smoothness.
Technical Points
Strictly control the electrophoretic liquid concentration, temperature, pH value, and power-on time. Parameter fluctuations will directly lead to uneven film thickness, color differences, and exposure. Phosphating treatment must be uniform and complete to enhance coating adhesion and corrosion resistance. For concealed parts such as edges, gaps, and crevices of the workpiece, optimize the electric field parameters to ensure no missed coating or thin coating. The drying temperature should be gradually increased at a constant rate to avoid appearance defects such as blistering, orange peel, and cracking on the coating.
Key Points of the Equipment
The entire equipment consists of a pre-treatment tank, an electrophoretic tank, a pure water system, a constant-temperature drying oven, and an electrically controlled stabilizing system. The equipment must be equipped with an accurate parameter control system to maintain the stable temperature and pH value of the electrophoretic liquid, as well as the voltage and current.
The pure water purification system is the core, eliminating the influence of water quality impurities on the coating quality. The fully automatic electrophoretic production line can achieve uniform coating on the workpiece in all directions, and is suitable for batch precision processing of complex-structured workpieces, with an extremely high yield rate.
Galvanizing Surface Treatment (Hot Dipping/Galvanizing Electrolytic)
The galvanizing process is divided into electro-galvanizing and hot-dip galvanizing. It is the most classic and cost-effective rust prevention treatment process for steel materials in hardware, achieving sacrificial anode protection by attaching a zinc layer on the steel surface, significantly enhancing the rust resistance of the steel.
Processing Flow
The workpiece is first subjected to degreasing, acid washing, and water washing for pre-treatment to remove rust and oil stains on the steel surface.
Electro-galvanizing: Place the workpiece in the galvanizing electrolyte, and after power-on, zinc ions deposit on the surface of the workpiece to form a thin zinc layer, followed by passivation and sealing treatment.
Hot-dip galvanizing: Clean the steel workpiece and immerse it in the high-temperature molten zinc liquid, fully immerse it, take it out, cool and shape, to form a thick zinc protective layer.
Applicable Scenarios
It is exclusively suitable for carbon steel, cold-rolled steel, hot-rolled steel, and other steel material hardware parts. Electro-galvanizing is suitable for precision sheet metal, small hardware accessories, and lightweight chassis structural parts, with a thin coating, high precision, and flat appearance. Hot-dip galvanizing is suitable for outdoor heavy-duty hardware, equipment brackets, large-scale steel structure chassis, and engineering hardware, featuring strong corrosion resistance and durability, suitable for outdoor, humid, and corrosive harsh working conditions.
Technical Points
Electro-galvanizing requires strict control of the coating thickness, with a conventional thickness of 3–15 μm. Passivation treatment can further enhance corrosion resistance, including white zinc, blue zinc, colored zinc, and black zinc, with various appearances. Hot-dip galvanizing requires controlling the zinc immersion temperature and duration to avoid under-coating, zinc nodules, and rough surfaces.
After galvanizing, timely sealing treatment is carried out to prevent zinc layer oxidation and whitening, and the formation of white rust. Precision thin-walled workpieces are preferred for electro-galvanizing to avoid deformation caused by high temperature in hot-dip galvanizing.
Key Points of Equipment
Electro-galvanizing equipment includes electroplating tanks, rectifier power supplies, passivation tanks, drying equipment, and water circulation systems; Hot-dip galvanizing equipment includes high-temperature zinc pots, preheating equipment, dust removal equipment, and cooling and shaping equipment.
The electroplating production line requires stable current output to ensure uniform and consistent coating; Hot-dip galvanizing equipment needs precise temperature control to adapt to large-scale workpiece processing. The equipment is equipped with an environmental protection sewage treatment system, meeting industrial production environmental protection standards, and suitable for batch mass production requirements
Заключительные мысли
Different surface treatment processes for hardware have significant differences in terms of protective performance, appearance effect, cost, compatible materials and working conditions: Sandblasting is suitable for basic leveling pre-treatment and matte texture. Metal polishing mainly features high-end decorative metal textures.
Anodizing is the exclusive high-end anti-corrosion process for aluminum alloys. Electrostatic spraying has high cost-effectiveness and rich colors. Electrocoating is suitable for complex and precise parts; Galvanizing is the preferred cost-effective rust prevention method for steel parts. Hardware processing manufacturers can, based on the product material, usage scenario, precision requirements and budget, combine the most optimal surface treatment plan, taking into account both product quality and production cost.
