Analyze the rear surface of aluminum, steel, copper, iron and other hardware parts after machining

The surface treatment of hardware is a process of artificially forming a surface layer on the surface of the base material that is different from the mechanical, physical and chemical properties of the base. The purpose of surface treatment is to meet the product's corrosion resistance, wear resistance, decoration or other special functional requirements. For metal castings, our commonly used surface treatment methods are mechanical polishing, chemical treatment, surface heat treatment, and spray surface. Surface treatment is to clean, sweep, deburr, degrease, and deoxidize the surface of the workpiece.

1. Manual processing

Such as scrapers, wire brushes or grinding wheels. The rust and oxide scale on the surface of the workpiece can be removed by hand, but the manual processing has high labor intensity, low production efficiency, poor quality, and incomplete cleaning.

2. Chemical treatment

It mainly uses acidic or alkaline solution to chemically react with the oxide and oil on the surface of the workpiece to dissolve it in an acid or alkaline solution to remove rust, oxide scale and oil on the surface of the workpiece, and then use nylon to make Brush roller or 304# stainless steel wire (a steel wire brush roller made of acid and alkali solution can be cleaned to achieve the purpose. Chemical treatment is suitable for cleaning thin plates.

3. Mechanical treatment

Mainly include wire brush roller polishing method, shot blasting method and shot blasting method. The polishing method is that the brush roller is driven by the motor, and the brush roller rotates at a high speed on the upper and lower surfaces of the strip in the direction opposite to the movement of the rolling piece to remove the oxide scale. The brushed iron oxide scale is washed away by a closed circulating cooling water washing system. Shot blasting is a method of using centrifugal force to accelerate the projectile and project it to the workpiece for rust removal. However, shot blasting has poor flexibility and is limited by the site. It is a little blind when cleaning the workpiece, and it is easy to produce dead corners on the inner surface of the workpiece that cannot be cleaned. The structure of the equipment is complex, there are many wearing parts, especially the parts such as blades wear quickly, the maintenance man-hours are many, the cost is high, and the one-time investment is large.

Surface treatment with shot blasting has great impact force and obvious cleaning effect. However, the treatment of thin plate workpieces by shot peening is easy to deform the workpiece, and the steel shot hits the surface of the workpiece (no matter shot blasting or shot blasting) to deform the metal substrate. Because the ferroferric oxide and the ferric oxide have no plasticity, they are broken After peeling off, the oil film deforms together with the material, so the shot blasting and shot blasting of the oily work piece cannot completely remove the oil. Among the existing surface treatment methods for workpieces, the best cleaning effect is sandblasting. Sandblasting is suitable for cleaning the workpiece surface with higher requirements. However, the current general sandblasting equipment in my country is mostly composed of primitive and heavy sand conveying machinery such as hinged dragons, scrapers, and top-quality hoists. The user needs to build a deep pit and make a waterproof layer to install the machinery. The construction cost is high, the maintenance workload and the maintenance cost are huge, and a large amount of silica dust is generated during the sandblasting process, which cannot be removed, which seriously affects the health of the operators and pollutes the environment. .

The sand suction machine is often used as a machine for conveying sand in foreign countries. The sand suction machine is actually a super large vacuum cleaner. The hopper is connected to the sand suction machine with a thicker conveying pipe to suck the sand into the storage tank and the sand suction machine The characteristic is that the construction difficulty and process are simpler than the bucket elevator, and it is convenient and easy to control, and requires less maintenance, but it consumes a lot of power. At present, there are several domestic manufacturers specializing in the production of sand suction machines, but the technology is relatively immature , So most surface treatment companies mainly use bucket elevators.

When selecting sand conveying equipment and dust removal equipment, factories that need to do blasting must fully consider the actual production situation, and try to choose equipment with a larger power than production. Because the equipment used for shot blasting generally wears faster , After long-term use, problems of one kind or another will affect production a lot. Choosing more powerful equipment will greatly reduce the time and cost of maintenance. Insufficient power of dust removal equipment not only harms the health of workers, but also seriously affects the visibility of the sandblasting room. The inability of dust to be discharged also affects the quality of the sand itself and the surface roughness of the workpiece.

The manual sandblasting room should be designed according to the actual situation to be more spacious than the accommodating workpiece. It should not be too restrictive or it will affect the manual work of the workers. At the same time, the lighting conditions must be good. For dry areas, sand throwing can be done outdoors.

4. Plasma treatment

Plasma, also known as plasma, is an aggregate composed of positively charged positive particles and negative particles (including positive ions, negative ions, electrons, free radicals and various active groups, etc.), in which the positive and negative charges are equal Therefore, it is called plasma, which is the fourth state in which matter exists in addition to solid, liquid, and gaseous states-plasma state.

The plasma surface processor is composed of a plasma generator, gas delivery pipelines and plasma nozzles. The plasma generator generates high-pressure and high-frequency energy in the nozzle steel pipe to be activated and controlled to generate low-temperature plasma in the glow discharge, with the help of compressed air The plasma is sprayed to the surface of the workpiece. When the plasma and the surface of the object to be processed meet, the object changes and chemical reactions occur.