China Metal Machining Surface Finish Manufacturer
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Surface finish 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, including machining surface finish, casting surface finish, forging surface finish, and stamping surface finish.
The purpose of machining / casting / forging / stamping surface finish is to meet the product’s corrosion resistance, wear resistance, decoration or other special functional requirements. For metal castings, our more commonly used surface finish methods are mechanical polishing, chemical treatment, surface heat treatment, and spray surface. Surface finish including machining surface finish is to clean, sweep, deburr, degrease, and deoxidize the surface of the workpiece.
One is surface finish in a broad sense. The surface finish includes pretreatment, electroplating, coating, chemical oxidation, thermal spraying and many other physical and chemical methods.
The other is a narrowly-defined surface finish, that is, the pre-treatment part that only includes sandblasting, polishing, etc., which is what we often say.
Since there were humans on the earth, surface finish is the earliest technology that humans have mastered. The life of primitive humans is extremely hard and they live in groups. In order to survive, they make stone tools and apply grinding technology to make the stone tools have sharp edges and produce a “pointing” effect.
The stone tools used by primitive people were polished, the surface was delicate and smooth, and the decoration effect was emphasized, which has become the mainstream of the times. In primitive society, as important as grinding stone tools is primitive painting technology. Primitive humans have a sense of beauty.
They used mineral dyes to paint and paint small personal entertainment items.
The invention of pottery brought the original color coating technology to its peak, forming a famous painted pottery art in history, and unveiling the prelude to surface finish coating technology.
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.
Chemical treatment mainly uses acidic or alkaline solutions to react with oxides and oil stains on the surface of the workpiece to dissolve them in an acid or alkaline solution to remove rust, oxide scale and oil stains on the surface of the workpiece, and then use nylon Brush roller or 304# stainless steel wire (a steel wire brush roller made of acid and alkali resistant solution can be cleaned to achieve the goal.
Chemical treatment is suitable for cleaning thin plates, but the disadvantage is: if the time is not properly controlled, even if the corrosion inhibition is added It can also cause over-corrosion of steel. For more complex structural parts and porous parts, after acidic solution pickling, the residual acid immersed in the crevices or cavities is difficult to completely remove. If it is not handled properly, it will become a workpiece. Corrosion is a hidden danger, and the chemicals are volatile, and the cost is high. The chemical discharge after treatment is difficult. If not handled properly, it will cause serious pollution to the environment.
With the improvement of people’s environmental protection awareness, this treatment method is being mechanically treated Method to replace. Mechanical treatment of nylon brush roller nylon brush roller mainly includes wire brush roller polishing method, shot blasting method and shot peening method.
Polishing method means that the brush roller is driven by the motor, and the brush roller moves in the opposite direction to the movement of the rolled piece. The upper and lower surfaces of the strip are rotated at a high speed to remove the oxide scale. The brushed iron scale is washed away by a closed-circulation cooling water washing system.
Shot blasting is a method of using centrifugal force to accelerate the projectile and projecting it to the workpiece for rust cleaning. But throwing The pill has poor flexibility, limited by the site, and some blindness when cleaning the workpiece.
It is easy to produce dead spots on the inner surface of the workpiece. The structure of the equipment is complex, and there are many vulnerable parts, especially the blades and other parts. , One-time investment is large. Using shot blasting for surface finish, the impact force is large, and the cleaning effect is obvious.
However, the treatment of thin plate workpieces by shot blasting can easily deform the workpiece, and the steel shot hits the surface of the workpiece (whether shot blasting or shot blasting) The metal substrate is deformed. Because ferroferric oxide and ferric oxide have no plasticity, they peel off after being broken, and the oil film deforms together with the material. Therefore, shot blasting and shot blasting can not completely remove the oil stains on the work piece with oil stains.
Among the existing surface finish methods for workpieces, the best cleaning effect is sandblasting.
Sandblasting is suitable for cleaning the surface of workpieces with higher requirements.
The sand suction machine is used as a machine for conveying sand. The sand suction machine is actually a super large vacuum cleaner. A thicker conveying pipe connects the hopper with the suction. The sand machine is connected to suck the sand into the storage tank.
The characteristic of the sand suction machine 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.
The sand suction machine is currently available in China Several manufacturers specialize in sand suction machines, but the technology is relatively immature, so most surface finish companies mainly use bucket elevators. Plants that need to do blasting are choosing sand conveying equipment.
When working with dust removal equipment, you must fully consider the actual production situation, and try to choose equipment with a larger power than the production needs. Since the equipment used for shot blasting generally wears out quickly, such or other problems will have a lot of impact after long-term use.
For production, the selection of equipment with higher power will greatly reduce the time and expense wasted in future 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 drier areas, sand throwing can be carried out outdoors.
According to the different methods used, the surface finish technology can be divided into the following categories.
The process of forming a coating on the surface of the workpiece in the electrolyte solution as the cathode under the action of external current is called electroplating. The plating layer can be metal, alloy, semiconductor or containing various solid particles, such as copper plating, nickel plating, etc.
In the electrolyte solution, the workpiece is the anode, and under the action of external current, the process of forming an oxide film on the surface is called anodization, such as the anodization of aluminum alloy. The oxidation treatment of steel can be done by chemical or electrochemical methods. The chemical method is to put the workpiece in an oxidizing solution, and rely on chemical action to form an oxide film on the surface of the workpiece, such as bluing of steel.
This method is no current action, using the interaction of chemical substances to form a coating on the surface of the workpiece. The main methods are:
Chemical conversion coating treatment is the process in which the metal workpiece is in the electrolyte solution without external current, and the chemical substance in the solution interacts with the workpiece to form a coating on its surface, which is called chemical conversion coating treatment. Such as bluing, phosphating, passivation, and chromium salt treatment on the metal surface.
Electroless plating is in the electrolyte solution, the surface of the workpiece is catalytically treated, and there is no external current effect. In the solution, due to the reduction of chemical substances, the process of depositing certain substances on the surface of the workpiece to form a coating is called electroless plating. Such as electroless nickel plating, electroless copper plating and so on.
This method is to melt or thermally diffuse the material under high temperature conditions to form a coating on the surface of the workpiece. The main methods are:
The process of putting a metal workpiece into molten metal to form a coating on its surface is called hot-dip plating, such as hot-dip galvanizing and hot-dip aluminum.
The process of atomizing molten metal and spraying it on the surface of the workpiece to form a coating is called thermal spraying, such as thermal spraying zinc and thermal spraying aluminum.
The process of heating and pressing the metal foil to cover the surface of the workpiece to form a coating layer is called hot stamping, such as hot stamping aluminum foil.
The process in which the workpiece is in contact with chemical substances and heated, and a certain element enters the surface of the workpiece at a high temperature is called chemical heat treatment, such as nitriding and carburizing.
The process in which deposited metal is piled up on the surface of the workpiece to form a welding layer by welding is called surfacing, such as surfacing welding with wear-resistant alloys.
This method is a process in which materials are vaporized or ionized and deposited on the surface of the workpiece in a high vacuum state to form a coating. The main method is.
The process of vaporizing metals into atoms or molecules or ionizing them into ions under vacuum conditions and directly depositing them on the surface of the workpiece to form a coating is called physical vapor deposition. The particles are deposited The beam comes from non-chemical factors, such as evaporative plating, sputtering plating, ion plating, etc.
The process of implanting different ions into the surface of the workpiece under high voltage to modify its surface is called ion implantation, such as boron injection.
The process in which gaseous substances form a solid deposition layer on the surface of the workpiece due to chemical reactions under low pressure (and sometimes normal pressure) is called chemical vapor deposition, such as vapor deposition of silicon oxide and silicon nitride. Wait.
Other methods are mainly mechanical, chemical, electrochemical, and physical methods. The main methods are:
Idle spraying or brushing method, the process of applying paint (organic or inorganic) on the surface of the workpiece to form a coating, called painting, such as spraying or brushing.
The process of forming a coating layer on the surface of the workpiece by mechanical impact is called impact plating, such as impact galvanizing.
The process of irradiating the surface of the workpiece with laser to change its structure is called laser surface finish, such as laser quenching and laser remelting.
The technology of preparing super-hard film on the surface of the workpiece by physical or chemical methods is called super-hard film technology. Such as diamond film, cubic boron nitride film and so on.
The workpiece is put into the conductive water-soluble or water-emulsified paint as an electrode, and forms a circuit with the other electrode in the paint. Under the action of the electric field, the coating solution has been dissociated into charged resin ions, the cations move to the cathode, and the anions move to the anode. These charged resin ions, together with the adsorbed pigment particles, are electrophoresed to the surface of the workpiece to form a coating. This process is called electrophoresis.
The process in which the atomized negatively charged paint particles are directed to the positively-charged workpiece under the action of a DC high-voltage electric field to obtain a paint film is called static spraying.
Anodizing is the electrochemical oxidation of metals or alloys. Aluminum and its alloys form a layer of oxide film on aluminum products (anode) under the action of applied current under corresponding electrolyte and specific process conditions. If anodizing is not specified, it usually refers to sulfuric acid anodizing. The workpiece can be oxidized into different colors, such as red, white, silver, green, black, gold, yellow, army green.
Powder coating refers to a treatment process for industrial metal surfaces. The plastic powder is a powder coating, which is a new type of solvent-free 100% solid powder coating.
Part is deburred and scratched using a brush/sander to create a specific grain. This is ideal for parts where a uniform bare finish is required, but powder coating is not desired. Due to geometry, grained finish can only be applied to the outside surfaces of CNC machined and sheet metal fabrication parts, NOT on the inside of the parts.
Non-textured paints (Smooth Polyester, Smooth Epoxy and Smooth Polyester-Epoxy Blend Hybrid) will not cover tool marks on their own. As a result, an additional finishing operation such as grained finish will need to be performed as well.
This is ideal for branding (such as your logo), labelling connectors and switches and for decorative purposes. (Silkscreening is also available, as an alternative to digital printing).
This is a form of permanent marking, ideal for labelling, branding or schematics. Also known as etching, machined engraving is available with powder coat painting, grained finish, anodising and chem film chromate coating, depending on the material.
6061, 7075, 5052, 6063, 7001, 5752
201, 202, 301, 302, 303, 304, 305, 304L, 316, 316L, 420, 430, 430F
Q345, Q235, ST37, AISI 1020, AISI 1045, AISI 1008, AISI 1035, AISI 1016, AISI 1019, AISI 1039, AISI 12L14, AISI 1144, AISI 5115, AISI 5120, AISI 5140, AISI 4140, AISI 5115, AISI 8720CR-MO, CR-V, AISI 4141
AISI C21000, AISI C27400, AISI 28000, AISI C37000, CW617