Monthly Archive May 2020

Bychengcg

The planning of the processing route of precision parts is to make the overall layout of the process

General principles for drawing up process routes of precision parts

The process planning of precision parts can be divided into two steps. First of all, it is to draw up the process route of parts processing, and then determine the process size of each process, used equipment and process equipment, cutting specifications, working hours quota, etc. These two steps are interrelated and should be analyzed comprehensively.

The main task is to select the processing methods of each surface, determine the machining sequence of each surface, and determine the number of processes in the whole process.

General principles of the proposed process route

1. Machining datum first

In the machining process of parts, the surface used as the positioning reference should be machined first, so as to provide the precision reference for the subsequent processing as soon as possible. It is called “benchmark first”.

2. Division of processing stages

Surfaces with high machining quality requirements are divided into three stages: rough machining, semi finish machining and finish machining. It is mainly to ensure the processing quality, to facilitate the rational use of equipment, to facilitate the arrangement of heat treatment process, and to facilitate the detection of blank defects.

3. Face before hole

For the box, bracket, connecting rod and other parts, the plane shall be machined before the hole is machined. In this way, the hole can be machined by plane positioning, ensuring the position accuracy of plane and hole, and bringing convenience to the machining of hole on plane.

4. Finishing

The finishing of main surfaces (such as grinding, honing, finishing rolling, etc.) shall be placed at the last stage of the process route.

Bychengcg

The planning of the processing route of precision parts is to make the overall layout of the process

General principles for drawing up process routes of precision parts

The process planning of precision parts can be divided into two steps. First of all, it is to draw up the process route of parts processing, and then determine the process size of each process, used equipment and process equipment, cutting specifications, working hours quota, etc. These two steps are interrelated and should be analyzed comprehensively.

The main task is to select the processing methods of each surface, determine the machining sequence of each surface, and determine the number of processes in the whole process.

General principles of the proposed process route

1. Machining datum first

In the machining process of parts, the surface used as the positioning reference should be machined first, so as to provide the precision reference for the subsequent processing as soon as possible. It is called “benchmark first”.

2. Division of processing stages

Surfaces with high machining quality requirements are divided into three stages: rough machining, semi finish machining and finish machining. It is mainly to ensure the processing quality, to facilitate the rational use of equipment, to facilitate the arrangement of heat treatment process, and to facilitate the detection of blank defects.

3. Face before hole

For the box, bracket, connecting rod and other parts, the plane shall be machined before the hole is machined. In this way, the hole can be machined by plane positioning, ensuring the position accuracy of plane and hole, and bringing convenience to the machining of hole on plane.

4. Finishing

The finishing of main surfaces (such as grinding, honing, finishing rolling, etc.) shall be placed at the last stage of the process route.

Bychengcg

What is precision part processing technology?

Many people know what precision parts processing, but for the machining process, presumably many people are not very familiar with it. The machining process specification is one of the process documents that stipulate the machining process and operation method of parts. It is a process document which is written in the specified form according to the more reasonable process and operation method under the specific production conditions, and is used to guide production after approval. Machining process specification generally includes the following contents: process route of workpiece processing, specific contents of each process, equipment and process equipment used, inspection items and methods of workpiece, cutting amount, time quota, etc.

Precision parts processing technology is to change the shape, size, relative position and nature of the production object on the basis of the process to make it a finished or semi-finished product. It is a detailed description of each process. For example, as mentioned above, rough machining may include rough manufacturing, grinding, etc., and finish machining may be divided into turning, fitter, milling machine, etc., each step is necessary There are detailed data, such as how much roughness to achieve, how much tolerance to achieve.

According to the quantity of products, equipment conditions and quality of workers, technicians determine the adopted process and write the relevant contents into process documents, which are called process procedures. This is more targeted. Every factory may be different, because the actual situation is different.

Generally speaking, the process flow is the program, the processing technology is the detailed parameter of each step, and the process procedure is a specific processing technology compiled by a factory according to the actual situation.

Bychengcg

Reaming process of stainless steel parts

The reaming process of stainless steel parts is as follows:

(1) The reaming of stainless steel material mostly uses carbide reamer. The structure and geometric parameters of reamer are different from those of common reamer. In order to enhance the strength of cutter teeth and prevent chip blocking during reaming, the number of reamer teeth is generally small. The manufacturer of stainless steel parts tells you that the front angle of reamer is generally 8 ° ~ 12 °, but in some special cases, in order to achieve high-speed reaming, the front angle of 0 ° ~ 5 ° can also be used; the back angle is generally 8 ° ~ 12 °; the selection of main deflection angle depends on the different holes, in general, the through hole is 15 ° ~ 30 °, and the through hole is 45 °; in order to make the chips discharged forward, the angle of blade inclination can also be increased properly The angle of blade inclination is generally 10 ° ~ 20 °; the width of blade belt is Zero point one ~ 0.15mm The reverse taper of reamer shall be larger than that of common reamer, and the carbide reamer is generally zero point two five ~ 0.5mm/100mm , high speed steel reamer is Zero point one ~ 0.25mm/100mm The length of reamer correction part is generally 65% ~ 80% of common reamer, and the length of cylinder part is 40% ~ 50% of common reamer.

(2) When selecting the cutting amount, the feed amount is zero point zero eight ~ 0.4mm/r The cutting speed is 10-20 M / min, and the coarse reaming allowance is generally Zero point two ~ 0.3mm The allowance of finish reaming is Zero point one ~ 0.2mm 。 Hard alloy cutter shall be used for coarse reaming and high speed steel cutter shall be used for fine reaming.

(3) The manufacturer of stainless steel parts tells you that when the cutting fluid chooses stainless steel material for reaming, the oil or molybdenum disulfide used in the total loss system can be used as the cooling medium.

Bychengcg

Identification skills of stainless steel in processing of stainless steel parts

Stainless steel parts manufacturers tell you that with the development of economy, the use of stainless steel has become more and more extensive. People’s daily life is closely related to stainless steel, but many people do not know enough about the performance of stainless steel and the maintenance of stainless steel. Most people think stainless steel will never rust. In fact, the reason why stainless steel has good corrosion resistance is that a passivation film is formed on its surface, and it exists in a more stable oxide form in nature. That is to say, although stainless steel is oxidized to different degrees according to different service conditions, it is eventually oxidized, which is usually called corrosion.

The manufacturer of stainless steel parts tells you that stainless steel refers to the steel that is resistant to weak corrosive media such as air, steam, water and chemical corrosive media such as acid, alkali and salt, also known as stainless acid resistant steel. Here are some stainless steel identification techniques for your reference.

1. Liquid medicine detection method: at present, there are several chemical liquid medicines used to detect stainless steel on the market. When one drops onto the surface of stainless steel, 201 turns dark brown and 304 turns red.

2. Price estimation method: fully understand the market situation of each steel grade. If the price of the same steel grade varies greatly, we should consider whether it is “Li Gui”.

3. Integrity of traders: enterprises with better integrity will do business in the market. It’s better to select more traders for comparison, which is also the way to prevent “Li Gui”.

4. Contract agreement law: stainless steel parts manufacturers tell you that in the transaction of stainless steel, those with large amount shall sign a good contract, indicating steel type, quantity, material, time, delivery date, responsibility for violating laws and disciplines, etc. In case of material discrepancy, the loss can be recovered through negotiation or law.

Bychengcg

Introduction of ultra precision machining and special machining

Cutting of ultra precision parts

The machining of ultra precision parts mainly includes ultra precision turning, mirror grinding and grinding. Micro turning is carried out on ultra precision lathe with a single crystal diamond turning tool which has been finely ground. The cutting thickness is only about 1 μ m. It is commonly used to process high-precision and smooth surface parts such as spherical, aspheric and plane mirrors of non-ferrous materials. For example, the aspherical mirror with a diameter of 800 mm used for processing nuclear fusion device has a maximum accuracy of 0.1 μ m and a surface roughness of rz0.05 μ M.

Special machining of ultra precision parts

When the machining precision of ultra precision parts is nanometer, or even the atomic unit (atomic lattice distance is 0.1-0.2nm), the cutting method of ultra precision parts can not adapt. It needs to use the special precision parts processing method, that is, chemical energy, electrochemical energy, thermal energy or electric energy, to make these energy exceed the combined energy between atoms, so as to remove the surface of the workpiece In order to achieve the purpose of ultra precision machining, some atoms are attached, combined or lattice deformed. These processes include mechanical chemical polishing, ion sputtering and ion implantation, electron beam exposure, laser beam processing, metal evaporation and molecular beam epitaxy.

The feature of these ultra precision parts machining methods is that the amount of material removed or added to the surface layer can be controlled very slightly. However, to obtain the machining accuracy of ultra precision parts, it still depends on the precise machining equipment and precise control system, and the ultra precision mask is used as the intermediary. For example, in VLSI plate making, electron beam is used to expose photoresist (see photolithography) on the mask to make the atoms of photoresist polymerize (or decompose) directly under electron impact, and then developer is used to dissolve the polymerized or unpolymerized parts to make the mask. It is necessary to use the ultra precision machining equipment with the positioning accuracy of ± 0.01 μ M.

Bychengcg

Characteristics of large deep hole drill

1. The whole casting adopts high-quality mihanna cast iron, and after aging treatment, the structure of the casting is uniform and stable, with high rigidity and good stability.

2. The three-axis adopts imported high rigidity and high precision screw rod, which provides more powerful torque and durability during processing.

3. The imported high rigidity, heavy load, high speed and high precision ball linear guide rail is adopted for the three-axis, which ensures the high precision of processing and prolongs the service life of the linear guide rail.

4. The three-axis feed drive adopts Japanese AC servo motor and driver, and is directly connected with the ball screw. The transmission is stable without backlash. At the same time, its good rigidity and optimized shock absorption performance greatly improve the dynamic rigidity of the transmission system, which can realize rapid movement.

5. The spindle adopts imported powerful motor, which can meet the processing requirements of high and low speed, and is equipped with automatic oil cooling system to ensure constant temperature during processing.

6. The operating system adopts Taiwan system, which can be compatible with CAD / CAM software to use more metadata.

Bychengcg

Fault analysis of processing large horizontal computer gongs

As a processing industry, especially machining, it is the basic knowledge that every enterprise must know how to analyze and solve its faults. It is also the first step of the processing and maintenance of large horizontal computer gongs. By analyzing the faults, we can quickly find out the causes of the faults and solve them. At the same time, it is also a function of preventing and expanding the machinery. Generally speaking, large horizontal computer The fault analysis of Gong processing has the following aspects:

1. Action analysis method action analysis method is a method to determine the bad part of the action and trace the root cause of the fault by observing and monitoring the actual action of the machine tool. Generally speaking, the hydraulic and pneumatic control parts of Dongguan computer gonging machine tool, such as automatic tool change device, exchange table device, fixture and transmission device, can be determined by action diagnosis.

2. State analysis state analysis method is a method to determine the cause of failure by monitoring the working state of the actuator. This method is most widely used in the maintenance process of Dongguan computer gongs.

3. Conventional analysis conventional analysis is a method to check the mechanical, electrical, hydraulic and other parts of Dongguan computer gong processing machine tool, so as to determine the cause of the failure. The above is a large horizontal computer gongs processing failure analysis methods and solutions, hope to help the majority of users

Bychengcg

Classification and application of aluminum plate

According to different processing technology, it can be divided into cold rolling and hot rolling.

According to the different thickness, it can be divided into thin plate and medium thick plate. The aluminum foil with thickness less than 0.2mm specified in GB / t3880-2006 is called aluminum foil. Commonly used brand: pure aluminum plate, strip. Foil. Thick plate, stretch tube. Squeeze the tube. Type. Great. Cold processed bar is mainly used in the situation of high corrosion resistance and formability, but not high strength parts, such as chemical equipment, ship equipment, railway tank car, conductive material, instrument material, welding rod, etc.

3003: plate and strip. Foil. Plate. Stretch the tube. Squeeze the tube. Type. Great. wire rod. Cold working bar, cold working wire, rivet wire, forging, radiator material. It is mainly used for processing parts requiring good molding performance, high corrosion resistance, or weldability, or parts requiring these properties and higher strength than 1 *, such as tanks and tanks for liquid transportation, pressure tanks, storage devices, heat exchangers, chemical equipment, aircraft oil tanks, oil ducts, reflectors, kitchen equipment, washing machine cylinder, rivets, welding Silk. Aluminum clad 3003 alloy: plate, thick plate, stretch tube. Extrusion pipe house partition, top cover, pipeline, etc. 3004: plate, thick plate, tensile pipe. As long as the extruded tube is used for the whole aluminum can body, it requires higher parts than 3003 alloy, chemical product production and storage device, sheet metal processing parts, building baffles, cable ducts, sewers, various lighting parts.

3004 aluminum clad alloy: plate and thick plate are mainly used for building partition, baffle, sewer, roof cover of industrial building 5052: plate, thick plate, foil, tensile pipe, cold processed bar, cold processed wire, rivet wire. This alloy has good forming and processing performance, corrosion resistance, weldability, fatigue strength and medium static strength, and is used for making aircraft oil tank and oil pipe , as well as traffic vehicles, ship’s sheet metal parts, instruments, street lamp brackets and rivet wires, etc. 6061: plate, thick material, tensile pipe. Extrusion pipe, bar, profile, wire, conduit, rolled or extruded structural profile, cold processed bar, cold processed wire, rivet wire, forging. All kinds of industrial structural parts with certain strength, corrosion resistance and high weldability are required, such as pipes, bars and profiles for manufacturing trucks, tower buildings, ships, trams, railway vehicles, furniture, etc.

According to the classification of aluminum plate brand, according to the different metal elements contained in the aluminum plate, we will introduce it gradually.

1. The 2000 series aluminum plate represents 2A16 (Ly16) 2A12 (LY12) 2A06 (LY6) 2000 series aluminum plate, which is characterized by high hardness, of which the copper element content is the highest, about 3-5%. 2000 series aluminum plate belongs to aviation aluminum material, which is not often used in conventional industry at present. At present, there are few manufacturers of 2000 series aluminum plates in China. The quality cannot be compared with that of foreign countries. At present, the imported aluminum plates are mainly provided by Korean and German manufacturers. With the development of China’s aerospace industry, the production technology of 2000 series aluminum plate will be further improved.

In such humid environment, the price is higher than 1000 series, which is a more commonly used alloy series.

2. 5000 series represents 5052.5005.5083.5a05 series. 5000 series aluminum plate belongs to the commonly used alloy aluminum plate series, the main element is magnesium, and the magnesium content is between 3-5%. Also known as aluminum magnesium alloy. It is characterized by low density, high tensile strength and high elongation. In the same area, the weight of aluminum magnesium alloy is lower than other series, so it is often used in aviation, such as aircraft fuel tank. It is also widely used in conventional industry. The processing technology is continuous casting and rolling, belonging to the hot rolling aluminum plate series, so it can do deep oxidation processing. In China, 5000 series aluminum plate belongs to one of the more mature aluminum plate series.

3. 6000 series represents 6061, which mainly contains two elements of magnesium and silicon. Therefore, 6061 is a cold-treated aluminum forging product with the advantages of 4000 series and 5000 series. It is suitable for applications with high requirements of corrosion resistance and oxidation resistance. The utility model has the advantages of good usability, excellent interface characteristics, easy coating and good processability. It can be used on low-pressure weapons and aircraft joints. General features of 6061: excellent interface features, easy coating, high strength, good usability, strong corrosion resistance. Typical uses of 6061 aluminum: aircraft parts, camera parts, couplers, ship accessories and hardware, electronic accessories and joints, decorative or various hardware, hinge head, magnetic head, brake piston, hydraulic piston, electrical accessories, valves and valve parts.

4. The 7000 series represents the 7075 mainly containing zinc. It also belongs to the aviation series. It is an aluminum magnesium zinc copper alloy. It is a heat-treatment alloy. It belongs to super hard aluminum alloy. It has good wear resistance. 7075 aluminum plate is stress relieved and will not deform or warp after processing. All super thick 7075 aluminum plates are detected by ultrasonic, which can ensure no sand holes and impurities. 7075 aluminum plate has high thermal conductivity, can shorten forming time and improve working efficiency.

The main feature is that the hardness of 7075 is a high hardness and high strength aluminum alloy, which is commonly used to manufacture aircraft structures and futures. It requires the manufacture of high stress structural parts and dies with high strength and corrosion resistance. At present, China’s production process still needs to be improved. (a foreign company in our company once proposed that the annealing of 7075 aluminum plate made in China is uneven, and the surface and internal hardness of aluminum plate are inconsistent.).

Bychengcg

How to process parts in large CNC machining center

CNC machining is flexible and highly automatic, especially suitable for machining curve and curved surface parts with complex contour and shape, as well as complex box and prism parts with a large number of holes and grooves. In the case of multiple varieties and small batch production, the use of CNC machining can obtain higher economic benefits.

The processing technology of large-scale CNC is basically the same as that of common processing, but it has its own characteristics. Therefore, when designing the NC machining process of parts, we should not only follow the principle of good flexibility and high automation of NC machining, especially suitable for machining the curve and curved surface parts with complex contour and shape, as well as the complex box and prism parts with a large number of holes and grooves. In the case of multiple varieties and small batch production, the use of NC machining can obtain higher economic benefits.

The determination of tool setting point and tool change point in large CNC machining center is the starting point of tool movement relative to workpiece. Since the program is also executed from this point, the tool setting point is also called the program starting point or starting point. When programming, the selection of tool setting point should be considered first. When the machining accuracy requirements are not high, some surfaces on the workpiece or fixture can be directly used as the tool alignment surface; when the machining accuracy requirements are high, the tool alignment point should be selected on the design basis or process basis of the part as much as possible, for example, for the parts with hole positioning, the axis of the hole taken as the tool alignment point is more appropriate. The tool setting point must have a certain coordinate relationship with the positioning datum of the workpiece, so as to determine the relationship between the coordinate system of the machine tool and the workpiece. The selection of tool setting point shall facilitate the calculation of coordinate value and the tool setting. During the tool setting, the tool setting point shall coincide with the tool position. The so-called tool point refers to the intersection point of the tool axis and the tool bottom surface for the flat end milling cutter; the ball end milling cutter refers to the ball center of the ball head part; the turning tool refers to the tool tip; the drill bit refers to the drill tip; the line electrode cutting machine tool refers to the focus of the line electrode axis and the part surface. When the tool change is needed in the process of machining, the tool change point shall be specified, and the position of the tool change point shall be set according to the principle that the workpiece, fixture and machine tool shall not be damaged during the tool change.

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