Machining technology refers to the whole process of making the shape, size, relative position and performance of the blank into qualified parts by traditional machining methods according to the drawings and sizes. Processing technology is the work that workers need to do before processing to avoid processing errors and economic losses.
Machining process is a step of manufacturing workpieces or parts. The process of directly changing the shape, size and surface quality of the blank to make it a part is called machining process. For example, the processing flow of an ordinary part is rough machining-finish machining-assembly-inspection-packaging, which is a general processing flow.
Machining technology is to change the shape, size, relative position and properties of the production object on the basis of technology, so as to make it a finished product or a semi-finished product. It is a detailed description of each step and each process. For example, as mentioned above, rough machining may include blank manufacturing, polishing, etc. And finishing can be divided into lathe, fitter, milling machine, etc. And each step should have detailed data, such as how much roughness and tolerance to achieve.
Technicians determine the technological process to be adopted according to the quantity of products, equipment conditions and workers' quality, and write relevant contents into technological documents, which are called technological 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 parameters of each step, and the process specification is the specific processing technology compiled by a factory according to the actual situation.
Mechanical products refer to finished products or accessories provided by machinery manufacturers to users or markets, such as automobiles, engines and machine tools. , are called mechanical products. According to the traditional custom, any mechanical product can be regarded as a component composed of several parts, and can be divided into different levels of sub-components (also known as sub-components or assemblies) to the most basic parts unit.
1, production process
The production process of products refers to the whole process in which raw materials become finished products. The production process of mechanical products generally includes:
(1) Production and technical preparation, such as process design, design and manufacture of special process equipment, preparation of production plan, preparation of production materials, etc.
(2) blank manufacturing such as casting, forging, stamping, etc. ;
(3) Processing, cutting, heat treatment and surface treatment of parts;
(4) product assembly, such as assembly, assembly, debugging, inspection and painting;
5] Production services such as supply, transportation and storage of raw materials, purchased parts and tools.
2. Production type
The classification of production specialization degree of enterprises (or workshops, sections, teams and groups, workplaces) is called production type. Production types can generally be divided into three types: single production, mass production and mass production.
3. Piece production
The basic characteristics of one-piece production are: there are many kinds of products, the output of each product is very small, and there are few repeated production. For example, the manufacture of heavy machinery products and the trial production of new products all belong to one-piece production.
4. Mass production
The basic characteristics of mass production are: mass production of the same product and periodic repeated production. Such as machine tool manufacturing and motor manufacturing, belong to mass production. Mass production can be divided into three types according to its batch size: small batch production, medium batch production and large batch production. Among them, the technological characteristics of small batch production and large batch production are similar to those of single piece production and large batch production respectively; The technological characteristics of medium batch production are between small batch production and large batch production.
5. Mass production
The basic characteristics of large-scale production are: large output, few varieties, and most workplaces repeatedly process a certain process of a certain part for a long time. For example, the manufacture of automobiles, tractors, bearings, etc. It belongs to mass production.
6. Product design
Product design is the core of enterprise product development, and product design must ensure the advanced technology and economic rationality.
There are generally three forms of product design, namely, innovative design, improved design and deformation design. Innovative design (development design) is a brand-new design according to the user's use requirements; Improved design (adaptive design) is a design that improves or modifies the original products of the enterprise according to the user's use requirements, that is, only part of the structure or parts are redesigned; Deformation design (parameter design) only improves some structural dimensions of products to form a series of product designs. The basic contents of product design include: preparation of design task book, scheme design, process design and pattern design.
7. Process flow design
The basic task of process design is to ensure that the products produced can meet the design requirements, formulate the product manufacturing process regulations with high quality, high yield and low consumption, and formulate all the process documents required for product trial production and formal production. Including: process analysis and review of product drawings, formulation of processing scheme, formulation of process regulations, design and manufacture of process equipment.
8, parts processing
The processing of parts includes the production of blanks, and the process of machining, special processing and heat treatment of blanks to make them qualified parts. Few parts are processed by chip-free processing methods such as precision casting or precision forging. Usually, the production of blank includes casting, forging, welding and so on. Commonly used machining methods include: locksmith machining, turning machining, drilling machining, planing machining, milling machining, boring machining, grinding machining, CNC machine tool machining, broaching machining, grinding machining, honing machining and so on. Common heat treatment methods include normalizing, annealing, tempering, aging, tempering and quenching. Special machining includes: EDM, WEDM, electrolytic machining, laser machining, ultrasonic machining and so on. Only according to the material, structure, shape, size and service performance of the parts, the appropriate processing method can be selected to ensure the product quality and produce qualified parts.
9. check
Inspection is to detect the dimensional accuracy, shape accuracy and position accuracy of blanks, parts, finished products and raw materials with measuring instruments, and to identify the product quality through appearance inspection, nondestructive testing, mechanical performance test and metallographic examination.
Measuring instruments include measuring tools and gauges. Commonly used quantities are steel ruler, tape measure, vernier caliper, caliper gauge, plug gauge, micrometer, angle gauge, dial gauge, etc. Used to detect the length, thickness, angle, cylinder diameter and aperture of parts. In addition, thread can be measured by thread micrometer, three-needle method, thread template, thread ring gauge, thread plug gauge and so on.
Commonly used measuring instruments include buoy pneumatic measuring instrument, electronic measuring instrument, electric measuring instrument, optical measuring instrument and coordinate measuring instrument. , not only can measure the length, thickness, cylinder diameter, aperture and other dimensions of parts, but also can measure the shape error and position error of parts.
Special inspection mainly refers to the detection of internal and external defects of parts. Among them, nondestructive testing is a modern testing technology to detect internal and external defects of parts without damaging the inspected object. Non-destructive testing methods include direct visual inspection, radiographic inspection, ultrasonic inspection and magnetic inspection. Appropriate methods and testing specifications should be selected according to the purpose of nondestructive testing.
10, assembly and debugging
Any mechanical product is composed of several parts, assemblies and components. According to the specified technical requirements, the process of matching and connecting parts to make them into semi-finished or finished products is called assembly. The process of assembling parts into components is called component assembly; The process of assembling parts, assemblies and components into final products is called final assembly. Assembly is the last production stage in the process of mechanical manufacturing, including adjustment, testing, inspection, painting and packaging.
Common assembly work includes: cleaning, connection, calibration and matching, balancing, acceptance and testing.
1 1, warehousing
Finished products, semi-finished products and various materials produced by enterprises are put into warehouses for safekeeping to prevent loss or damage, which is warehousing.
Warehousing inspection should be carried out when warehousing, and inspection records and related original records should be filled in; Do a good job in the maintenance and custody of measuring tools, instruments and tools; Relevant technical standards, drawings, files and other information should be properly kept; Keep the workplace and indoor and outdoor clean, pay attention to fire prevention and moisture prevention, and do a good job in safety.
Development status of machining;
With the rapid development of modern machining technology, many advanced machining technologies and methods have emerged, such as micro-machining, rapid prototyping, precision ultra-precision machining and so on.
1, micromachining technology
With the development of micro/nano science and technology, micromechanics, which is characterized by tiny shape and size or extremely small operation scale, has become a high-tech for people to understand and transform the micro-world. Because MEMS can work in a narrow space without disturbing the working environment and objects, it has broad application potential in aerospace, precision instruments, biomedicine and other fields, and has become an important means of nanotechnology research, so it has been highly valued and listed as the first key technology in 2 1 century.
2. Rapid prototyping technology
Rapid prototyping technology was developed in the 20th century, which can quickly manufacture samples or parts according to CAD models. It is a method of material stacking processing and manufacturing, that is, three-dimensional forming is completed by orderly stacking of materials. Rapid prototyping technology integrates modern scientific and technological achievements such as numerical control technology, material technology, laser technology and CAD technology, and is an important part of modern advanced processing technology.
3, precision ultra-precision machining technology
Precision and ultra-precision machining is an important part of modern processing and manufacturing technology, and it is also one of the important symbols to measure the level of a country's high-tech manufacturing industry. Since the 1960s, with the development of computer and information technology, higher requirements have been put forward for manufacturing technology, which requires not only extremely high dimensional and shape accuracy, but also extremely high surface quality. It is in this market demand that ultra-precision machining technology develops rapidly, and various technologies and new methods are constantly emerging.