Six aspects that need to be paid attention to in the process route of non-standard parts processing plants are indispensable!

1. Selection of positioning datum

In the process design, the positioning datum is divided into the fine datum and the rough datum. The surface of the blank that has not been processed by non-standard parts is used as the positioning datum. This kind of positioning datum is called the rough datum. Use the processed surface as a positioning reference, and this positioning reference becomes a fine reference.

(1) Selection principle of fine benchmark

①The principle of coincidence of benchmarks; ②The principle of unified benchmarks; ③The principle of mutual benchmarks; ④The principle of self-standards

The above-mentioned four principles for selecting fine benchmarks are sometimes impossible to meet at the same time, and the decision should be made based on actual conditions.

(2) Selection principle of rough benchmark

①A rough datum should be used in a process of workpiece processing; ②The principle of reasonable allocation of machining allowance; ③The principle of easy clamping; ④The principle of rough datum is generally not to be reused. The above four principles of choosing rough benchmarks sometimes cannot be considered at the same time, and can only be selected based on primary and secondary.

2. Selection of surface parts processing method

The structural shapes of machine parts are composed of some of the most basic geometric surfaces, and the machining process of machine parts is the process of obtaining these geometric surfaces. A variety of different processing methods can be selected for the same surface, but the processing quality, processing time and cost that each processing method can obtain are different.

The task of engineering and technical personnel is to select the most appropriate processing method according to the specific processing conditions to ensure that the machine parts that meet the requirements of the drawings are processed. The machined surface of the parts has certain processing requirements. Generally, it is impossible to meet the requirements through one processing, but to gradually meet the requirements through multiple processing (ie, multiple processes).

Small batch non-standard parts processing plant

The steps to determine the processing method can be summarized as follows, based on the analysis of the part drawing:

①First, determine the processing method and processing plan according to the technical requirements of each processed surface.

②The nature of the processed material should be considered when determining the processing method.

③Determining the processing method should take into account the type of production, that is, the question of productivity and economy. Large batches can use special high-efficiency equipment, single-piece small batch production usually uses general-purpose equipment and process equipment.

④To determine the processing method, the existing equipment and technical conditions of the factory (this workshop) should be considered, and the existing equipment should be fully utilized to tap the potential of the enterprise.

3. Division of processing stages

When the processing quality requirements of parts are high, they generally have to go through different processing stages to gradually meet the processing requirements, which is the so-called "gradual refinement" principle. Generally, it needs to go through three stages of rough machining, semi-finishing and finishing. If the machining accuracy of the part is particularly high and the surface roughness is particularly small, it must also go through the finishing process.

The main tasks of each processing stage are summarized as follows:

①Rough machining stage: Efficiently remove most of the margin on the machined surface, so that the blank is close to the finished part in shape and size.

②Semi-finishing stage: cut off the error left after roughing, make the processed workpiece reach a certain accuracy, prepare for finishing work, and complete some secondary surface processing.

③Finishing stage: Ensure that the main surfaces meet the processing quality requirements specified in the part drawing.

④The main task of the finishing process is to reduce the surface roughness or further improve the dimensional accuracy and shape accuracy, but generally the position error between the surfaces cannot be corrected.

The main purpose of dividing the processing stage is:

①Ensure the quality of parts processing: ②It is conducive to early detection of blank defects and timely treatment. ③Conducive to the rational use of machine tools. ④In order to insert the necessary heat treatment process in the machining process. In addition, dividing the workpiece processing into several stages also helps to protect the finished surface from damage such as bumps and chip slips.

4. Concentration and dispersion of processes

After determining the processing method, it is necessary to determine the number of processes in the process according to the production type of the part and the specific conditions of the factory (workshop). There are two different principles for determining the number of processes in a part processing process, one is the principle of process concentration, and the other is the principle of process dispersion.

Non-standard parts processing

The characteristics of organizing the process according to the principle of process concentration are:

① It is conducive to the use of high-efficiency machine tools and process equipment with a high degree of automation, and high production efficiency;

②The number of processes is small and the number of equipment is small, which can reduce the number of operators and production area accordingly;

③The number of clamping times of the workpiece is small, not only can shorten the auxiliary time, but also because many surfaces are processed in one clamping, it is helpful to ensure the mutual position accuracy requirements between the processed surfaces.

The characteristics of organizing the process according to the principle of process dispersion are:

①The machine tool and process equipment used are simple, easy to adjust the tool setting;

②The technical level of the operators is not high;

③ There are many processes, many equipments, many operators, and large production area.

5. Arrangement of process sequence

(1) Arrangement of machining procedures

Generally follow the following principles: ①Process the positioning reference surface first, and then process other surfaces; ②Process the main surface first, then process the secondary surface; ③Arrange the rough machining process first, then arrange the finishing process; ④Process the plane first, then Machining holes.

(2) Arrangement of heat treatment process and surface treatment process

The heat treatment process arranged to improve the cutting performance of the workpiece material, such as annealing, normalizing, quenching and tempering, etc., should be carried out before cutting.

The heat treatment process arranged to eliminate the internal stress of the workpiece, such as artificial aging, annealing, etc., is arranged after the rough machining stage.

In order to improve the mechanical properties of the workpiece material, heat treatment processes, such as quenching, carburizing and quenching, are generally arranged between semi-finishing and finishing.

The heat treatment process arranged to improve the wear resistance and corrosion resistance of the workpiece surface and the heat treatment process arranged for the purpose of decoration, such as chrome plating, zinc plating, and blue, are generally arranged in the final stage of the process.

(3) Arrangement of other processes

In order to ensure the quality of parts manufacturing and prevent the production of waste products, inspection procedures should be arranged in the following occasions:

①After all rough machining is finished; ②Before and after sending to the outside workshop for processing; ③Before and after the long working hours and important processes; ④After the final processing.

6. Selection of machine tool equipment and process equipment

The correct choice of machine tool equipment is very important. It not only directly affects the processing quality of the workpiece, but also affects the processing efficiency and manufacturing cost of the workpiece. The size of the selected machine tool equipment should be compatible with the shape and size of the workpiece, the accuracy level should be compatible with the processing requirements of this process, the motor power should be compatible with the power required for this process, and the degree of automation and production efficiency of the machine tool should be consistent with Adapt to the type of workpiece production.

The selection of process equipment will directly affect the processing accuracy, production efficiency and manufacturing cost of the workpiece, and should be appropriately selected according to different situations. Under the conditions of medium and small batch production, general process equipment should be considered first; in mass production, special process equipment can be designed and manufactured according to processing requirements.