What are the contents of metal cutting technology code?

1, subject content and scope of application

This standard specifies the basic rules that should be followed in various cutting processes.

2. Reference standards

Basic terms of GB4863 machinery manufacturing technology

ZB/J3800 1 general technical conditions for cutting.

3. Preparation before processing

3. 1 After receiving the processing task, the operator should first check whether the product drawings, process regulations and related technical data required for processing are complete.

3.2 Understand and see clearly the process regulations, product drawings and their technical requirements. If in doubt, ask relevant personnel before processing.

3.3 According to the product drawings or (and) process regulations, check whether the blank or semi-finished products of the workpiece meet the requirements, report the problems to the relevant personnel in time, and process them only after the problems are solved.

3.4 According to the requirements of process regulations, prepare all the process equipment needed for processing, handle problems in time when found, and be familiar with the use requirements and operation methods of new fixtures and molds.

3.5 The process equipment used for processing shall be placed in the specified position, and shall not be misplaced, and shall not be placed on the guide rail of the machine tool.

3.6 The process equipment shall not be disassembled and changed at will.

3.7 Check the machine tools and equipment used for processing, and prepare all necessary accessories. Before machining, the machine tool should be lubricated and idling according to regulations.

4, tool and workpiece clamping

4. 1 tool clamping

4. 1. 1 Before clamping various tools, be sure to wipe the handle, arbor and guide sleeve clean.

4. 1.2 After the tool is clamped, check its correctness with the tool alignment device or trial cutting.

4.2 Workpiece Clamping

4.2. 1 When installing the fixture on the machine tool table, first clean its positioning base surface and find its relative position with the tool.

4.2.2 Before the workpiece is clamped, its positioning surface, clamping surface, shim and positioning surface of fixture should be wiped clean without burrs.

4.2.3 According to the positioning datum specified in the process specification, if the clamping mode is not specified in the process specification, the operator can choose the positioning datum and clamping mode by himself, and the selection of positioning datum should follow the following principles:

(1) Make the positioning datum coincide with the design datum as much as possible;

(2) As far as possible, make each machining surface adopt the same positioning datum;

(3) The rough machining positioning datum should try to select the plane with rough machining or small allowance, which can only be used once;

(4) The positioning datum of the finishing process should be the machining surface;

(5) The selected positioning datum must make the positioning and clamping of the workpiece convenient, stable and reliable in the machining process.

4.2.4 For the workpiece without special fixture, the alignment should be carried out according to the following principles when clamping:

(a) The marked workpieces shall be aligned according to the marks.

(2) For the non-intersecting workpiece surface that needs to be processed after this process, the alignment accuracy should be guaranteed, and the next process should have sufficient machining allowance;

(3) The alignment accuracy of the surface processed to the finished product size in this process should be less than one third of the size tolerance and position tolerance;

(4) The alignment accuracy of the surface that is not marked with dimensional tolerance and position tolerance in the finished product size processed in this process shall ensure the requirements of ZBJ3800 1 that are not marked with dimensional tolerance and position tolerance.

4.2.6 When clamping the workpiece, the action point of clamping force should pass through the bearing point or bearing surface. For workpieces with poor rigidity (or workpieces with suspended parts during machining), auxiliary supports should be added at appropriate positions to enhance their rigidity.

4.2.7 When clamping machined surfaces and soft workpieces, soft pads, such as copper skin, should be used.

4.2.8 When pressing the workpiece with a pressure plate, the support point of the pressure plate should be slightly higher than the surface of the pressed workpiece, and the pressing bolt should be as close as possible to the workpiece to ensure the pressing force.

5. Processing requirements

5. 1 In order to ensure machining quality and improve productivity, cutting parameters should be reasonably selected according to workpiece materials, precision requirements, machine tools, tools and fixtures. When machining castings, the cutting depth should be greater than the depth of sand inclusion or hardened layer, so as to avoid surface sand inclusion and hardened layer from damaging the tool.

5.2 For dimensions with tolerance requirements, the intermediate tolerance should be processed as much as possible.

5.3 The surface roughness Ra value of the rough machined surface not specified in the process specification shall not be greater than 25um.

5.4 The surface roughness Ra value before reaming should not be greater than12.5um.

5.5 The surface roughness Ra value before fine grinding should not be greater than 6.3um, and the surface roughness Ra value before fine grinding of piston rod should not be greater than 5um.

5.6 The chamfering, chamfering and groove depth in rough machining should be increased or deepened according to the finishing allowance to ensure that the design requirements can be met after finishing.

5.7 The dimensions and tolerances of chamfers and chamfers not specified in the drawings and process regulations shall comply with the provisions of ZBJ3800 1.

5.8 When the surface of the workpiece needs surface quenching, ultrasonic flaw detection or hydraulic machining in the next process, the surface roughness Ra value processed in this process shall not be greater than 6.3um.

5.9 When there is no deburring process after this process, the burr generated by this process should be removed in this process.

5. 10 During the processing of large pieces, always check whether the workpieces are loose, so as to prevent the processing quality from being affected or accidents.

5. 1 1 When rough machining and finish machining are processed on the same machine tool, the workpiece should generally be loosened after rough machining and re-clamped after cooling.

5. 12 In the process of cutting, if the machine tool, cutter and workpiece have abnormal sounds or the machined surface roughness suddenly deteriorates, the cutter should be withdrawn immediately and stopped for inspection.

5. 13 mass production, the first piece must be inspected, and the processing can continue only after it is qualified.

5. 14 In the process of machining, the operator must conduct self-inspection on the workpiece.

5. 15 Correct use of measuring instruments during inspection. Gauge, micrometer, etc. You must push or screw in gently, but not too hard. When using calipers, micrometer, dial indicator, dial indicator, etc. , zero should be adjusted in advance.

6. Post-processing

6. 1 The workpiece should be free of debris, water and dirt after processing in each working procedure, and should be placed neatly on the designated workstation appliances to avoid bumping and scratching.

6.2 The surface that has not been treated in the next working procedure or trimmed shall be rustproof.

6.3 Hold the workpiece to be processed with a magnetic clamp, and demagnetize it after processing.

6.4 All the processed related parts shall be marked (or numbered) after processing.

6.5 The workpieces processed in each working procedure can not be transferred to the next working procedure until they are inspected by full-time inspectors.