General lathe: lathe is mainly used for processing shafts, discs, sleeves and other workpieces with rotary surfaces, and is the most widely used type of machine tool processing in machinery manufacturing. (Can achieve the accuracy of 0.01mm)
General milling machine: it can process plane, groove, also can process various surfaces, gears, etc., but also can process more complex type surface. (Can achieve accuracy of 0.05mm)
Grinder: A grinder is a machine tool that grinds and processes the surface of a workpiece. Most grinders use high-speed rotary grinding wheels for grinding processing, and a few use other abrasives such as oil stones, abrasive belts and free abrasives for processing, such as super-finishing machines, abrasive belt grinders, grinding machines and polishing machines. (Can achieve the accuracy of 0.005mm, small pieces can achieve 0.002mm)
Clamping: Clamping operations mainly include filing, sawing, scribing, drilling, reaming, tapping and snapping, scraping, grinding, straightening, bending and riveting, etc.
CNC lathe: mainly processing batch products, high precision parts, etc. (Can achieve precision 0.01mm)
CNC milling machine: mainly processing batch products, high precision parts, complex parts, large workpieces, etc. (Can achieve precision 0.01mm)
wire cutting: the electrode used for slow-walking wire is brass wire, and molybdenum wire is used for medium wire. Slow walking wire processing high precision, good surface finish. Machining some fine holes, fine grooves, etc. (Slow walking wire can achieve precision 0.003mm, medium walking wire can achieve precision 0.02mm)
spark machine: EDM can process the materials and complex shape workpieces that are difficult to cut by ordinary cutting methods (such as groove corners of molds, small holes, deformed holes, machining on carbide), processing without cutting force, no burrs and tool marks grooves and other defects. Not affected by material hardness and not affected by heat treatment condition. (Can achieve accuracy of 0.005mm)
Machining process procedures is one of the process documents that specify the mechanical machining process and operation methods of parts, it is in the specific production conditions, the more reasonable process and operation methods, written in accordance with the prescribed form of process documents to guide production.
Parts of the machining process by a combination of many processes, each process can be divided into a number of installations, stations, work steps and tool walking.
A process needs to include which processes, is determined by the complexity of the structure of the parts to be processed, processing accuracy requirements and production type.
Different production quantities result in different machining processes.
Holes with accuracy less than 0.05 cannot be done by general milling, CNC machining is required; if it is a through hole, it can also be wire-cut.
Quenched fine holes (through-hole) need wire-cutting processing; blind holes need rough machining before quenching and finishing after quenching. Non-finish holes can be done before quenching (leave a quenching allowance of 0.2 on one side).
The width of 2MM below the groove need wire cutting processing, 3-4MM groove depth is very deep also need wire cutting processing.
Rough machining of quenched parts at least leave a margin of 0.4, non-quenched parts rough machining to leave a margin of 0.2.
The thickness of plating is generally 0.005-0.008, processing according to the size before plating.
Time quota is the time required to complete a process and it is an indicator of labor productivity. Based on time quotas, production operations can be planned, costs can be accounted for, the number of equipment and staffing can be determined, and the production area can be planned. Therefore, time quotas are an important part of the process procedures.
The time quota should be determined according to the production technology conditions of the enterprise, so that most workers can reach it after efforts, some advanced workers can exceed it, and a few workers can reach or approach the average advanced level after efforts.
With the continuous improvement of the production technology conditions of the enterprise, the time quota is revised periodically to maintain the average advanced level of the quota.
Time quotas are usually determined by a combination of craftsmen and workers through direct estimation by summarizing past experience and referring to relevant technical information. Or the time quotas of workpieces or processes of similar products can be compared and analyzed, or can be determined by measuring and analyzing the actual operation time.
Process Man-Hours = Preparation Man-Hours + Basic Time
Preparation work time is the time consumed by workers to familiarize with process documents, receive blanks, install fixtures, adjust machine tools, disassemble fixtures, etc. Calculation method: Estimation based on experience.
The basic time is the time consumed to cut away the metal.