Detailed understanding of machining equipment and process knowledge


1.Processing equipment

(1)Common lathes: lathes are mainly used for processing shafts, discs, sleeves and other workpiece with rotary surface, which is the most widely used in machine manufacturing. (can achieve accuracy of 0.01mm)

(2)Ordinary milling machine: it can process the plane, groove, can also process all kinds of surfaces, gears, etc., but also can process more complex surface. (can achieve accuracy of 0.05mm)

(3)Grinder: Grinder is a machine tool for grinding the surface of the workpiece. Most grinders use high-speed rotary grinding wheels for grinding processing, while a few use whetstone, sand belt and other abrasive tools and free abrasive for processing, such as ultra-finishing machine tools, sand belt grinders, grinding machines and polishing machines. (can achieve precision 0.005mm, small can achieve 0.002mm)

(4)Fitters: fitters mainly include filing, sawing, scribing, drilling, hinging, tapping and nesting, scraping, grinding, correction, bending and riveting, etc.

(5)CNC lathe: mainly processing batch products, high precision parts, etc. (can achieve accuracy of 0.01mm)

(6)CNC milling machine: the main processing batch products, high precision parts, complex parts, large pieces, etc. (can achieve accuracy of 0.01mm)

(7)Wire cutting: the electrode used for slow walking wire is brass wire, and the wire is molybdenum wire. Slow wire processing precision is high, the surface finish is good. Processing some fine holes, fine grooves, etc. (Slow wire can achieve accuracy of 0.003mm, middle wire can achieve accuracy of 0.02mm)

(8)Spark machine: EDM can process materials and complex shape workpieces that are difficult to cut by ordinary cutting methods (such as groove corner of the mold, small hole, deformed hole, carbide processing), no cutting force, no burr and tool marks, grooves and other defects. Not affected by the hardness of the material, not affected by the heat treatment condition. (can achieve accuracy of 0.005mm)

2.Process flow

Machining process regulation is the provision of parts machining process process and operation method of one of the process documents, it is in the specific production conditions, the more reasonable process and operation method, in accordance with the prescribed form written into process documents to guide production.

The machining process of parts is composed of many processes, and each process can be divided into a number of installation, station, step and cutter.

What processes a process needs to include are determined by the complexity of the structure of the processed parts, the requirements of machining accuracy and the type of production.

Different production quantity, there are different processing technology.

Process knowledge

1) Hole milling with accuracy less than 0.05 cannot be done, and CNC machining is required; If it is a through hole, it can also be cut by wire.
2) the fine hole (through hole) after quenching needs wire cutting; The blind hole should be roughed before quenching and finished after quenching. The non – fine hole can be positioned before quenching (leaving a quenching allowance of 0.2 on one side).
3) the width of the slot below 2MM need wire cutting processing, 3-4 mm slot depth deep also need wire cutting processing.
4) The minimum allowance for rough machining of quenched parts is 0.4, and that for non-quenched parts is 0.2.
5) coating thickness is generally 0.005-0.008, processing should be according to the size before plating.

3.rocess hours

Time quota is the time required to complete a process, it is an indicator of labor productivity. According to the time quota can arrange the production operation plan, cost accounting, determine the number of equipment and personnel, planning the production area. Therefore, the time quota is an important part of the technological procedure.

With the continuous improvement of production technology conditions, the time quota is revised regularly to maintain the average advanced level of the quota.

The time quota is usually estimated directly by the combination of process personnel and workers by summarizing past experience and referring to relevant technical data. Or to the same kind of products of the workpiece or process time quota as the basis for comparative analysis after calculation, can also be determined by the actual operation time and analysis.

Process hours = Preparation hours + basic hours

The preparation time is the time that the worker is familiar with the process document, gets the blank, installs the fixture, adjusts the machine tool, disassembles the fixture, etc. Calculation method: Estimate according to experience.

The base time is the time it takes to cut away the metal.