Technological Characteristics and Quality Factors of Metal Cutting

Technological Characteristics and Quality Factors of Metal Cutting

With the continuous development of machine tools and cutting tools, the accuracy, efficiency and automation of cutting process are constantly improving, and the application scope is also expanding, which greatly promotes the development of modern machinery manufacturing industry. There are many classifications for metal cutting. There are three common classifications: according to process characteristics, according to material removal rate and processing accuracy, and according to surface forming method. The main factors affecting the quality of cutting are machine tools, tools, fixtures, workpiece blanks, cutting oil, process methods and processing environment. Following is a brief introduction of the common types of metal cutting technology and methods to improve quality.

I. Characteristics of Cutting Technology

(1) Large-scale

With the increasing size of parts and the high efficiency of parts, a multi cavity mold is required, which makes the mold more and more large-scale, requiring large operation, large shaft stroke, heavy bearing, high rigidity and high consistency.

(2) Complexity

With the complexity of the shape of die parts, it is necessary to improve the design and manufacturing level of the die. The multi-functional composite die with various grooves and materials forming or assembling components in a set of dies requires a large amount of process programming, high comprehensive cutting ability and high stability of deep hole cavity, and improves the processing difficulty.

(3) Precision

The refinement of die processing makes the compounding and high efficiency of processing equipment more stringent. High-speed milling has many advantages, such as Machinable high-hard materials, stable processing, small cutting force, small workpiece warming deformation and so on. Die and mould enterprises pay more and more attention to high-speed milling

Types of Cutting Technology

(1) Classification by process characteristics

The technological characteristics of cutting depend on the structure of cutting tool and the relative motion form of cutting tool and workpiece. Generally, it can be divided into turning, milling, drilling, boring, reaming, planer, slotting, broaching, sawing, grinding, grinding, honing, ultra-precision processing, polishing, gear processing, worm wheel processing, thread processing, ultra-precision processing, fitter and scraping.

(2) Classification by process accuracy

According to material removal rate and machining accuracy, cutting can be divided into rough processing, semi-finish processing, finish processing, finishing processing, decoration processing, ultra-precision processing, etc.

(3) Classification by surface forming

In cutting, the machined surface of the workpiece is obtained by the relative movement of the cutting tool and the workpiece. According to the surface forming method, cutting can be divided into three categories: tool path method, forming tool method and generating method.

3. Ways to Improve Quality

Cutting quality mainly refers to the machining accuracy and surface quality of the workpiece. The main factors affecting the cutting quality are machine tools, tools, fixtures, workpiece blanks, process methods and processing environment. In order to improve the cutting quality, appropriate measures must be taken in the above aspects, such as reducing the working error of machine tools, selecting cutting tools correctly, improving the quality of blanks, arranging the process rationally and improving the environmental conditions.

(1) Selection of process methods

Each kind of surface has a variety of processing methods, and the specific selection should be based on the Parts’processing accuracy, surface roughness, material, structural shape, size and production type, select the appropriate processing methods and processing programs.

(2) Determination of process steps

The general principle of working procedure arrangement is to process the datum first, then other surfaces, first roughing and then finishing, roughing and finishing independently. Two important factors should also be considered in the specific operation to minimize the clamping times so as to improve efficiency and ensure accuracy.

(3) Measures to ensure accuracy

The process assurance measures of key dimensions and technical requirements are very important for the design of process plans, so as to avoid the factors such as clamping deformation, thermal deformation, and processing ripple caused by workpiece vibration affecting the processing quality of parts.

(4) Use of cutting oil
Cutting oil is a kind of medium which must be used in metal cutting process. It mainly plays the roles of lubrication, cooling and cleaning in the process of processing. Special cutting oil contains vulcanized extreme pressure and anti-wear additives, which can effectively protect cutting tools and greatly improve process accuracy.