1、 Varieties and characteristics of tools commonly used in CNC computer gong processing
CNC computer gong machining tool has the characteristics of high speed, high efficiency and high degree of automation. It usually includes general tool, general connecting tool holder and a small number of special tool holders. The tool holder needs to be connected with the tool and installed on the power head of the machine tool, so it has been gradually standardized and serialized. There are many ways to classify CNC tools.
According to the tool structure, it can be divided into three parts
- Integral type;
- Mosaic type, welding or clip type connection, clip type can be divided into two situations: non transposable and transposable;
- Special type, such as compound cutting tool, shock absorption cutting tool, etc.
According to the data used to make the cutting tool, it can be divided into:
- High speed steel cutting tools;
- Cemented carbide tools;
- Diamond tools;
- Other information tools, such as CBN tools, ceramic tools, etc.
From the cutting process can be divided into
- Turning tools, extra round, inner hole, thread, cutting tools, etc;
- Drilling tools, including drill, reamer, tap, etc;
- Boring tools;
- Milling tools, etc.
In order to get used to the requirements of CNC machine tools for tool durability, stability, easy adjustment, replaceability, etc., in recent years, the clip type indexable tool has been widely used, with the number reaching 30% – 40% of all CNC tools, and the metal removal amount accounting for 80% – 90% of the total.
2、 CNC computer gong processing tool selection
Tool selection is carried out in the state of human-computer interaction of CNC programming. The tool and tool holder should be selected accurately according to the processing capacity of the machine tool, the function of workpiece data, processing procedures, cutting parameters and other relevant factors. The general criteria for tool selection are: convenient adjustment, good rigidity, high durability and accuracy. On the premise of satisfying the machining request, the shorter tool holder should be selected as far as possible to improve the rigidity of tool processing.
When selecting the cutting tool, the dimension of the cutting tool should be used to the external dimension of the workpiece to be processed. In production, the end mill is often used for the processing of plane parts; when milling plane, the cemented carbide cutter should be selected; when machining boss and groove, the high speed steel end mill is selected; when machining rough surface or rough hole, the corn milling cutter with cemented carbide cutter can be selected; when machining some three-dimensional surface and variable bevel angle, the ball end mill and ring mill are often selected Cutter, taper cutter and disc cutter.
In free-form surface machining, because the end cutting speed of the ball head tool is zero, in order to ensure the machining accuracy, the cutting line spacing is usually very close, so the ball head is often used for surface finishing. The flat head tool is superior to the ball head tool in terms of surface processing quality and cutting power. Therefore, as long as it can not be cut, whether it is rough or finish machining of curved surface, the flat head tool should be selected first. In addition, the durability and accuracy of cutting tools are closely related to the quotation of cutting tools. It is necessary to pay attention to that in most cases, although the cost of cutting tools is added to the selected cutting tools, the improvement of processing quality and processing power can greatly reduce the total processing cost.
In the machining base, all kinds of tools are separately installed on the tool magazine, and the tool selection and tool change actions are carried out at any time according to the program rules. Therefore, it is necessary to select the standard tool holder, so that the standard tools used in drilling, boring, expanding, milling and other processes can be quickly and accurately installed on the machine tool spindle or tool magazine. The programmer should know the structural dimension, adjustment method and adjustment scale of the tool holder used on the machine tool, so as to determine the radial and axial dimension of the tool when programming. At present, China’s processing base adopts TSG East-West system, with straight shank (three standards) and taper shank (four standards), including 16 different kinds of toolholders.
ken.tang @ chengcg.com
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