Machining refers to cutting tools (including tools and abrasives) to cut away the excess material layer on the blank or workpiece into chips so that the workpiece obtains the specified geometry, size and surface quality of processing methods. When machining, the machined surface of the workpiece is obtained by the relative motion of the cutting tool and the workpiece.
Machining can be manual processing (clamp), workers with hand-held tools to the workpiece machining process. But more is the use of machining machine tools for mechanical processing.
Machine according to the type of tool used can be divided into two categories.
One category is the use of cutting tools with fixed edge shape and number of edges for processing, such as turning, milling, drilling, planing, boring, etc..
The other category is the use of abrasive tools or abrasives with variable edge shape and number of edges for processing, such as grinding, honing, lapping, and polishing.
Features of CNC machining:
Machining can obtain a fairly high dimensional accuracy and small surface roughness values.
Machine processing is more adaptable, almost independent of the material, size and quality of the part.
The organization and mechanical properties of the part remain unchanged.
Processing is flexible and convenient, and the parts are easy to clamp and form, and can process various different shapes of parts.
Short production preparation cycle, no need to make molds, etc.
CNC Machining process
In the machining motion, the relative motion between the tool and the workpiece is made for the purpose of removing the excess material from the surface of the part and machining it into the required shape, and these motions are called machining motion.
Main classification of machining
Machining movements are mainly classified into turning, milling, drilling, etc.
Table of Contents
CNC Turning Machining
The rotary motion of the workpiece and the linear motion (or curve motion) of the tool on the lathe to process the parts (workpiece) to change the shape and size of the blank, the blank will be processed to meet the requirements of the drawing of the workpiece, known as turning. Turning is one of the most widely used machining methods.
Features of CNC turning processing
Suitable for processing various internal and external rotary surfaces.
Turning tool structure is simple, easy to manufacture, and easy to make a reasonable choice of tool material and geometric angle according to the processing requirements. In addition, turning tool sharpening and assembly and disassembly are also more convenient.
Turning has strong adaptability to the structure, material, and production batch of the workpiece, and can be widely used to turn and process different kinds of materials. For some non-ferrous metals not suitable for grinding can be used diamond turning tool for fine tuning, can get very high machining accuracy and very small surface roughness value.
Small change of cutting force, smooth cutting process, conducive to high-speed cutting and powerful cutting, high production efficiency.
CNC Milling Maching
Milling is a mechanical processing method that uses a milling edge as a tool to process the surface of an object on a milling machine. Using a rotating multi-edge tool to cut the workpiece is a highly efficient processing method.
The production process of CNC milling
The workpiece can also be fixed, but at this time the rotating tool must also move (completing both the main motion and the feed motion) to cut out the desired shape and features.
Advantages and disadvantages of CNC milling
Advantages of milling:
The use of multi-edge tool processing, alternate cutting edge, good cooling effect of the tool, high durability.
High productivity and wide machining range
High machining accuracy.
It is conducive to reduce the wear of the tool teeth and improve the life of the tool.
Disadvantages of milling:
It is easy to generate vibration. Because the cutting teeth are discontinuous cutting, and the cutting thickness and cutting force are changing all the time, so it is easy to generate vibration, which affects the machining quality.
CNC Drilling Machining
Drilling is a basic method of hole processing. Drilling is often carried out on drilling machines and lathes, but also on boring machines or milling machines. High-speed rotary drilling, the process of removing material requires the injection of coolant into the drilling tool to cool the drilling tool, lubricate the cutting surface, and at the same time flush away the drilling debris generated during the drilling process. Drilling is generally used when the diameter of the hole is not large and the accuracy requirement is not high.
Disadvantages of drilling process:
The drill bit is cut in a semi-enclosed state, the cutting volume is large and chip removal is difficult.
Friction is serious, generating much heat and making heat dissipation difficult.
High rotational speed and high cutting temperature cause serious wear of the drill bit.
Severe extrusion, large cutting force required, easy to produce cooling hardening of the hole wall.
The drill bit is thin and long, easy to produce bending, fracture and vibration during processing.
Low drilling accuracy.