How to choose CNC aluminum alloy machining tool？

With the increasingly updated processing technology, CNC machining has also undergone a lot of changes. Many experts pointed out that in the future, CNC will be the mainstream processing mode. In the CNC machining process, the tool is the most important, today, we will understand the CNC tool in detail.

A tool is a tool used for cutting in mechanical manufacturing. Generalized cutting tools include both cutting tools and abrasive tools. The vast majority of knives are used for machines, but there are also hand tools. Since the tools used in mechanical manufacturing are basically used to cut metal materials, the term "tool" is generally understood as a metal cutting tool. The cutting tools used for cutting wood are called woodworking tools.

Tool classification

Cutting tools can be divided into five categories according to the form of the workpiece machined surface.

Cutting tools for processing various outer surfaces, including cutting tools for processing various outer surfaces, including turning tools, planing knives, milling cutters, outer surface broach and file, etc.

Hole processing tools, including drill, reaming drill, boring cutter, milling cutter and internal surface broach, etc.

Thread processing tools, including tap, die, automatic opening thread cutting head, thread turning tool and thread milling cutter.

Gear processing tools, including hob, gear shaper cutter, shaving cutter, bevel gear processing tool, etc.

Cutting tools, including inserted circular saw blade, band saw, bow saw, cutting tool and saw blade milling cutter, etc.

In addition, there are combination tools.

Tool structure

The structure of various tools is composed of a clamping part and a working part. The clamping part and working part of the overall structure of the tool are done on the tool body; The working part of the tool (the tooth or blade) is mounted on the tool body.

The clamping part of the tool has two kinds of holes and handles. The tool with hole relies on the inner hole set on the spindle or mandrel of the machine tool, and transmits the torsional torque with the help of the axial key or the end key, such as the cylindrical milling cutter and the sleeve face milling cutter.

The tool with the handle is usually rectangular handle, cylindrical handle and conical handle three kinds. Turning tools, planing tools, etc. are generally rectangular handles; The conical handle withstands the axial thrust with the taper and transmits the torque with the help of friction. Cylindrical shank is generally suitable for smaller twist drill, end mill and other tools, cutting with the help of the friction generated when clamping torque transfer. The shank of many tools with handles is made of low alloy steel, and the working part is made of high speed steel welded to each other.

The basic properties that the tool material should have

1. High hardness

The hardness of the tool material must be higher than the hardness of the workpiece material to be machined, which is the basic feature that the tool material should have.

2. Sufficient strength and toughness

The material of the cutting part of the tool must withstand great cutting force and impact force when cutting. The bending strength and impact toughness reflect the ability of tool material to resist brittle fracture and edge breakage.

3. High wear resistance and heat resistance

The wear resistance of tool materials refers to the ability to resist wear. The higher the hardness of the tool material, the better the wear resistance; The higher the high temperature hardness, the better the heat resistance, the tool material at high temperature resistance to plastic deformation, anti-wear ability is also stronger.

4. Good thermal conductivity

Large thermal conductivity means good thermal conductivity, and the heat capacity generated during cutting is easily transmitted out, thereby reducing the temperature of the cutting part and reducing tool wear.

5. Good technology and economy

In order to facilitate manufacturing, the tool material is required to have good machinability, including forging, welding, cutting, heat treatment, grindability and so on. Economy is one of the important indexes to evaluate and promote the application of new tool materials.

6. Resistance to bonding

Prevent the workpiece and the tool material molecules under the action of high temperature and high pressure adsorption bond.

7. Chemical stability

It means that the tool material is not easy to react chemically with the surrounding medium at high temperature.

Tool coating

Aluminum alloy indexable inserts are now coated with hard or composite layers of titanium carbide, titanium nitride, alumina by chemical vapor deposition. The physical vapor deposition method that is being developed can be used not only for aluminum alloy tools, but also for high-speed steel tools such as drills, hobs, taps and milling cutters. As a barrier that prevents chemical diffusion and heat conduction, the hard coating slows down the wear rate of the tool during cutting, and the life of the coated blade is about 1 to 3 times higher than that of the uncoated blade.

Tool selection is carried out in the human-machine interaction state of NC programming. The tool and handle should be correctly selected according to the machining capacity of the machine tool, the performance of the workpiece material, the processing procedure, the cutting amount and other relevant factors.

The general principle of tool selection: easy installation and adjustment, good rigidity, high durability and accuracy. On the premise of meeting the processing requirements, try to choose a shorter tool handle to improve the rigidity of the tool processing. When selecting the tool, the size of the tool should be adapted to the surface size of the workpiece to be machined.

1. End milling cutter is often used to process the peripheral outline of plane parts.

2. When milling the plane, carbide blade milling cutter should be selected.

3. When processing convex and grooves, choose high-speed steel end milling cutter.

4. When processing the blank surface or roughing the hole, you can choose the corn milling cutter with cemented carbide blade.

5. For the processing of some vertical surface and variable bevel contour, ball end milling cutter, ring milling cutter, conical milling cutter and disk milling cutter are often used.

6. In the processing of free-form surface, because the cutting speed of the end of the ball head tool is zero, so in order to ensure the processing accuracy, the cutting line spacing is generally very dense, so the ball head is often used in the finishing of the surface.

7, flat head tool in the surface processing quality and cutting efficiency are better than the ball head knife, therefore, as long as the premise of ensuring but cutting, whether it is rough surface machining or finishing, should be preferred to choose flat head knife.

8. In the machining center, various tools are installed on the tool library, and the tool selection and tool change are carried out at any time according to the procedure. Therefore, the standard tool handle must be used in order to make the standard tool for drilling, boring, expanding, milling and other processes quickly and accurately installed on the machine spindle or tool library. The number of tools should be reduced as far as possible; After a tool is installed, it should complete all the processing parts that it can carry out; Rough finishing tools should be used separately, even if the same size specifications of the tool; Milling before drilling; Surface finishing is carried out first, and then 2D contour finishing is carried out. Where possible, the automatic tool change function of CNC machine tools should be used as much as possible to improve production efficiency.

Problems encountered in processing aluminum and solutions when processing pure aluminum, easy to stick knife analysis and solutions:

1. Aluminum material is soft in texture and easy to stick at high temperature;

2. Aluminum is not resistant to high temperature, easy to open;

3. Related to processing cutting fluid: good oil lubrication performance; Good water-soluble cooling performance; High dry cutting cost;

4. When processing pure aluminum, the end mill dedicated to aluminum processing should be selected: positive front Angle, sharp cutting edge, large chip discharge slot, 45 degrees or 55 degrees helix Angle;

5. The material of the workpiece and the CNC tool has a greater affinity.

6. Rough front tool processing soft materials.

Recommendation: Machine tool conditions are poor to good requirements are low to high, please use high-speed steel, coated polished carbide, PCD polycrystalline diamond and single crystal diamond.

7. Low speed can be avoided by cutting fluid, high speed oil mist lubrication, the effect can be improved, aluminum alloy suitable

Due to the high temperature, high pressure, high speed, and the parts working in the corrosive fluid medium, the application of difficult to process more and more materials, the automation level of cutting processing and the processing accuracy requirements are getting higher and higher. In order to adapt to this situation, the development direction of the tool will be the development and application of new tool materials; Further develop the vapor deposition coating technology of the tool, and deposit higher hardness coating on the matrix of high toughness and high strength, so as to better solve the contradiction between hardness and strength of the tool material; Further development of indexable tool structure; Improve the manufacturing accuracy of the tool, reduce the difference in product quality, and optimize the use of the tool.How to choose CNC aluminum alloy machining tool.