Since the production of standard cutting tools is aimed at cutting large-scale common metal or non-metal parts, when the workpiece is overheated and the hardness increases, or the workpiece is made of stainless steel, it is very easy to stick to the tool. There are also some workpieces with very complex surface geometry, or the surface to be processed has high roughness requirements, etc., in which case standard cutting tools cannot meet the processing needs. Therefore, during the processing, the material of the tool, the geometry of the blade, the geometric angle, etc. need to be designed specifically, which can be divided into two categories: those that do not require special customization and those that do. Tools that do not require special customization mainly solve two problems, such as size problems and surface roughness problems.
In the process of mechanical processing, we often encounter some situations that are difficult to process with standard tools. Therefore, the production of non-standard tools is very important for mechanical cutting. Because non-standard tools are mostly used in milling for metal cutting, the production of non-standard tools in milling is briefly introduced.
No Need Specially Customized Non-standard Tools
If it is a size problem, you can choose a standard tool with a size close to the required size. It can be solved by re-grinding, but two points should be noted: the size difference cannot be too large, generally not more than 2mm, because if the size difference is too large, it will cause the groove shape of the tool to change, directly affecting the chip space and geometric angle.
If it is an end mill with a cutting hole, it can be re-grinded on an ordinary machine tool at a low cost. If it is a keyway milling cutter without a cutting hole, it cannot be performed on an ordinary machine tool. It needs to be re-grinded on a special five-axis linkage machine tool, and its cost will be higher.
If it is a surface roughness problem, it can be achieved by changing the geometric angle of the blade. For example, increasing the degree of the front and rear angles will significantly improve the surface roughness of the workpiece. However, if the rigidity of the user’s machine tool is not enough, the blunt edge may improve the surface roughness. This aspect is very complicated and a conclusion can only be drawn after analyzing the processing site.
Need Specially Customized Non-standard Tools
The tools that need to be specially customized are mainly to solve the following problems.
The workpiece to be processed has special shape requirements, such as lengthening the tool required for processing, adding end teeth R, or having special taper angle requirements, shank structure requirements, blade length size control, etc. If the shape requirements of this type of tool are not very complicated, it is actually easy to solve. The only thing to note is that the processing of non-standard tools is relatively difficult. Therefore, the user should not excessively pursue high precision when it can meet the processing requirements. Because high precision itself means high cost and high risk, which will cause unnecessary waste of the production capacity and cost of the manufacturer.
The workpiece to be processed has special strength and hardness. If the workpiece is overheated, the strength and hardness are high, and the general tool material cannot be cut, or the tool is very sticky. In this case, special requirements are required for the tool material. The general solution is to use high-end tool materials, such as cobalt-containing high-speed steel tools with high hardness to cut tempered workpiece materials, and high-quality carbide tools can be used to process high-hardness materials, and even milling can be used instead of grinding.
Of course, there are some special cases. For example, when processing aluminum parts, there is a type of super-hard tool on the market that may not be suitable. Although aluminum parts are generally soft, they can be said to be an easy-to-process product. However, the material used for super-hard tools is actually an aluminum high-speed steel, which is indeed harder than ordinary high-speed steel. However, when processing aluminum parts, it will cause affinity between aluminum elements, which will increase the wear of the tool. At this time, if you want to achieve high efficiency, you can use cobalt high-speed steel instead.
The workpiece being processed has special chip capacity and chip removal requirements. At this time, you should use fewer teeth and deeper chip grooves. But this design can only be used for materials that are easier to process, such as aluminum alloys.
Precautions in the Design and Processing of Non-standard Tools
There are many issues that need to be noted during the design and processing of non-standard tool processing:
The geometric shape of the tool is relatively complex. During heat treatment, the tool is prone to bending, deformation, or local stress concentration. Therefore, attention should be paid to avoiding parts that are prone to stress concentration during design, and adding bevel transition or step design to parts with large diameter changes.
If it is a slender piece with a large length-to-diameter ratio, it needs to be checked and straightened every time it is quenched and tempered during heat treatment to control its deformation and runout.
The material of the tool is relatively brittle, especially cemented carbide. This means that once the vibration is large or the processing torque is large during processing, the tool will break. This often does not cause great damage in the processing of conventional tools. Because the tool can be replaced if it breaks, but in the processing of non-standard tools. Since the possibility of replacement is small, once the tool breaks, it will cause a series of problems, such as delivery delays, which will cause great losses to the user.
The above is all about the tool itself. In fact, the manufacture of non-standard tools is by no means so simple. It is a systematic project. The experience of the design department of the manufacturer and the understanding of the processing conditions of the user will affect the design and production of non-standard tools. The processing and testing methods of the production department of the manufacturer will affect the accuracy and geometric angle of non-standard tools. The repeated visits, data collection and information collection of the sales department of the manufacturer will also affect the improvement of non-standard tools, which will play a decisive role in the success of the user’s use of non-standard tools.
In short, non-standard tools are special tools that are born for special requirements. Choosing a manufacturer with rich experience will save the user a lot of time and energy.
