17、How to set the cutting conditions when the tool is overhung for a long time?

The cutting condition table recorded in the product catalog is used on the premise of how much extension?When the extension is extended, how should the cutting conditions be changed?

18、The correct use of end milling cutter for chamfering and V-slot machining when machining parts, the end milling cutter for chamfering and V-slot machining is often used, but it is vexed by frequent blade breakage. Please tell me how to use the knife.

The main points of chamfering or V-groove machining are as follows

（1）chamfering

•It must be processed under conditions that take into account the maximum depth of cut.

•When the amount of cutting is large, it is recommended to cut gradually.

（2）V-slot machining

•Mainly consider the use of ordinary flat end milling cutter and special tool V-slot machining.

①When using an ordinary flat end mill

A method of cutting V-slots by tilting the tool or workpiece. If the accuracy of the bottom shape of the V-slot is not high, you can choose to process the C-type end mill with arc Angle or chamfer.

②When using an end mill for V-slot machining

•When using only the front end of the tool, please consider the line speed and set the condition to increase the speed.

•When the cutting quantity increases, it is recommended to cut gradually.

③Choose the right tool for the cutting purpose

•According to the chamfer, V-slot, positioning and other processing shapes, processing efficiency and workpiece materials, it is very important to choose the most suitable tool.

List of end mills for carbide chamfer and V-slot machining

19、In order to make the cutting amount of roughing and semi-finishing high-speed grooving processing large, it is necessary to consider shortening the roughing and semi-finishing time. To this end, what kind of processing methods and tools should be used?

The arc Angle end mill is used for high speed machining Using the following methods will not help to solve the high-speed roughing and semi-finishing. •Machining with rough-worked end mills, for example, can not increase the feed speed, so the processing efficiency will be reduced.  •When the ball end mill is used, the large step value cannot be obtained, so the complete high efficiency cannot be achieved.  The use of large feed arc Angle end mill for grooving rough and semi-finishing of high-speed milling can effectively shorten the processing time, improve the service life of the tool, and obtain good machining results. High speed machining is characterized by cutting conditions that effectively inhibit the depth of cut and improve the cutting speed (tool speed) and feed speed. The tool path of tooth profile and complex shape machining (spiral tool path) are helpful to realize the actual feed speed close to the command value of the feed speed set in the NC program.

20、How to process high hardness steel smoothly? When the end mill is used to process high hardness steel, the tool life will be shortened. Therefore, tools are sometimes changed frequently or dimensional corrections are made several times. If there is a solution, please let us know.

Select suitable tools and handles of high hardness materials

In terms of tool selection, it is more effective to choose a tool with high tip strength, many blades and high rigidity. If it is a coated carbide tool, it is very important to choose a coating with high temperature, heat resistance and other excellent. MISUMI XCP coating not only has a high hardness, but also a high oxidation temperature, so it can effectively improve the wear resistance of the tool. In addition, the use of high gripping force thermal expansion tool handle will be more effective. Due to the excellent runout accuracy of the thermal expansion tool handle, it was mainly used for finishing more cases, and the characteristics of strong clamping force and not easy to flutter make it also play a role in rough machining, and at the same time, it can ensure stability in the processing of high-hardness steel that is prone to collapse.

Adjust the cutting depth, do not adjust the feed speed

If the tool is not normal wear, but the sharp wear caused by the collapse of the edge, the tool selection and cutting conditions must be re-discussed. A negative front Angle is very effective for increasing the strength of the tip. Select high hardness, fine particles of extremely ultrafine carbide suitable for tool materials. In addition, it is expected that CBN tools for high-hardness steel processing will also increase in the future. At the same time, when setting cutting conditions, it is recommended not to significantly reduce the feed speed, and the depth of cutting should first be reduced. In order to ensure the wear resistance of the tool and the smooth and beautiful machining surface, it is very important to use high-speed machining compared with low speed. At the same time, by reducing the cutting depth, stable machining can be ensured even at high speeds.

21、How to suppress the knife marks when the side is segmented? In order to achieve stable side machining, end mills with long and short blades are usually used, and Z-section machining is carried out, but the joints between the sections will leave knife marks. How do you suppress the knife marks?

The cause of knife marks on the machined surface The machining marks on the cutting surface are caused by the end of the end mill's peripheral cutting edge cutting into the workpiece surface during the cutting process. The end of the cutting edge is designed in an R shape to prevent the end of the cutting edge from cutting into the surface.
Comparative test of end milling cutter with end R machining of cutting edge and common neck avoidance tool
Tool SN−TSC−EM4B6−20−9 SNR−TSC−EM4B6−20−9 Workpiece material S50C speed 3,290min-1 Feed speed 479 mm/min Feed width (Rd) 0.4mm depth of cut (Ad) 9mm results SNRC(Blade end R neck avoidance type) The surface roughness fluctuation is still small (red circle) and the surface finish is good even when machining to the deep side.

22、How to achieve high precision surface machining? When finishing the surface shape of the mold, in order to reduce the time of manual polishing and grinding, it is hoped to improve the precision of cutting processing as much as possible. What works best?

23、Consult the advantages of using a thermal expansion shank

With the trend of high-precision processing content, the use of thermal expansion shank is becoming popular, but the specific advantages are not clear. Consult the advantages of using a thermal expansion shank.

Basic principle of thermal expansion tool handle

Heat the front end of the handle so that it expands before loading the tool.

It is then cooled and shrunk to hold the tool.

advantage①High precision and reliability

Compared with the previously widely used collet shank, the number of components is minimal, and the tool clamping with high rigidity and precision can be achieved.

The tool holding accuracy is within a few μm at the clamping point of the fixture, and the repetition accuracy is high, so there is no need for the proficiency requirements of the tool holding operation and the measurement for accuracy verification. The use of thermal expansion tool handles simplifies tool assembly and disassembly and improves reliability.Advantages ② Extend tool life

High rigidity clamping with low runout stabilizes and extends tool life.

Advantages ③ High precision machining

Low runout ensures stable cutting for high precision machining.

24、Consult the use of thermal expansion tool handle should pay attention to matters are considering the use of thermal expansion tool handle, so far has been using the collet type tool handle, more worried about the use of thermal expansion tool handle will happen what trouble. Consult the first use of thermal expansion knife handle should pay attention to matters.