一、milling

1、The front Angle of the end mill is divided into negative front Angle blade type and positive front Angle blade type. What is the difference between the two? The front Angle of the end mill is divided into negative front Angle blade type and positive front Angle blade type. What are the differences in specific terms? In addition, how to distinguish the use of processing?

According to the different processing purposes, it is necessary to choose the right material and the right place

Under normal circumstances, the positive front Angle blade type with small cutting resistance is used, but when processing materials such as high-hardness steel, it is recommended that you choose an end mill with a negative front Angle because of the need for sufficient tip strength.

Rake Angle	Positive front corner blade type	Negative front corner blade
Apex view
peculiarity	Sharp cutting edge shape design, reduce cutting resistance, even at low speed conditions, can also obtain good machining surface roughness. Positive front Angle cutting tools are suitable for soft materials that are prone to cracking and melting.	When machining at low speed, the cutting resistance is enhanced and the roughness of the machined surface is reduced. When machining at high speed, good surface roughness can be obtained. The negative front Angle cutting tool with high tip strength is suitable for the processing of high hardness steel which is easy to produce a falling edge.
applicable Chipped wood	Resin, copper, aluminum, stainless steel, ordinary steel, tempered steel, etc	High hardness steel, cast iron, etc

2、What are the advantages of using arc Angle end mill for copying? Recently, it is often heard that the arc Angle end mill is used in 3D copying machining instead of the ball end mill. So, what are the specific advantages of using an arc Angle end mill?

Optimized cutting conditions

The blade diameter of the ball end mill is twice that of the tip R, while the blade diameter of the arc Angle end mill is not affected by the size of the tip R, and a larger value can be selected. Once the blade diameter is increased, it can be seen from the following points that the cutting conditions will be optimized.

The rigidity of the tool increases with the increase of the blade diameter, especially for small diameter tools, which can suppress the bias in the minimum range and achieve stable processing. In addition, the actual machining diameter increases, and the cutting speed can be improved, which can improve the machining surface accuracy and tool life.

Improve the processing efficiency of flat parts

Compared with ball-end end milling cutter, arc Angle end milling cutter can obtain larger step value, which can effectively improve the machining efficiency during roughing.

The use of arc Angle end milling cutter and ball end milling cutter

Processing method	Arc Angle end mill	Ball-end mill
Machining of multiple planar parts	◎	○
Cavity machining with R at the bottom	◎	○
Deep groove processing of high hardness materials	◎	○
Complex 3D processing	×	◎
Machining on low speed machinery where the speed cannot be increased	◎	○
Cutting stability	◎	○
programming	△	◎

3、How to improve the accuracy of the machining surface when machining the side? When the end mill is used for side machining, it will be because the machining surface is too rough or can not be processed out of the right Angle, etc., which tool and which method are used for processing, can meet the accuracy requirements of the machining surface?

Reasons for not obtaining machining accuracy Even if the high rigidity carbide end mill, if the cutting edge length, neck length size is too large, the cutting edge will appear a spring knife or chatter, resulting in processing accuracy, tool life is reduced. Cutting edge knife refers to the bending phenomenon in the front end of the tool when machining the workpiece material, resulting in the machining surface becoming bow. In addition, the tool clamping rigidity and low runout accuracy, cutting conditions are not optimized, but also easy to cause low machining accuracy.

Use high-rigidity tools If a high rigidity tool is used, the cutting edge can be suppressed. The tool with long blade, large diameter and many blades is a high-rigidity tool.

The effectiveness of segmented processing Although the rigidity of the tool with long and short edge is high, it may interfere with the tool handle during side machining. To avoid interference, use a tool with a neck diameter smaller than the tool diameter. If it is such a tool, it can be segmented in the Z direction. In addition, the cutting speed and feed speed can be set higher, so it also helps to shorten the processing time.

Method of machining surfaces to avoid high and low differences During machining, the cutting surface is marked because the end of the outer cutting edge of the end mill bites into the cutting surface. By setting an R-shaped blade at the cutting edge end, the cutting edge end can be prevented from biting.

4、Hope efficient, high-precision machining keyway when machining keyway slot width is difficult to be uniform, very confusing. If the slot width is not uniform, the key is difficult to fit. Consult the key points of high precision machining keyway.

Cutting mode using end mill In order to reduce the cutting resistance of the cutting edge, reduce the cutting depth and adopt the tool path that makes the blade load stable, it can be said that it is the most suitable cutting machining for the keyway. According to the above reasons, the conditions of high speed and large feed can achieve stable cutting. Moreover, because the cutting resistance and thermal effect are suppressed to a small degree, the tool performance is stable and the service life is long. ①Reciprocating profile tool path The cutting mode is divided into several times with a smaller Z-direction cutting depth (see Figure 1). Because of the layered cutting mode, the short-edge circular arc Angle end mill can effectively suppress flutter. ②Trochoidal tool path The cutting is carried out in a circular arc path (see Figure 2). The cutting depth of the peripheral edge is small and stable. Using a tool with a diameter smaller than the width of the slot is conducive to chip removal. The cutting stability can give full play to the tool performance, and the multi-edge large spiral Angle end mill is the most effective.

Recommended tool ①Reciprocating tooth profile tool path，②For trochoid tool paths, use a circular Angle end mill with a rounded R for the shape and a neck length for the depth of the keyway.

5、How to effectively deal with the burrs produced when the knife is withdrawn?In order to remove the burrs produced when the knife is withdrawn, it takes quite a long time.

Why do they produce burrs? Is there any way to remove the burrs that have been produced in a short time？

About the production of burrs

The residual part of the cut that extends into space when the tool is withdrawn becomes a burr. According to the classification of the workpiece, different workpiece materials will produce different burrs. Soft materials such as aluminum alloy and copper alloy produce larger burrs, high-hardness materials produce smaller burrs, and cast iron produces negative burrs (defects). There are other examples of burrs that cannot be avoided, as well as the "cracking" of cut surfaces. It can be said that the phenomenon of burr in cutting processing.

Methods to suppress burrs

①Compress the burr space as much as possible

To suppress the burrs produced when the knife is removed, eliminating the space generated by the burrs is an effective method. For example, measures to reduce space such as chamfering can be taken before the tool is withdrawn.

②Appropriate cutting conditions are used to suppress burrs

To minimize the amount of cutting residue, the most appropriate tool and cutting conditions must be selected.

・ Choose a tool with large front Angle and sharp cutting edge.

・ Increase cutting speed and improve cutting characteristics.

・ In particular, when finishing cutting, the minimum cutting depth and feed amount must be used.

The use of a chamfered end mill can effectively remove burrs.

6、How to suppress flutter in deep cavity cutting? When the die is deep cavity cutting, the end milling cutter vibrates, which leads to the cutting tool breakage or the machining surface is not beautiful and smooth, and can not meet the design requirements. Have you ever wondered if there is a cure for flutter suppression？

Cause of flutter When the end mill cuts, if the load borne by the tool is too large, exceeding its own rigidity, it will chatter. In order to avoid interference with the workpiece during deep cavity machining, the extended part of the tool is long, so it is difficult to ensure the rigidity of the tool and easy to chatter.

Reduce the load on the tool To reduce the load of the tool, the cutting amount can be reduced and the cutting speed can be increased, which can effectively improve the cutting characteristics of the blade. Especially for the cutting speed is difficult to improve, the blade performance is difficult to play the small diameter end mill, the lack of speed may become the cause of load increase.

Increase tool rigidity The use of a good rigid end mill can effectively suppress chatter. Try to choose an end mill with a long edge and a short extension length. The circular arc Angle end mill has a larger tool diameter and is therefore more rigid than a ball end mill of the same R-size. As far as the tool shape is concerned, the rigidity of the cone neck tool is larger than that of the long neck tool. The thermal expansion tool handle has good proximity to the cutting parts, and can be cut with a short extension length even if the deep parts are cut, and its clamping rigidity is large, the clamping accuracy is high, and it can effectively inhibit flutter.

Reduced cutting load

Ball-head and arc Angle end milling cutter, the outer edge of the taper shape of the cutting tool, due to the point cutting state during the machining to reduce the cutting load, is conducive to suppress the tool yield and chatter.

7、In order to eliminate the drilling of preset holes in the grooving process To carry out the grooving process, it is necessary to first use the drill for preset hole processing, and then use the end mill with a diameter smaller than the aperture for lateral processing. In order to achieve the purpose of shortening the processing time, please inform the method of grooving without cutting holes. Foot machining surface accuracy requirements？

To eliminate the need to drill preset holes in the grooving process without drilling preset holes can be dug processing, please use a flat end mill, cutting methods are roughly 2. ①After cutting in by way of slope machining or spiral machining, transverse machining is carried out. This method ensures that high speed rotation is maintained while machining, thus reducing man-hours when machining shallow bottom and large width slots. And because it can avoid the center edge of the end mill and use its peripheral edge to implement machining, it can effectively improve the service life of the tool and obtain good machining results. ②Without the need to drill a preset hole, the machine is cut to the necessary depth by deep (drilling) machining, and then complex shapes are machined. This method ensures that a large cut depth is obtained in the Z direction, thus reducing the working time when machining the cavity with a deep bottom and a small width. And because the tool tip will bear the load during machining, special tools for deep machining must be used. The processing methods of ① and ② must be differentiated according to the use of tools and cavity shapes.