HSS end mill 1 from ukocarbide.com

Description

End Mill Bits can be used for a variety of milling operations on most materials, including steel, at an economical price. HSS End Mills feature a variety of regular length sizes and can use for most milling operations.

UKO manufactures and supplies hundreds of both standard and custom size End Mill Bits for most applications literally. Whether you need a standard or non-standard end mills with flat, ball nose or corner radius forms, or even Micro End Mills forms, UKO can turn your design into an end mill in just days. It doesn't matter if it's steel machining or stainless steel machining or cast iron machining, regardless of its use, our end mills are exceptionally made from quality ground ultrafine carbide.

Reliable quality and competitive price
Versatility, good stability, long service life, high cost-effective machining, profile milling, etc.

Detail Uko Economical Price High Toughness m42 Hss End Mill

We offer a broad selection of End Mills (Carbide End Mills and HSS End Mills) that ensures you will be able to get the job done most efficiently and at very competitive prices. End Mill Bits are
used in a milling machine to remove stock & shape workpieces in a wide range of materials in both high volume production and maintenance and repair applications. Choose from a wide range of styles, including finishing, roughing, ball, corner
rounding, and more. Tool materials include solid carbide, cobalt, carbide tipped & high-speed steel. Cutting diameters include fractional & metric size.

Basic Specification

SizeDiaShank DiaFlute LengthOverall Length
1*6*3*4716347
2*6*7*5126751
3*6*8*5236852
4*6*11*55461155
5*6*13*57561357
6*6*13*57661357
7*8*16*60781660
8*8*19*69881969
9*10*19*699101969
10*10*22*7210102272
11*12*22*7911122279
12*12*26*8312122683
13*12*26*8313122683
14*12*26*8314122683
15*16*32*9215163292
16*16*62*9216166292
17*16*32*9217163292
18*16*32*8218163282
19*20*38*104192038104
20*20*38*104202038104
21*20*38*104212038104
22*20*38*104222038104
24*25*45*121242545121
25*25*45*121252545121
26*25*45*121262545121
28*25*45*121282545121
30*25*45*121302545121
32*32*53*133323253133
36*32*53*133363253133

The Spiral Flute
Design permits a faster and smoother cutting action and the end mills are sized to provide a good cutting range while affording adequate rigidity

Center Cutting Design
Make end mill more sharp and wearable

Large Chipping Space
The cutting can be discharged in time and can be processed efficiently

Chamfer
The chamfer is easy to operate to clamp

The Spiral Flute
Center Cutting Design
Large Chipping Space
Chamfer

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FAQ

hss end mill

What Are the Three Materials of High-Speed Steel Tools?

High-speed steel can be used to manufacture complex tools, and when the cutting temperature is higher than 600 degrees, the hardness will not be significantly reduced. Such excellent performance is mainly due to the high carbon content of high-speed steel, which is the third of high-speed steel tools. What are the different materials? What are the characteristics of powder metallurgy high speed steel?

  • The three materials of high-speed steel tools are: ordinary high-speed steel, high-performance high-speed steel, powder metallurgy high-speed steel.
  • Ordinary high-speed steel can be divided into: tungsten high-speed steel, tungsten-molybdenum high-speed steel.
  • High-performance high-speed steel can be divided into: high-carbon high-speed steel, high-vanadium high-speed steel, cobalt high-speed steel, aluminum high-speed steel.

What are the classifications of powder metallurgy high-speed steel?

The classification of powder metallurgy high speed steel is actually the same as ordinary high speed steel, divided into tungsten series and molybdenum series, but the manufacturing process is different from traditional high speed steel. Powder metallurgy high speed steel is molten steel produced by high-frequency induction furnace. High-pressure gas jet cooling is used to obtain crystalline powder, and then the obtained powder is pressed into a knife blank under high temperature and high pressure, or a steel blank is forged and rolled into a knife shape.

Features of powder metallurgy high speed steel:

  • There is no carbide segregation, which improves the strength, toughness and hardness of steel, with a hardness value of 69~70HRC.
  • Obtain a very fine, uniform and non-directional microstructure, reducing the internal stress and deformation of heat treatment.
  • Continuous and stable heat treatment results and stable heat treatment dimensions.
  • The grinding processability is good, and the grinding efficiency is 2~3 times higher than that of melting high speed steel.
  • Good wear resistance.
  • The cost is high, and its price is equivalent to cemented carbide. Therefore, the main scope of application is the manufacture of complex forming tools.
  • It is suitable for manufacturing tools for cutting difficult-to-machine materials, large-size tools (such as hobs and gear shapers), precision tools and complex tools with large grinding capacity.

What Are the Advantages of Four-Edge End Mills in Milling Processing?

For four-flute end mill bits, generally speaking, if the number of edges is small and the chip pockets are large, the discharge of chips can be relatively smooth. However, at the same time, the cross-sectional area of ​​four-flute end mills is small, and the rigidity of the cutter body is low. It is prone to bending of the knife body.

On the contrary, if the number of blades increases and the cross-sectional area of ​​the workpiece increases, the rigidity of the four-blade end mill body will increase, but the chip pockets will become smaller, and the chip holding force will decrease, which will easily cause chip jams and reduce the surface finish of the workpiece. . The shorter the blade of the four-flute end mill, the more rigid the four-flute end mill cutter body and the better the cutting performance. The rigidity of a four-blade end mill is inversely proportional to the length of the blade to the third power. Therefore, if the blade length of a four-flute end mill is doubled, the rigidity of the four-flute end mill body will be reduced to 1/8 of the original.

In actual on-site processing, customers mostly use four-blade end mills to process planes, steps, etc. Four-blade end mills use right-handed and right-cut spiral teeth, so that the chips are discharged from the front end of the milling cutter when the material is processed, and the four-blade stand The milling cutter has a better chip removal effect, and increases the cutting rake angle, reduces the amount of chips, and is more convenient for material cutting. Therefore, four-edge end mills are widely used in mold processing, auto parts production and other fields.

6 Choosing A Milling Cutter Tips You Need To Learn Now.

The spindle speed of the CNC machine tool is very high, and the output power of the spindle is relatively large. Compared with the traditional cutting method, the requirements for the milling cutter are more stringent, and the requirements for the elements of rigidity, precision, durability, and strength are more stringent. At the same time, dimensional stability is required, and installation and adjustment are convenient.

These series of problems have put forward very strict requirements on the structure of milling cutters, the standardization and serialization of geometric parameters. To improve the efficiency of milling processing, the choice of CNC milling cutter is particularly important, so there are 5 important factors to consider when choosing a milling cutter:

    • When choosing a milling cutter, the cutting performance of the milling cutter material should be considered. For example, when processing titanium alloy, high-strength steel, and stainless steel workpieces, it is recommended to choose indexable carbide milling cutters with better wear resistance.
    • We can choose the milling cutter according to the different processing stages of the workpiece. For example, in the rough machining stage, our main purpose is to remove the margin, then we can choose a large milling cutter with better rigidity, lower precision, and higher chip removal performance. In the semi-finishing and finishing stages, The most important thing is to ensure the machining accuracy of the workpiece and the quality of the product. At this time, you should choose a finishing milling cutter with higher durability and higher accuracy.
    • If the milling cutter of the same specification for roughing and finishing can reduce the cost of milling cutters, we can choose the milling cutters eliminated in the finishing stage during roughing, because most of the milling cutters eliminated from finishing are caused by slight wear on the edge. Elimination, in addition to the abrasion of the blade, the coating also has slight abrasion, and these losses will directly affect the precision of the finishing process, thereby affecting the product quality, but the main purpose of roughing is to remove the margin. Finishing milling cutters eliminated for roughing can effectively save costs.
    • Choose the milling cutter according to the characteristics of the area to be processed. When the workpiece processing permits, we can choose a milling cutter with a larger diameter and a smaller length-to-diameter ratio; when we are processing thin-walled and ultra-thin-walled workpieces, the end edge of the over-center milling cutter should have sufficient centripetal angle , In order to reduce the cutting force of the milling cutter and the cutting part. When processing soft workpieces such as aluminum and copper, an end mill with a slightly larger rake angle should be used, and the number of blades should not exceed 4 blades.
    • When choosing a suitable milling cutter, we try to make the size of the milling cutter fit the surface size of the workpiece to be processed. In actual production, for the peripheral contour processing of flat workpieces, end mills are usually used; when milling planes, cemented carbide milling cutters are preferred; when processing bosses and grooves, high-speed steel end mills are preferred; When rough machining the surface of the blank or the hole, it is recommended to use corn cutters with carbide inserts; for some three-dimensional profiles and variable bevel contour contours, use ball-end milling cutters, ring cutters, tapered milling cutters and discs More knives.
    • For the processing of free-form surfaces, because the end cutting speed of the ball-end milling cutter is zero, in order to ensure the accuracy of the processing, the cutting line spacing will be very small, so the ball-end milling cutter has a higher degree of friendliness for surface finishing. However, the advantages of end milling cutters compared with ball-end milling cutters in surface processing quality and efficiency will be more obvious. Therefore, when ensuring that there is no over-cutting phenomenon in workpiece processing, we try to choose end mills when roughing and semi-finishing the surface. Milling cutter. In addition, the durability and accuracy of milling cutters have a greater impact on the price of milling cutters. In most cases, a good milling cutter must increase the cost of the milling cutter.

What Is a High-Speed Steel End Mill?

High-performance high-speed steel end mill are usually made of M42 material. The vanadium content is not high (1%) and the cobalt content is high (8%). Cobalt can cause carbides to dissolve more in the matrix during quenching and heating. The hardness of the matrix to improve wear resistance.

The hardness, hot hardness, wear-resistance and grindability of this high-speed steel are very good. When the cutting temperature is above 600 ℃, the hardness still does not drop significantly.

Cobalt high-speed steel milling cutters are often used to cut difficult-to-machine materials, and because of their good grinding performance, they can be made into complex tools, which are widely used at home and abroad.

How to Choose an End Mill?

In general, we will select the end mill from the following three points:

1. Select the type of tool coating according to the type and hardness of the workpiece to be processed. For example, when machining workpieces with hardness below HRC40 such as carbon steel, MIRACLE40 coating of Mitsubishi Materials Corporation can be selected. When machining alloy steel S, tool steel and other workpieces with hardness around HRC50, MIRACLE coating can be selected. When machining workpieces with higher hardness, the tool shape, hard alloy material, and coating can be selected as MIRACLE coatings for high hardness processing, which are dedicated to processing high hardness materials.

2. Select the shape of the end mill neck according to the shape of the workpiece. Ball neck end mills are divided into standard, long and tapered neck shapes, which can be selected according to the processing depth and shape of the workpiece. Long-neck type and tapered-neck type can be used for deep digging. The interference angle should be considered when choosing between the two. At the same time, compared with the long-neck type, the tapered-neck end mill has higher rigidity, which can improve cutting conditions and achieve better machining accuracy. Try to choose a tapered-neck end mill.

3. Select end mills with different ball nose accuracy according to the machining accuracy. The arc accuracy of ball end mills is usually ± 10μm, but there are also high precision endmills of ± 5μm, which can be used for high precision machining.

When selecting an end mill for a particular milling operation, many factors need to be considered to ensure successful operation.

Tool material
The material of the tool (the material of the tool itself) is the main characteristic of the tool, regardless of whether the tool has a coating or the cost of the tool, it plays a vital role in your milling operation.

High-speed steel (HSS): High-speed steel is the most basic and common tool material. It is mostly used in old-style grinders for simple, short-term operation. High-speed steel tools do not have the same speed and feed advantages as high-speed steel-cobalt alloy and hard alloy tools.
High-speed steel-cobalt alloy: a tool made by adding 8% cobalt to ordinary high-speed steel has a hardness that is greater than that of pure high-speed steel. In this way, the speed, feed rate, and price will be higher than the latter. Increase; of course, even after the increase, it is far from being comparable to the tool of hard alloy material.

Carbide: Carbide cutters run 2 to 2.5 times faster than HSS and HSS-Co alloy cutters, which actually improves production efficiency and yield. If you are using or typing
When using hard alloy tools, please pay attention to the following points: Make sure that your tool has a solid shaft so that it will not move on the tool holder. Because hard alloy cutting tools are more brittle in texture and have a higher speed, they can easily break if the connection is not secure.

The initial cost of purchasing hard alloys may be higher than the previous two, but using it is very efficient in production, and has a long service life, which saves the cost of replacement; the overall profit is much greater than that cost. Carbide tools are more susceptible to cutting debris than high-speed steel tools, so be careful when handling them.

High-speed steel-cobalt alloy: a tool made by adding 8% cobalt to ordinary high-speed steel has a hardness that is greater than that of pure high-speed steel. In this way, the speed, feed rate, and price will be higher than the latter. Increase; of course, even after the increase, it is far from being comparable to the tool of hard alloy material.

Parameters of the tool
Need to choose the appropriate end mill parameters according to the specific operation. Here are some basic elements to consider:
Tool total length: If the operation permits, use a shorter end mill as much as possible to reduce the deviation during milling. Therefore, as short as possible to choose the end mill to save tool costs.

Two grooves: has the largest chip removal space. Mostly used for ordinary milling operations and milling operations for softer materials.

Three-slot: Very suitable for drilling operations, but also for ordinary milling operations. Chip removal performance and processing quality are in the middle.

Four grooves: suitable for harder ferrous metal operation, higher processing quality.

Six-slot and eight-slot: The chip removal ability of a large number of sipes is reduced, and the surface quality of the finished product is improved. Such tools are particularly suitable for the processing of final products. Remove debris and dirt before operation.

Face angle (front angle): A normal end mill has a positive face angle of 10-12 °, which is more suitable for cutting soft, viscous and high-toughness materials. The blade angle must be adjusted according to the material being processed. When selecting the tool face angle (front angle), the clearance angle (back angle) of the tool must also be considered to directly increase the force behind the cutting edge.

Helix angle: The helix angle of general end mills is usually around 30 °. A higher helix angle is conducive to chip discharge, and is more suitable for rapid milling and pin processing of materials such as aluminum.
Tool design style

Ball end: The shape of the end of the tool is round or semi-circular. This type of end mill is used to mill the cavity of the die and the concave surface of the tooth, and cut the bottom hole and the bottom groove.

Square end: Square end milling cutters have center cutting type and non-center cutting type. The former is very central for inclined plunge milling; the latter is only suitable for side milling.

Corner radius end (round nose corner end): Because the weakest part of an end mill is its sharp corner, the use of a corner radius to help protect the end of the tool from chip damage. This angular radius end mill cuts faster and more than ordinary ball end mills, but at the same time, considering the type of workpiece being processed, it is most suitable for mold processing.

Single-ended: The tool has a blade on only one end. This is the most commonly used tool style type.
Double end: An end mill with blades at both ends. Clean the knife holder before use.
Bit end: This is a multifunctional cutting milling cutter, which can be used for drilling, vertical planing, bevel cutting and contour milling.

Beveled cut end: It has unique cutting quality, which can save the finished product from manual trimming operation.
Sharpening type milling cutter (or chipping type milling cutter): Sharpening is very effective for operations that need to quickly remove a large amount of material. The small short grooves on the file edge allow more metalworking fluid to flow through the machining surface and better remove heat. There are various design styles of the outer contour of the grinding file to adapt to the processing of various materials. The rougher the short groove of the file edge, the more material is abraded, and the less smooth the surface of the finished product. Since the eccentric force of most grinding files is reduced, the secondary grinding can only be done with the cutting surface. If you have the secondary grinding equipment, the cost will be greatly reduced.

Left-handed spiral end: suitable for milling thin-layer pieces, and the chips will be directly discharged from the workpiece.
Coating type

The coating of the tool can improve the performance of high-speed steel and hard alloy tools. Different coatings can be selected according to the specific processing operation. It should be noted that although the coating can increase the surface hardness of the tool, if the material of the tool itself is poor and cannot meet the requirements of the machining surface, then even the coating will not help.

How Much Runtime of HSS End Mill

High-speed steel cylindrical milling cutter life T = 100 ~ 400min, hard alloy face milling cutter life T = 80 ~ 600min.

1. Among the several cutting parameters of the tool, the cutting line speed has the greatest impact on the service life of the tool (the parameter corresponding to the cutting line speed is the speed). Therefore, reducing the speed can maximize the service life of the tool;

2. The degree of influence of the cutting depth and feed speed of the tool on the service life is the second and the second respectively.

In other words, the true meaning of increasing the life of milling tools is to use the highest cutting depth and feed rate at the lowest possible speed (to meet the requirements of the limit of the tool's tolerance and the surface roughness of the workpiece and other factors) Whichever is greater) to maximize the product of these three values.

3. Cutting method (clockwise and counter-clockwise milling), the cutting vibration during down milling is smaller than that during reverse milling. The cutting thickness of the tool during down milling is reduced from the maximum to zero. After the tool is cut into the workpiece, there is no spring-up phenomenon caused by the inability to cut chips. The rigidity of the process system is good and the cutting vibration is small;

During counterclockwise milling, the cutting thickness of the tool increases from zero to the maximum. At the beginning of the cutting, the path of the workpiece will be scratched due to the thin cutting thickness. At this time, if the cutting edge encounters hard points in the material or remains on the surface of the workpiece, Chip particles will cause spring or flutter of the tool, so the cutting vibration of back milling is large; but the experience of countless people has told us that the cost of the tool only accounts for no more than 10% of the entire machining cost, many The cost of tools in mechanical processing plants does not even exceed 2%.

Reducing the cost of the tool has little effect on the overall cost of the entire machining process. However, besides the machine tool, the tool is the most influential factor in machining efficiency. A good tool, combined with appropriate processing parameters, can improve the efficiency of the entire machining process, thereby increasing the output value of the machining process per unit time. Under the premise of a small increase in costs, improving production efficiency per unit time is the only rule for cost savings in machining.

It is recommended that machining engineers focus more on how to improve the efficiency of machining, rather than how to increase the service life of the tool.

Type of Tool Steel?

According to different chemical compositions, tool steel is often divided into three categories: carbon tool steel, alloy tool steel, and high-speed steel (essentially high alloy tool steel). According to the use of steel, it can be divided into three categories: cutting tool steel, die steel and measuring tool steel.

1. Carbon tool steel: Carbon tool steel has a high carbon mass fraction between 0.65-1.35%, which belongs to sub-eutectoid, eutectoid or hypereutectoid steel according to its organization. After heat treatment, the surface of carbon tool steel can obtain higher hardness and wear resistance, the core has better toughness; the annealing hardness is low (not greater than HB207), and the processing performance is good.

However, its red hardness is poor. When the working temperature reaches 250 ℃, the hardness and wear resistance of the steel drop sharply, the hardness drops below HRC60, and the hardenability of this type of steel is low. Larger tools cannot be hardened (the diameter of hardened in water is 15mm), and the hardness of the surface hardened layer differs greatly from the central part during water quenching. Make the tool easy to deform during quenching. Or the formation of cracks. In addition, the quenching temperature range is narrow, and the temperature should be strictly controlled during quenching. Prevent overheating, decarburization and deformation.

2. T7, T7A hypoeutectoid steel: It has good plasticity, toughness and strength, and a certain hardness, can withstand vibration and impact loads, but has poor cutting ability. Used to manufacture tools that are not subject to impact load, and require appropriate hardness and wear resistance, and good toughness, such as forging dies, chisels, hammers, punches, metal shears, reamers, steel stamps, woodworking Tools, pneumatic tools, machine tool tops, fitter tools, drilling tools, blunt surgical instruments, etc.

3. T8, T8A eutectoid steel: It is easy to overheat during quenching and heating, the deformation is also large, the plasticity and strength are relatively low, it is not suitable to manufacture tools that withstand large impact, but after heat treatment, it has higher hardness and wear resistance. Used to manufacture tools with cutting edges that do not heat up during work, such as woodworking tools, pneumatic tools, fitter tools, simple molds, rivet punches, center hole punches and punches, tools for cutting steel, bearings, cutting tools, aluminum tin alloy Die-casting plates and cores, and various types of springs.

4. T8Mn, T8MnA eutectoid steel: with high hardenability and hardness, but low plasticity and strength. It is used to manufacture woodworking tools, hand saw blades, engraving tools, rivet dies, clockwork, band saw blades, circular saw blades, coal mine chisels and masonry chisels.

5. T9, T9A hypereutectoid steel: with higher hardness, but lower plasticity and strength. It is used to manufacture various tools that require higher hardness and certain toughness, such as marking tools, rivet dies, press dies, punches, woodworking tools, agricultural machinery cutting parts, rock drilling tools, and mold shunts.

6. T10, T10A hypereutectoid steel: the grain is fine, and it will not be overheated during quenching and heating (temperature reaches 800 ℃), and it can still maintain the fine grain structure; after quenching, there is undissolved excess carbide in the steel, so it has a ratio T8 and T8A steels have higher wear resistance, but lower toughness.

How to Improve the Safety of High-Speed Milling Cutter?

Combined with the safety standards of high-speed milling cutters, through the analysis of the finite element calculation model, in order to adapt to the safety requirements, the following measures can be taken:

(1) Reduce tool quality, reduce the number of tool components, simplify tool structure

The relationship between the fracture limit of different tools of the same diameter and the tool body quality, the number of tool components and the number of component contact surfaces obtained from the experiment. After comparison, it was found that the lighter the tool quality, the less the number of components and the component contact surface. The higher the limit speed of rupture. The study found that the use of titanium alloy as the material of the cutter body reduces the quality of the component, which can increase the fracture limit and speed limit of the cutter. However, due to the sensitivity of the titanium alloy to the cut, it is not suitable for manufacturing the knife body, so some high-speed milling cutters have used high-strength aluminum alloy to manufacture the knife body.

In the structure of the cutter body, care should be taken to avoid and reduce stress concentration. The grooves on the cutter body (including the tool holder groove, chip holding groove, and key groove) will cause stress concentration and reduce the strength of the cutter body. The bottom of the groove has sharp corners. At the same time, the structure of the cutter body should be symmetrical to the axis of rotation so that the center of gravity passes through the axis of the milling cutter. The clamping and adjustment structure of the blade and the tool holder should eliminate the play as much as possible, and require good repeatability. At present, high-speed milling cutters have widely used HSK tool holders to connect with the machine tool spindle, which has greatly improved the rigidity and repeated positioning accuracy of the tool system, which is conducive to the improvement of the tool breaking limit speed. In addition, the diameter of the machine clamp type high-speed milling cutter reveals the development trend of smaller diameter and reduced number of cutter teeth, which is also conducive to the improvement of cutter strength and rigidity.

(2) Improve tool clamping
Simulation calculations and rupture test studies have shown that the clamping method of high-speed milling cutter blades does not allow the usual frictional clamping, and the blade with a central hole, screw clamping method, or a specially designed tool structure should be used to prevent the blade from flicking. fly. The direction of the clamping force of the tool holder and the blade is preferably the same as the direction of the centrifugal force. At the same time, the pretension of the screw must be controlled to prevent the screw from being damaged in advance due to overload. For small-diameter shank milling cutters, hydraulic chucks or thermal expansion and contraction chucks can be used to achieve high precision and high rigidity.

(3) Improve the dynamic balance of the tool
Improving the dynamic balance of the tool is very helpful to improve the safety of the high-speed milling cutter. Because the unbalance of the tool will produce an additional radial load on the spindle system, its size is proportional to the square of the speed.

If the mass of the rotating body is m and the eccentricity between the center of mass and the center of the rotating body is e, the inertial centrifugal force F caused by the unbalance is:
F = emω2 = U (n / 9549) 2
Where: U is the tool system unbalance (g • mm), e is the tool system centroid eccentricity (mm), m is the tool system mass (kg), n is the tool system speed (r / min), and ω is the tool system Angular velocity (rad / s).

As can be seen from the above formula, improving the dynamic balance of the tool can significantly reduce the centrifugal force and improve the safety of the high-speed tool. Therefore, according to the requirements of the draft standard, the milling cutter used for high-speed cutting must pass the dynamic balance test and should meet the requirements of the G4.0 balance quality level specified in ISO1940-1.

4 Conclusion
High-speed milling cutter safety technology is an important part of researching high-speed cutters. Quantitative analysis of tool safety should be strengthened to accurately determine the small amount of factors that affect the safety of high-speed milling cutters. The safety of high-speed milling cutters.

How to Choose a Milling Cutter for Nickel-Based Alloy Processing?

The alloy milling cutter manufacturer pointed out that regardless of the design of the cutter or the material used, the manufacturer of the cutter should provide the initial value of the cutting speed and the feed per tooth. If these data are not available, the manufacturer’s technical department should be consulted.

Manufacturers should be familiar with the capabilities of their products when performing full-width slot milling, profile milling, plunge milling, or ramp milling because most standard milling cutters are unable to complete so many machining operations. For example, if the milling cutter does not have a sufficiently large second clearance angle, the bevel angle for ramp milling will be reduced.

Obviously, if the machining capacity of the nickel-based alloy milling cutter is exceeded, the tool will be damaged. The same is true for plunge milling. If the chips cannot be discharged from the bottom of the groove in time, the chips will be squeezed and the tool will be damaged later. In short, when milling a superalloy, these conditions are detrimental to tool life.

If you think that the slow feed rate of alkali can prolong the tool life, this concept is not entirely correct. For example, when cutting the first knife, you will find that the material is quite hard. If the feed rate is reduced (for example, the feed rate per tooth of the indexable milling cutter is reduced to 0.025~0.5mm), the cutting edge of the tool will strongly rub the workpiece, and the result is that the tool is quickly or immediately damaged. Friction energy bow | Work hardening on the surface of the workpiece. To avoid work hardening, a constant cutting load (0.15~0.2mm/feed per tooth) should be maintained when cutting the first knife.

Cutting depth depends on many factors, such as tool design, blade height, fixture rigidity, total tool length, machine horsepower, etc. However, when the back angle and rake angle of the tool are positive from 5° to 11°, it is most suitable for processing materials with high viscosity. The helix angle of the end mill should be between 35° and 50°. The inclined edges of these milling cutters have a sawing effect, which can form ideal chips and take away the cutting heat.

Of course, when milling nickel-based alloys, it is also very important to choose an appropriate cutting speed. It determines how much heat is generated in the cutting zone. The recommended speed range is from a low 12~15m/min (high-speed steel milling cutter) to 23~37m/min (hard alloy milling cutter), and then to 180~245m/min or higher (for ceramic milling cutter). Increasing the feed and cutting depth will also increase the cutting heat because the cutting force and the contact area between the tool and the workpiece are increased accordingly.

According to the stress and cutting force when milling the nickel-based alloy, the sub-fine grain cemented carbide should be selected as the base of the milling cutter blade, and the nitrogen aluminum titanium coating with heat resistance should be adopted. The use of such carbide alloy blades for milling processing can achieve very good processing results. At a lower cutting speed, the titanium carbonitride coating is used for processing, and its effect is also good.

If the nickel-based alloy milling cutter is used, the tool is improperly used, even if a better substrate and coating are used, a good machining effect will not be achieved. For example, a groove is to be milled on the part-a depth of 3.8mm, and you want to cut it out in three passes. Generally, the CAM system will display the same depth of cut three times during this process.

Because the workpiece repeatedly touches the same position on the tool, the same depth of cut will cause a gap in the Xu layer, and this gap will cut through the coating, which will damage the substrate and damage the tool. Therefore, in milling, select the appropriate cutting depth (generally 0.5 ~ 0.75mm), in milling, to prevent the workpiece from repeatedly contacting the same part of the blade, so as to extend the life of the tool.

Influence of cutting heat

When milling nickel-based alloys, a lot of cutting heat is generated. Therefore, when machining, sufficient coolant is used to submerge the cutting area, which is easy to achieve for small diameter milling cutters, but for large-diameter cutters (face milling cutters), it is impossible to submerge all of them during cutting. Use dry milling.

When the milling cutter cannot be covered by the coolant, heat is quickly transferred in and out on the insert, resulting in many small cracks perpendicular to the cutting edge. When the cracks gradually expand, the carbide will crack. In some cases, a relatively small milling cutter can be used, and no coolant is used during machining. If the cutting of the cutter is normal and the life of the cutter is improved, it can also be used for effective dry milling.

What Are the Common Clamping Methods for End Mill Bits?

1. Side locking type chuck
advantage:
(1). Low cost.
(2). Easy to buy.
Disadvantages:
(1) It is difficult to ensure the balance of the tool.
(2). Not suitable for high-speed processing.

2. Chuck type chuck
advantage:
(1) Strong clamping force.
(2) The concentricity is better.
(3). Suitable for tools of various sizes.
(4). Rigidity is better than spring clip chuck.
(5) The cost is not high and the cleaning is convenient.

Disadvantages:
(1). Each chuck is suitable for limited tool holders.
(2) To prevent tool damage, a special wrench must be used to tighten the chuck.

3. Spring clip chuck
advantage:
(1) Strong clamping force.
(2) Good concentricity.
(3). Suitable for tools of various sizes.
(4). Low cost and easy to clean.

Disadvantages:
(1). The concentricity of each tool must be inspected.
(2) It is difficult to maintain the balance standard specified by the manufacturer.
(3) The user needs certain skills.

4. Hydraulic chuck
advantage:
(1) The clamping force can meet the processing needs.
(2) The concentricity is better.
(3). Good dynamic balance performance.

Disadvantages:
(1). The size of the tool holder must match the inner diameter of the chuck.
(2) Generally, in order to maintain a proper aspect ratio, the handle cannot be too long.
(3) Higher cost.

5. Heat shrinkable chuck
advantage:
(1). Extremely strong tool holding force.
(2). Excellent concentricity.
(3). Excellent dynamic balance performance.

Disadvantages:
It is easily damaged due to improper operation by the user.

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