How to calculate the reaming force

1. The aqua hydrogen and oxygen team, which is composed of the core backbone of the former Alibaba, ant financial services, Goldman Sachs and other well-known enterprises, is the most powerful
head of aqua hydrogen and oxygen project: Cao Juntao's introction is as follows, worthy of the title of "big brother"
all previous ant gold clothing - chief architect and technical director of balance treasure, participating in the proct of Building 1 trillion and 800 billion assets - balance treasure
former ant gold service international business group solution team technology leader
Internetworking division solution senior architect. He has nearly ten years of working experience in Alibaba group. Participated in the technical preparation work of tmall double 11 for 9 consecutive times, and participated in building a world-class payment platform of 25.6w TPS
2008 has served as the head of Alipay's domestic business group and solution architecture team. It plans the three generation Alipay business platform and the four generation cloud financial architecture instry open platform to participate in the completion of the multi billion level user procts such as balance treasure, 12306 tickets purchase and so on.
in 2015, he served as the technical director of the solution team of ant financial services international business group, and led the implementation of billing solutions for overseas Ka merchants such as Uber, apple and Amazon
since 2016, I have been responsible for the architecture and technology of zhaocaibao and Yuebao in ant financial services wealth business group.

2.

The top five investment banks on Wall Street are Goldman Sachs, Morgan, Merrill Lynch, Lehman Brothers and Bear Stearns

Goldman Sachs: Goldman Sachs was founded by German immigrant Marcus Goldman in 1869. From the 1890s to the first World War, the investment banking business began to take shape. It is one of the oldest and largest investment banks in the world

headquartered in New York, with branches in Tokyo, London and Hong Kong, it provides a wide range of investment, consulting and financial services to the world, and has a large number of multi instry customers, including private companies, financial enterprises, government agencies and indivials

Morgan: Morgan Stanley is an international financial services company established in New York, USA, which provides various financial services including securities, asset management, business merger and reorganization, credit card, etc. at present, it has representative offices in more than 600 cities in 27 countries, with a total number of employees of more than 50000

Merrill Lynch: Merrill Lynch is one of the most famous securities retailers and investment banks in the world, headquartered in New York, USA. As one of the largest financial management consulting companies in the world, it has a place in the financial world. The company occupies the entire 34th floor of the world financial center building in Manhattan

4. Lehman Brothers: one of the most powerful underwriters and dealers of stocks and bonds in the world. At the same time, the company also serves as an important financial adviser to many multinational companies and governments around the world, and has a number of internationally best analysts recognized by the instry

Bear Stearns: founded in 1923 and headquartered in New York, it is the fifth largest investment bank on Wall Street in the United States. It is one of the top 500 companies in the world. It is a leading financial service company in the world, providing services to governments, enterprises, institutions and indivials all over the world

extended information:

The Morgan consortium has a strong foundation in the financial instry. Its main pillar is J.P. Morgan. Morgan is one of the world's largest multinational banks, with 10 subsidiaries and many branches in China, as well as more than 1000 communication banks

it has branches or representative offices in about 20 big cities abroad, and owns equity in financial institutions in nearly 40 countries. Its operation is characterized by a large number of stock transactions and huge trust assets

It controls the equity of 37 foreign commercial banks, development banks, investment companies and other enterprises. In addition, there are manufacturers such as Hanover Corporation, New York banker's Trust Corporation, northwest Bank Corporation, Prudential Life Insurance Company and New York Life Insurance Company

in instrial and mining enterprises, there are International Business Machines Corporation, general electric company, international telephone and Telegraph Company, American steel company and general motors company; In the public sector, there are at & T and southern< strong>

3. For example, when you transfer money to me, I will give you a string of codes. This code is the address where I collect money. The address format corresponding to different currencies will be different, so we must repeatedly confirm whether the address is the currency in the transfer operation. For example, if you use the address of bitcoin to transfer money to the address of Ethereum, it will judge that it is not the address of bitcoin and refuse. However, if you insist on doing so, it may cause the loss of assets. So the address must be verified repeatedly before transfer. You should also pay special attention to whether the first few and the last few are exactly the same as the address given to you by the other party< When it comes to this address, it actually has another function. Blockchain is a completely transparent network. When you give someone an address, it is possible for others to query the transfer, flow and balance of your address. So when we use the address, we should also pay attention to personal privacy. For example, if you give address a to someone, you'd better give address B to another person. This is the most convenient way to protect your privacy.

4. Different, the cross section of reaming is a circle, and the cross section of twist drill is a circle. The cutting force should be smaller. Otherwise, we all drill large holes first and then expand them. We are afraid that the direct cutting force is too large. As for the calculation formula, I wonder if I can subtract the force of undercutting from the force of reaming. After all, cutting force is proced by overcoming the plastic deformation of materials. For example, for 40 holes, drill 30 bottom holes first and then expand. Use the force to cut the bottom hole minus the force to cut the bottom hole. If you are not at ease, multiply the safety factor by 1.2 ~ 1.5

5. Pij= π 2ei / L2 means that PIJ is equal to the square of 3.14 times the ratio of E and the square of I and L.
in the formula, PIJ is the critical force; E is the molus of elasticity; I is the moment of inertia
the size of critical force PIJ is related to the following factors:
1. Material of compression bar: the PIJ of steel column is larger than that of wood column, because the elastic molus E of steel column is larger
2. Shape and size of compression bar section: large section is not easy to lose stability, because the moment of inertia is large
3. Length of compression bar L: large length of compression bar, small critical force PIJ, easy to lose stability

6. In my book, I said that it is very difficult to calculate the milling force of general milling machines and cutters, and it is even more difficult to calculate accurately, which is often an estimation.

7.

1. Measure the power of the machine tool and calculate the cutting force

after measuring the power PE consumed by the machine tool motor in the cutting process with the power meter, the cutting power PM can be calculated according to the following formula:

PM = PE η M

when the cutting speed V is known, the cutting force F can be obtained by using PM. This method can only roughly estimate the cutting force, not accurate enough. When it is required to know the cutting force accurately, the dynamometer is usually used to measure directly

2

the measuring principle of the dynamometer is to read out the values of FZ, FX and FY by using the deformation caused by the cutting force acting on the elastic element of the dynamometer or the charge generated by the action on the piezoelectric crystal after conversion. In the automatic proction, the signal generated by the force sensing device can also be used to optimize and monitor the cutting process< According to the working principle of dynamometers, they can be divided into mechanical, hydraulic and electrical dynamometers. At present, resistance strain gauge dynamometer and piezoelectric dynamometer are commonly used

3. Computer aided test of cutting force


at present, people have accumulated a large number of experimental data of cutting force. For general machining methods, such as turning, hole machining and milling, empirical formulas have been established, which can be directly used. The commonly used empirical formulas can be divided into two categories: one is exponential formula, the other is calculated by unit cutting force

practice has proved that there are many factors affecting the cutting force, such as workpiece material, cutting parameters, tool geometry parameters, tool material, tool wear state and cutting fluid

8. All the sources of cutting force, cutting force and its decomposition, cutting power

Research on cutting force is of great significance to further clarify the cutting mechanism, to calculate power consumption, to design tools, machine tools and fixtures, to formulate reasonable cutting parameters, to optimize tool geometric parameters, etc. When cutting metal, the cutting tool cuts into the workpiece and deforms the material to be machined, which is called cutting force. The cutting force comes from three aspects:

overcoming the resistance of the material to elastic deformation
overcome the resistance of processed materials to plastic deformation
to overcome the friction between the chip and the rake face and the friction between the transition surface and the machined surface

source of cutting force

the sum of the above forces forms the resultant force fr (national standard is f) acting on the tool. For practical application, FR can be decomposed into three components: FX (national standard: FF), FY (national standard: FP) and FZ (national standard: FC). In turning:

FZ -- cutting force or tangential force. It is tangent to the transition surface and perpendicular to the base surface. FZ is necessary to calculate the turning tool strength, design machine parts and determine the machine power

Fx -- awesome force, axial force or cutting force. It is a force in the base plane, parallel to the axis of the workpiece and opposite to the direction of the tool. FX is necessary to design the tool feed mechanism and calculate the tool feed power

FY -- cutting depth resistance, or back force, radial force and cutting force. It is a force in the base plane and perpendicular to the axis of the workpiece. FY is used to determine the deflection of the workpiece, the strength of the machine parts and the turning tool related to the machining accuracy of the workpiece. It is related to the vibration of the workpiece in the cutting process

the total force and component force of cutting force

the power consumed in the cutting process is called cutting power PM (national standard is po). The cutting power is the sum of the power consumed by the force FZ and FX. Since there is no displacement in the FY direction, no power is consumed. So

PM = (fzv + fxnwf / 1000) × 10-3

where: PM - cutting power (kw)< FZ - cutting force (n)

V-cutting speed (M / s)
Fx awesome feed force (N);
NW - rotational speed of workpiece (R / s)
F - feed rate (mm / s)

in the formula, the second term on the right side of the equal sign is the power consumed in the feeding movement, which is generally very small compared with the power consumed by F (& lt; So PM = fzv × 10-3

after calculating the cutting power according to the above formula, if the power (PE) of the machine tool motor is to be calculated so as to select the machine tool motor, the transmission efficiency of the machine tool should also be considered< br />
PE≥ Pm/ η M

where: η M - the transmission efficiency of the machine tool, generally 0.75-0.85. The large value is suitable for the new machine tool, and the small value is suitable for the old machine tool< In practice, the cutting force is usually calculated by the empirical formula based on the experimental results. When we need to know the cutting force under certain cutting conditions more accurately, we also need to carry out the actual measurement. With the modernization of testing methods, the measurement method of cutting force has been greatly developed, and it has been able to measure cutting force accurately in many occasions. The measurement of cutting force has become an effective means to study cutting force. At present, the main measurement methods of cutting force are:

1. Measure the power of the machine tool and calculate the cutting force

after measuring the power PE consumed by the machine tool motor in the cutting process with a power meter, the cutting power PM can be calculated as follows:

PM = PE η M

when the cutting speed V is known, the cutting force F can be obtained by using PM. This method can only roughly estimate the cutting force, not accurate enough. When it is required to know the cutting force accurately, the dynamometer is usually used to measure directly< The measuring principle of the dynamometer is to read out the values of FZ, FX and FY by using the deformation caused by the cutting force acting on the elastic element of the dynamometer or the charge generated by the action on the piezoelectric crystal after conversion. In the automatic proction, the signal generated by the force sensing device can also be used to optimize and monitor the cutting process< According to the working principle of dynamometers, they can be divided into mechanical, hydraulic and electrical dynamometers. At present, resistance strain gauge dynamometer and piezoelectric dynamometer are commonly used< At present, people have accumulated a large number of experimental data of cutting force. For general machining methods, such as turning, hole machining and milling, empirical formulas have been established, which can be used directly. The commonly used empirical formulas can be divided into two categories: one is exponential formula, the other is calculated by unit cutting force

practice has proved that there are many factors affecting the cutting force, such as workpiece material, cutting parameters, tool geometry parameters, tool material, tool wear state and cutting fluid.

9. FZ = {CF * AP [XF] * AF [YF] * aw [UF] * Z (number of teeth) * KZ (compensation coefficient)} / do [QF] * n [WF]

where XF, YF and UF are correction coefficients, which can be found in the machining process manual

10. D=V*60000/ π* N
d = outer diameter
V = cutting speed (cutting force)
n = number of revolutions

the saw blade speed is affected by the thickness and outer diameter of the body. Different specifications of saw blades can achieve different speeds, which is limited by the machine in practical application
FN = f / N * 1000
FN: feed rate per revolution
n: rotational speed (RPM)
F: material feed rate (M / min)