Yearly Archive October 15, 2020

The milling machine used in machining is very complex, and there are many kinds of milling cutters. “Milling” workpiece is: the workpiece is placed on the worktable and clamped with fixture, and the milling cutter is installed on the spindle. The spindle drives the cutter to rotate at high speed (main motion). The workpiece is driven by the worktable, which can realize the horizontal and vertical movement (feed motion). Under the joint action of the main motion and feed motion of the machine tool, the redundant part of the workpiece is removed. It can process plane, groove and curved surface on milling machine. The strengthening methods of aluminum alloy are as follows:

1. Solution strengthening

The addition of alloy elements into pure aluminum forms aluminum based solid solution, which causes lattice distortion, hinders the movement of dislocations, and plays a role of solution strengthening, which can improve its strength. According to the general law of alloying, when forming infinite solid solution or high concentration solid solution alloy, not only high strength, but also excellent plasticity and good press workability can be obtained. Al Cu, Al Mg, Al Si, Al Zn, Al Mn binary alloys can generally form finite solid solutions and have high limit solubility (see table 9-2), so they have great solution strengthening effect.

2

Another strengthening effect of alloying elements on aluminum is achieved by heat treatment. However, the transformation of aluminum during heat treatment is different from that of steel because there is no isomeric transformation of aluminum. The heat treatment strengthening of aluminum alloy is mainly due to the high solid solubility of alloy elements in the aluminum alloy, which decreases sharply with the decrease of temperature. Therefore, the supersaturated aluminum based solid solution can be obtained after the aluminum alloy is heated to a certain temperature and quenched. When the supersaturated aluminum based solid solution is placed at room temperature or heated to a certain temperature, its strength and hardness increase with time, but the plasticity and toughness decrease. This process is called aging. Aging at room temperature is called natural aging, and aging under heating conditions is called artificial aging. The phenomenon of increasing the strength and hardness of aluminum alloy during aging is called aging strengthening or aging hardening. The strengthening effect depends on the aging hardening phenomenon in the aging process.

1. Excess phase strengthening

If the amount of alloying elements in aluminum exceeds the limit solubility, there will be a part of the second phase which can not be dissolved into the solid solution, which is called excess phase. In aluminum alloys, these excess phases are usually hard and brittle intermetallic compounds. They hinder dislocation movement in the alloy and strengthen the alloy, which is called excess phase strengthening. This method is often used to strengthen cast aluminum alloy and heat resistant aluminum alloy in production. The more the amount of excess phase and the more dispersed the distribution, the greater the strengthening effect. However, if there are too many excess phases, the strength and plasticity will be reduced. The more complex the structure of the excess phase and the higher the melting point, the better the thermal stability at high temperature.

1. Refine the structure and strengthen it

Many aluminum alloys are composed of α solid solution and excess phase. If the microstructure of aluminum alloy can be refined, including refining α solid solution or refining excess phase, the alloy can be strengthened.

Because of the coarse structure of cast aluminum alloy, modification is often used to refine the alloy structure in actual production. Computer gong machining | mechanical parts processing | CNC machine tool processing | Dongguan high-speed computer gong machining modification is to add 2-3% modifier (commonly used sodium salt mixture: 2 / 3naf + 1 / 3nacl) to the molten aluminum alloy before pouring, so as to increase the crystal core and refine the microstructure. After modification, fine and uniform eutectic and primary α solid solution structure can be obtained, which can significantly improve the strength and plasticity of aluminum alloy.

It is found that there is abnormal sound in the spindle and gearbox when the spindle speed is below 500r / min. observing the power meter of the motor, it is found that the output power of the motor is unstable and the pointer swings greatly. However, the abnormal sound disappeared when it was used above 1201r / min. After startup, the power meter of the motor will swing automatically without rotation command, and the motor will drift and rotate automatically. After normal operation, the braking time is too long, and the machine tool has no alarm.

According to the phenomenon observed, the main shaft controller may be out of control, and the mechanical transmission or motor can not be eliminated. Due to the heavy workload of dismantling the mechanical part, the spindle controller of the electrical part is checked first. The controller is Siemens 6sc-6502. First, check the preset parameters in the controller, and then check the control board, all of which are normal. After checking that the circuit board is dirty, clean the circuit board according to the requirements, but after it is installed, the machine fails as usual. Therefore, the fault causes in the controller can be eliminated temporarily. In order to determine whether the fault is in the motor or in the mechanical transmission part, it is necessary to separate the motor from the machinery. After the separation, it is found that when the motor speed command is close to 450R / min, the abnormal sound starts to appear continuously, but when the instruction of 1201r / Min is given, the abnormal sound disappears again. For this reason, we analyzed the spindle part. The original 450 R / min command given at low speed and 4500r / min command at high speed are the same to the motor at the highest speed, but the gear decelerates at low speed, so the fault can be basically determined in the motor part. After analysis, the abnormal sound may be caused by poor bearing.

When the motor was disassembled for inspection, it was found that the bearing was damaged. When the bearing was stuck at high speed, the load was increased, which made the power meter swing and deflect. But after stopping, the motor drifted and the brake was too slow. After checking, the encoder disc was scratched. After replacing the bearing and encoder, all the faults were eliminated. This fault is mainly due to the abnormal sound when the spindle rotates. Therefore, it is necessary to find out the sound source before checking. Abnormal sound is common for mechanical rubbing, jamming and bearing damage.

CNC machining center spindle orientation usually adopts three ways: magnetic sensor, encoder and mechanical orientation. When using magnetic sensor and encoder, in addition to adjusting the position of components, it can also adjust the machine parameters. There is no alarm when the orientation error occurs, and it can only be detected when there is an interruption in the process of tool change.

Once in a refitted CNC machining center, there was a fault of inaccurate orientation. At the beginning, the machine tool was often interrupted in the work, but the frequency was not many. The machine could work again after restarting, and the fault occurred repeatedly. After careful observation of the machine tool after the fault occurred, it was found that the real cause of the fault was the position deviation of the spindle after orientation. It is strange that if the spindle is touched by hand after orientation (similar to the situation when the tool is inserted into the spindle during tool change), the spindle will drift in the opposite direction. Check the electrical part without any alarm, and the mechanical part is very simple.

The orientation of the machine tool uses encoder, so from the fault phenomenon and possible parts, the possibility of electrical part is relatively small, the most important mechanical connection. Therefore, it was decided to check the mechanical connection part. When checking the connection of the encoder, it was found that the set screw of the coupling sleeve on the encoder was loose, which caused the coupling sleeve to retreat, resulting in excessive clearance between the coupling part and the spindle, and the rotation was not synchronous. The failure was eliminated after the set screw was fixed as required. In case of spindle orientation failure, the analysis and treatment shall be carried out according to the specific structure of the machine tool. The electrical part shall be checked first, and then the mechanical part shall be considered if it is confirmed to be normal.

Mechanical processing cost calculation must understand the process, in order to estimate the processing time, to quote.

The calculation of machining cost can be said to be very simple or complex. The key depends on your company’s situation. For a large company, you should consider various cutting efficiency, tool performance, machinery and equipment performance, etc. if it is a small mechanical processing plant, according to your expenses, including rent, water and electricity, master’s wages, tool wear, equipment loss, etc., how much should you spend a day, plus your own estimated profit.

You’ll have to finish your parts in three hours. If your profit is 5%, your profit on this part is 15 yuan. In this way, it is very simple. In addition, mechanical processing cost calculation must know the process, in order to estimate the processing time, to quote.

Wire cutting processing fee is generally calculated according to the total cutting area, 0.xx yuan / square millimeter

For example, according to the processing area / 1200 * 8 yuan

There are usually two calculation methods

1. 01 yuan / mm2,
2. Parts that are too small are generally calculated by piece

In most places, it’s 5cm / m2!

The machining cost of ordinary WEDM is generally calculated according to the wire cutting area, and the workpiece height is also high, and the corresponding price will be high

The price of slow wire cutting is about 10 times that of ordinary wire cutting

In Jiangsu and Zhejiang provinces, slow wire processing generally costs 60 yuan per hour (the average cutting efficiency is 40-60mm / min), but the higher precision die cutting costs 80 yuan, because once scrapped, it needs to pay the material cost

Processing time calculation: Processing cross-section area / (1200-1800) = the required time, 1200-1800 is an adjustable parameter, generally taken as 1500, and then multiplied by the hourly processing fee

Fast silk words some can 0.015 yuan mm, also have 0.005 yuan mm

There are also 10 yuan hours

Slow wire cutting tool 0.03mm

Slow wire cutting two cutters 0.038mm

Slow wire cutting with three cutters 0.045mm

Slow wire cutting four cutters 0.055mm

Fast wire is 5 yuan per hour. Generally, each machine can cut 2.5 hours per hour

The cost of WEDM here is basically 10 yuan / hour

WEDM is divided into fast wire and slow wire, and their processing accuracy is different, such as computer gong processing, mechanical parts processing, CNC machine tool processing, Dongguan high-speed computer gong processing

The slow wire can reach 0.001 mm, but the fast wire can’t. I’ve made Sadik’s slow silk. The processing fee is calculated according to the area and also depends on the number of knives. The price of cutting one repair is obviously different from that of cutting a few. If the height of parts processed exceeds one, it will be doubled. If the processed materials are different, their prices are not the same. For example, cutting tungsten steel is twice as much, usually 2-3 times. They can process at least 50 yuan a piece (excluding batch)

Standard charging method: 0.08 yuan / square millimeter

Common wire cutting; sectional area / 1200 * man hour unit price

Standard charging method: batch processing 0.08 yuan / square millimeter, mould 0.12 yuan / square millimeter

The fast one is 8 yuan / hour

Generally, Sodick aq550ls is used to make the first cutting, and the second cutting is about 5 times of the first cutting. The third one is faster!!

Fastwire is about 1200-1800

And then take your own set fee!!

Wire cutting is divided into fast wire and slow wire

Ordinary wire cutting is generally calculated by wire cutting area, and the workpiece height is also high, and the corresponding price will be high

The price of slow wire cutting is about 10 times that of ordinary wire cutting

In Jiangsu and Zhejiang provinces, slow wire processing generally costs 60 yuan per hour (the average cutting efficiency is 40-60mm / min), but the higher precision die cutting costs 80 yuan, because once scrapped, it needs to pay the material cost

Processing time calculation: Processing cross-section area / (1200-1800) = the required time, 1200-1800 is an adjustable parameter, generally take 1500, and then multiply the hourly processing fee.

In the case of fast wire, some can be 0.015 yuan mm, and there are 0.005 yuan mm

There are also 10 yuan hours

Slow wire cutting 0.03mm

Two cutting tools 0.038mm

Slow wire cutting three cutters 0.045mm

Professional mechanical processing fee calculation, mechanical processing fee calculation formula, mechanical processing fee calculation method.

The general principle of non-standard parts processing and cutting process arrangement is: the front work must be ready for the later work, lay a good foundation, and do a good service. The working principle of non-standard parts processing can be divided into four aspects

Just like building a house, the foundation determines the height. Only when the foundation is built well can the house be built high. The same is true for precision mechanical parts processing, which always processes the precise datum first, and then processes other surfaces by the precise datum positioning. For example, for box parts, the main hole is generally used as the rough datum to process the plane, and then the plane is used to process the hole system; for the shaft parts, the outer circle is generally used as the rough datum to process the central hole, and then the center hole is used as the fine datum to process the outer circle, end face and other surfaces. If there are several precision datum, the machining of base surface and main surface should be arranged according to the sequence of datum transformation and the principle of gradually improving machining accuracy.

Secondly, the processing sequence of non-standard parts should be determined, and the sequence should be done well. Generally, the main part should be done first

A part of an electronic or electrical device or equipment that is processed by a computer gong. It is used as the two terminals of input or output current in a conductive medium (solid, gas, vacuum or electrolyte solution). One pole of input current is called anode or positive pole, and the other pole of discharging current is called cathode or negative pole. There are various types of electrodes, such as cathode, anode, welding electrode, electric furnace electrode, etc.

In the battery, the electrode generally refers to the position where the redox reaction occurs with the electrolyte solution. The electrode can be divided into positive and negative. Generally, the positive electrode is the cathode, which obtains electrons and reacts with reduction. The negative electrode is the anode, which loses electrons and reacts with oxidation. The electrode can be metal or nonmetal. As long as it can exchange electrons with electrolyte solution, it is called electrode. The concept of electrode was put forward by M. Faraday in 1834 after the systematic electrolysis experiment. The original meaning only refers to the metal rod inserted in the electrohydraulic system to form the battery. The component of a battery, which consists of a series of phases in contact with each other. One end of the battery is an electronic conductor metal (including graphite) or a semiconductor, and the other end must be an ionic conductor electrolyte. The electrode with the simplest structure should consist of two phases and a phase interface, i.e., [metal electrohydraulic]. The electrode defined above in machining mechanical parts is also called “half cell”. The naming method is very complicated. Some are named according to the metal part of the electrode, such as copper electrode and platinum electrode; some are named according to the characteristic substances in the redox pair of electrode activity, such as calomel electrode and hydrogen electrode; some are named according to the shape of the metal part of the electrode, such as drop mercury electrode and rotary electrode; some are named according to the shape of the metal part of the electrode The function of the electrode is named. These names, such as reference electrode and sodium ion selective electrode (see ion selective electrode), are conventional. Any metal in contact with electrolyte will produce potential (potential), which is the most important characteristic property of electrode.

electrode

If there is a fast electron exchange of a single redox pair on the electrode interface, that is, there is a single electrode reaction with a large exchange current (see transition overpotential), this kind of electrode can quickly establish an electrochemical equilibrium, which is called reversible electrode. The potential energy of the reversible electrode is stable for a long time, and it has strong anti-interference ability and can be measured accurately. It is a necessary part of the reversible battery and the core part of the potential analysis measuring device. Reversible electrodes have the following types:

① Metal electrodes, such as copper electrodes (Fig. 2), are characterized by the fact that redox pairs can migrate across the phase interface.

② Redox electrodes, such as Pt | Fe, Fe electrode (Fig. 3), Pt | Mn, MnO 嬄 h electrode, etc. Its redox pair can not move across the electrode phase interface. The platinum pt of the electrode only indicates that the electrode metal is inert. It only provides a place for electron exchange. Any inert metal can be used in practical application.

electrode

③ The gas electrode is a component of redox pair, and the redox electrode when it is composed of gas (Fig. 4), such as hydrogen electrode (pt| h2| h), chlorine electrode (pt| Cl2 | CL), etc. In order to accelerate the equilibrium, platinum black is needed to be plated on platinum to increase the surface area and act as electrocatalysis.

electrode

④ One component of redox pair is insoluble salt or other solid phase. Therefore, Dongguan CNC machining center consists of three phases and two interfaces (Fig. 1). There is a single rapid transition process at each phase interface, such as calomel electrode (hg| Hg2Cl2 | CL) and mercury oxide electrode (Hg | HGO | oh). In the calomel electrode, the dissolution equilibrium of calomel and electrolyte is completely controlled by the higher concentration of CL in the electrolyte. The exchange rate of CL on the interface of Hg2Cl2 | is also very fast, so its electrode potential is very stable. It is the most commonly used reference electrode. Some books and periodicals call this kind of electrode the second type.

electrode

Membrane electrode a device for measuring the activity of specific ions in an electrohydraulic system (Fig. 5), such as a glass electrode or an ion selective electrode, using the permeability of the membrane to a single ion or the potential established by the ion exchange equilibrium between the membrane surface and the electrolyte (Fig. 5).

Chemically modified electrodes attach active groups and catalytic substances to the surface of electrode metals (including graphite and semiconductors) by adsorption, coating, polymerization, chemical reaction and other methods to make them have strong characteristic functions. This is a new development of electrode preparation methods since 1970s.

Single electrode and multiple electrode: if there is only one dominant electrode reaction on the metal electro-hydraulic interface of the electrode, it is a single electrode; if there is not only one electrode reaction, it is multi electrode. For example, there may be two kinds of electrode reactions on the zinc electrode (zn| ZnSO4 aqueous solution)

Zn─→Zn+2e ⑴

2H+2e─→H2 ⑵

electrode

However, due to the high Superpotential of hydrogen on the metal zinc, the rate of reaction (2) is too small, and the reaction (1) is dominant. The above zinc electrode is considered as a single electrode and is a typical reversible electrode. When the impure zinc is immersed in sulfuric acid, the reaction rate of (1) and (2) is fast, so [Zn | H2SO4] electrode is a double electrode, and its static potential can be judged according to the polarization curve and polarization law of reaction (1) and (2). Metal corrosion system is often a double electrode. Multiple electrodes cannot be reversible

In practical application, the studied electrode is called working electrode W, which is also called indicator electrode in electrochemical analysis. Its potential can be measured by two electrode measurement battery composed of reference electrode R. When the working electrode needs to be polarized, another auxiliary electrode (or corresponding electrode, represented by C) should be used to form a three electrode measuring battery system (Fig. 6)

Drilling and tapping center is a kind of metal cutting equipment. Its style and function are basically similar to the machining center, but it is smaller than the machining center. The general stroke is not more than (x / y) 800 × 400mm. Its main purpose is to process drilling and tapping processes such as nonferrous metals, 3C industry and aluminum substrate. Although boring and milling can be realized, due to the low power of the main motor, ferrous metal can not be used Cutting, but the efficiency and quality of drilling and tapping speed is more than 10 times that of ordinary machining center. It is the most ideal processing equipment for 3C, communication industry and other industrial customers.

At present, the overall market analysis is as follows:

Due to the rise of mobile phone industry, communication industry and tablet computer industry in recent years and the continuous upgrading to please consumers, the following supporting processing industry is also rising, especially the demand for drilling machines is growing.

At present, the common well-known brands include Japan fanco, Japan brother, British jiamite, including Korea Kia and so on.

Fanaco α – T21: FANUC α – T21 mainly produces X-axis stroke 500 with independent system + turret type tool magazine as its main products: fanaco drilling machine is the only machine tool manufactured by fanaco company in Japan, and its market share is in the forefront in Japan. Its core technology is fanuc-31 system, which is matched with the machine tool, and has high performance in spindle acceleration and high-speed displacement. The machine tool is very popular in China, especially in Guangdong electrode market, known as “the king of copper”. The biggest drawback of the machine is that the overall rigidity is insufficient, it can not carry out load cutting, and the use efficiency is not high. In addition, the price of the machine tool is also quite expensive, especially the technical support and accessories price after the warranty period is beyond the ordinary enterprises’ affordability.

Japan brother tc-s2d: Japan’s brother tc-s2d series mainly focuses on X-axis travel of 500 and 700, and has exchange worktable options: brother group was first known as a machinist sewing machine, and later developed printer equipment and machine tool drilling machine equipment. Japan brother drilling and tapping machine is the only one in Japan that can compete with fanco in system calculation. However, brother’s overall workmanship is more rigorous, and the main shaft is different from fanco. The main shaft adopts JIS form and short nose structure, which is stable in high-speed tapping and is not easy to break the tap. In recent years, the sales volume of brother drilling machine in some areas of China has been increased Hold the top position.

Camit t-fm600: jamit is the latest European brand drilling and tapping machine to enter the Chinese market. The most widely used drilling machine in the European market is jamitt drilling machine, with pure European processing technology. The tool change speed and overall mechanical structure of the drilling machine are stronger than those of Japanese machine tools, and the casting of bed body is subject to secondary aging treatment. Its advanced servo tool magazine and optical fiber panel technology is the biggest bright spot advantage of the machine tool. At the same time, it can be combined with BT40 simultaneous action tool library to realize drilling, milling, boring, tapping and other processes, and the price is cheaper than Japanese machine tools, and the comprehensive cost performance ratio is the strongest.

Hyundai Weiya vx380: Hyundai Kia drilling and attack center and Hyundai Weiya belong to Hyundai Group, the largest group in South Korea, and its technology basically comes from Japan. The brand entered the Chinese market late, but its excellent performance price ratio has been favored by enterprises, but after-sales service has always been a short board of the brand, which can not meet the needs of Chinese users. At the beginning of using the drilling and tapping center, the cutting fluid (water-based) was used in the separate cooling water tank, which was used in both stations. However, after a period of time, it was found that the water-based cutting fluid in the drilling and tapping center was not good for drilling and thread tapping. Especially for the tap, it was “astringent” during processing, which was easy to break, and the quality of the finished screw hole was poor. Therefore, we changed the drilling of this drilling center to dry machining. When we arrived at the tapping station, we used kerosene lubrication (kerosene was supplied by the pump separately, and electrical control) the quality of the thread was good, and the tap was rarely broken. Computer gong processing | mechanical parts processing | CNC machine tool processing | Dongguan high-speed computer gong processing drilling and tapping center processing form: manually pushing the material to the conveying position, pressing the “swing up” button will start to enter the automatic cycle, and the two headstock will act at the same time. After the second working feed of the two headstock, they return to the original position.

CNC machine tools are widely used in drilling and tapping center. CNC machine tool is a kind of advanced equipment with excellent performance, wide range of technology, high precision of drilling and tapping center and high production efficiency. It can complete drilling, reaming, boring, groove cutting and plane milling processing at one time. In addition, it can also carry out hole series processing with high precision. CNC machining is heavy machinery, engineering machinery, locomotive and rolling stock, mining equipment, large motor and water turbine , steam turbine, ship, iron and steel, military and other industrial sectors of essential processing equipment. The CNC machine tool has the characteristics of good rigidity, high precision, strong reliability, convenient operation and beautiful appearance. Especially, various accessories can be installed on the end face of the square ram or used with the rotary table, which can further expand the application range of the CNC machine tool. CNC machine tools are mainly used for boring holes of large and medium-sized parts, and can also complete drilling, expanding, reaming, milling plane and other work. The CNC machine tool is equipped with change gear device, which can process metric or British internal thread. The radial tool holder of flat rotating disc can be used to process internal thread