2019 – Page 26 – CNC Machining & Turning, Milling, Metal parts

What are the causes of errors in machining

The machining of metal parts is accomplished in a process system consisting of machine tools, cutters, fixtures and workpieces. Metal machining error refers to the degree of deviation between the actual geometric parameters and the ideal geometric parameters after machining. The degree of conformity between the actual geometric parameters and the ideal geometric parameters after machining is machining. Precision. In any machining process, due to the existence of various original errors in the process system, such as machine tools, fixtures, tool manufacturing errors and wear, workpiece clamping errors, measurement errors, adjustment errors of the process system and errors caused by various forces and heat in the processing, the correct geometric correlation between the process systems is achieved. The system is damaged and produces machining errors. The smaller the machining error, the higher the conformity degree, the higher the machining accuracy. Machining accuracy and machining error are two formulations of a problem. So the machining error reflects the accuracy of machining. The following is a brief introduction of what causes the errors of metalworking.

Error of machining principle

Machining principle error refers to the error produced by using approximate tool edge profile or approximate transmission relationship. For example, in order to make the hob easy to manufacture, Archimedes basic worm or normal straight profile basic worm is used instead of involute basic worm to make the involute gear profile error.

Two. Geometric error of process system

The errors caused by the deviation of the actual geometric parameters and positions of each component in the process system from the ideal geometric parameters and positions are collectively called the geometric errors of the process system. The geometric error of process system is only related to the geometric elements of every link in the process system.

Three. Error caused by mechanical deformation of process system.

The process system will produce deformation under the action of cutting force, clamping force, gravity and inertia force, thus destroying the mutual position relationship of the components of the adjusted process system, resulting in machining errors and affecting the stability of the machining process.

Four. Error caused by thermal deformation of process system

In the process of machining, due to the influence of cutting heat, friction heat and the heat source around the worksite, the temperature of the process system will produce complex changes. Under the action of various heat sources, the process system will be deformed, resulting in the change of the correct relative position of the components of the system, resulting in machining errors.

Five. Machining error caused by internal stress of workpiece

Internal stress is the error factor of the workpiece itself. The workpiece will produce a certain internal stress after cold and hot working. Usually the internal stress is in equilibrium state, but when the workpiece with internal stress is processed, the original internal stress equilibrium state of the workpiece is destroyed, so that the workpiece is deformed.

Six. Measurement error

In the process of adjusting and measuring the workpiece in the machining process, the measurement error is called measurement error because of the influence of measurement method, measuring tool accuracy and other factors on the accuracy of measurement results.

These are the common causes of metal processing errors. Reasonable arrangement of process, use of high precision equipment, selection of good performance tools and cutting oil can effectively reduce errors.

Energy saving design of electrical engineering automation

1. design principles

In the energy-saving design of electrical engineering automation, the design principle is the first problem to be clear. Only on the premise of adhering to the appropriate principles, can the scientific and effective energy-saving design be promoted. Specifically speaking, the principles of energy-saving design mainly have four points: first, safety, in the process of energy-saving design, can not put all attention on energy-saving, but also need to pay attention to the safety of electrical equipment operation, in order to ensure the safety of electrical engineering on the basis of energy-saving; second, advanced, in the community In the process of development, a variety of new energy-saving technologies and energy-saving equipment emerge in endlessly. In the process of electrical engineering automation design, attention should be paid to the introduction of advanced technology and equipment, so as to effectively improve the energy-saving effect; third, environmental protection, some electrical equipment in the course of operation will also produce on the surrounding environment. Certain influence, when carrying on the energy-saving design, also want to fully consider this point, as far as possible reduces the surrounding environment damage; Fourth, renewal, electrical equipment in operation for a period of time, will gradually aging, which requires staff timely replacement of equipment, in order to ensure the normal operation of electrical engineering, in the When replacing, if energy-saving can be achieved after maintenance, and with better operational efficiency, then the equipment can continue to use, otherwise it needs to be updated.

2. transformer selection

In transformers, the more important components include insulators, steel, silicon steel sheets, etc. For these components, when any part of the fault, the performance of the transformer will be affected, thereby increasing energy consumption, therefore, in energy-saving design, the choice of transformer is very important, especially The choice of the main components should be very prudent under the guidance of the concept of energy conservation. When choosing the line and cabinet, generally choose copper material; when choosing silicon steel sheet, on the basis of ensuring the normal operation of the equipment, choose the thinnest. In addition, it is also necessary to pay attention to the load rate of the transformer, generally speaking, the load rate between 40% and 60% is the best.

3. power transmission loss reduction

Wire has a certain resistance, affected by this, electric energy transmission process, will produce a certain loss, in the energy-saving design, in order to reduce the loss, it is necessary to reduce the resistance as far as possible, because the strength of the current can not be changed. Generally speaking, the larger the cross-section of a wire, the smaller the resistance, and the shorter the length of the wire, the smaller the resistance. Based on this, the resistance reduction design can be carried out from the following aspects: first, select a cable with high transmission current capacity; second, wire in a straight line manner. The length of the transformer is shortened; third, the location of the transformer is reasonably selected; fourth, the wire with larger cross-section is selected.

4. reactive power compensation design

In the process of electric automation system operation, some useless power will be produced, which will have a certain impact on the potential difference of the system, and will also lead to the quality of power decline. Therefore, in the energy-saving design, reactive power compensation design is also needed. The main aspect of the design is the selection of reactive power compensation methods, through the reasonable choice of compensation methods, improve the operation efficiency of electrical engineering automation system, while ensuring the normal operation of the system.

5. selection of power cables

Power cable is an important part of electrical engineering automation system. When choosing power cable, we should fully consider the normal operation of transmission lines in order to ensure the rationality of selection. At present, the more common power cable materials are aluminum and copper materials, aluminum material prices are relatively low, but its energy-saving effect is poor, and the price of copper material is much more expensive than aluminum material, but in terms of energy-saving effect is better, and has a higher economy. In actual power cable selection, material selection is also necessary in combination with the actual system.

About Xinhua Control in Shenyang:

As an excellent service provider of automatic control system, Shenyang Xinhua Control System Co., Ltd. has devoted itself to the R&D and design of automation systems in different industries for many years. It has always provided the best quality automation products and automation control system solutions for customers in the industry. It has already provided petroleum, chemical industry, electric power, alcohol, textile and so on. Many enterprise users have successfully implemented the automatic control system engineering service. At the same time, Xinhua Control Company specializes in the design and production of a variety of complete sets of equipment, including PLC control cabinet, low-voltage switchgear, frequency conversion control cabinet, console, control box and other equipment, and according to customer requirements for non-standard design and processing.

What are the characteristics of stainless steel fume hood

Stainless steel hood has beautiful appearance and excellent stainless steel structure. The whole forming has no dead angle, and has the advantages of corrosion resistance and high temperature resistance. Durable. It is suitable for medicine, hygiene, food and other industries. Once formed stainless steel operation surface is corrosion resistant, impact resistant and easy to clean.

Small crank lift platform safe use tips

Small crank-type lifting platform is mainly suitable for high-altitude operations, because of its simple operation is loved by people, is now widely used in industrial, mining, municipal and other places, its use of safety has become our top priority. So how much do you know about the safety of hydraulic lifting platform small skills? Next, Anden machinery introduces some tips for safe use of small lift platforms.

1. Every time you use a small crank lifting platform, you should run the equipment without load to see if it works well.
2. Do not overload or bias load when using equipment.
3, equipment should be shut down immediately after use.
4. If you are using a four-wheel mobile hydraulic lifting platform, do not use it on unstable ground, use it to support your legs.
5. When the hydraulic lifting platform is used outside, it is prohibited to use it in strong wind or rainy days.
6, equipment is prohibited from mobile devices under operation.
7. Under the operation platform, stand and litter should be strictly prohibited.

Another thing is to do a good job in the maintenance of hydraulic lifting platform, in fact, the equipment is just like us, you are good to it, you use the process it will not give you a problem.

Motion transmission of machine tools

According to the role played in cutting process, cutting motion is divided into main movement and feed motion.

Main motion: a working movement that forms the cutting speed of machine tools or consumes the main power.

Feed motion: the movement of redundant materials to be removed.

There is only one main movement in cutting process, and the feed motion can be more than one. The main movement and feed motion can be accomplished by cutting tools or workpiece separately, or by cutting tools alone. In addition to the cutting motion, there are also some auxiliary movements that must be carried out to realize the auxiliary work of the cutting process.

Machine tool transmission

The transmission mechanism of a machine tool refers to the mechanism that transfers motion and power, or is referred to as the transmission of machine tools.

According to the characteristics of transmission mechanism, the transmission mode of machine tool is divided into mechanical transmission, hydraulic transmission, electric transmission, pneumatic transmission and combined transmission of the above transmission modes. According to the adjustment characteristics of transmission speed, the transmission is divided into a class and a stepless transmission.

drive system

The transmission system is also called the transmission chain. He has first and two ends. The first end is also called the active part, and the end part is also called the follower. Every transmission system from the head to the end is composed of a certain transmission law, which is the transmission ratio, in order to ensure the performance of the machine tool. General machine tool transmission system can be divided into main motion transmission system, feed motion transmission system and fast empty stroke transmission system according to the nature of its movement. Generally understand the transmission system diagram.

Characteristics of desulfurization dust remover

1, washing principle, high efficiency of dust removal and desulfurization, catching more harmful gas.

BYJ flue gas purifier integrates desulfurization and dust removal. For spraying mode, the nozzle is designed uniquely. The glass fiber reinforced plastic spiral nozzle made by American technology sprays out dense water mist under certain water pressure, and the dust and harmful gases are fully in contact with water mist. Therefore, the effect of dust removal, desulfurization, nitrogen removal and carbon black washing is better than that of others. Other wet dust collectors have been greatly improved. The removal rate is more than 98%, the removal rate of sulfur dioxide is more than 85%, and the smoke level is <1.

2, the design of dehydrating plate is reasonable and unique, and the dehydration effect is good. The dewatering device is installed in the cylinder body, and the dewatering plate has a reasonable and unique design. When the fog passes through the dewatering device, it is intercepted by collision and flows down the cylinder wall, thus preventing the secondary water entrainment and high dewatering efficiency.

3, small resistance, water saving, electricity saving, low operating costs.

The flue gas is naturally introduced from the lower part of the cylinder with large cross section and small wind speed, so the flue gas resistance is small, the main resistance is less than 900Pa, and the system resistance is less than 1200Pa. Because the resistance is small, the power consumption is also small. In addition, the discharged water through sedimentation, closed recycling, on the one hand to save water resources, on the other hand to prevent sewage flow into the sewer, resulting in secondary pollution, water saving, power saving, so that the operation cost is reduced.

4, small size, light weight, small footprint, convenient installation and transportation.

Cylindrical body, is an integral structure, with brackets when factory, installation, removal is very convenient, according to the size of the local ground situation, to hang around, overhead laying and other ways of installation, adaptability is very strong.

5. The operation is relatively simple and convenient, the amount of maintenance is very small, easy to operate, manage, maintain, high operating rate, adapt to various working environments.

6. The flue gas SO2 concentration fluctuation adaptability is strong, different desulfurization process can adapt to different coal sulfur content; desulfurization agent can be used in lime, alkali, magnesium oxide and other forms, can achieve good desulfurization effect.

Debugging method of centrifugal fan

Centrifugal fan is a complex equipment, mainly composed of air inlet, air valve, impeller, motor, air outlet. Under different conditions, the effect of centrifugal fans is also different. Therefore, the operation of different parts is not uniform, and the effect of centrifugal fans will be affected. The centrifugal fan can be debugged to the best condition, starting from many aspects.

1. Centrifugal fans allow full-voltage start-up or step-down motor, but it should be noted that the full-voltage start-up current is about 5-7 times the rated current, step-down starting torque is proportional to the voltage square, when the grid capacity is insufficient, step-down starting should be used.

2. When the centrifugal fan is in commissioning, it should read the product specification carefully to check whether the wiring method is in conformity with the wiring diagram; it should carefully check whether the working voltage supplied to the fan power supply meets the requirements, whether the power supply is out of phase or in phase, and whether the capacity of the components of the distribution device meets the requirements.

3. There are no less than two people in the test run, one controls the power supply, one observes the operation of the fan, and discovers the abnormal phenomena and immediately stops the machine for checking; first checks whether the rotation direction is correct; after the centrifugal fan starts running, it should check immediately whether the running current of each phase is balanced and whether the current exceeds the rated current; Elephants should be stopped for inspection. After running for five minutes, stop the fan to check if there is any abnormal phenomenon, confirm that there is no abnormal phenomenon and then start operation.

4. When the two-speed centrifugal fan is running, it should start at low speed to check whether the rotation direction is correct; when starting at high speed, it must wait for the fan to be still before starting, in order to prevent high-speed reverse rotation, causing switch tripping and motor damage.

5. When the centrifugal fan reaches the normal speed, the input current of the fan should be measured, and the running current of the centrifugal fan should not exceed its rated current. If the running current exceeds its rated current, check whether the supply voltage is normal.

6. The motor power required by centrifugal fans refers to the larger power required when the inlet of centrifugal fans and fan boxes is fully open under certain working conditions. If the inlet is fully opened for operation, the motor is in danger of damage. It is better to close the valve on the inlet or outlet pipe of the blower when the blower is running, and gradually open the valve after running until the required working condition is reached, and pay attention to whether the operating current of the blower exceeds the rated current.

The efficiency of centrifugal fan can reach over 98% if the centrifugal fan is debugged strictly according to the above debugging method.

Matters needing attention for electric tractors loading

The electric tractor is powered by electricity. The switch on the handle of the control arm controls the walking and the steering of the control arm.

The electric traction vehicle adopts 24V electronic system to adjust its speed stepless by an integrated circuit controller. In order to ensure stable speed and acceleration during driving. Yufeng’s EPQ30A electric tractor is suitable for handling goods that can’t roll. The maximum loading capacity is 3000kg. The following are the matters needing attention in carrying the goods:

1. the weight of the goods shall be within the range permitted by the tractor.

2. slow down when turning.

3. irregular objects should be safe in transit. When turning, pay attention to space.

4. if the operator’s front view is affected, he can be asked to direct the direction.

5. decelerate on the upper and lower slopes and do not turn on the slopes.

Turning on the slope, the tractor has the risk of rollover.

On the downhill, the braking distance of the tractor is prolonged and the braking time is increased. Therefore, we should speed down to reduce braking time. Don’t force up and down the high slope.

6. Before entering the elevator, the tractor should ensure that the elevator can withstand the entire load (tractor weight, cargo weight, operator weight). The tractor should first enter the elevator and finally leave the elevator.

Warning!

Before starting the elevator, we should clearly understand the elevator carrying capacity and avoid accidents.

Problem analysis of electrostatic precipitator in foundry

Analysis of the problems existing in the rapping device before the transformation of the electrostatic precipitator in the foundry.

The problems existed in the vibrating device before the transformation of electrostatic precipitator in foundry plant are as follows: first, the vibrating system has frequent faults; second, the effect of vibrating dust removal is poor. In the final analysis, these two problems will cause serious deposit of anode and cathode ash, intuitively manifested as low operating voltage, low current, frequent flashover. This is the main problem of the high frequency of the dust collector and the good operation of the dust collector. The effect of vibrating dust removal has a great influence on the efficiency of dust removal. The function of vibrating dust removal is to keep the cathode and anode of electric field clean all the time and to keep the recapturing ability of ESP. It is the key factor to decide whether ESP can keep stable and efficient operation for a long time. At present, the ESP is cleaned by vibrating method. Whether the beating system (cycle, time and mode) is reasonable or not has a great influence on the efficiency of ESP when the beating force and uniformity meet the requirements. The effect of rapping cycle on the efficiency of dust removal is whether the falling dust will fall directly into the ash hopper.

The causes of the problems existing in the vibrating device of the electrostatic precipitator in foundry factory before its renovation are analyzed as follows: the long vibrating period and the thick dust deposited on the plate will reduce the conductivity of charged dust on the plate and reduce the efficiency of dust removal; if the vibrating period is too short, the dust will be dispersed into crushing and falling, resulting in a larger secondary dust, i.e. deposited in the electrostatic precipitation Dust on the dust collector pole is again taken out of the dust collector by air flow, especially the secondary dust emission of the terminal electric field will greatly reduce the efficiency of the ESP. There are many factors leading to secondary dust, such as high specific resistance of dust, uneven distribution of flue gas velocity or high velocity of flue gas, resulting in turbulence and eddy current. Therefore, it is required that the flue gas velocity of the electric field should not exceed 1.5m/s, and the flue gas distribution should be uniform as far as possible. Over-frequency vibration is the main factor causing the secondary dust emission of the dust collector. Other reasons include: vibration device failure, not found and repaired in time, resulting in serious dust accumulation on the plate and polar line, excessive discharge. Bad beating and poor cleaning effect. The main reason is that the vibration acceleration is not enough, or the vibration acceleration attenuation is serious, which affects the dust removal effect. The problem of daily operation and operation leads to the accumulation of dust on the pole line and not to shake up.

Characteristics of small vacuum pumps

In recent years, with the further requirement of miniaturization and non-polluting working medium of vacuum pumps from all walks of life, small vacuum pumps and small air pumps with compact size, no oil and no maintenance, low noise and DC power supply have been widely used. Four

However, due to the variety of small vacuum pumps, small air pumps, such as: small vacuum pumps, small air pumps, micro sampling air pumps, micro pumps, micro pumps, dual-purpose pumps, micro circulating air pumps and so on; resulting in customers often a fog, in the end how to choose the most suitable working conditions, Xinweicheng What about the product?

Small vacuum pump, small air pump selection general principle: can use brushless motor as far as possible on the small vacuum pump, brushless vacuum pump parameters can not reach, and then use brush products.

The selection and classification of small vacuum pumps can be classified into two categories:

First, the classification of small vacuum pump, small air pump according to small vacuum pump integration is “brush motor” or “brushless motor” to classify.

Characteristics of small vacuum pumps

Advantages: the use of brush motor power, so the negative pressure, flow can be done relatively high, new technology for the brush product quality, performance, reliability are better, and the overall cost is lower than high-grade brushless vacuum pump.

Disadvantages: the life of the brush vacuum pump is shorter than that of high-grade imported brushless.

Characteristics of small vacuum pumps

Advantages: Long life, especially the use of high-grade imported brushless motor (Xinweicheng technology is), life is often close to tens of thousands of hours (full load); especially suitable for day and night continuous operation occasions, such as long-term on-line sampling pump use… It also has the function of “speed regulation”, that is, adjusting the speed of the motor (pwm speed regulation) by “duty cycle”, and even can realize advanced applications such as constant voltage, constant current and constant speed.

Disadvantages: negative pressure and other parameters are smaller than those with brush; the cost is higher than that with brush.

Therefore, in the case of parameters can be reached, should try to choose small brushless vacuum pump, brushless product parameters are not enough, then consider brush products

1. Micropump medium temperature problem: According to the temperature of the medium gas passing through the pump, choose ordinary or high-temperature type.

2. The reliability of the micro-pump: according to the severity of the consequences of the failure of the micro-pump, completely according to their own requirements. The average fault free running time of high quality products is greater than 1000 hours, some up to thousands of hours. In particular, this parameter is measured under full load, uninterrupted operation, is the worst working conditions, if the actual use is not full load or continuous operation, the value will be higher, depending on the pump operating conditions. This performance is a complete test of the technical strength of the manufacturer, from the appearance of some products can be seen, such as the use of special motors rather than ordinary low-cost motors, the volume of the case of heavy weight. You can know a little about the price of the product.

3. Electromagnetic Interference Problem of Micropump: If there is a precise circuit to control the micropump, depending on the anti-interference ability of the circuit, it may be necessary to order a micropump with low electromagnetic interference.