News

The speed control method of machining spindle with CNC lathe

In order to meet the requirements of machining main drive of CNC lathe, the stepless speed regulation system of electric motor is often selected for CNC lathe. In order to expand the speed regulation boundary and meet the requirements of low speed and large torque, the stepless speed regulation of gear and motor is also commonly used to complete the spindle speed regulation.

1. Mechanical gear shifting

In the main drive system of CNC lathe machining, the traditional spindle box structure is greatly simplified due to the use of stepless speed regulation of electric thoughts. However, due to the limitation of the spindle motor and driving power, the constant torque transmission is often used in its low speed section. In order to make the main shaft provide the high transmission power of the main electric idea within the full speed limit as far as possible, and meet the demand of low-speed powerful cutting of CNC machine tools, it is often selected to use the combination of 1-4 gear speed change and stepless speed change, that is, the so-called stepless speed change in sections. The selection of mechanical gear slows down, which not only enlarges the transmission power, but also enlarges the speed regulating boundary.

When the CNC lathe is cutting, the spindle operates automatically according to the rotation speed specified by the s command in the part processing program. Therefore, there must be two kinds of spindle speed command information in the numerical control system, that is, to control the drive and speed regulating circuit of spindle motor by using analog or digital information (s code), and to control the implementation and organization of automatic gear shifting by using switch information (M code). Automatic shift organization is a kind of electric mechanical conversion device, commonly used are hydraulic fork and electromagnetic clutch.

2. Electric drive

There are two main types of speed regulating electric thoughts used in NC lathe machining spindle drive: DC and AC.

(1) DC motor speed regulation? The speed regulation boundary of ordinary CNC machine tools is relatively large. For DC motor speed regulation, two methods of voltage regulation and magnetic regulation are used simultaneously. The typical characteristic curve of DC spindle electric? Machine is shown in Figure 6-1. From its characteristic curve, it can be known that the electric idea is a constant torque speed regulation under the speed N0, that is to say, the armature voltage is selected to be changed to complete; the speed above N0 is a constant power speed regulation, which is completed by changing the excitation current.

The more commonly used “FANUC DC separately excited spindle electric machine” is a three-phase fully controlled thyristor non circulation reversible speed regulation system, which can complete the speed regulation of voltage regulation and magnetic regulation, and the speed regulation boundary is 35? ～ 3500r / min.

(2) AC motor speed regulation

At present, the cage type induction motor is used in the AC spindle drive of CNC machine tools, and the vector control variable frequency speed control method is commonly used.

With the improvement of the new DC and AC spindle speed control electric ideas, electric ideas speed control will be used in the ordinary, but in order to reduce the cost of economic CNC machine tools, mechanical gear shifting is often used to change the spindle speed.

The division of CNC machining stage

When the machining quality of parts is high, it is often impossible to use one process to meet the requirements, but to use several processes to gradually reach the required machining quality. In order to ensure the quality of CNC machining parts and the correct use of equipment and manpower, the machining process of parts can be divided into four stages: rough machining, semi finishing, finishing and finishing.

The differentiation of CNC machining stage should be based on the quality requirements, structural characteristics and manufacturing program of parts, and should not be absolute. It is unnecessary to distinguish processing stages for equipment with low processing quality requirements, good equipment rigidity, high blank precision, small machining allowance and small production program. For heavy workpieces with good rigidity, due to clamping, transportation and time-consuming, all rough and finish machining are often completed under one clamping.

As for the workpiece without distinguishing the processing stage, in order to reduce the impact of various deformations on the processing quality during the rough processing, it is necessary to loosen and accelerate the organization after the rough processing, park the workpiece for a period of time, make the workpiece fully deformed, and then use a small accelerating force to accelerate from the beginning for finishing.

Instructions for use of steel wire joint clamp accessories

Instructions for use of wire joint clamp accessories. Clamp accessories, transportation belt clamp accessories, lifting belt clamp accessories, joint clips, transportation belt connector clips, lifting belt connector clips, belt clamp plates, transportation belt connector clamp plates, lifting belt connector clamp plates, transportation belt connector installation methods, how to install the transportation belt connector.

Our company has been making steel wire rope lifting belt for more than 10 years, specializing in manufacturing steel wire rope lifting belt and its accessories: alloy clamp accessories, steel plate clamp accessories, high-strength galvanized hopper bolts, heat-resistant rubber pad, etc

Introduction to fixture accessories

1. Product classification: special alloy clamp fittings, steel plate clamp fittings

2. Product composition

Special alloy band clamp composition:

Main belt clamp: 1 inner clamp and 2 outer clamps

Accessories: special clamp bolt, steel wire buckle, filler, filling rubber, filling box

Composition of steel plate with clamp:

Main belt clamp: 1 internal clamp, 2 external clamps accessories: special clamp bolt, steel wire buckle

3. Product specification:

Width: 200mm ~ 1700mm

Fixture accessories

4. Installation method of fixture accessories:

1) . use the main belt clamp to clamp the two ends of the lifting belt with bolts.

2) . after clamping, peel off the cover glue at both ends of the lifting belt, and peel off the wire rope core.

3) . fasten the wire rope cores at both ends of the belt with the U-shaped buckle of the wire rope in sequence.

4) . cover the filling box with filling material and filling glue, wait for 15 minutes until it solidifies.

Clamp accessories, transportation belt clamp accessories, lifting belt clamp accessories, joint clips, transportation belt connector clips, lifting belt connector clips, belt clamp plates, transportation belt connector clamp plates, lifting belt connector clamp plates, transportation belt connector installation methods, how to install the transportation belt connector.

The production content mainly includes: cotton canvas, nylon, polyester conveyor belt, steel wire core conveyor belt, bucket elevator steel wire rope lifting belt, large angle corrugated edge conveyor belt, electronic skirt belt, pattern conveyor belt, ring conveyor belt, all kinds of cold, high temperature, burning, acid and alkali, oil, tear, flame-retardant, flame-retardant rubber conveyor belt, food conveyor belt, Rubber base plate and steel wire rope lifting belt alloy clamp accessories, steel plate clamp accessories and other special accessories for conveyor belt. The products are widely sold in China’s metallurgy, coal, cement, transportation, electric power, building materials, chemical industry and transportation machinery industries. Some of the products are directly sold or exported to Australia, Ukraine, India, Vietnam, North Korea, Mongolia, Africa, the Middle East and other countries and regions. They enjoy a high reputation among users. The market share keeps rising. The comprehensive technical ability of the same industry ranks first.

How to determine the machining coordinate system of CNC lathe

CNC lathe processing is a cause with high requirements. If there is a small error in coordinate configuration during the processing and manufacturing of workpieces, the products will be scrapped, and even may bring safety incidents. So how to confirm the coordinate system of CNC lathe?

(1) Reference point of CNC machine tool: the reference point is also an invariable point on the machine tool. It is the limit position of the tool holder movement limited by mechanical stop or electrical device. Its key function is to locate the coordinate system of machine tool.

(2) Machine coordinate system: the right-hand Cartesian Cartesian coordinate system is selected as the coordinate system on the CNC machine tool.

(3) Workpiece coordinate system: workpiece coordinate system is the coordinate system set by the programming staff during programming, also known as programming coordinate system.

Origin of workpiece coordinate system:? In NC programming, first of all, set a point on the part drawing as the origin of programmed coordinate according to the form characteristics and dimensions of the parts to be processed, which is called the origin of programmed coordinate. From the point of view, it’s OK to choose the origin of the workpiece coordinate system at any point on the workpiece, but this may represent tedious calculation problems and add programming troubles. In order to make the calculation simple and simplify the programming, the origin of the workpiece coordinate system is usually selected on the turning center of the workpiece, and the detailed position can be studied and configured on the left end face (or right end face) of the workpiece, even if the programming datum coincides with the design datum and positioning datum.

Tool setting: the coordinate system of machine tool is the only benchmark of machine tool, so it is necessary to know the position of program origin in the coordinate system of machine tool and finish the tool setting. The essence of tool setting is to confirm the only position of the origin of workpiece coordinate system in the machine coordinate system. Tool setting is an important skill in NC machining. At the same time, the efficiency of the tool also directly affects the efficiency of NC machining.

Tool change: when it is necessary to change the tool in the process of NC machining, it is necessary to study and select the appropriate tool change point when programming. The so-called tool change point refers to the position of tool holder rotation and tool change. When the CNC lathe confirms the workpiece coordinate system, the tool change point may be a fixed point or an arbitrary point relative to the workpiece origin. The tool change point shall be set on the outside of the workpiece or fixture, so as to ensure that the tool holder does not touch the workpiece and other parts during tool change.

What causes the abnormal machining accuracy of CNC machine tools

1、 Causes of abnormal machining accuracy of CNC lathe

The reasons for the abnormal machining accuracy of CNC lathe are highly hidden and difficult to diagnose. Five main reasons are summed up: the feed unit of machine tool is changed or changed; the zero point offset of each axis of machine tool is abnormal; the reverse clearance of axis is abnormal; the running state of motor is abnormal, that is, the electrical and control parts are abnormal; the mechanical faults, such as lead screw, bearing, coupling and other parts. In addition, the programming of NC lathe, the selection of cutting tools and human factors may also lead to the abnormal machining accuracy of NC lathe.

2、 Fault diagnosis principle of CNC machine tools

1. The first external and then internal CNC machine tool is a machine tool integrating mechanical, hydraulic and electrical, so the occurrence of its fault will also be comprehensively reflected by the three. The maintenance personnel shall check one by one from the outside to the inside first, and try to avoid opening and disassembling at will, otherwise the fault will be enlarged, the machine tool will lose precision and performance.

2. Generally speaking, mechanical fault is easy to detect, while the fault diagnosis of CNC system is more difficult. Before troubleshooting, first of all, pay attention to eliminate mechanical faults, which can often achieve twice the result with half the effort.

3. The machine tool can be powered on only when it is confirmed as a non-destructive fault through understanding, observation, test, analysis under the static state of power failure of the machine tool; under the operation condition, it can be dynamically observed, inspected and tested to find the fault. Wechat for metal CNC lathe processing, good content, worthy of attention.

For destructive faults, the danger must be eliminated before power on.

4. Simple first, then complex. When there are many kinds of faults interwoven and covered up, and there is no way to start for a while, the easy problems shall be solved first, and then the difficult problems shall be solved. Often after simple problems are solved, difficult problems may become easy.

3、 Fault diagnosis method of CNC machine tools

1. Intuitionistic method: (looking, hearing, questioning and cutting) ask – the fault phenomenon of machine tool, CNC lathe processing status, etc.; see – CRT alarm information, alarm indicator light, capacitor and other components deformation, smoke burning, protector tripping, etc.; listen – abnormal sound; smell – the smell of electrical components burning and other peculiar smell; touch – heating, vibration, poor contact, etc. Wechat for metal CNC lathe processing, good content, worthy of attention.

2. Parameter inspection method: the parameters are usually stored in RAM. Sometimes, the battery voltage is insufficient, the system will lose or be confused due to long-term power failure or external interference. The relevant parameters shall be checked and calibrated according to the fault characteristics.

3. Isolation method: for some faults, it is difficult to distinguish whether they are caused by CNC part or servo system or mechanical part, isolation method is often used.

4. In the same kind of method, the spare board with the same function is used to replace the suspected faulty template, or the templates or units with the same function are exchanged with each other.

5. The function program test method compiles some small programs for all the instructions of G, m, s, t and functions, and runs these programs when diagnosing faults to judge the lack of functions.

Classification and repair of lathe common faults

Because the CNC lathe adopts the computer control skills, the mechanical structure is greatly simplified compared with the common machine tools, and the opportunity for the mechanical system to expose the defects is greatly reduced. The common mechanical defects are mainly as follows: the defects of lathe spindle components. Because of the application of adjustable speed motor, the structure of spindle box of CNC lathe is simple, the disadvantages of which are the tool handle active tension equipment, active speed control equipment, etc.

Disadvantages of ATC. More than 50% of the disadvantages of machining center machine tools with active tool change equipment are related to active tool change equipment, which are mainly revealed in: the disadvantages of tool magazine activity, large missing of positioning difference, unstable clamping handle of manipulator, large error of manipulator activity, etc. When the disadvantages are serious, the tool change is stuck and the lathe is forced to stop working.

It is used to detect the disadvantages of the travel switch voltage in the moving direction of each axis. On CNC machine tools, in order to ensure the reliability of active homework, a lot of travel switches are selected to detect the active position. During the long-term operation of the machine tool, the moving characteristics of the moving parts change. The reliability of the travel switch pressing equipment and the change of the quality characteristics of the travel switch itself have a great impact on the generation and elimination of the defects of the lathe.

Disadvantages of lathe feed drive chain. Because the rolling collision pairs are widely used in the guide rail of CNC machine tools, the main disadvantages of the feed transmission chain are caused by the falling of the active quality, such as the mechanical parts are not moving to the regular position, the operation is stopped, the positioning accuracy is falling, the reverse leisure is increased, the mechanical crawling, the noise of the bearing is increased (usually exposed after the collision), etc., which can be adjusted and maintained from beginning to end Force, adjust the loose link, improve the accuracy of activities and adjust the compensation link.

The method of eliminating the shape error of the spherical surface in CNC machining

When CNC machining spherical surface is more and more quadrant ball and surface, due to improper adjustment, it is very easy to produce shoulder, shovel back and other conditions. The reasons are as follows:

1. System gap formation

In the driving pair of CNC machining equipment, there is a certain gap between the lead screw and the nut. With the increase of the time when the equipment is put into operation, the gap increases gradually due to wear. Therefore, the key factor for the shoulder on the machining surface is to compensate for the corresponding gap during the reverse movement. The clearance measurement usually adopts dial indicator measurement method, and the deviation control is within 0.01-0.02MM. It should be pointed out here that the base and rod should not be extended too long, because the cantilever is long, the base is easy to be moved by force, resulting in inaccurate counting, and the compensation value is not true.

2. Uneven formation of workpiece machining allowance

Before finishing the design surface of CNC machining parts, whether the machining allowance of the surface to be machined is average is also an important reason for forming whether the forming surface can reach the design requirements, because the machining allowance is not uniform, which is easy to form a “reflection” deviation. Therefore, for the parts with high requirements on surface form, before forming, the machining allowance should be as average as possible to reach the design requirements by machining one more profile.

3. Improper tool selection

In the cutting process, CNC cutting tools remove the raw materials through the main cutting edge. However, after the arc passes the quadrant and the arc is tangent to the cutting edge (the intersection of the back edge and the base surface), the cutting may be added to the back edge. Therefore, when choosing or grinding tools, we must study the wedge angle of the tools.

Development and application of precision parts processing technolog

Precision parts processing technology is an advanced manufacturing technology developed to meet the needs of modern high technology, which is the basis of other high-tech practices. It comprehensively uses the new achievements in the development of mechanical technology and modern electronics, sensor technology, optics and computer and other high-tech technologies. It is the basic technology in the high-tech boundary and plays an important role in the modernization of national defense science and technology and the economic construction of the people. At the same time, as the basic technology and an important part of modern high-tech, it promotes semiconductor technology and photoelectric technology , raw material science and other technologies. The machining precision reaches 1 μ m, and the precision parts processing is completed by using precision machine tools, precision measuring tools and meters under strictly controlled environmental conditions.

Precision parts processing

When the machining accuracy reaches or exceeds 0.1 μ m, it is called ultra precision part machining. In aerospace industry, precision parts processing is mainly used to process precision mechanical parts in aircraft control equipment, such as precision mating parts in hydraulic flattening and dynamic servo organization, frame and shell of gyroscope, air flotation, liquid floating bearing components and floats, etc. The structure of aircraft precision parts is complex, the rigidity is small, the precision is very high, and the proportion of difficult to process raw materials is large. The processing efficiency of precision parts is as follows: ① the geometric form and mutual position accuracy of parts reach to micron or angular second level; ② the boundary or characteristic dimension of parts are below micron; ③ the surface micro roughness (surface uniformity height difference) of parts is less than 0.1? Micron; ④ the mutual parts can meet the requirements of coordination; ⑤ Some parts can also meet the requirements of accurate mechanical or other physical characteristics, such as the change of stiffness of torsion bar of float gyroscope, the stiffness coefficient of flexible element, etc.

In recent years, most of the automobile, mold parts and metal processing are made with CNC machine tool as the center, and most of the hole processing is made with advanced equipment such as machining center and CNC machine tool. High-speed and high-precision drilling processing has been put on the agenda. No matter which boundary of precision parts processing, the completion of high-precision and high-speed is an important competitive means to obtain user orders.

Automatic parts show you the function of ultrasonic cleaning

Ultrasonic cleaning is to use the cavitation effect, acceleration effect and direct inflow effect of ultrasonic in the liquid to directly and tactfully affect the liquid and dirt, so that the dirt layer is distributed, emulsified and peeled to reach the cleaning target. At present, more cavitation and direct flow are used in the ultrasonic washing machine.

According to the frequency wave, it can be divided into three types: infrasound wave, acoustic wave and ultrasonic wave. The frequency of infrasound wave is below 20Hz; the frequency of sound wave is 20Hz ~ 20kHz; the frequency of ultrasonic wave is above 20kHz. The infrasound wave and ultrasonic wave in it can’t be heard by ordinary people. Because of the high frequency and short wavelength, the ultrasonic wave has good target and strong penetration, which is the reason of designing and manufacturing the ultrasonic washing machine.

It is one of the methods for protecting teeth and cleaning teeth. In today’s society, a lot of people will do ultrasonic tooth washing.

1. Complete: the key point of ultrasonic tooth washing lies in the subgingival calculus, which is the key cause of periodontitis. Only when the area is clean, can periodontitis be prevented and gum bleeding be improved. This is one of the advantages of ultrasonic tooth washing.

2. Painless: This is also the most important advantage of ultrasonic tooth washing. Adjust the frequency of the head of the cleaning machine according to the amount of calculus of the person who washed the teeth, so as to ensure that the process of tooth washing can be completed in a painless environment.

3. Polishing after operation: it can leave microscopic tiny scratches on the surface of teeth after cleaning. After polishing, it is better to make the teeth more bright and not easy to attach calculus and tooth stains.

4. Safety: all the equipment is sterilized by high temperature and high pressure. The advantages of ultrasonic tooth washing can be used to prevent cross effects.

Discussion on the design of fixture

With the development of machining industry, fixture is more and more valued. It is used in the boundary of machining and becomes an indispensable part of machining. With the development of machine tool technology towards the goal of high speed, high efficiency, meticulous, composite, intelligent and environmental protection, fixture technology is developing towards the goal of high precision, high efficiency, module, combination, general and economic.

Problems in design and research of fixture

Generally, the structure of fixture design is single, which makes people feel that the structure is not very complex. The more we find that the hydraulic fixture is widely used, which greatly simplifies the original mechanical structure. However, if we do not conduct detailed research in the design process, we will inevitably encounter unnecessary difficulties:

1. Blank allowance of machined parts

The size of forming blank is too large, and interference occurs. So we must plan the rough drawing before design. Leave plenty of space

2. Chip removal fluency of fixture

Due to the limited machining space of the machine tool, the fixture is often designed in a compact space. At this time, the iron chips in the machining process are often ignored to accumulate at the dead corner of the fixture.

There are many difficulties in the later processing because of the poor discharge of the liquid containing chips. Therefore, at the beginning of essence, we should study the problems in the process of machining. After all, the fixture will increase efficiency and be easy to operate

3. Overall opening of fixture

Neglecting the opening, making it difficult for the operator to install the card, time-consuming and laborious, and design taboo

4. Basic comment principle of fixture design

Each set of fixture has to go through many times of clamping and loosening behavior, so it may reach the user’s requirements at the beginning, but the fixture should have its accuracy maintenance, so do not design some unreasonable equipment.

Even if you are lucky now, it will not last forever. A good design should be tempered by time.

5. Interchangeability of positioning elements

It is important to wear the positioning elements, so it is necessary to study the quick and simple replacement. It is better not to design large parts

The accumulation of fixture design experience is very important, occasionally design is one thing, and in essence use is another thing, so good design is a process of accumulation and summary.

While studying the problems that should be paid attention to in the design of tooling and fixture, we should adhere to the following basic principles in the design of tooling and fixture

1. Meet the safety and reliability of workpiece positioning in the process of application

2. Sufficient bearing or clamping force to ensure the processing process of workpiece on the fixture

3. Meet the requirements of simple and rapid operation in the clamping process

4. Vulnerable parts must be structures that can be exchanged quickly. When conditions are sufficient, it is better not to use other equipment

5. Meet the reliability of repeated positioning of fixture in the process of adjustment or exchange

6. Try to prevent complex structure and high cost

7. Try to select standard parts as component parts

8. Systematization and standardization of internal products of the company

Because of the importance of fixture, its quality and accuracy directly affect the efficiency of machining, so it is very important to control its quality and accuracy from the source and choose a reliable and capable fixture manufacturer. Shenzhen huayanghua has been focusing on automobile inspection tools, fixture, pallet and three-dimensional processing for 13 years. Our team has cooperated with each other and strictly implemented the customer’s product requirements as our guidelines. We have arranged to complete the product requirements according to the quantity and deliver the products on time.