2020 – Page 70 – CNC Machining & Turning, Milling, Metal parts

Continuous improvement of Chinese hardware Customization Technology

With the continuous improvement of domestic hardware customization technology, the dimensional tolerance and performance parameters of products are further improved. Due to the cost advantage of hardware customization products, precision hardware customization parts gradually replace forged parts.

At present, precision hardware components are mainly used in mechanical equipment, parts and components, electrical toys, electronic products, etc. the manufacturing process of customized precision hardware products is about 30% less than that of traditional metal forging process, and the utilization rate of materials is up to more than 80%. The manufacturing process conforms to the concept of environmental pollution, environmental protection, energy conservation and emission reduction, and sustainable development. In the future, domestic enterprises will use more CNC processing hardware customized process to produce more product parts, while improving the quality and cost management requirements of energy conservation and emission reduction policies.

In the background of Chinese market, domestic hardware accessories customization enterprises are trying to improve their technology and technology, so that they can cover the needs of all walks of life for hardware accessories customization. To provide customers with a variety of high-precision and complex mechanical parts hardware products, customized overall solutions and services, to multiply the productivity effect!

We must have rich experience in project practice to produce precision hardware accessories customized accessories processing products. The processing and customization of special-shaped frame put forward higher requirements for function and precision, and the existing processing of ordinary machine tools can not meet the requirements of new materials and new structures.

The structure of special shape becomes more and more complex. Compared with the traditional process, the cost of individual products increases directly. The technical difficulty and cost complement each other. By determining the alloy elements of special shape structure components and hardware tools, and improving some technical treatment, we can meet the requirements of different precision and hardness performance of precision parts. In addition, we can increase the same profile structure It does not increase the cost. Precision hardware customization including sheet metal pressure nut, furniture hardware hinge, small motor carbon brush copper sleeve, mining machinery Stone copper sleeve, motor oil shaft, coffee oil bearing, etc. technical innovation can meet the high quality requirements, which plays an important role in energy saving, performance improvement and productivity improvement.

CNC machining – precision hardware parts

In the production of CNC lathe, precision control has an important influence on the product quality. The machining accuracy depends on the mechanical accuracy, programming accuracy, servo accuracy and error compensation value accuracy. In order to improve the machining accuracy of CNC lathe, the machining accuracy of CNC lathe can be effectively improved in the design stage through CAD design and computer simulation technology. Strengthening the maintenance of the machine in use can effectively guarantee the high precision state of the CNC lathe.

1. Analysis of machining accuracy of CNC lathe

At present, the classification of CNC lathe is mainly set precision, position precision and machining precision. Different brands of CNC lathes have different material rigidity (the quality of CNC lathe equipment), and the working temperature will have a variety of effects on the machining accuracy of CNC lathes. The geometric accuracy of CNC lathe can be further subdivided into spindle geometric accuracy and linear motion accuracy.

In the machining operation of CNC lathe, the relative position between the main shaft and the rotating shaft remains relatively fixed. In actual production and theoretical knowledge, the relative spatial position between the two shafts does not have to be relatively fixed. This is because the bearing elements that make up the spindle may have different degrees of errors in the production plant where the lathe equipment is manufactured, and will be affected by the temperature, working strength, lubrication and other conditions during the use process. Due to the bearing accuracy of the main shaft, the manual assembly quality of the main shaft box is different, the mechanical vibration of the main shaft and rotating parts in the process of processing causes the runout, the roundness of the bearing journal of the central shaft is unstable in the manufacturing process, the concentricity before and after has certain error, and the thermal deformation may occur in the working process of the main shaft. All these factors affect the spindle geometric accuracy of CNC lathe.

In addition to the geometric accuracy error caused by the spindle in CNC lathe machining, the orbit may also affect the position accuracy of the machine due to the friction and the inertia matching of the servo motor used in CNC lathe machining. Some parts of CNC lathe that need to work continuously, such as cylinder pump, motor, hydraulic machine, etc., need to work continuously for a long time (even 24 hours). In the process of working, friction causes the specific internal parts. Because of the thermal expansion and deformation of the processing heat, the actual production size of the parts deviates from the designed predetermined size. Because of the role of internal heat, the asymmetry of the components of CNC lathe equipment results in the deformation of the production and processing parts. Therefore, the thermal deformation of the components of CNC lathe equipment will have a great impact on the position accuracy of the machine The effect of the key.

The machining accuracy of CNC lathe is closely related to the geometric accuracy of the whole CNC lathe, not only to the position accuracy, but also to the transmission system failure of CNC lathe machining, the inspection of fault compensation system, the friction of machine structural parts, the position error of cutting tools, etc., as well as to whether the program editing of CNC lathe machining is correct and the production process is reasonable. Therefore, in the actual production, in order to improve the machining accuracy of CNC lathe, we must improve the geometric accuracy and position accuracy of CNC lathe machining.

Selection of CNC milling machine

1、 To buy a machine, you still need to choose a brand. Although the brand is more expensive, it’s worth the money. I believe the assembly gap will not exceed 50000 yuan, but it’s still cost-effective in a comprehensive way. A good machine can create value for you virtually. If you buy a bad machine for three days or two ends fail, or the accuracy cannot be reached, you’re exhausted. In the end, all the customers are gone.

2、 Choose a regular manufacturer and register with the industrial and commercial department. It’s better to have quality certification. Those small factories without factory agents or with only a few people should not be tested. They can’t figure out how to be cheap for a while. When no one can be found, they will have to cry a lot in China.

3、 Look at the service attitude. No matter how good the machine is, there will be colds. At this time, you need to choose a good service provider. Those who don’t trust us and don’t repair them in time should not be ignored. When choosing machines, sometimes I prefer to choose the ones with slightly poor quality, but the ones with timely service make people feel relieved.

4、 Choose the domestic assembly machine, if it is a brand machine, then rest assured. For the sake of their long-term efforts to establish credit, merchants do not need to quote random prices, and the machine will not cut corners. For example, Yongjin, Chaoqun, Zhongmao (now called Shenghong), Liwei, Dali, you can buy with ease. If other brands want to see if the controller is Mitsubishi m64sm, don’t spend the price of m64sm to buy a m64as controller (to prevent businesses from selling mutton and dog meat). Although they are all 64 series, the price difference is more than 10000, and the performance gap is even less high-speed and high-precision, which is an important function. Although some businesses agree to reduce the price, they buy different things. Therefore, we need to eliminate the cost The fee maker thought that he had taken advantage of it. In fact, the merchant was stealing it

Analysis of CNC machining structure technology

The structural processability of large CNC machining parts refers to the adaptability of parts to machining methods, that is to say, the designed parts structure should be easy to machining and forming, with low cost and high efficiency. When machining parts on CNC lathe, we should carefully examine the rationality of part structure according to the characteristics of CNC turning. In the structural analysis, if any problem is found, the designer or relevant department shall generally ask for instructions and put forward modification opinions.

When CNC machining CNC lathe turning parts, the tool only makes plane movement, its forming movement form is relatively simple, and the tool path is not too complex. In the process of structural technology analysis, for the parts with narrow space and poor structural rigidity, such as small deep hole, thin-walled part, narrow deep groove and so on, the factors such as tool path, tool type, tool angle, cutting amount, clamping method and so on should be specially considered when arranging the working procedure, so as to reduce the tool loss, improve the machining accuracy, surface quality and labor productivity.

Classification of CNC machining cente

Large CNC machining centers are usually classified into horizontal, vertical and multi axis machining centers according to the relative position of the spindle and the worktable.

A horizontal machining center: refers to the machining center with the spindle axis parallel to the workbench, which is mainly suitable for machining box type parts.

B vertical machining center: it refers to the machining center set vertically between the spindle axis and the workbench, which is mainly used for machining complex parts such as plates, plates, molds and small shells.

C multi axis linkage machining center, also known as universal machining center: it refers to the machining center that can control linkage change through the angle between the machining spindle axis and the rotary axis of the worktable to complete complex space surface machining. It is applicable to the machining of impeller rotor, mould, cutting tool and other workpieces with complex space curved surface.

Construction of CNC machine

1. Casting, which is the most important part of CNC machine, directly affects the accuracy, stability, wear resistance and service life of computer gongs. After the casting is finished, it is not immediately used in production. A good casting is after wind and rain, sun exposure, natural weathering, some of which are soaked by sea water. After the casting does not change, it will be processed. The machine tool is not easy to change. CNC machining can maintain the stability and accuracy of the machine tool for a long time.

2. CNC machine machining spindle, the spindle is used to directly face the workpiece, it is driven by the motor to work, high-speed rotation, on the spindle with a tool handle, it can chip the workpiece, to meet various production needs, the quality of the spindle will directly affect the processing accuracy, if there is wear of the internal bearing, it is easy to cause the spindle swing processing out of the thing accuracy naturally Deviate several wires. At present, the rotating speed of the main shaft is generally around 8000 revolutions, and the high-speed machine can achieve more than 20000 revolutions. In the traditional machining center, each machine has only one main shaft. In recent years, there have been two or more main shaft machining centers.

3. The screw rod is also a part of the fuselage. It is driven by the servo motor. The displacement of the working table is driven by the copper sleeve of the screw rod to meet the processing needs. If there is a gap between the screw rods, it is also directly reflected in the processing accuracy and smoothness.

4. Dongguan machine parts processing motor, there are two kinds of motors: servo motor and frequency conversion motor. The stability of servo motor is good, the power of spindle drive motor is large, and the cooperation rate of three-axis drive motor is small.

5. The coupling is installed between the screw rod and the motor, which is only a linkage.

6. The lubricating cold system is composed of automatic oil pump, spindle oil cooler and chip liquid circulation system. The oil is fed automatically without manual operation. When the machine tool is working, the oil is pumped once every few minutes, and the oil pipe is connected to every corner, such as screw rod, guide rail, etc. if the oil path is blocked, it is easy to cause the guide rail wear and affect the accuracy. Dongguan machine parts processing spindle oil cooling is to cool the spindle and add a cycle of cold power system, 8000 rotation of the spindle can not be, 8000 rotation of the spindle must be equipped with more than. The chip liquid circulation system uses the pumping motor to pump up the oil from the oil tank and rush it to the workpiece being processed.

7. When machining sheet metal, the requirements for sheet metal are not too high, as long as there is no oil leakage, but it also involves the problems of beautiful appearance and image

How to change tools in CNC operation

When programming a large-scale computer gong, the selection of tool setting point should be considered first. The determination of tool setting point and tool change point is the starting point of tool movement relative to workpiece in the process of numerical control machining. Since the program is also executed from this point, the tool setting point is also called the program starting point or starting point. When the machining accuracy requirements are not high, some surfaces on the workpiece or fixture can be directly used as the tool alignment surface; when the machining accuracy requirements are high, the tool alignment point should be selected on the design basis or process basis of the part as much as possible, for example, for the parts with hole positioning, the axis of the hole taken as the tool alignment point is more appropriate. The tool setting point must have a certain coordinate relationship with the positioning datum of the workpiece. In this way, the relationship between the coordinate system of the machine tool and the workpiece can be determined. The selection of tool setting point in computer gong processing should be convenient for the calculation of coordinate value and the tool setting. During the tool setting, the tool setting point shall coincide with the tool position. The so-called tool point refers to the intersection of the tool axis and the tool bottom surface for the flat end milling cutter; the ball end milling cutter refers to the ball center of the ball head part; the turning tool refers to the tool tip; the drill bit refers to the drill tip; for the machining of Dongguan Mechanical parts, for the WEDM machine, it refers to the focus of the WEDM axis and the part surface. (1) Stress and warpage analysis based on double side flow technology

According to the analysis results of gate solidification effect and pressure and temperature distribution, the stress and warpage analysis module calculates the change of stress with time in the wall thickness and plane direction of the product and the shrinkage of the product in the wall thickness direction at the time of demoulding. A special double-layer shell element is used to predict the warpage of the product at the time of demoulding.

(2) The combination of numerical calculation and artificial intelligence technology

Traditional CAE software is basically a passive computing tool. Before analysis, users need to design the forming scheme and process parameters first, and often do not know how to use the analysis results to guide production after analysis. To a certain extent, this has affected the promotion and popularization of CAE software. In order to play a greater role in CAE software, HsCAE 6.10 successfully introduced artificial intelligence technology. In the simulation system, the parameters with continuous value space, such as injection time and injection temperature, are optimized by the method of artificial neural network, and the interpretation and evaluation of the analysis results are processed by the method of rule-based reasoning.

There are two lights on the power supply of NC machining center unit, one is the power indicator light, which is green; the other is the power alarm light, which is red. The power supply unit here includes the power input unit and the power control part.

When the power of CNC machining center cannot be connected, if the power indicator light (green) is not on.

Fuse F1 and F2 of power supply unit have been blown. This is caused by high input voltage, or the components of the power supply unit itself are damaged.

The input voltage of CNC machining center is low. Please check the voltage entering the power supply unit. The allowable voltage is AC 200V + 10%, 50Hz ± 1Hz.

The power supply unit is poor, and there is damage in the unit

The power indicator light is on and the alarm light disappears, but the power cannot be connected.

This is because the power on condition is not met. By the following switch circuit, the conditions for power on are as follows:

There are three conditions for turning on the power supply of CNC machining center: (1) the source on button is closed. Dongguan Mechanical parts processing (2) power off button is closed. (3) The external alarm contact is open.

In the process of using CNC machining center, there may be tool imbalance. If not adjusted in time, the processing effect will be affected. Therefore, we should always pay attention to the tool balance of CNC machining center. The main reasons for the imbalance of the tool handle are the asymmetry of the tool design, the defects in the tool body, and all the adjustments on the tool. The tool with correct balance can significantly reduce the noise and vibration, which can increase the tool life and improve the accuracy consistency of parts.

The centrifugal force of CNC machining center magnifies the vibration caused by unbalance in proportion to the square of speed. The vibration of CNC machining center caused by this increase minimizes the life of bearing bush, bearing, shaft, spindle and gear.

Before balancing the tool in CNC machining center, it is necessary to measure the unbalance and the angle position of each selected correction plane. These variables are measured on two general types of balancing machines: non rotating or gravity machines for measuring single plane imbalance, and rotating or centrifuge for measuring single plane or two plane imbalance.

After determining the magnitude and angle of the unbalance in the correct plane, you can correct it by adding or removing material from the workpiece. Machining center for components that are not tools, the most widely used material adding method of drilling and tapping center is to weld the counterweight on the components. Other methods for components with slight unbalance include adding solder to the component body or adding weight in pre drilling.

, stable high precision:

The main parts of gantry milling equipment, such as crankshaft, gear, transmission shaft and so on, have high wear resistance after hardening and heat treatment. The long-term performance is stable, ensuring the requirements of high accuracy and stability.

2、 Slider adjustment mechanism:

The sliding speed adjustment is divided into manual adjustment and electric adjustment, which is convenient, reliable, safe and fast with an accuracy of 0.1mm.

3、 Reliable and safe operation performance:

Safety knowledge in CNC operation

1. Effective protective measures shall be taken for the equipment prone to injury accidents in the processing area.

2. The protective measures shall ensure that any part of the operator’s body is prevented from entering the dangerous area under the working condition of the equipment, or that the equipment cannot operate (run) or make emergency braking when entering the dangerous area.

3. The following protective measures shall be taken for machining equipment separately or simultaneously:

(1) Completely fixed and semi fixed airtight cover;

(2) Mechanical or electrical barriers;

(3) Mechanical or electrical interlocks;

(4) Automatic or semi-automatic feeding and discharging device;

(5) Hand limiter, hand release device;

(6) Mechanical or electrical hands off device;

(7) Automatic or manual emergency stop device;

(8) Limiting devices that cause dangerous travel, feeding, or feeding;

(9) Prevent misoperation or misoperation of the device;

(10) Warning or alarm device;

(11) Other protective measures.

CNC machining selection and positioning reference

① Try to choose the design basis as the positioning basis;

② When the positioning datum and the design datum cannot be unified, the positioning error shall be strictly controlled to ensure the machining accuracy;

③ When the workpiece needs to be clamped for more than two times, the selected benchmark can complete the processing of all key precision parts in one clamping and positioning

④ The selected benchmark shall guarantee to complete as many processing contents as possible;

⑤ In batch machining, the positioning datum of parts should coincide with the tool setting datum of workpiece coordinate system as much as possible;

⑥ When it is necessary to clamp several times, the benchmark shall be uniform.

Contents and scope of CNC machining self inspection

1. Before processing, the processor must clearly see the contents of the process card, clearly know the parts to be processed, shapes, dimensions of drawings and know the processing contents of the next process.

2、 Before clamping the workpiece, measure whether the blank size meets the drawing requirements. When clamping the workpiece, carefully check whether the placement is consistent with the programming operation instruction.

3. After rough machining, self inspection shall be carried out in time so as to adjust the data with errors in time and effectively. The content of self inspection is mainly the position and size of processing parts. For example: (1). Whether the workpiece is loose; (2). Whether the workpiece is correctly divided; (3). Whether the dimension from the processed part to the reference edge (reference point) meets the drawing requirements; (4). Position and dimension of machining parts. After checking the position and dimension, measure the rough machined shape ruler (excluding arc).

4. Finish machining can only be carried out after rough machining and self inspection. After finishing, the workers shall conduct self inspection on the shape and size of the processed parts: inspect the basic length and width of the processed parts of the vertical surface; measure the base point size marked on the drawing for the processed parts of the inclined surface. 5。 The workers can remove the workpiece and send it to the inspector for special inspection after completing the self inspection of the workpiece and confirming that it is in conformity with the drawings and process requirements.