Monthly Archive September 24, 2020

There are few and no composite materials processed by machining center, but it is strict to process composite materials with machining center, and there are some precautions:

Now the amount of composite materials has been rising, so the use of machining centers to add composite materials has also been rising. In the past, we used to drill and cut the edge by hand, but now we use machinery to finish it. Using machining center to process composite materials is much faster than manual processing, and the precision is high. However, once there is a problem, there will be serious loss. Therefore, the process, tool selection and processing parameters are particularly important for processing composite materials.

Matters needing attention in selecting cutting tools for machining composite materials

1、 Generally, the size of composite auxiliary materials is relatively large, and its workpiece structure is complex, and its hardness and strength are very high. The cutting force used in the machining process is relatively large, and the heat produced by the processing is difficult to transfer out, which may severely scorch the resin or soften the resin, resulting in severe tool wear. Therefore, the tool used must have carbon fiber, and the cutting speed should be greater than 500 / min, and the feed speed must be small. In the process of edge cutting, carbide hobbing cutter, electroplated diamond grinding wheel, diamond inlaid milling cutter and copper based diamond grain saw blade should be selected.

2、 The cutting effect of the three new types of special milling cutters for machining monolithic cemented carbide composites is better. They all have some common characteristics: high rigidity, small helix angle, even 0 ° angle. The specially designed herringbone blade can effectively reduce the axial cutting force and delamination, and their machining efficiency and effect are very good.

3、 The interlaminar strength of carbon fiber composites is low, and it is easy to produce delamination under the action of cutting force. Therefore, the axial force should be reduced when drilling or trimming. High speed and small feed are required for drilling. The rotating speed is generally 3000 ~ 6000r / min, and the feed rate is 0.01 ~ 0.04mm/r. It is better to select three tips and two edges or two tips and two edges for the drill bit. The sharp tip can cut off the carbon fiber layer first. The two edges play a repair role on the hole wall. The diamond embedded drill head is sharp and wear-resistant. It is a difficult problem to drill the interlayer between composite and titanium alloy. Generally, the integral cemented carbide bit is used to drill according to the cutting parameters of drilling titanium alloy. From the titanium alloy side, the drilling is carried out until the drilling is through. Lubricant is added during drilling to alleviate the burn of composite materials. Boeing company specially developed PCD combined bit for interlayer drilling.

Special attention: the composite chip is powder, which is harmful to human health. High power vacuum cleaner should be used for dust collection, and water cooling can also effectively reduce dust pollution

The cutting fluid plays a very important role in the machining of workpiece in CNC machining center. Cutting fluid will be used in any material processed by CNC machining center. Therefore, cutting fluid is an indispensable liquid in CNC machining center. The main function of the cutting fluid is lubrication, cooling, anti-corrosion, anti rust, etc. if there is no cutting fluid for processing, the workpiece will be easy to deform and rust under high temperature. Therefore, CNC machining center must use cutting fluid to avoid this undesirable phenomenon.

There are many kinds of cutting fluids. Today, we will talk about several commonly used in the market. These are emulsion, chemical synthetic cutting fluid and cutting oil added with extreme pressure additives. Today, we will introduce these three common cutting fluids.

Advantages and disadvantages of cutting oil with EP additive

Advantages: the general use and cutting speed is not higher than 60m / min, the main cutting speed is not higher than 60m / min, regardless of any material cutting processing. Disadvantages: in high-speed cutting, due to the large amount of heat, oil-based cutting fluid heat dissipation effect is poor, so in high-speed cutting will produce stable and high smoke or fire. Therefore, due to high stability will have a certain impact on the workpiece, such as workpiece deformation, poor machining accuracy and other adverse phenomena.

Advantages and disadvantages of emulsion

Advantages: the biggest advantage of emulsion is strong heat dissipation, can clean the workpiece and high cost performance, which is conducive to the health and safety of operators. Therefore, the general metal processing plant is to choose the use of emulsion processing. In addition to the materials that are particularly difficult to machine, emulsion can be used for almost all light and medium load cutting and most heavy load processing, especially for processing thread grinding, groove hemp cutting and other complex grinding. Disadvantages: the biggest defect of emulsion is that it is easy to make bacteria and mold multiply, and make the effective components in emulsion decompose and stink and deteriorate In general, organic fungicides with low toxicity should be added.

Advantages and disadvantages of chemical synthetic cutting fluid

Advantages: it has the advantages of high cost performance, fast heat dissipation, strong cleaning ability and excellent workpiece visibility. It is very easy to control the size of the workpiece. Its stability and anti-corruption ability are better than emulsion. The disadvantage is that the lubrication ability is not strong, it is easy to suck the adhesion and wear of the moving parts of the machining center. Moreover, the viscous residue left by the chemical synthesis will affect the movement of the parts of the machining center and cause the rust of the overlapping surfaces of the parts.

Many friends who are new to machining centers don’t know much about machining centers, so occasionally some customers will ask what kind of CNC machining centers there are. CNC machining center we have had a lot of introduction, to introduce the types of CNC machining center, CNC machining center in the end what kind? After reading the following content introduction, you will understand.

1、 What kinds of CNC machining centers are there

In fact, CNC machining centers can be divided into vertical machining centers and horizontal machining centers according to the structure of CNC machining centers. CNC machining centers can be divided into vertical machining centers and horizontal machining centers according to their structures, which can be divided into vertical machining centers, vertical machining centers, vertical machining centers, and horizontal machining centers Horizontal machining center, gantry machining center, high-speed machining center, drilling and drilling center are all types of CNC machining centers.

2、 Recommendation of different products of CNC machining center

We have already talked about the types of CNC machining centers. At present, the types of CNC machining centers of mingwan machine tools include vertical machining center, gantry machining center, high-speed machining center and drilling and drilling center. Let’s introduce their respective advantages. Vertical machining center is our most commonly used machining center, and so are our small machining center A kind of vertical machining center, with the characteristics of miniaturization and high cost performance, gantry machining center is called the terminator of Dali Canada. Our gantry machining center can replace vmc1270, vmc1370 and vmc1580. With many advantages, the price is lower than Dali plus. The high-speed machining center is mainly used to make high-precision and high-finish products, with 12000 rotary direct spindle. Drilling and tapping center tool library is different, mainly used for making precision 3C products.

Five axis machining centers are not new to you. Five axis vertical machining centers generally have five moving axes, which are three linear axes / (XYZ /) and two rotating axes / (AB /) or / (AC /), which are represented by different representation methods according to their installation positions. Today, I mainly introduce the installation position of a and C rotating shafts of five axis vertical machining center.

The A and C rotation axes of the five axis machining center can be installed in different positions. For example, the A and C rotation axes can be installed on the worktable or the spindle, or they can be installed on the workbench or the spindle respectively. The A and C rotation installation positions of the five axis machining center are mainly determined by the product. In the market, the A and C rotation of the common five axis vertical machining center are both Installed on the workbench, there are few other types of installation. Now let’s introduce it to you.

Five axis machining center a, C rotation axis is installed on the worktable

In general, the A, C rotating shaft is installed on the worktable in this way, and it is the most seen in the market. Because of the limited size of the workpiece, this kind of installation method can not process large workpieces or load the machining center, because the bearing capacity of a rotation is limited.

Five axis machining center a, C rotation axis is installed on the spindle

There are few ways to install a and C rotating shafts on the main shaft. This kind of a and C rotating shaft installation mode is used to process large workpieces, and its load capacity is stronger than that of installing a and C rotating shafts on the workbench. Therefore, this kind of a, C rotating shaft installation method will be used in processing large-size workpieces.

The A and C rotating axes of the five axis machining center are respectively installed on the worktable and the spindle

In general, the a-axis is installed on the main shaft, while the c-axis is installed on the table. This kind of a-axis and c-axis installation mode is also relatively rare. It can process large-scale workpieces and grab the load capacity.

After using the belt drive spindle machining center for a long time, it is found that the spindle box belt has abnormal noise, whether it is in forward or reverse rotation, there will be some noise. According to many years of experience, most of them are belt problems. As long as we start from the belt of the main shaft, we can find out the key problem of making noise.

The belt tension of the spindle connected to the servo motor is too high

The tension of the belt connecting the main shaft to the servo motor should not be too tight. If it is too tight, it will easily lead to the wear of the belt, slip and make abnormal noise,

The belt tension between the spindle and the servo motor is too low

The tension of the belt connecting the spindle to the servo motor should not be too low. If the tension is too low, it will appear that the belt connecting the spindle to the servo motor is too loose. In this way, it is easy to cause slipping and make abnormal noise during heavy cutting.

The belt connecting the spindle to the servo motor is damaged

In general, the machining center has been used for a long time, and it is inevitable that there will be some defects, such as the transmission belt, which will wear after a long time, which is also one of the reasons for the abnormal noise of the belt. Therefore, the better quality of the drive belt to use a longer time, poor quality drive belt use time is shorter.

The tooth profile of the drive belt does not match that of the servo motor and the spindle

As the drive belt of the machining center is used for a long time, it will cause some wear, so many customers purchase the drive belt to replace it in order to save the cost. After replacement, it is found that the tooth shape of the drive belt is not consistent with that of the servo motor and the spindle, which will cause abnormal noise during use. It is suggested that customers should pay attention to whether the model of the purchased drive belt is the same as that of the removed worn belt. If different types of drive belts are used persistently, the abnormal noise of the belt in the transmission process will be caused, and even the gear wear of servo motor and spindle will be caused, resulting in serious consequences.

Vice clamp is installed on the working table of machining center

In fact, the installation method of vice clamp is very simple. Firstly, move the vice onto the workbench of the machining center, correct it to the pre-determined position, and then fix the locating block under the Vice Clamp in the T-groove of the working table of the machining center. This method is to prevent the vice clamp from deviated from the position corrected before the re cutting process, and also confirm the vice clamp position The parallelism and verticality of the fixture. This will allow the fixture to be installed.

Key points for installation of workpieces

Just after the vice clamp has been installed, then it will introduce how to install the workpiece on the clamp just now.

1. Before installing the workpiece, the parallelism and verticality of the workpiece shall be confirmed. If the parallelism and verticality are poor, the clamping force after the installation of the workpiece cannot be guaranteed.
2. It is necessary to ensure that the workpiece is installed in the middle of the clamp, and the clamping force of the clamp is consistent with the center of the workpiece, and there will be no offset.
3. Pay attention to not too hard when installing workpiece clamping, otherwise excessive force will cause deformation and poor machining accuracy.
4. The two used gasket must be of the same model. The same type of gasket referred to here is the same size and material of gasket. If the gasket is not the same type, the parallelism and verticality of the workpiece will be poor, which directly affects the processing accuracy of the workpiece.

1、 What is the vacuum sucker of CNC computer gong

Vacuum suction cup, also known as vacuum spreader, is one of vacuum equipment actuators. Generally speaking, it is the cheapest way to grab the product with vacuum sucker. There are various types of vacuum suction cups. Rubber suction cups can be operated at high temperature. The suction cups made of silicone rubber are very suitable for grasping products with rough surface, while those made of polyurethane are very durable. In addition, in the actual production, if the sucker is required to have oil resistance, polyurethane, nitrile rubber or polymer containing vinyl can be used to make sucker. Generally, in order to avoid scratches on the surface of the products, it is better to choose the suction cup with bellows made of nitrile rubber or silicone rubber. The material of suction cup is made of nitrile rubber, which has large breaking force, so it is widely used in various vacuum holding equipment.

2、 Vacuum sucker used in CNC computer gongs

The vacuum chuck plays the role of fixture in CNC machining center. Some workpieces require high surface smoothness, so they can’t use the fixture of common CNC computer gong. At this time, the vacuum chuck can be put into use. However, we seldom use rubber vacuum cups in CNC computer gongs. We use CNC vacuum cups more. The so-called CNC vacuum sucker is a kind of special vacuum suction cup with vacuum generator and switch. The suction principle is the same as rubber vacuum chuck, which creates a vacuum environment to make the suction cup press on the workpiece under atmospheric pressure, but CNC vacuum chuck is the only one The vacuum environment is produced by the vacuum generator. The rubber vacuum chuck is a simple vacuum component, while the CNC vacuum sucker is like a large plate.

CNC computer gongs usually use vacuum chuck because the workpiece has high requirements for surface smoothness, or when the fixture of CNC computer gong itself can not clamp the workpiece well, it is a relatively cheap special fixture in CNC machine tools