CNC Technology – Page 84 – CNC Machining & Turning, Milling, Metal parts

The gantry milling machine has enough rigidity

The gantry milling machine is suitable for milling the horizontal plane, vertical plane or inclined plane groove of large and medium-sized ferrous metal or non-ferrous metal parts on various machines, milling and boring head, boring and drilling as well as various improvements according to the needs of users, and undertaking various processing and manufacturing at the same time.

The gantry milling machine has the characteristics of enough rigidity, high efficiency, convenient operation, simple structure and comprehensive performance.

The main drive of gantry milling machine adopts switched reluctance motor (planer and milling dual-purpose gearbox) with stepless speed regulation. Its wide speed regulation range can meet various speed requirements of planer and milling. It can process horizontal plane, vertical plane, inclined plane, T-groove, circular arc groove, guide rail combination surface and rack of various materials

1. The advanced super audio frequency quenching technology makes the service life of the machine tool longer.

2. The column and crossbeam separate feeding system makes the operation more convenient and quick.

3. Independent oil pump lubrication system makes all kinds of work more smoothly.

4. All castings are aging and vibration aging treatment, so that the machine tool is more stable and durable, and the accuracy is more durable.

The principle of fast clamp

This kind of quick clamp is designed according to the mechanical principle of the double rocker mechanism in the plane four-bar mechanism, and its basic structure is composed of four components, such as connecting rod, frame and two connecting frame rods.

When the two hinge points of connecting rod and connecting rod and one hinge point of connecting rod and frame are in the same straight line, the mechanism is in the dead point position. At this time, no matter how much reaction force (except destructive reaction force) is exerted on the compacted workpiece, the indenter can not be loosened, which is the dead point clamping principle in mechanical mechanics.

In order to avoid the influence of external force load change and mechanical vibration in use, the middle hinged joint shall be slightly inclined to the inner side of the other two hinged joint wires during design, so as to ensure that the clamp mechanism is always locked in a stable state without loosening under the condition of maximum central tightening force.

Central nervous system

The central tightening force refers to the maximum pressing force of the ram on the workpiece when the fixture is in the locked position without mechanical deformation. This pressing force is generated when the ram is raised to the nearest position from the mounting base on the force arm.

The pressure of the indenter to the workpiece is not constant, it changes with the different position of the indenter on the force arm. When it is far away from the mounting base, the clamping force decreases.

Characteristic

Simple structure and installation.

The clamped workpiece can be loaded and unloaded quickly and operated conveniently.

All parts are electroplated and antirust, and the surface is clean and beautiful.

The key parts of the fixture for heavy load have been heat treated to have high strength and wear resistance.

Matching requirements of automatic parts processing punch

According to different stamping materials, the design of stamping die is different, which is basically through multi-step stamping to complete a product or semi-finished work. Different steps require different shapes and specifications of cemented carbide punches, which is designed to match the special punches of the stamping die for customized production. According to different shapes and uses, the special-shaped carbide punching needles can be divided into:

Guide punch is also called guide punch for short. According to the needs of the press, there can be various shapes, such as type A, type B, type Hb, type TAPP, type TP, etc.

It’s also called mother and child punch. It’s called mother and child punch for short. There is a small protrusion at the top of the punch. I don’t know the origin of the name, maybe it’s because of the protrusion at the top of the punch. The letter punching needle can be divided into standard A-type JS * * type and other models.

There are teeth drawing punch, inspection tip, hexagonal punch, elliptical punch, forming punch, fan punch, special punch, high-speed steel punch, tungsten steel punch, etc.

The key point of cemented carbide punching pin customization is to design the accuracy and consistency of products, and its physical parameters are as follows:

1. CO content: 10% – 20%. 2. Density g / cm3: 14.0-14.5.

3. Hardness: 87-92.0hra. 4. Grain size: 0.6-1.2um.

5. Bending strength: 4000mpa. 6. Elastic modulus GPA: 490.

7, coefficient of thermal expansion 10-6 / 0C: 5.4. 8. The external dimension specification of cemented carbide punch is customized according to the drawing, and the accuracy requirement is ± 0.002.

The precision of carbide punching needle used in high-precision die matching is very high, and the consistency of products is also required. Every punching needle in batch production must be strictly in accordance with the requirements of dimensional accuracy tolerance, so as to maximize the service life of die. The consistency of products is a key factor for the use of carbide punching pins as a complete set of precision dies, which will directly affect the service life of dies and the dimensional accuracy of products.

The stamping die work is continuous operation, so the service life requirement of the hedging needle becomes the focus. According to the material and thickness of the stamping, different alloy materials should be selected for the hard alloy punching needle. Generally, the thicker the product is, the lower the hardness and the better the toughness of the hard alloy should be selected. The harder the material is, the harder the cemented carbide is, the lower the hardness is. This can effectively avoid the punching needle being missed. For the punching of thin plates, or those with low hardness, the carbide punching needle can be used with higher hardness for hole processing of this product, so as to improve the service life of the punching needle.

In addition to the selection of cemented carbide materials, one of the important factors affecting the quality and service life of the punching needle is whether the gap between the cold dies is even. In the process of hard alloy punching pin assembly, it is necessary to ensure that the gap between the convex die and the concave die is the same. In order to ensure that the gap between the punch and the die is even, the position of one piece (punch or die) must be determined first according to the drawing requirements, and then the accurate position of the other piece can be determined by aligning the gap based on this piece. Some stamping dies are equipped with many hard alloy punches at one time, which requires the scientificity and rationality of die design.

There are several ways to control the gap between punch and die to be uniform when assembling punching pin:

1. Light transmission method: place and install the upper mold and the lower mold, irradiate with light or flashlight, and observe the light transmission in the blanking hole of the lower mold.

2. Gasket method: for copper or paper pieces with uniform thickness around the edge of the die and thickness equal to the unilateral gap between the punch and the die, insert the punch into the corresponding hole of the die, observe the tightness between the punch and the gasket, and gently tap the fixing plate with a hammer to make the tightness between the punch and the gasket consistent. After proper adjustment, fasten the upper die.

Advantages of precision metal processing

1. CNC machining precision of precision metal shaft is high, with stable machining quality;

2. It can carry out multi coordinate linkage and process parts with complex shapes;

3. When the precision hardware CNC machining parts are changed, generally only the NC program needs to be changed, which can save the production preparation time;

4. The machine tool itself has high precision and rigidity, so it can choose favorable processing amount and high productivity (generally 3-5 times that of ordinary machine tools);

5. The machine tool has a high degree of automation, which can reduce the labor intensity;

CNC precision machining uses short cutting tools, which is the main feature of precision hardware parts. The short cutting tool will obviously reduce the deviation of cutting tool, so as to obtain good surface quality, avoid rework, reduce the usage of welding rod, and shorten the processing time of EDM. When considering the five axis machining, the goal of using the five axis machining die must be considered: to finish the machining of the whole workpiece with the shortest cutting tool possible, including reducing the programming, clamping and machining time, but also to get a more perfect surface quality.

What should be paid attention to before CNC machining

1、 CNC precision machining machine maintenance

1. Clean and maintain the machine tool half an hour before going to work every day. If the air gun or oil gun is used to clean the chips, there must be a knife on the spindle.

2. It is forbidden to use air gun or oil gun to blow the taper hole of the main shaft, so as to avoid the small particles such as chips being blown into the main shaft hole and affecting the cleanliness of the main shaft.

3. Check whether the lubricating machine works normally and whether the lubricating oil is sufficient. Start the machine in normal order.

4. Before the machine tool is put into operation, start the spindle (speed is 501r / M) to preheat the spindle.

2、 CNC precision machining machine operation

1. Before operation, confirm the model, size and machining allowance of the workblank according to the program sheet, and sand and polish the workblank.

2. Confirm the placement position of the workpiece and the processing sequence after the machine is put on, and complete the comparison action

3. If it is necessary to “split the middle bar” during split, the rotating speed is 501r / m. if it is necessary to split the middle bar with a knife, the rotating speed depends on the cutter. In this process, it should also be noted that the data must be taken at the same height to ensure the accuracy of split. After split, it can be inspected with “G0 g54 x0 Y0”

4. Before formal processing, recheck and confirm whether the placement position and access of workpieces are correct

3、 Precautions for CNC precision machining

1. Before each process, it is necessary to strictly confirm whether the upper tool is consistent with the program

2. It is necessary to confirm the length of the tool and whether the selected clamping head is suitable when installing the tool

3. In the same workpiece, each tool setting should be kept in the same area to ensure the accuracy of tool receiving

4. Try to blow with air in the opening procedure, and spray oil in the smooth knife procedure

5. Clean up the aluminum slag in the machine tool before oil injection of the smooth knife to prevent oil absorption of the aluminum slag

6. During the self operation of CNC precision machining, the operator shall not leave the machine tool or check the operation condition of the machine tool regularly. If it is necessary to leave in the middle of the process, relevant personnel must be appointed to check

7. If too much machining allowance is found during machining, it is necessary to use “single section” or “pause” to clear x, y and Z values, then manually mill them out and then swing them back to “zero” for self operation

8. In case of knife impact during machining, the operator must stop the machine immediately, such as pressing the “emergency stop” button or “reset” button or setting the “feed rate” to zero, etc

9. Do not open the door to avoid flying knife or workpiece during the operation of the machine tool

10. The workpiece shall be cleaned and deburred in time after dismounting

11. At the end of work, the operator must make timely and accurate handover to ensure the normal follow-up processing

12. Before shutdown, make sure the tool magazine is in the original position and the XYZ axis is in the center position. Turn off the power supply and the main power supply on the operation panel of the machine tool in turn

13. In case of severe thunderstorm, the power must be cut off and the work must be stopped immediately

What are the processing methods of Automatic Parts

Stamping: the pre manufactured die is used for cold stamping with punch, and the focus is on sheet metal processing, that is, most of the processed materials are sheet metal, and the processing efficiency is compared with high and appropriate mass production.

The process flow of automatic parts is divided into engineering die and continuous die, which is also called single punch die. Some complex parts are compared with several sets of dies, while the continuous die divides the product form into several parts in a mold in the mold cavity, so that one stroke of punch machining is a molding article. High speed continuous press can process 340 products per minute.

Lathe: the lathe for the processing of fine parts belongs to the fine processing machinery, which is divided into ordinary lathe, automatic lathe, instrument lathe and computer lathe. After the material is clamped, it can rotate and be processed radially or axially by turning tool.

Now the use of automatic lathe and computer lathe is more and more ordinary. Because both of them are fully automatic machining, the precision deviation caused by manual operation is reduced to the lowest point, and the machining speed is fast, which is used for mass production. Now most of the computer lathes are equipped with side turning tools and back turning tools, that is to say, milling can also be carried out on the lathe.