What Is a CNC Punch Press?
NC punch is an abbreviation of digital control punch, which is an automatic machine tool equipped with a program control system. The control system can logically process and decode a program specified by a control code or other symbolic instructions, thereby causing the punch to operate and process the part.
The operation and monitoring of the CNC punch are all done in this CNC unit, which is the brain of the CNC punch. Compared with ordinary punches, CNC punches have the following characteristics:
High processing accuracy and stable processing quality;
Large processing format: 1.5m * 5m processing format can be completed at one time;
Multi-coordinate linkage can be performed, and parts with complex shapes can be processed, such as shear forming;
When the processing parts are changed, generally only the NC program needs to be changed, which can save production preparation time;
The punch itself has high precision and rigidity, and can choose favorable processing amount and high productivity;
The high degree of automation of the punch can reduce the labor intensity;
Easy operation, with a certain basic computer knowledge training can be used in 2-3 days;
NC punch can be used for processing various metal sheet parts. It can automatically complete a variety of complex hole types and shallow stretch forming at one time. (Automatically process different shapes and holes with different sizes and pitches according to requirements. Small punches can also be used to step through. The punching method punches large round holes, square holes, waist holes, and curved contours of various shapes, and can also be processed by special processes, such as blinds, shallow stretching, countersinking, flanging holes, stiffeners, embossing, etc.) . Compared with traditional stamping, the simple mold combination saves a lot of mold costs. It can use low cost and short cycles to process small batches and diversified products, with a large processing range and processing capacity, so as to adapt to the market in a timely manner. With product changes.
Enter the programmed processing program into the CNC system. The specific operation method is:
X axis: servo drive axis that moves the workpiece perpendicular to the length of the bed
Y axis: servo drive axis that moves the workpiece parallel to the length of the bed
A axis: Rotary turret tool magazine selects the rotation axis of the mold
C axis: Rotation axis for automatic indexing of the mold, which can rotate the mold at any angle
1) Single punching: punching is completed in a single pass, including straight line distribution, circular arc distribution, circumferential distribution, and grid hole punching.
2) Continuous blanking in the same direction: The method of partially overlapping rectangular molds can be used to process long holes, trimming, etc.
3) Multi-directional continuous blanking: a processing method for processing large holes with a small die.
4) Cannibalization: a small round die is used to perform continuous punching arc processing in smaller steps.
5) Single-shot forming: a processing method of shallow stretch forming according to the shape of the mold.
6) Continuous forming: forming processing methods larger than the size of the mold, such as large-scale shutters, rolling ribs, rolling steps and other processing methods.
7) Array forming: processing multiple pieces of the same or different workpieces on a large plate.
General thick turret mold is generally classified according to the aperture size that the mold can process, which is convenient for the selection of the mold. Usually divided into A, B, C, D, E five gears.
A (1/2 ) station: processing range & Oslash; 1.6 & Oslash; 12.7mm
B (11/2 ) station: processing range & Oslash; 12.7 & Oslash; 31.7mm
C (2 ) station: processing range & Oslash; 31.7 & Oslash; 50.8mm
D (31/2 ) station: processing range & Oslash; 50.8 & Oslash; 88.9mm
E (41/2 ) station: processing range & Oslash; 88.9 & Oslash; 114.3mm
The puncher must learn independently, master the structure and performance of the equipment, be familiar with the operating procedures and obtain an operating permit before operating independently.
The safety protection and control devices on the equipment should be used correctly and must not be dismantled arbitrarily.
Check whether the transmission, connection, lubrication and other parts of the machine tool and the protective safety device are normal. The mold mounting screws must be firm and must not be moved.
Before working, the machine tool should be idle for 2-3 minutes. Check the flexibility of the control devices such as foot brakes, etc., and use it only after confirming that it is normal.
The mold must be tight and firm, the upper and lower molds are aligned to ensure the correct position, and the machine tool is tested and punched (empty car) by hand to ensure that the mold works in a good condition.
Pay attention to lubrication before driving and remove all floating items on the bed.
When the punch is moving or during the punching process, the operator should stand properly, and his hands and head should be kept a certain distance from the punch, and he should always pay attention to the action of the punch.
When punching or stamping short workpieces, special tools should not be used to directly feed or pick up parts by hand.
When punching or stamping long-body parts, a safety support rack or other safety measures should be set to avoid digging injuries.
When single punching, hands and feet are not allowed to be placed on the hand and foot brakes. You must move (step on) one time to prevent accidents.
When two or more people work together, the person who is responsible for moving (stepping) the brake must pay attention to the action of the feeder. It is strictly forbidden to take the part while moving (stepping) the brake.
Stop at the end of the work in time, cut off the power, wipe the machine, and clean up the environment.
To ensure the safety of people and equipment and prevent production accidents, please observe the following safety rules.
1. Please set up a safety warning sign near the CNC punch.
2. Please set up a partition around the CNC punch to form a working area.
During the work of the equipment, there are moving parts out of the platform. If anyone accidentally passes, the platform may be damaged. If a partition is set up around the equipment, the work area is enclosed, and the operator operates in a safe area, the production accidents can be reduced.
3. CNC punches must be managed and operated by a person (trained and qualified).
4. This equipment can only process certain plates. Do not process plates beyond the capabilities of the equipment to prevent damage to the CNC punch.
5. Before the CNC punch press starts to operate, please check the equipment, the punch and the die and other components to ensure that the components meet the normal operating conditions of the equipment.
6. Without the permission of the CNC punch manufacturer, please do not make any modification to this equipment to avoid damage to the equipment and potential safety hazards.
According to the punching shape and material thickness, the punching force required for punching can be calculated. The following is the calculation method of punching force for punching without oblique cutting edge:
Punching force (kN) = perimeter of punching core (mm) × sheet thickness (mm) × shear strength of material (kN / m)
Converted to metric tons: kN ÷ 9.81
Note: Punch perimeter -refers to the sum of the side lengths of any shape
Sheet thickness -refers to the thickness of the sheet to be punched through by the punch
Shear strength of the material -the physical properties of the board are determined by the material of the board.
The shear strength of common materials is as follows:
material | Shear strength |
Aluminum (5052H32) | 0.1724 |
brass | 0.2413 |
Low-carbon steel | 0.3447 |
stainless steel | 0.5171 |
For example:
Punching a 2mm thick cold plate with a shape of 25 and calculating the punching force
Punch perimeter = 3.14 × 25 = 78.5mm
Material thickness = 2mm
Shear strength = 0.3447 kN / m
Punching force = 78.5 × 2 × 0.3447 = 54.1179 kN
54.1179 kN ÷ 9.81 = 5.52 metric tons
Clearance of mold
The gap between the upper die and the lower die is expressed by the total difference. For example: when using the upper die of 12 and the lower die of 12.25, the clearance is 0.25mm. This gap is one of the most important factors in punching. If the gap is not selected properly, the life of the mold will be shortened, or burrs will appear, causing secondary shearing, etc., making the shape of the cut irregular, and the demolding force increasing. Therefore, it is very important to choose the gap correctly. The gap is affected by the material. Generally, 10-20% of the plate thickness of carbon steel is the best. If there is no special requirement for the CNC turret punch, you can select it according to the following table:
gap Plate thickness | material |
Carbon steel | aluminum | stainless steel |
0.8-1.6 | 0.15-0.2 | 0.15-0.2 | 0.15-0.3 |
1.6-2.3 | 0.2-0.3 | 0.2-0.3 | 0.3-0.4 |
2.3-3.2 | 0.3-0.4 | 0.3-0.4 | 0.4-0.6 |
3.2-4.5 | 0.4-0.6 | 0.4-0.5 | 0.6-1.0 |
4.5-6.0 | 0.6-0.9 | 0.5-0.7 | |
Pneumatic clamp of CNC punching machine is one of the important reasons that affect the accuracy of machining parts. After long-term use of the upper clamp body and the left and right guide arms of the pneumatic clamp, the upper clamp body is controlled to sway within 0.05 mm after being stressed from left to right. When the upper jaw body also has a large deflection after it is stressed in the front-rear direction, the gap should be reduced by adjusting the T-axis. The deflection should be controlled within 0.03-0.05mm. Due to the design of the pneumatic clamp of the CNC punching machine based on the floating principle, the upper clamp body should be able to float up and down after the gap is adjusted. If the tooth plate in the clamp is loose, the tooth plate coupling screw should be tightened. If the tooth surface of the tooth plate in the CNC punch pneumatic clamp is smooth, the tooth plate should be replaced.
Testing and adjustment of lubricating oil output and pressure detection function. The air filter, oiler adjustment valve and other functions and moisture impurity test check and necessary adjustment. 3. Air pressure switch set value check and pressure detection function test and adjustment. Check the set value of the height indicator switch and check the measured value. With adjustments. Check the sprocket, chain, transmission shaft, worm gear and other parts of the mold height adjustment device for looseness, abnormality and chain tension check. With adjustments. Remove the top cover of the gearbox, check the internal parts for wear and loose key positions and clean the oil tank, renew the lubricant NC turret punch press, and check the operating conditions, noise and vibration testing. Drive Train
Test the oil output and pressure of the oil injection points of various parts of the system. With adjustments. Testing point inspection of piston action, brake angle, brake clearance, and consumption of meters. With necessary adjustments.
Sliding rail with
According to the frequency of failure of CNC punches, the entire service life of CNC punches can be roughly divided into three phases, namely the initial use failure period, the relatively stable operation period and the end of life.
Failure period of initial use of CNC punch
After the whole machine is installed and debugged, the fault frequency is relatively high during the period of half a year to one year from the start of operation.
From a mechanical point of view, during this period, although the host machine has undergone trial production run-in, due to the micro and macro geometrical deviations of the machining surface of the part, the surface is still rough before the run-in is complete; the part is in assembly There is also a form and position error, which may cause a large running-in wear during the initial use of the machine tool, causing an excessive gap between the machine's relative moving parts. In addition, because the internal stress of the new concrete foundation has not been balanced and stabilized, some precision deviations have also occurred in the machine tool. From an electrical point of view, the CNC machine tool control system and execution components use a large number of electronic and electrical devices. Although these components and devices have been strictly screened and tested in the manufacturing plant, in actual operation, due to the alternating load and circuit, The instantaneous "surge" current and back-EMF impact during opening and closing make some components not able to withstand the initial impact, and fail due to current or voltage breakdown, causing the entire equipment to malfunction. Generally speaking, during this period, the failure rates of electrical, hydraulic and pneumatic systems are relatively high. To this end, it is necessary to strengthen the monitoring of machine tools and make regular electromechanical adjustments of machine tools to ensure that various operating parameters of the equipment are within technical specifications.
Relatively stable operation period of CNC punch
The equipment has experienced the aging of various electrical components in the initial stage, and after the grinding and adjustment of mechanical parts, it has entered a relatively stable normal operating period. At this time, the failure of various types of components is relatively rare, but it does not rule out incidental The occurrence of faults, so during this period, we must keep a good record of equipment operation for reference when troubleshooting. At the same time, we must insist on comprehensive mechanical and electrical testing and verification of the equipment every 6 months. During this period, the incidence of electromechanical failures is small and most can be ruled out. Relatively stable operation period is longer, generally 7 ~ 10 years.
End of life of CNC punch
After the machine enters the end of its life, various components begin to accelerate wear and aging, and the failure rate starts to increase year by year. The nature of the fault is gradual and organic. For example, the aging of rubber parts, the wear of bushings and hydraulic cylinders, the limit sensitivity of limit switches, and the quality factors of some electronic components have begun to decline. Equipment operation records, most of the failures can be eliminated. Since the CNC punch is a technology-intensive and knowledge-intensive device, there are both conventional methods and special methods and special technical and testing methods for its maintenance and discretion. In fault diagnosis, it is often not possible to consider mechanical or electrical aspects, but comprehensive analysis must be performed. [1]
