How To Reduce Punching Machine Noise?

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A punch is a punching press. In national production, the stamping process saves materials and energy compared with traditional machining, has high efficiency, does not require high technical requirements for operators, and can make products that cannot be achieved by machining through various mold applications. Its uses are getting wider and wider.

Stamping production is mainly for sheets. Through the die, blanking, punching, forming, deep drawing, trimming, fine blanking, shaping, riveting and extrusion parts can be made, which are widely used in various fields. Such as the switches and sockets we use, cups, cupboards, dishes, computer cases, and even missile aircraft... There are many accessories that can be produced by punching through molds.

Working Principle：

The design principle of the punch press is to convert circular motion into linear motion. The main motor outputs power to drive the flywheel, and the clutch drives the gear, crankshaft (or eccentric gear), connecting rod, etc. to operate to achieve the linear motion of the slider, from the main motor to The movement of the connecting rod is a circular motion.

Between the connecting rod and the slider, there needs to be a transition point for circular motion and linear motion. There are roughly two types of mechanisms in its design, one is a ball type and the other is a pin type (cylindrical type), through which the circular motion is moved. Converted to linear motion of the slider. The punch presses the material to plastically deform it to obtain the required shape and precision. Therefore, it must cooperate with a set of molds (the upper mold and the lower mold), place the material in between, and apply pressure by the machine to deform it. , The reaction force caused by the force applied to the material during processing is absorbed by the punching machine body.

Among the mechanical equipment, the punch press is very common processing equipment, and its noise is very prominent. The noise of the punch press shop is generally as high as 90-110 dB(A), which causes great harm to the workshop workers and also has a bad impact on the surrounding acoustic environment.

Punch Noise Control Measures:

1.Sound source noise reduction, the fundamental measure of punch noise reduction lies in sound source control.

● Noise reduction of the punch itself: When selecting equipment, try to choose punch equipment with relatively low noise when the cost allows.

● Reduce mold noise: Die designers often ignore the consideration of noise. Reasonable selection of the matching clearance of the concave and convex dies can achieve noise reduction of 5dBA, changing the convex geometry, and replacing the flat die with stepped dies and oblique blade dies, can also reduce noise by about 5-10dBA. However, because the geometry of the workpiece is sometimes very complicated, it brings certain difficulties to mold processing. In addition, there are measures such as adding buffers in the mold and reducing the noise of unloading.

● Eliminate the noise of the working mechanism:

The crank-slider type transmission mechanism is commonly used in mechanical punches. To reduce the clearance, the bearing should be installed according to the specified requirements, and the fitting clearance of the assembly should be appropriate. The clearance is increased due to movement, and lubricating oil with higher viscosity can be used at the bearing to increase the damping and reduce the no-load noise of the punch.

● Improve the punch structure:

The series of open double-column fixed table punches and the series of open double-leg tilting punches are changed to friction clutches. The transmission system of the punch is mostly driven by spur gears. When the gears of the punch have meshed, there will be a sound. If the helical or herringbone gear transmission is used, this frictional noise can be basically eliminated.

● Improve the mold structure:

The inclined die is used instead of the flat die, and the inclined surface of the knife-edge is used to gradually separate the sheet material, thereby delaying the punching time and achieving a certain noise reduction effect. The noise reduction is related to the shearing angle. The larger the shearing angle is, the longer the punching time is, and the lower the noise level is correspondingly larger. It is the relationship between the shearing angle and the amount of noise reduction. ° ~ 10 ° is appropriate.

● Set up sound-absorbing and vibration-damping devices

The flywheel of the punch press and its transmission system plus a cover are enclosed, which can significantly reduce the noise of the transmission part. For motors with high power and high noise, a partial sound insulation cover or a closed sound insulation cover should also be configured. At the lower part of the punch block or outside the mold working area, install a movable protective grille or a soundproof cover. If a soundproof cover is installed outside the mold, and the inner wall of the cover is pasted with sound-absorbing material, the noise reduction effect is more obvious.

2. Propagation Path Noise Control:

To control the harm of punching machine noise to the human body, control measures are taken in the transmission route, and the technological innovation is relatively mature, and certain effects can be achieved.

● Sound absorption and noise reduction: The sound absorption treatment is done by hanging space sound absorption body or wall, the purpose is to reduce the noise reflection sound in the workshop, and the noise reduction effect can generally be reduced by about 6dB(A).

● Partial sound insulation: The sound insulation screen with sound absorption is used to protect the key affected areas so that the area can have a noise reduction effect of about 8 dB(A).

● Fully enclosed sound insulation cover: The fully enclosed sound insulation cover can have a noise reduction effect of about 15-25 dB(A) and is especially suitable for high-speed continuous punching machines. The cover body can be assembled and installed with air intake and exhaust mufflers for ventilation and heat dissipation to ensure heat dissipation inside the cover. At the same time, for the convenience of operation and maintenance, multiple electric or manual sound insulation doors and sound insulation observation windows for easy observation are installed.

3. Use of Noise Dampening Materials

●Install Soundproofing Mats: Place mats or pads under the machine to absorb vibrations.

●Apply Acoustic Enclosures: Use soundproof enclosures around the machine to contain noise.

●Install Sound-Absorbing Panels: Attach panels to walls and ceilings around the machine to absorb and reduce noise levels.

●Use Low-Noise Tools: Opt for punching tools designed to produce less noise.

●Modify Punching Parameters: Adjust the punching speed and force to levels that minimize noise without compromising performance.

●Install Noise Reduction Covers: Use covers or shields specifically designed to reduce noise from punching operations.