1.How is the noise level during stamping/punching/shearing?
Process: Steel sheets are cut, punched, and blanked using molds and immense pressure.
Noise Sources:
Material Fracture Moment: This is the primary and sharpest noise source, a high-frequency pulse noise generated by the rapid tearing of the metal lattice. Sound pressure levels easily exceed 100 dB, with peak values reaching 110-120 dB or higher (similar to gunshots or thunderstorms). Thicker plates are louder than thinner plates.
Die Impact: Rigid collision between the upper and lower dies.
Characteristics: Short, sharp, and high-intensity. This is the most typical noise hazard source in cold-rolled coil processing.
2.How noisy is plasma cutting?
Noise sources: The high-temperature, high-speed jet generated by the plasma arc, and the high-speed ejection of compressed air/gas. This produces high-frequency hissing and whistling sounds, and the overall sound pressure level is also very high, but the frequency characteristics are different from those of ramjet.
3.How much noise does the roll forming/bending process generate?
Process: The sheet metal is continuously bent into a specific shape using multiple sets of rollers or bending machines.
Noise Source: Primarily, the low-frequency, muffled "rumbling" or "squeaking" sound emitted by the metal during plastic deformation near its yield point. The noise is continuous and relatively low-frequency, but prolonged exposure is still harmful. Poor lubrication will increase frictional noise.
4.What are the key influencing factors?
Material thickness and strength: Thicker and stronger steel plates (such as high-strength steel) require more energy to process, and release more energy when fractured or deformed, resulting in louder noise.
Processing speed and precision: High-speed stamping and shearing generate significantly more noise than low-speed precision forming.
Equipment condition and mold design: Old, poorly maintained equipment, unreasonable mold clearances, and dulled cutting edges all significantly increase noise.
Environment and noise reduction measures: Whether the workshop is open, whether it has soundproof enclosures, and whether the equipment has vibration-damping foundations have a significant impact.
5.What are the necessary protective measures?
Engineering Controls (Preferred):
Equipment Soundproof Enclosures: Install fully or semi-enclosed soundproof enclosures for punch presses, shearing machines, etc.
Sound Absorbing Materials: Lay sound-absorbing cotton and panels on workshop walls and ceilings.
Vibration Damping Foundation: Prevent equipment vibrations from amplifying noise through the ground.
Process Alternatives: Where possible, replace some punching with laser cutting and some impact forming with hydraulic bending.
Management Controls:
Area Isolation: Concentrate high-noise equipment in a separate area and install soundproof walls.
Work Hour Restrictions: Reduce the continuous exposure time of employees in high-noise environments and implement job rotation.
Equipment Maintenance: Maintain good lubrication of equipment and replace dull cutting tools and dies promptly.
Personal Protective Equipment (Last Line of Defense, but Mandatory):
Mandatory Wearing: In high-noise areas (typically >85dB), employees must be provided with qualified noise-canceling earplugs or earmuffs, and their proper wearing must be supervised.