How to Reduce Punch Press Noise by Controlling Air Pressure

The ear is a sensitive instrument that is easily damaged by high decibel noise.

Noise pollution is a common concern when operating a punch press. It can disturb neighbors, if the facility is near a residential area. More important, the high decibel noise can cause significant hearing impairment for the operator. Older machines can expose punch press operators to over 100 decibels of sound. To prevent this, constraints on air pressure and other measures should be implemented.

Things You'll Need

• Sound level meter
• Rubber pads
• Punch press jet nozzles
• Thick cardboard sheets
• Polyurethane foam

Instructions

1. 

   Measure decibels to see how much noise reduction is needed.

   Measure the decibel output of the punch press with a sound level meter. The meter should be set at the operator's work station, to accurately reflect the level of exposure. Punch presses that subject their operators to less than 90 decibels require personal hearing protectors. But if levels are over 90 decibels, further measures must be employed to protect the operator's hearing, in compliance with the Noise at Work Regulations of 1989.

2. 

   The vibration of steel plates is limited by rubber.

   Mount the punch press onto thick rubber pads. The vibration of steel plates results in a high decibel output. The rubber pads will quell the vibration and extend the life of your punch press. Pads should be installed between the press frame and the legs. The anti-vibration mountings should be inspected routinely for wear and tear. Damaged pads should be replaced to keep noise reduction at optimal levels. When combined with self-adhesive damping sheets, anti-vibration mounting can reduce punch press noise by nine decibels.

3. 

   Lower air pressure to reduce noise.

   Reduce the pressure of air ejection by installing multiple jet nozzles. A single exhaust point will have higher air pressure than multiple exhaust points. High air pressure causes high-decibel noise when expelled from the press. An American Industrial Hygiene Association study demonstrated an eight decibel drop when air ejection was replaced by mechanical ejection. Jet nozzles should be wide and short, to quickly diffuse air pressure. Damping materials can be applied to the chutes for more effective noise reduction.

4. 

   The polyurethane foam will act as a buffer between the press and its operator.

   Install an acoustically insulated shield between the air expulsion system and the operator. Construct the shield out of several sheets of thick cardboard. Line the cardboard with a thick, heavy coat of polyurethane foam. The shield can be plated with steel to heighten its durability, but the steel will have little to no impact on noise reduction. If possible, you can enclose most of the machine with acoustic insulation. Leave ample room for feed material, operator access to the controls and air expulsion.

References

• Center for Disease Control and Prevention- National Institute for Occupational Safety and Health; Combination of Treatments
• Health and Safety Executive: Reducing Noise from CNC Punch Presses; 2002
• Department of the Air Force: Engineering Noise Control
• UNSW School of Physics: What is a Decibel?
• Ysxbcn.com: Noise Reduction of Punch Press Mechanical Clutch Engagement