How to control the punch noise？
Punch noise has a great harm to the operation of the machine and health of operators. Let’s see how to control the noise of the punch press. The following is noise control measures for punch presses.
(1) the sound sources
A. The punch itself
The sound source control is the fundamental measure to reduce the noise of punch press. Richards from The UK applied the theoretical research on impact noise to the punch press, which could reduce the noise by 30dBA. The basic theory is that the acceleration noise is equal to half the kinetic energy of an equal volume of air driven by the hammer in motion.
When CTO/VO increases from 1 to 10, the noise level can be reduced by about 30dBA. C is the speed of sound, and TO is the time when hammer motion stops. VO is the motion speed of hammer hitting billet. Such a large reduction in noise would be difficult to achieve in any other way. IN the late 1970s, a new type of hydraulic servo punch press appeared in the world. The punch can work according to the predetermined movement rules, which greatly reduces the noise of the punch press.
There is an essential fit clearance between each transmission part of the punch press and the structure. Such as the crankshaft connecting rod slowing down the backflush device. Reform of the existing traditional process design is not easy for the factory punch; the fundamental way is to reform the impact process of the punch. There are many technical measures for noise reduction of punch press, which are still in the stage of experimental research, and it will take a long time for them to be fully mature and fully popularized.
B. Reduce mold noise
Die designers often overlooked the noise . Reasonable selection of the fit clearance of the concave and convex mold can reduce the noise by 5dBA, change the convex geometry, and replace the flat die with the stair die and inclined die, also reduce the noise by 5-10dba or so. Because the geometry of the workpiece is sometimes very complex, it brings some difficulties to mold processing. In addition, there are additional buffer in the mold and reduce the unloading noise and other measures.
(2) Noise control of propagation path
To control the harm of punch noise to human body, to take control measures in the way of transmission, the technical innovation is relatively mature, and can obtain certain effect.
A. Sound absorption and noise reduction
The purpose of sound absorption is to weaken the reflected sound in the workshop. It generally reduce noise of about 6dBA.
B. Local sound insulation
Adopting sound insulation screen and mold area sound insulation cover with sound absorption can reduce noise of 8dBA.
C. Fully enclosed acoustic enclosure
The noise reduction effect of the fully closed sound shield is about 20dBA. Cover body can be assembled type, generally occupies a large area.
The control punch noise is eliminated in the transmission path, but it is simple and easy to operate, and can receive better noise reduction effect, so it is more used. People need to pay attention to operation, maintenance and other problems during application. Although the noise problem of the machine tool itself cannot be solved immediately, there are still many control measures available to the unit using the punch. It is not very difficult to solve the damage of punch noise, the key is to see the importance of the leadership.
