Vibration welding noise

[Iank]

I'm working with a client who is developing a vibration welding machine (joining thermoplastics) that should have much lower noise level than currently available equipment.

Is the noise level of these machines currently a problem?
What is it now (dba) and what would you like it to be?

 

[MachineTooler]

About 15 years ago I worked for an industry leader in the ultrasonic (20 & 40 kHz) and "vibration" (60 & 120 Hz) welding field.

Customer reaction seemed to be pretty much, "If it's okay with OSHA, it's okay with me.", whether for ultrasonic or vibration welding.

If I remember correctly, the peaks of the vibration welding were in the high 80 dbA to mid 90 dbA range.

The low frequency "welding" was an even longer cycle time than the ultrasonic (see below), and with longer weld times (as I'm sure you know). We typically had a machine cycle time of about 1.0 minute with a weld and hold time included in that. It did not have a problem from an OSHA defined dose point of view (see note below on ultrasonic welding), but notably, the low frequencies generated, and their harmonics, were more difficult to reduce. Of concern was the possibility of peaks that would require hearing protection (under OSHA guidelines), but we never saw any such peaks.

At that time, while noisy, the ultrasonic applications were generally a low "dose" by OSHA standards since the machine cycle was about three a minute (20 seconds) for ultrasonic with a typical duration of "weld" time of 0.2-0.5 seconds. This low dose was confirmed when we did an investigation for a major hand tool manufacturer because of our differing interpretations. We hired a consultant who was on the board of, and a contributer to, the NMTBA board and wrote the noise control section of their guide and he confirmed a dose far below the OSHA standard for personal protection.

Good luck, Dave (the Machine Tooler)

 

[chicopee]

IT IS NOT ONLY THE INTENSITY THAT YOU HAVE CONSIDER BUT ALSO THE DURATION OF EXPOSURE. EVERY 5 DB INCREASE OR DECREASE WILL EITHER HALF OR DOUBLE THE ALLOWABLE EXPOSURE TIME PER OSHA NOISE STANDARD.