reduction of mechanical shock between parts by:
- modifying parts to prevent rattle and ringing;
- using an adjustable height collector (see Figure 10.5a) for parts falling into a bin, so
that impact speed and thus radiated noise is reduced;
- using an adjustable height conveyor and rubber flaps to minimise the fall height of
the parts (see Figure 10.5b);
- lining of tumbling barrels, parts collecting bins, metal chutes, hoppers, etc. with elastic
material, e.g. cork, hard rubber, plastic, conveyor belt material, with the choice of
material being as soft as possible but sufficiently hard to withstand the particular
operating environment without wearing out prematurely. In extreme cases, an effective
alternative is to line the chute or bin with a thin layer of viscoelastic material such as
silicone rubber or silastic, sandwiched between the bin and a second layer of steel or
other abrasion resistant material, with the latter layer being of similar thickness to the
wall of the bin or chute (see Figure 10.6);
- covering metal tables, metal wheels, etc. with a material, such as rubber;
- using conveyor belts instead of chutes to avoid noisy falls.