I. Products That Typically Require a Soundproof Enclosure
| Product Type / Characteristic | Reason for High Noise |
|---|---|
| Hard, heavy metal parts (e.g., steel screws, bolts, nuts, rivets, pins) | Metal‑to‑metal contact generates loud impact noise. |
| Small, rigid parts (e.g., bearings, small gears, machine components) | High‑frequency impacts produce sharp, irritating sounds. |
| High‑speed feeding applications (e.g., feeding at 300+ parts/min) | Faster bowl operation increases both vibration noise and part‑to‑part collision noise. |
| Large bowl with high amplitude (e.g., feeding parts > 50 mm) | Larger bowls and higher vibration energy produce louder mechanical noise. |
| Parts with sharp edges or rough surfaces (e.g., stamped metal parts, formed components) | Rough surfaces increase friction noise and part‑to‑part scraping. |
| Parts that tumble or bounce (e.g., disc‑shaped or irregular parts) | Parts that roll or fall over during feeding create additional impact noise. |
| Long or heavy parts (e.g., long pins, thick washers) | Heavier parts create more kinetic energy and louder impact when they strike the track or each other. |
II. When an Enclosure Is Almost Always Required
| Condition | Why |
|---|---|
| Operator station nearby | Exposure > 85 dBA for 8 hours is a health risk; enclosure protects workers. |
| Open workshop with multiple machines | Factory‑wide noise level must be controlled to avoid cumulative noise exposure. |
| Medical / pharmaceutical / cleanroom environment | Noise can be a disturbance and may affect operator concentration; enclosure also contains dust. |
| Office or laboratory attached to the production area | Noise must be kept below typical office noise limits (e.g., < 55–60 dBA). |
| Local noise regulations require ≤ 75–80 dBA at operator position | Enclosure is a simple and effective way to meet legal noise limits. |
| Night‑shift operation | Noise restrictions are often stricter at night. |
III. When an Enclosure May NOT Be Needed
| Condition | Why |
|---|---|
| Plastic or soft rubber parts | Lower impact noise due to softer material. |
| Very low speed (< 30 parts/min) | Low‑energy impact produces little noise. |
| Remote installation (bowl is far from operator, e.g., behind a wall or in a separate room) | Operator exposure is already low. |
| Small, lightweight parts (e.g., plastic clips, foam pieces) | Minimal collision noise. |
| Short production runs (e.g., 1–2 hours per day) | Exposure time is short; risk is lower. |
| Factory has no noise limit requirement | If no regulation exists, an enclosure is an optional extra. |
IV. Typical Noise Levels by Part Type
| Part Type | Typical Noise Level (Without Enclosure) | Enclosure Recommended? |
|---|---|---|
| Plastic caps (soft) | 70 – 80 dBA | Optional (usually not needed) |
| Aluminum screws / nuts | 75 – 85 dBA | Yes, if operator nearby |
| Steel screws / rivets | 85 – 95 dBA | Strongly recommended |
| Steel bearings / heavy pins | 90 – 100+ dBA | Required for most factory conditions |
| Glass / ceramic parts | 85 – 95 dBA | Required (also protects parts) |
| Rubber O‑rings / seals | 65 – 75 dBA | Usually not needed |
V. Summary Table
| Consideration | Action |
|---|---|
| Hard metal parts (steel, brass, stainless) | ✅ Highly recommended |
| High speed (> 200 parts/min) | ✅ Recommended |
| Operator works within 2 meters | ✅ Strongly recommended |
| Noise level measured > 85 dBA | ✅ Required (to meet safety standards) |
| Soft / plastic / rubber parts | ❌ Usually not needed |
| Low speed & remote location | ❌ Not needed |

