Enclosure and acoustic damping
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Purpose
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- Reduce airborne noise emissions
- Contain flood coolant
- Provide operator protection
- Do not participate in the mechanical force loop

Enclosure construction
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- Fully enclosed machine housing
- Construction from outside to inside:

  - MDF outer panels (mass)
  - automotive interior acoustic foam
  - thin inner sheet-metal liner

Inner liner
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- Sheet metal sealed against coolant ingress
- Acts as washable and durable inner surface
- Treated with viscoelastic damping tape (e.g. 3M)
- Purpose:

  - suppress panel ringing
  - reduce tonal noise radiation

Acoustic strategy
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- Mass-spring-mass principle:

  - MDF (mass)
  - foam (spring / absorber)
  - sheet metal (inner mass)
- Avoidance of large undamped flat panels
- No reliance on active noise cancellation

Mechanical integration
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- Enclosure mechanically decoupled from machine frame where possible
- Enclosure does not contribute to stiffness or damping of the force loop
- Enclosure panels removable for service

Openings and airflow
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- Openings minimized
- Any required airflow paths:

  - acoustically baffled
  - not line-of-sight for noise propagation

Design constraints
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- Enclosure designed for apartment-compatible operation
- Noise reduction prioritized over cosmetic appearance