Therapy Chair Part Castings

This casting functions as a connection, mechanical support, and mounting component within a therapy chair—likely a bracket or pivot element for an adjustable arm or positioning mechanism. Compared to dental chair parts that primarily face the patient and carry strict aesthetic requirements, therapy chair structural components must balance appearance quality with load-bearing capability, supporting repeated patient interaction cycles across the chair's adjustable range while maintaining dimensional stability at the mounting interfaces.

The 147 × 82mm footprint with only 36.4mm depth means the part is predominantly planar, but the multiple functional openings, grooves, and connection features described in the brief create undercuts and directional conflicts that a simple two-part mold cannot release cleanly. Side actions or lifters are needed for features that run perpendicular to the main mold opening direction, and their alignment directly affects parting line quality on the appearance surfaces where coating particle standards (≤0.3mm, ≤2 in number) apply.

ADC12 provides adequate yield strength and rigidity for a structural bracket subject to repeated mechanical loads from chair adjustment, while its aluminum base offers inherent corrosion resistance in the disinfectant-heavy environment of medical facilities. The powder coating adds a further barrier layer, and together they meet the 240-hour neutral salt spray requirement. ADC12's good machinability also allows the ±0.1mm tolerance on mounting holes to be achieved reliably through CNC machining after casting.

Vibratory finishing uniformly smooths all surfaces, edges, and internal corners simultaneously—including recessed features that manual polishing cannot reach consistently. For a part with strict powder coating appearance standards (particles ≤0.3mm), surface preparation quality directly determines coating uniformity: rough or sharp edges accumulate excess powder and create lumps, while smooth, radius-edged surfaces allow even film build. Vibratory finishing also removes any residual burrs from drilling and reaming that could compromise the coating adhesion.

Both parts share the same application context (medical chair components), material (ADC12), appearance standards, and functional requirements (connection, support, mounting with precision holes). The process sequence—HPDC, deburring, drilling, reaming, vibratory finishing, powder coating—is the established optimal flow for this class of medical equipment castings: each step builds on the previous to achieve the required combination of dimensional precision, hole accuracy, surface smoothness, and coating quality. Standardizing the process across similar parts also improves consistency and reduces setup variation between production runs.