PIAD Precision Casting Corp.,
Greensburg, Pennsylvania
Component: Rack block and gear.
Application: Internal components in an aluminum housing that hydraulically activates pumps on fire trucks.
Casting Process: Permanent mold casting.
Metal: AO21 Aluminum bronze.
Dimensions: 2.75 x 2.75 x 2 in., 5 x 2.5 x 2 in.
Weight: 3 lb., 2.75 lb.
Converted from: Machined bar stock.
- After a stainless steel version was
thought to be cost-prohibitive, these parts were considered for
production from machined aluminum-bronze bar stock. By instead
creating a new casting design to utilize the chill mold process, key
requirements of high-strength, corrosion resistance, minimal
finishing and precision were met at a reduced total product cost.
- The casting design allowed the
foundry to cast the teeth to size with less than a 0.015 backlash.
Gear diameters and tooth profiles are cast within ±0.005-in.
tolerance range. Lifecycle testing has shown no measurable wear on
either component.
- The foundry supplies machine-finished components to the customer. This design allowed the customer to maintain it's market share by attaining a 20% cost savings over an initial stainless steel design.