Valve Spools

Valve spool manufacturing involves grinding the slots and metering flats on spool valves from a solid blank. Throughput is increased by combining multiple operations, with all operations completed in a single chucking. Huffman machine systems have an integrated automatic wheel truing to maintain stringent SPC requirements.

Process

• Each shaft has equally spaced slots with metering flats on each side of the slot. Critical tolerances are maintained on both the slots and flats. The grinding process produces slot and flat symmetry to a six-sigma limit.
• Slots are ground with a 2.0" - 2.5" (51 - 64 mm) diameter, 100 grit metal bond CBN wheel traveling at speeds up to 24,000 rpm.
• Flats are ground with a 12" (305 mm), 320 grit vitrified aluminum oxide or CBN grinding wheel.

Cycle Time

• Floor to floor cycle time is less than 60 seconds.

Machine Features and Benefits

• Available on the Huffman HS-150 series grinding systems.
• Precision A-axis workhead with hydraulic expanding chuck for part holding and positioning.
• Rotary axis accuracy of ±36 arc seconds with repeatability of ±18 arc seconds.
• Critical linear axes accuracy better than ±0.0002" (0,01 mm) and repeatability less than ±0.0001" (0,005 mm).
• One spindle, 21.7 hp (15 kW) and 24,000 rpm, uses a 2.5" (64 mm) OD wheel for grinding flats.
• CNC controlled rotary diamond truing device for 12" (51 mm) grinding wheel.
• Scale feedback for Y, Z and A axes.
• Push button chuck expansion/contraction.
• Four axis movement under CNC control.
• Retractable steady rest support.
• Automatic front door opener.