Makers of small engines, hydraulic valves, gears, compressors and pumps, to name just a few, are increasingly turning to honing to produce tight component tolerances with high process capability (Cpk). The goal is gearboxes and transmissions that run quieter, smoother, and longer; hydraulic systems that are more precise, responsive, efficient and leak-resistant; and small engines that deliver higher power densities and produce less pollution. According to Sunnen Products Corp., automation through multispindle honing machines will be crucial to produce these parts in high volumes.
Multispindle vertical honing machines are not new. Hydraulic versions have been around for years, but carry all the disadvantages of hydraulics. Single-pass honing machines are usually multispindle verticals, too, but lack the capabilities of a conventional hone for correcting geometric error in long bores and producing a true crosshatch finish.
Factors influencing the development of automated multispindle machines include: The need to hone increasingly complex parts with keyways, ports, and blind bores; upstream processes that while fast, tend to produce a spread of tolerances on parts that require more stock removal in honing to hit the size, straightness, cylindricity and roundness specs; and a retiring pool of craftspeople.
A new generation of vertical CNC multi-spindle machines transforms honing into high-volume precision bore machining. Equipped with in-line air gaging for process and tool-feed control, these machines â€šÃ¢â‚¬â€œ configured as automated cells â€šÃ¢â‚¬â€œproduce more than 15 million parts per year with accuracies of 0.25 â€šÃ‚Âµm to 1.25 â€šÃ‚Âµm (0.00001 to 0.000050 in.).
These machines also deliver a crosshatch pattern that can be controlled to a specific angle and depth (with plateau honing) to retain and distribute lubricating oil films. Such patterns are useful for manufacturers that pay attention to cylindricity and the surface parameters Rk, Rpk and Rvk. Makers of hydraulic cartridge valves and similar components, for example, fine-tune these parameters based on the characteristics of the mating/sliding parts.
The SV-1000, SV-310 and SV-500 vertical CNC honing machine series are the basic platforms that transform honing into automated precision bore machining. All are modular, engineered to scale up from a single-spindle job-shop machine to fully automated multi-spindle cells.
Sunnen Products Company
Filed Under: Machine tool industry + subtractive manufacturing, Fluid power, Gears • gearheads • speed reducers, Hydraulic equipment + components, Motors (gearmotors)