Wednesday, November 7, 2012
TMC and Precitech increase yield two-fold
USA: TMC and Precitech, Inc., both units of AMETEK Ultra Precision Technologies, have teamed up to provide one of Precitech’s customers, a major consumer electronics manufacturer, with a vibration control solution that has more than doubled that customer’s yield of ultra-precision optical components.
The manufacturer, with its extremely high quality criteria, had been concerned with the yields from mold inserts used to create small, high-volume precision optics that had been machined using a Precitech Nanoform 250 Ultra precision diamond turning machine.
After investigating its customer’s operation, Precitech suspected that ambient floor vibration in the factory was contributing to the low yield, even though the building’s floor design included vibration-isolated floor sections beneath the diamond turning machines. To solve the problem, Precitech turned to TMC, the world leader in precision floor vibration control.
“Low frequency, low amplitude building floor vibration increasingly has become a limiting factor in the performance of extremely high-resolution, micro-manufacturing tools. Among these tools are ultra-precise diamond turning machines,” notes Steve Ryan, VP, Sales & Marketing for TMC.
The Nanoform 250 already has an embedded TMC MaxDamp pneumatic vibration isolation system and finite element analysis optimized dual sub frame construction that are adequate for most applications where ambient floor vibration may be a factor. MaxDamp is a low frequency, highly damped, isolator designed to isolate horizontal and vertical building floor vibration starting at 2-3 Hz.
After an extensive site survey of the manufacturer’s floor and the tool itself, a TMC vibration expert confirmed that extremely low frequency building floor vibration – from forklifts, HVAC units, other machinery, even walking past the equipment – exceeded the tool specification and was, in fact, limiting the quality of the molds.
To improve performance, TMC engineers recommended the STACIS active piezoelectric vibration cancellation system to support the entire Nanoform 250, including the embedded MaxDamp air isolators. STACIS cancels vibration down to extremely low frequencies. Those often are related to difficult-to-measure transient or random vibration, such as foot traffic or nearby machinery.
Designed specifically as a second stage of vibration isolation, STACIS starts to isolate at 0.5 Hz and delivers a much higher level of performance than air isolators, particularly in less than optimal environments. Also, because the piezo technology is a “hard-mount,” STACIS can be “stacked” (placed beneath a tool with an internal vibration isolation system).
The combined performance of the MaxDamp isolators supported by a STACIS platform system results in performance that is the sum of the two vibration isolation transfer functions. That is the vibration isolation of the two systems is additive.
When the Nanoform 250 was reinstalled on the STACIS platform system, the results were immediate and dramatic. Yield more than doubled.