Machining of valve seats,
a whole century of development... and a solution!
During traditional milling of valve seats from powder materials and some cast iron valve seats, chatter formation is almost inevitable.
Corrugations have a very detrimental effect on the valve when blowing off gases when the valve is closed.
The machined seat will consequently deform quickly and its tightness will never be adequate. The notch is created by the operation of the profiled plate, which scrapes a large surface area in granular materials (powder materials, alloy cast iron...).
Traditional sockets, machined with profiled inserts, are characterized by undulations measured in hundredths of a millimeter, which is the result of irregular cutting forces around the circumference of the socket. The consequence of variable cutting resistance is the transfer of uneven pressure to the machine spindle, which yields more or less and creates irregular shapes. This phenomenon, well known to operators of manual machines, is sometimes offset by quick and strong pressure on the spindle.
The spindle manipulations described above can smooth out the visible distortions, but they will not improve the geometry of the cavity in any way.
This undulation, inherent in profiled plate processing, has an obvious effect on valve tightness and requires further valve lapping treatment to achieve the required tightness. Valve lapping, previously accepted out of necessity by engine builders and their customers, is no longer allowed by the automotive industry or anyone who cares about maintaining the quality required by next-generation engines.
FIXED-TURNINGR interpolation machining completely eliminates all distortions shown in Figures 1 and 2.
The occurrence of crimps and waves is virtually impossible. One-point machining does not allow this type of distortion to form. You only need to analyze the socket machining principle to see for yourself.
Machining with a rotary tool moving in two interpolated axes produces perfectly round circular microgrooves. The depth of the furrows and the distance between them is controlled by the numerical control of the machine, creating the best possible surface.
Significant reduction of cutting resistance (300x and more), minimization of machining imperfections makes FIXED-TURNINGR at the highest level in the quality scale defined by the OEM.