Definitions for "Contact angle"
The angle of load path between the balls and the inner and outer ring. Can be 15, 25, 30, 40 and 60 degrees. Larger contact angles tend to be reserved for high axial load applications such as ball screws.
contact angle = zero for full wetting contact angle = 180 degrees for immiscible liquids contact angle = 90 degrees for meniscus maintaining fluids. On adding surfactant to the oil-water interface the contact angle decreases. This can be understood as: surfactants reduce (interfacial tension): Cosine(contact angle) ~1/(interfacial tension), therefore as Cosine(contact angle) increases the contact angle decreases.
The angle of wetting between the solder fillet and termination or land pattern. A contact angle is measured by constructing a line tangential to the solder fillet that passes through a point of origin located at the plane of intersection between the solder fillet and termination or land pattern. Contact angles of less than 90° (positive wetting angles) are acceptable. Contact angles greater that 90° (negative wetting angles) are unacceptable.