Probe Needle Specifications – Taper Types

Besides the specification of dimensions as shown in last page the customer should also specify the taper type. There are two main types of tapers – Isolinear and Parabolic.

Isolinear Taper is also referred to as Straight Taper. This type of taper is characterized by the taper silhouette lines that are straight rather than curved. To further determine the straightness of the taper a Back or a number of Backs can be provided.

Parabolic Taper is also referred to as Nonlinear Taper. This type of taper is characterized by the taper silhouette lines that are parabolic rather than straight. The shape of parabolic taper is normally convex rather than concave. To determine the thickness and shape of the taper a Back or a number of Backs should be provided.

Back is the diameter at a certain position of the taper. A Back or a number of Backs can be specified by the customer to determine the thickness and shape of the taper. Back requirements can be applied to both the isolinear and parabolic types of taper.

A Back specification composed of two values. The first value is the distance from the tip end measured back to a certain position in the taper, hence the term Back. (Currently some customers do not measure the distance from the tip end but from a position that is close to the tip end where a diameter value is pre-set. The measurement in this case is the distance from that point backward to another position of the taper.)

For instance, the Back requirement 16B (1^st value)=2.3 +/-0.1 (2^nd value) means that at the position of the taper that is 16 mils away from the tip end the diameter is required to be 2.3 mils with the tolerance of +/-0.1.