Anisotropic Shrinkage Variance in Glass-Filled Polyamide Secondary Tooling Nests
Secondary tooling nests for glass-filled polyamide accommodate anisotropic shrinkage through floating datum pins aligned with transverse contraction vectors.
Spherical Tooling Button
Meaning
Precision locating elements establish accurate reference points on assembly fixtures and inspection nests to support the workpiece. A spherical tooling button utilizes a precision-ground hemispherical surface to create a single point of contact against the part datum. This design minimizes the contact area, reducing the risk of part distortion and preventing dirt buildup from affecting the alignment.
Point Contact
The hemispherical shape prevents the locator from binding against non-flat datum surfaces on the part. This ensures that the workpiece settles into its correct position repeatably and without force, which is essential for manual loading.
Metrology Application
In plastic component inspection, these elements are placed beneath primary and secondary datum surfaces to support the part during measurement. Using a spherical tooling button prevents the flexible plastic from flexing or bending over a wider, flat support pad. This isolated contact allows the coordinate measuring machine to capture the true dimensions of the part without fixture-induced errors.
This setup is particularly effective for large, warped automotive panels.
Material Compatibility
Molding shops must choose the correct material for these buttons to prevent scratching or denting the plastic parts. Hardened steel or carbide buttons are used for glass-filled resins, whereas plastic or brass buttons are selected for soft polymers. This material selection ensures that the fixture does not leave cosmetic marks or micro-cracks on the critical datum surfaces of the molded component.