Side Viewing Interferometric Probe Alignment for near Vertical Steel Sidewalls
Aligning side-viewing optical probes on vertical steel sidewalls requires tip-tilt control within 0.05 degrees to preserve coherence fringe visibility.
Wire EDM Surface Roughness
Meaning
Texture of the steel surface produced by the spark erosion process using a continuously feeding brass or zinc-coated wire. In mold manufacturing, wire EDM surface roughness dictates the friction and finish of the vertical walls of the mold cavity. This texture must be carefully controlled to balance the ease of molded part release with the cosmetic requirements of the plastic component.
Texture Control
Toolmakers adjust the generator settings of the EDM machine to achieve the desired finish on the steel insert. Increased wire EDM surface roughness can act as a matte texture on the molded polymer, while a smoother finish is required for parts that need post-molding pad printing or painting. Controlling this texture during machining reduces the need for manual polishing, which can alter the dimensional accuracy of the cavity.
Tooling Release
High friction from excessive steel roughness causes molded polymer parts to drag or tear during the ejection phase. This issue is particularly severe when using polymers with low melt strength or high shrinkage rates, which shrink tightly onto the mold core projections. Corrective texturing ensures that the ejection force remains low, preventing white ejector marks and part distortions from ruining the production run.
Quality Calibration
Measuring this roughness requires non-contact optical profilometry to capture the surface peaks and valleys. This assessment ensures the mold texture meets both the cosmetic and performance standards before it enters the production line.