Micro Molded Part Metrology Standards for Receiving Acceptance Inspections
Establishing rigorous non-contact metrology standards and ISO 14253-1 guardbanding protocols prevents defective micro-molded parts from entering production.
Datum Target Establishment
Meaning
Engineering standards define specific points or areas on a part used to create a reference frame for metrology. This process is called datum target establishment, which governs the positioning of the workpiece during dimensional inspection.
Fixture Design
Inspection fixtures must physically replicate the theoretical points designated by the design engineer. During datum target establishment, the toolmaker places spherical or flat-tipped pins at the exact coordinates specified on the drawing. This physical contact ensures the part sits in the same orientation every time it is measured.
A failure to match these points leads to false failure reports.
Geometric Consistency
Manufactured parts always exhibit some degree of surface irregularity or warping. By utilizing datum target establishment, the metrologist ignores these local variations and focuses on the functional mating areas of the part. This selective contact prevents minor surface ripples from skewing the overall dimensional assessment of the component.
The result is a more reliable check of whether the part will assemble correctly.
Production Cost
Defining these reference points early in the design cycle prevents costly disputes between the quality department and the machining shop. When datum target establishment is executed incorrectly, the manufactured parts might be functional but fail the inspection due to a mismatch in how they are held. Redesigning the inspection fixture after production has started introduces delays and adds unnecessary tooling expenses.