Meaning
Instrumented puncture testing provides polymer technologists with a standardized procedure for evaluating the high rate impact behavior of rigid plastic sheets. ISO 6603-2 defines the drop weight method for determining multidirectional impact properties under controlled velocity conditions. Polypropylene homopolymers and glass filled engineering thermoplastics undergo rapid penetration loading to establish force displacement curves during the transition from ductile to brittle states.
Testing applies strictly to flat specimens prepared by compression molding or injection molding, whereas extruded pipes and blow molded hollow bodies fall outside the methodological scope.
Impact Dynamics
Fast acting pneumatic or gravity driven strikers descend onto rigidly clamped circular disks to measure energy absorption limits. ISO 6603-2 records dynamic force signals through piezoelectric transducers mounted directly on the striker tip while optical gates capture penetration velocity at the exact moment of contact. Ductile polyamides absorb high deformation loads before tearing, whereas brittle polycarbonates fracture abruptly without enduring significant post yield elongation.
Crosshead speeds reaching five meters per second simulate severe mechanical shocks encountered during handling or service life.
Regrind Degradation
Thermal history accumulated during repeated extrusion cycles alters molecular weights and degrades impact energy absorption across recycled polymer batches. ISO 6603-2 detects these subtle property drops long before tensile testing reveals any mechanical compromise. Virgin acrylonitrile butadiene styrene compounds maintain consistent peak force values, whereas streams containing high percentages of degraded regrind exhibit premature matrix failure and jagged load drops.
Compounders monitor these deflection signatures to establish maximum allowable regrind ratios without sacrificing final part toughness.
Process Verification
Injection molding parameters determine whether a molded housing meets structural durability requirements or shatters under sudden stress. ISO 6603-2 evaluates skin core morphology variations induced by excessive melt temperatures or inadequate packing pressures during cavity filling. Tool designers adjust gate locations and runner dimensions to eliminate anisotropic molecular orientation that invalidates circular disk drop tests.
Datasheet values represent ideal laboratory specimens, whereas production parts frequently fall short due to localized crystallinity gradients and internal residual stresses.
