Friction Determination
Kinetic and static slide resistance for film substrates defines the quantitative output described by the coefficient of friction iso 8295 standard. Test equipment registers the force required to move one weighted surface across another stationary surface at a constant speed. This protocol monitors sliding characteristics between two plastic film or sheet samples under specific laboratory conditions.
Accurate data derived from this method permits converters to predict how substrate stacks behave during machine feeding or automatic bagging. High values indicate material tackiness that hinders separation while low values risk load slippage during pallet transport.
Measurement Mechanism
Laboratory setups rely on a horizontal sled pulling system to generate continuous motion between test pieces. The load cell records the peak force at the start of movement to define static resistance. It continues to measure the average force over a defined displacement distance for kinetic values.
Weights ensure uniform pressure across the contact area to simulate pressures found in real production stacks. Precision relies on maintaining constant velocity without mechanical vibration or motor stall. Deviations in film thickness or surface coatings alter the measured pull force significantly.
Processing Impact
Converter operations utilize these empirical values to calibrate tension settings on high speed automated packaging lines. Film stock with excessive friction disrupts mechanical suction cups or vacuum belt assemblies during rapid indexing. Printers manage these specific mechanical demands by adjusting slip additives within the film resin matrix or applying specialized lacquers to the top surface.
A uniform slip profile ensures consistent product stacking height without causing telescoping in roll goods. Correctly managed surface resistance keeps the feed velocity within the tolerance of automated filling sensors. Engineers maintain these values through strict batch testing because minor deviations in environmental humidity or additive bloom change the physical behavior of the sheet.
Proper adherence to the protocol ensures machines pull exactly one sheet at a time from a magazine or hopper. Consistent slip properties provide the mechanical foundation for automated handling efficiency.
