Calculating Substrate Compression Ratios in Embossing Operations
Substrate compression ratio measures z-axis compaction, balancing tool impression depth against fiber strain limits to maximize embossing height without shearing.
ISO 2758 Burst Strength
Pressure Limit
The maximum hydrostatic pressure that a single sheet of paper can withstand before rupturing provides an index of the material’s toughness and resistance to puncture. As specified in iso 2758 burst strength measurements are obtained by clamping the test specimen over a circular elastic diaphragm, which is then expanded by hydraulic pressure until the paper bursts. This value is recorded in kilopascals and represents a benchmark for packaging papers.
It is a baseline for grades intended for multi-wall sacks and wrapping.
Fibre Quality
The cohesive strength of the paper web depends heavily on the extent of refining and the length of the constituent cellulose fibres. Kraft pulp with long, unbleached softwood fibres gives high iso 2758 burst strength, which is needed to withstand the stress of bag-filling machines. Excessive bleaching or the addition of short-fibre hardwood fillers will reduce the burst resistance.
This property shows how well the fibre network can distribute tensile stress in all directions.
Measurement Protocol
Standard conditions for the test require that the hydraulic fluid is pumped at a constant, controlled rate to ensure the diaphragm expands smoothly. If the pumping rate is incorrect, the pressure peak will be misread, leading to inaccurate data.