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Relating Blanket Design to its Performance

Rubber Composites

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Regardless of the undeniable progress of the blanket industry, some aspects of blanket response have stubbornly remained unpredictable, specially when it comes to controlling rubber rebound and blanket feed properties.
It is widely acknowledged how recurrent design attempts to overcome blanket response unpredictability have had its intended goal not confirmed by field results.

The persistent study and research carried in our laboratory, required to satisfy our standards of Blanket Conversion, Commercial Advise and After Sales Service, was in the end rewarded:
A significant segment of blankets response has an oscillatory nature.
Due to the very peculiar rubber characteristics, blankets have an innate and most disturbing aptitude to respond resonantly to a wide range of oscillatory stimuli frequencies.
Those stimuli are typically external, such as press vibration and the cyclic bump preceding every new copy and may generate a resonant reaction in one or more of the blanket layers.

Each of the various blanket layers may dampen or boost any such vibrations according to its particular structure characteristics.

In order that noise is not added to the printed image, any vibration induced into a blanket layer must be damped during its travel to the surface rubber layer, which often acts as resonance box.

The compressible layer, with its very low tensile modulus, due to the gas inside its plastic “balloons” is the default candidate to have lazy, but still resonant reactions.

A safer way to avoid vibration at the blanket surface is to prevent resonance buildup in the compressive layer.
This can be achieved by increasing the losses – larger hysteresis area – of the compressive layer, so that no free energy remains available.

Most rubber industry applications (NASA developed mattresses, for one) have already succeeded in incorporating this technic and are currently delivering advanced products where rubber rebound is no longer present.

For further details please contact forum@printersblankets.com.

Indentation

Conventional Blankets (doc. date: 04-19-2011)
Comparison of some Conventional Blankets


Comparative Tests 1 (doc. date: 01-08-2011)
Comparing samples from manufacturers A, B, C, H and I


Comparative Tests 2 (doc. date: 02-08-2011)
Comparing samples from manufacturers D and E


Comparative Tests 3 (doc. date: 02-08-2011)
Comparing samples from manufacturers F and G


Layers Influence (doc. date: 11-29-2010)
Layers Influence Study (samples from manufacturer D)


Comparing Samples (doc. date: 10-29-2010)
Comparing 3 ply samples from the same manufacturer


Gauge Loss Details (doc. date: 10-25-2010)
Gauge Loss details of model I from manufacturer C


Compressibility Report 1 (doc. date: 09-15-2010)
Comparing samples from manufacturers A, B, C, H and I


Compressibility Report 2 (doc. date: 09-25-2010)
Comparing samples from manufacturers D and E


Deflection

Conventional Blankets (doc. date: 05-06-2011)
Comparison of some Conventional Blankets


Sheet Fed Blankets (doc. date: 05-05-2011)
Comparison of some Sheet Fed Blankets


Web Blankets (doc. date: 04-27-2011)
Comparison of some Web Blankets

Feed Properties Tests (doc. date: 03-03-2015)
Varying Test Pressure


Feed Properties 013 (doc. date: 15-10-2014)
Analysis Method, Compression Schemes and Rubber Reaction


Whip Reaction (doc. date: 07-08-2011)
Comparing Whip Reactions of different materials


Whip Energy of Blanket Layers (doc. date: 07-08-2017)
Whip Energy @ the Printing Nip


Understanding Printers Blankets (doc. date: 15-10-2019)
Understanding Printers Blankets Behaviour

Blankets Comparison (doc. date: 06-24-2011)
Comparing 2 and 3 ply samples from distinct manufacturers

Conventional Blankets (doc. date: 04-19-2011)
Comparison of some Conventional Blankets


Carcass and Fabrics 011 (doc. date: 02-20-2012)
Understanding Fabrics and their application on Blankets Carcass


Cotton Missouri minutes (doc. date: 02-20-2012)
Introduction to Cotton Fibres and Processing basics.


Analysis Environment 008 (doc. date: 07-01-2015)
Environment Influence on Cotton and Ruber


The Happy & the Unhappy Balls
Reactivity decreases with Lower Tensile Moduluses


Deflection versus Indentation (doc. date: 08-25-2011)
Analysing Whip Reaction showed by distinct test procedures

Hardness Testing (doc. date: 10-21-2011)
Test Methods used at Iberográfica


µHardness (doc. date: 08-26-2011)
Layers Influence Study