Blisters

About: Blisters is a research topic. Over the lifetime, 980 publications have been published within this topic receiving 16229 citations.

The formation of indicia in the base of a blister pack for transference to a body cast therein

Abstract: A laminated film (2) in which a metal foil is sandwiched between two polymeric films is cold formed to define one or more blisters (8), and the base of the blister (8) stamped with indicia (12), in two discrete stages. The blister (8) is formed in the first stage using a standard technique of advancing a pin (6) in a direction transverse relative to the plane of the film (2). According to the invention, once the blister (8) forming stage is completed, indicia (12) are stamped into the base of the blister (8) in the second stage by advancing a die (10, 14) from one side thereof to clamp the blister (8) base against a mould held against the other side. The direction of the die (10) and disposition of the die (10) and mould may be selected such that the indicia (12) project inwardly or outwardly from the blister (8) base.

Random blisters on stickers: metrology through defects

Abstract: Blisters are commonly observed when an adhesive sheet is carelessly deposited on a plate. Although such blisters are usually not desired for practical applications, we show through model experiments on angular blisters how material properties can be deduced from height profile measurements. In particular the typical curvature of the crests is found to be proportional to an elasto-capillary length that compares the bending stiffness of the sheet with the adhesion energy. In addition, the radius of the tip allows the estimation of the product of this length with the thickness of the sheet. The relevance of these results to realistic random configurations is finally confirmed.

Substrate composition effects on the interfacial fracture of tantalum nitride films

Abstract: In this study we combined nanoscratch testing with a multilayer sapphire and aluminum nitride single-substrate system to determine the effects of interface composition and structure on susceptibility to fracture of hard, thin tantalum nitride films. Nanoindentation tests showed that the elastic moduli of the tantalum nitride and aluminum nitride films, as well as the sapphire substrate, were essentially equal at 400 GPa. On both portions of the substrate, these tests also showed that near surface hardness was near 35 GPa. Nanoscratch tests triggered long blisters and circular spalls on both the sapphire and aluminum nitride portions of the substrate. The blisters showed that the tantalum nitride film was subjected to a compressive residual stress of {minus}6.7 GPa. The spalls showed that failure occurred along the tantalum nitride film-substrate interface regardless of substrate composition. Most importantly, the blisters and spalls showed that the mode I component of the fracture energies were essentially equal on both substrate materials at a value near 3.1 J/m{sup 2}. These energies are on the order of the energies for metallic bonding. {copyright} {ital 1999 Materials Research Society.}

A method and a unit for producing blister packs by cutting a blister band

Abstract: A method and a relative unit (1) for producing blister packs (7) by cutting a blister band (4), according to which a band (4) with blisters (2) housing products is fed in a selected feeding direction (A), through subsequent stations: a band (4) verifying station, a closing station where the blister band is closed with a covering band, and to a cutting station (5) for cutting the closed blister band (4). In the cutting station (5), the closed blister band (4) is cut by progressive shearing, to obtain relative blister packs (7) detached from at least one strip (9a, 9b) or scrap longitudinal edge of the blister band (4). If portions of the blister band (4) considered unsatisfactory are detected in the control station, the subsequent shearing is performed partially or incompletely, so as to prevent detachment of the corresponding blister packs (8), considered faulty and destined to be rejected, from the strip (9a, 9b) of the band (4).