1,721,046 research outputs found
Study of autoclave process to manufacture thermoplastic composites constituted by PP/flax fibers
No full textAutoclave processes are widely used from industries that produce thermoset polymer composite parts. However, these materials show sustainability issues as they are non-recyclable and produced by energy-intensive processes. The use of thermoplastic matrices reinforced with natural fibers can solve these problems; however the optimal use of this material is linked to the knowledge of the forming parameters. In this work, starting from semipreg sheets, the autoclave forming process for parts in flax woven and polypropylene is studied and developed: it represents a fundamental step to develop the use of these new eco-friendly materials starting from the wellestablished industrial knowledge, not only in terms of environmental sustainability, but also economic and social sustainability. First, working temperatures were determined by DSC and TGA; while optimal forming pressure were determined by ILSS tests
Analysis of the material removal mechanism in the sawing of marble
No full textThe present research aims at consolidating the theoretical aspects related to the use
of chain-saw machines in the quarrying of marble. Cutting conditions conventionally
adopted during quarrying operations have been reproduced in an experimental set-up
and forces exerted during the material removal have been monitored by means of a
piezoelectric dynamometer.
The complex action of the chain into the stone has been decomposed into simpler
conditions by analyzing each tool singularly. Once established the effect of every
single tool, three main tools with different geometries have been tested varying the
rake angle γ. Data relative to the monitored forces revealed that better proficiencies, in
terms of feed force reduction, can be obtained with negative values of the rake angle
while the effects on the cutting force can be retained negligible. A wide overview on
the experimental tests was also given to asses the repeatability of the obtained
results
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