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Co-design activities of
the LATI technical service: design support for
the customer
In addition to the existing
MoldFlow and NASTRAN programs, the LATI Technical
Service has acquired new software for FEA activities.
The applicational flexibility of technical
thermoplastic materials allows to produce increasingly
refined products, which must be finalized correctly
during the design phase in order to keep the development
and industrialization costs low.
This is the setting for the MoldFlow MPI/STUDIO
software, which consists of a set of programs
dedicated to fluid dynamics analysis of polymers
capable of providing a valid help for optimum
production of extremely complex products by means
of injection moulding, safeguarding as far as
possible the properties and main characteristics
of the compound concerned.
To carry out this computing activity, the MPI/STUDIO
system requires:
- a three-dimensional model
of the part
- a three-dimensional model
of the conditioning circuit
- rheological and thermal
data, PVT curves and mechanical specifications
of the material chosen
- thermal data of any inserts
present in the mould
- position and type of injection
on part
- part moulding parameters
- position of constraints
on the geometry of the cavity for calculating
deformation.
The mathematical model used up to now to represent
the structure of the cavity is defined midplane
and consists essentially in representing the
object by means of surfaces shown visually as
"sheets of paper" that is, two-dimensional
geometrical entities in which the thickness
is an attribute associated with each surface.
Although this type of model
is extremely reliable, its precision is reduced
when the object is extremely thick or has variations
in thickness whose simplification using the midplane
model would create major imprecision in the computing
phase. In addition, for these geometries, the
generation of a "mid plane", that is,
a surface set between the opposite surfaces of
the actual object may prove to be rather uncertain
and inaccurate.
In order to meet these new requirements, the MPI/STUDIO
software has been enriched with two new programs
capable of providing reliable results even with
particularly problematic geometries from the modelling
point of view:
- MPI/FUSION is a variant of the basic
package studied to work with models consisting
exclusively of the border surfaces obtained
by CAD through exportation to IGES, STL,
I-DEAS UNiVersal file, PARASOLID, STEP
format. The thickness is determined by the
program, which evaluates the distance between
the borders. The FUSION module also comprises
tools for simulating fibre-reinforced materials
and estimating deformation, making the software
complete and suitable for handling all cases.
- MPI/3D is a new program which, through
exportation to I-DEAS, Pro/ENGINEER, Unigraphic
or CATIA format, is used to carry out
filling and packing analysis on particularly
thick products by means of a special computing
algorithm in which the thickness of the part
non longer exists as a dimension of the object
but only as a distance with respect to the
outer surface.
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The FUSION module provides a set of
extremely accurate information in that it takes
into account the actual external geometry of
the product avoiding an approximation obtained
by sticking "sheets of paper" together.
The main disadvantage with respect to the midplane
system is represented by the time required to
compute and prepare the grid of finished elements,
which is considerably longer.
Particularly refined management of the fluid
dynamics of the molten polymer is the predominant
feature of the 3D package, which is capable
of generating a set of comprehensive indications
on the injection and maintenance phase. The
computing times are rather long for this module,
too.
With a view to satisfying the increasingly specific
market requirements, LATI has chosen to purchase
both packages, so that it may provide its customers
with increasingly broad, flexible and precise
design support.
| Contact: |
email: marketing@it.lati.com
LATI Industria Termoplastici S.p.A.
Via F. Baracca, 7 21040
Vedano Olona (VA) - Italy
Tel. : +390332409111 - Fax: +390332409307 |
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