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Manufacturing
companies in various industries, including automotive and
aerospace, are generally interested in predicting the effects
of part and tooling variation on final product quality during
the design stage. This is especially important for
manufacturing processes with compliant/flexible parts.
Tolerancing must
be considered early during the design phase in order to
develop cost-effective product specifications. However,
existing approaches to allocate tolerances require detailed
knowledge of the geometry of assemblies and are applicable
mostly during advanced stages of design, leading to a less
than optimal design process. During the design process of
assemblies, both the assembly structure and associated
tolerance information evolve continuously. Therefore,
significant gains can be achieved by effectively using this
information to influence the design of the assembly.
This research
addresses these limitations by presenting a tolerance
allocation methodology for compliant assemblies using a
beam-based model of the product.
The beam-based
model provides a simplified but effective representation of
tolerancing information during the early stages of design that
can be used to model dimensional discrepancies before detailed
3D CAD models are available. The development of the
beam-model requires only limited information such as part
stiffness (modeled via beams) and geometrical position of both
ends, which is consistent with the information that is used
during the early stages of the design process. Detailed part
geometries are typically based on the structural requirements
from the early stages. Hence, beam-based tolerancing is well
suited for use during very early stages of design.
The proposed
tolerancing method minimizes manufacturing costs associated
with tolerances of key product functional
requirements/characteristics under the constraint(s) of
satisfying process control requirements/characteristics.
It is developed
for stochastic and deterministic cases and is based on
projection theory that can considerably simplify the solution
for linear as well as non-linear constraints. Experimental
results verify the proposed tolerance allocation method.
Details in
poster1.
poster2, as well as in the following papers: also see [5,
12,
13,
C2, 20,
21, 25,
32,
35,
42,
52,
55] |
