09-07-2012, 02:02 PM
VIRTUAL MANUFACTURING
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INTRODUCTION
Manufacturing is an indispensable part of the economy and is the central
activity that encompasses product, process, resources and plant. Nowadays
products are more and more complex, processes are highly-sophisticated
and use micro-technology and Mechatronic, the market demand (lot sizes)
evolves rapidly so that we need a flexible and agile production. Moreover
manufacturing enterprises may be widely distributed geographically and
linked conceptually in terms of dependencies and material, information and
knowledge flows.
Virtual manufacturing definitions
The term Virtual Manufacturing is now widespread in literature but
several definitions are attached to these words. First we have to define the
objects that are studied. Virtual manufacturing concepts originate from
machining operations and evolve in this manufacturing area. However one
can now find a lot of applications in different fields such as casting, forging,
sheet metalworking and robotics (mechanisms). The general idea one can
find behind most definitions is that “Virtual Manufacturing is nothing but
manufacturing in the computer”. This short definition comprises two
important notions: the process (manufacturing) and the environment
(computer).
The scope of Virtual Manufacturing
The scope of VM can be to define the product, processes and resources
within cost, weight, investment, timing and quality constraints in the context
of the plant in a collaborative environment. Three paradigms are proposed in
[5]:
a) Design-centered VM: provides manufacturing information to the
designer during the design phase. In this case VM is the use of
manufacturing-based simulations to optimize the design of product and
processes for a specific manufacturing goal (DFA, quality, flexibility, …)
or the use of simulations of processes to evaluate many production
scenario at many levels of fidelity and scope to inform design and
production decisions.
b) Production-centered VM: uses the simulation capability to modelize
manufacturing processes with the purpose of allowing inexpensive, fast
evaluation of many processing alternatives. From this point of view VM
is the production based converse of Integrated Product Process
Development (IPPD) which optimizes manufacturing processes and adds
analytical production simulation to other integration and analysis
technologies to allow high confidence validation of new processes and
paradigms.
Methods and tools used in Virtual manufacturing
Two main activities are at the core of VM. The first one is the “modeling
activity” which includes determining what to model and the degree of
abstraction that is needed. The second one is the ability to represent the
model in a computer-based environment and to correlate to the response of
the real system with a certain degree of accuracy and precision: the
“simulation activity”. Even if simulation tools often appears to be the core
activity in VM, others research areas are relevant and necessary. One can
find in [5] a classification of the technologies within the context of VM in 4
categories. A “Core” technology is a technology which is fundamental and
critical to VM. The set of “Core” technologies represents what VM can do.