Design Changes
Product design is an iterative procedure. Several changes are usually made to the
initial product definition. A typical change could be the replacement of an object by a
different one or by another revision of the object, usually a more recent revision.
An important function of the manufacturing planner is to save the design changes
performed in the Product structure to the Manufacturing Assembly structure. The various types
of design changes are discussed below.
Correction
A correction is a modification of the attributes or the representation
attached to a Product structure object, mainly a reference object, that must have no
impact on any downstream application.
Typically, corrections are performed by:
- Demoting an object from released or shared status to a modifiable one
- Modifying the object
- Promoting the object back to shared or released status.
Minor Modification
A minor modification is a change that does not impact the interface of the
modified object, only its internal definition.
Minor modifications are performed by Replace by Revision
under Design Action authority. The naming of the object is kept, only a suffix
(- -) is added. Its history is also kept. The new instance becomes a substitute
of the replaced one. Both instances can be assembled.
Major Modification
A major modification is a change that has an impact on the interface
specification of the object.
Major modifications are performed by Replace by under
Design Action authority. The naming of the object is not kept. However, a
history link is defined between the references and the two instances have the
same logical identifier.
Interchangeability
Two objects are interchangeable if they can Fit to the same context, have the
same Form, and the same Function (FFF).
In this case, the objects
respect the same contract.
Minor Revision
A minor revision, also called minor, is a member of a family of minors.
It is an object that can be editable and interchangeable with other minors. It
reflects minor changes, with low impact, from one part to another.
Two minors have the same external identification. They are often called Part
Number, or Dash Number in the aerospace industry, for example. A minor revision
index is incremented when creating a new minor revision.
Revision
A revision is a family of minor revisions. A revision is not editable as
is. It is edited through the minors it comprises. Revisions are not meant to be
interchangeable, because one of the FFF may be broken.
A revision reflects major changes between different revisions that may have some
level of impact on assemblies relying on them.
Two revisions have the same external identification (Part Number or Dash Number
in aerospace industry, for example). The revision index is incremented when a
new revision is created.
Minor Sensitivity
A link is not minor sensitive if it can be solved on any minor of the
family present in the session. A link is minor sensitive if it is physically
linked to a minor of the family.
If another minor of the family is
present in session, the link is broken but it can be rerouted on that
minor.
The minor sensitivity is described in the metadata that defines the link.
Item-Product
Implement links are minor sensitive.
How Item Minor Revisions Are Managed
The impact of a minor change in the Product structure can be handled in the
Manufacturing Assembly structure. A number of capabilities are available to create
and manage item minor revisions to support common user scenarios.
item minor revisions may be created to:
- Take into account in the Manufacturing Assembly structure any modifications
to the Product structure.
- Stop propagation of the impact in the Manufacturing Assembly structure of
the management of item revisions.
- Take into account in the Manufacturing Assembly structure any low-impact
modifications.
The available capabilities enable the following scenarios to be addressed:
- Creation of a minor revision of a part, which leads to creating a minor
revision of the item that implements the part, to take into account this new
part minor revision. Here, there are two distinct cases:
- A standard part that is bought (BUY) and then provided to the
Manufacturing Assembly.
- A part that needs to be manufactured, MAKE. In this case, a
Manufactured Part implements the part. A Manufactured Part is
closely linked to a given part minor revision by means of a
reference-reference link.
- Impact propagation of part revision in the Product structure is stopped by a
minor revision of the product node that owns the part.
In this case, the
manufacturing planner may want to take into account the part revision by
a revision of the implementing item. The planner can then stop the
propagation of the impact of this revision in the Manufacturing Assembly
structure. They can do this by means of a minor revision of the item
node that owns the implementing item. Here, there are two distinct
cases:
- A standard part that is bought (BUY) and then provided to the
Manufacturing Assembly
- A part that needs to be manufactured, MAKE. In that case, a Manufactured Part implements the
part.
- Without any modification on the product side, the manufacturing planner may
want to manage different alternatives to manufacture the part by means of a
minor revision of the item node, which is a Manufactured Part. Here, there
are two distinct cases:
- Stock modification.
- Modification in the way the secondary fastener industrialization is
managed.
- Creation of a revision of a part, which leads to creating a revision of the
implementing item. Impact propagation in the Manufacturing Assembly
structure is stopped by means of a minor revision of the item node that owns
this revision.
In this case, no Product node corresponds to the
intermediate item node for which minor revisions are created.
Effectivity and Variability Space
Effectivity is the criteria that define the availability of an object for usage
in a controlled configuration.
In general, an effectivity is built from an expression. For example:
- An interval of serial numbers such as [1...100], meaning that an instance is
available for all serial numbers between 1 and 100
- An interval of two dates, such as [Aug 2009, 5th-Dec 2009, 23rd], meaning that
an instance is available for dates between the 5 August 2009 and the 23 December
2009
- A category, such as a roadster or a coupe
- A specification.
A variability space is a dictionary of configurations. It contains the different
elements that can be used to define an effectivity or a product configuration
expression.
Product Configuration
Product configuration is the criteria that identifies the suitable product
elements for a specific configuration based on their effectivity in a controlled
configuration.
Implement Link
An implement link specifies that a function performs the transformation that
realizes a product.
The main implement links are as follows:
- A reference-reference link, between an item reference and a product reference, which
defines a scope.
- An occurrence-occurrence link, between an item occurrence and a product
occurrence, to specify that an item occurrence performs the transformation that
realizes the product occurrence.
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