21 Closed Loop Tolerance Engineering Modelling and Maturity …
305
premature for most companies since CE is still mostly a vision more than reality. A
crucial point is however, to be able to optimize the selected tolerances not only for
simultaneous maximised product performance and minimised manufacturing costs,
but also the maximised lifetime of a product through maximised product durability
and maintainability, furthermore how to deal with a constant flow of remanufactured
and reusable components. Ultimately the selected tolerances at the Beginning Of
Life (BOL) of a product should reflect that a component should be allowed to live in
several loops in a Circular Economy manufacturing system.
Figure 21.6 shows a simplified Casual Loop Diagram which reflects this possible
future system. Adding the EOL processing feedback loops requires that manufacturing companies look outside their production processes and include additional
type of information in their tolerance specification. Such challenge increases the
complexity of the system, since the information delays are longer, data contains
more noise, and there are more actors in the system to interact with (that dynamic
hypothesis is represented in the CLD in the variable “effort to gather information
from external actors”). With a CE perspective manufacturing cost will also be affected
by environmental effects that are amplified by poor tolerance specification like the
increase in scrap and pollution. The analysis of the dynamics of the extended CLTE
model brings up the following additional questions for the CLTE maturity assessment
tool: (i) Are the delays involve in the information loops accounted for when using
accumulated knowledge? (ii) Are the designers involved in cultural change programs,
so accumulated knowledge is added in the tolerance specification routine? (iii) Are
actors in the supply chain involved in data accumulation? and (iv) Are the noises in
the data from EOL accounted for in tolerances specification?
Use of resources
Value for the customer
Component lifetime
Component
remanufacturability
Component reuseability
Scrap
Pollution
Manufacturing costs
Durablity and
maintainability
Functional performance
+
+
+
+
+
+
+
+
+
Taguchi loss function
Optimized tolerances
+
Durability and
functionality
requirements
+
+
Accumulated
knowledge from
existing products
+
Price and time
optimisation
+
-
Manufactured Volume
-
Tolerance specificatio
improvement effort
+
Customer orders
+
+
-
-
+
-
-
environmental effects
+
+
+
+
capability to gather and reuse
information from component
manufacturing, lifetime and end of
life
Revenue +
-
customer satisfaction
+
+
+
+
+
+
+
EXTENDED CLTE CLD
+
Fig. 21.6 Extended CLTE CLD
305
premature for most companies since CE is still mostly a vision more than reality. A
crucial point is however, to be able to optimize the selected tolerances not only for
simultaneous maximised product performance and minimised manufacturing costs,
but also the maximised lifetime of a product through maximised product durability
and maintainability, furthermore how to deal with a constant flow of remanufactured
and reusable components. Ultimately the selected tolerances at the Beginning Of
Life (BOL) of a product should reflect that a component should be allowed to live in
several loops in a Circular Economy manufacturing system.
Figure 21.6 shows a simplified Casual Loop Diagram which reflects this possible
future system. Adding the EOL processing feedback loops requires that manufacturing companies look outside their production processes and include additional
type of information in their tolerance specification. Such challenge increases the
complexity of the system, since the information delays are longer, data contains
more noise, and there are more actors in the system to interact with (that dynamic
hypothesis is represented in the CLD in the variable “effort to gather information
from external actors”). With a CE perspective manufacturing cost will also be affected
by environmental effects that are amplified by poor tolerance specification like the
increase in scrap and pollution. The analysis of the dynamics of the extended CLTE
model brings up the following additional questions for the CLTE maturity assessment
tool: (i) Are the delays involve in the information loops accounted for when using
accumulated knowledge? (ii) Are the designers involved in cultural change programs,
so accumulated knowledge is added in the tolerance specification routine? (iii) Are
actors in the supply chain involved in data accumulation? and (iv) Are the noises in
the data from EOL accounted for in tolerances specification?
Use of resources
Value for the customer
Component lifetime
Component
remanufacturability
Component reuseability
Scrap
Pollution
Manufacturing costs
Durablity and
maintainability
Functional performance
+
+
+
+
+
+
+
+
+
Taguchi loss function
Optimized tolerances
+
Durability and
functionality
requirements
+
+
Accumulated
knowledge from
existing products
+
Price and time
optimisation
+
-
Manufactured Volume
-
Tolerance specificatio
improvement effort
+
Customer orders
+
+
-
-
+
-
-
environmental effects
+
+
+
+
capability to gather and reuse
information from component
manufacturing, lifetime and end of
life
Revenue +
-
customer satisfaction
+
+
+
+
+
+
+
EXTENDED CLTE CLD
+
Fig. 21.6 Extended CLTE CLD