21 Closed Loop Tolerance Engineering Modelling and Maturity …
299
21.2 Closed Loop Tolerance Engineering
Krogstie and Martinsen (Krogstie and Martinsen 2012) developed a conceptual
model of Closed Loop Tolerance Engineering (CLTE). CLTE (Fig. 21.1) is a model
for “systematic and continuous re-use and understanding of product-related knowledge, with the aim of designing robust products and processes with the appropriate
limits of specifications”.
CLTE sees TE as activities not limited to the traditional activities of tolerancespecification, allocation, modelling/optimization and synthesis, but also an organizational process, with information flow and ability to collect, use and reuse data.
Preventing problems from occurring, attention to and understanding of tolerances in
the whole value chain, and fact (data) based tolerance engineering are some of the
benefits expected. Good tolerance engineering practice includes a collective ability
to detect critical situations in the product development phase (Badke-Schaub and
Frankenberger 2004) and the decision-making between future desirable vs. negative
consequences from variations on the product and processes. CLTE has been applied
for analyzing tolerance engineering practices in different companies, including a
high-precision aerospace company (Krogstie et al. 2014). The CLTE - model has
feed forward and a feedback information flow dimensions. It contains four interconnected activities: (1) Defining functional requirements (FR), (2) TE, (3) Manufacturing Process Capabilities Assessment (PC) and (4) Product Performance Assessment (PP) Furthermore, six pairs of closed loops of information flow (1a/b etc.
see Fig. 21.1) passing information forward in the project flow, as well feedback of
data to new product development collected from manufacturing and performance of
existing products. The ability to prepare and utilise information and data from both
feed forward and feed-back dimension is a main key element.
Fig. 21.1 The CLTE-model (Krogstie and Martinsen 2012)
299
21.2 Closed Loop Tolerance Engineering
Krogstie and Martinsen (Krogstie and Martinsen 2012) developed a conceptual
model of Closed Loop Tolerance Engineering (CLTE). CLTE (Fig. 21.1) is a model
for “systematic and continuous re-use and understanding of product-related knowledge, with the aim of designing robust products and processes with the appropriate
limits of specifications”.
CLTE sees TE as activities not limited to the traditional activities of tolerancespecification, allocation, modelling/optimization and synthesis, but also an organizational process, with information flow and ability to collect, use and reuse data.
Preventing problems from occurring, attention to and understanding of tolerances in
the whole value chain, and fact (data) based tolerance engineering are some of the
benefits expected. Good tolerance engineering practice includes a collective ability
to detect critical situations in the product development phase (Badke-Schaub and
Frankenberger 2004) and the decision-making between future desirable vs. negative
consequences from variations on the product and processes. CLTE has been applied
for analyzing tolerance engineering practices in different companies, including a
high-precision aerospace company (Krogstie et al. 2014). The CLTE - model has
feed forward and a feedback information flow dimensions. It contains four interconnected activities: (1) Defining functional requirements (FR), (2) TE, (3) Manufacturing Process Capabilities Assessment (PC) and (4) Product Performance Assessment (PP) Furthermore, six pairs of closed loops of information flow (1a/b etc.
see Fig. 21.1) passing information forward in the project flow, as well feedback of
data to new product development collected from manufacturing and performance of
existing products. The ability to prepare and utilise information and data from both
feed forward and feed-back dimension is a main key element.
Fig. 21.1 The CLTE-model (Krogstie and Martinsen 2012)