Process Signature Modeling for Tolerance Analysis

2010 ◽  
Vol 10 (2) ◽  
Author(s):  
R. Ascione ◽  
W. Polini ◽  
Q. Semeraro
Keyword(s):  
Concurrent Engineering ◽  
Manufacturing Process ◽  
Tolerance Analysis ◽  
Actual Surface ◽  
Contact Points ◽  
Geometric Tolerances ◽  
Systematic Pattern ◽  
Process Signature ◽  
Nominal Surface

Many well-known approaches exist in the literature for tolerance analysis. All the methods proposed in the literature consider the dimensional and the geometric tolerances applied to some critical points (contact points among profiles belonging to couples of parts) on the surface of the assembly components. These points are generally considered uncorrelated since the nominal surface is considered. Therefore, the methods proposed in the literature do not consider the actual surface due to a manufacturing process. Every manufacturing process leaves on the surface a signature, i.e., a systematic pattern that characterizes all the features machined with that process. The aim of the present work is to investigate the effects of considering the manufacturing signature in solving a tolerance stack-up function. A case study involving three parts has been defined and solved by means of a method of the literature, the variational method, with and without considering the correlation among the points of the same surface due to the manufacturing signature. This work represents a first step toward the integration of the design and the manufacturing in a concurrent engineering approach.

A Geometric Model for Tolerance Analysis with Manufacturing Signature and Operating Conditions

2019 ◽  
Vol 9 (3) ◽  
pp. 1-13
Author(s):  
Wilma Polini ◽  
Andrea Corrado
Keyword(s):  
Concurrent Engineering ◽  
Manufacturing Process ◽  
Geometric Model ◽  
Tolerance Analysis ◽  
Operating Conditions ◽  
Geometric Reasoning ◽  
Assembly Sequence ◽  
Turning Process ◽  
Engineering Approach

In this work, a geometric model for tolerance analysis has been carried out. Geometric reasoning has been implemented in the model to simulate the manufacturing process and, then, the assembly sequence. The proposed geometric model has been applied to a case study consisting of two circular profiles due to the turning process, and a hollow rectangular box. The two circular profiles have been assembled inside the box by considering the gravity, and the friction among the parts and the actual points of contact with and without using the manufacturing signature. Matlab® software has been used to implement the geometric model for tolerance analysis. The results have been compared with those obtained by using a literature model with and without considering the manufacturing signature. This work aims to be a first step towards the integration of the design and the manufacturing in a concurrent engineering approach.

Manufacturing Signature for Tolerance Analysis

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Polini Wilma ◽  
Moroni Giovanni
Keyword(s):  
Sensitivity Analysis ◽  
Manufacturing Process ◽  
Tolerance Analysis ◽  
Variational Model ◽  
Form Tolerance ◽  
Systematic Pattern

Every manufacturing process leaves on the surface a signature, i.e., a systematic pattern that characterizes all the features machined with that process. The present work investigates the effects of considering the manufacturing signature in solving a tolerance stack-up function. A new variational model was developed that allows to deal with the form tolerance. It was used to solve a case study involving three parts with or without considering the correlation among the points of the same surface due to the manufacturing signature. A sensitivity analysis was developed by considering different values of the applied geometrical tolerances.

A Method for Integrating Form Errors Into Geometric Tolerance Analysis

2005 ◽  
Author(s):  
Robert Scott Pierce ◽  
David Rosen
Keyword(s):  
Manufacturing Process ◽  
High Speed ◽  
Tolerance Analysis ◽  
Analysis Model ◽  
Geometric Tolerance ◽  
Form Errors ◽  
Product Function ◽  
Component Models ◽  
Insight Into

In this research we describe a computer-aided approach to geometric tolerance analysis for assemblies and mechanisms. This new tolerance analysis method is based on the “generate-and-test” approach. A series of as-manufactured component models are generated within a NURBS-based solid modeling environment. These models reflect errors in component geometry that are characteristic of the manufacturing processes used to produce the components. The effects of different manufacturing process errors on product function is tested by simulating the assembly of these imperfect-form component models and measuring geometric attributes of the assembly that correspond to product functionality. A tolerance analysis model is constructed by generating-and-testing a sequence of component variants that represent a range of manufacturing process capabilities. The generate-and-test approach to tolerance analysis is demonstrated using a case study that is based on a high-speed stapling mechanism. As-manufactured models that correspond to two different levels of manufacturing precision are generated and assembly between groups of components with different precision levels is simulated. Misalignment angles that correspond to functionality of the stapling mechanism are measured at the end of each simulation. The results of these simulations are used to build a tolerance analysis model and to select a set of geometric form and orientation tolerances for the mechanism components. It is found that this generate-and-test approach yields insight into the interactions between individual surface tolerances that would not be gained using more traditional tolerance analysis methods.

An Approach Based on Process Signature Modeling for Roundness Evaluation of Manufactured Items

2008 ◽  
Vol 8 (2) ◽  
Author(s):  
Giovanni Moroni ◽  
Massimo Pacella
Keyword(s):  
Empirical Model ◽  
Frequency Model ◽  
Mechanical Parts ◽  
Geometrical Characteristics ◽  
Systematic Pattern ◽  
Actual Profile ◽  
Process Signature ◽  
Definition Of ◽  
Improved Accuracy

In evaluating the geometrical characteristics of mechanical part, cleverness may be added with the definition of an empirical model representing the “signature” left by the manufacturing process used to make the part. This manufacturing signature is the systematic pattern that characterizes all the features machined with that process. If such a model is available, it may be exploited to enhance geometrical inspection accuracy. In this paper, an approach for geometrical inspection of machined profiles is proposed. This approach consists in computing form deviations by reconstructing the actual profile using a frequency model of process signature. The method has been thoroughly investigated in different simulated scenarios and benefits in terms of improved accuracy are demonstrated. Within the paper, a case study, related to roundness of mechanical parts obtained by turning, is used. The relationships between the number of sampled points and fitting algorithms are also pointed out.

Geometric tolerance analysis through Jacobian model for rigid assemblies with translational deviations

2016 ◽  
Vol 36 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Wilma Polini ◽  
Andrea Corrado
Keyword(s):  
Tolerance Analysis ◽  
Geometric Error ◽  
Functional Requirements ◽  
Content Type ◽  
Geometric Tolerances ◽  
Mechanical Assemblies ◽  
Geometric Deviations ◽  
2D And 3D ◽  
Practical Implications

Purpose – The purpose of this paper is to carry out a tolerance analysis with geometric tolerances by means of the Jacobian model. Tolerance analysis is an important task to design and to manufacture high-precision mechanical assemblies; it has received considerable attention by the literature. The Jacobian model is one of the methods proposed by the literature for tolerance analysis. The Jacobian model cannot deal with geometric tolerances for mechanical assemblies. The geometric tolerances may not be neglected for assemblies, as they significantly influence their functional requirements. Design/methodology/approach – This paper presents how it is possible to deal with geometric tolerances when a tolerance analysis is carried out by means of a Jacobian model for a 2D and 3D assemblies for which the geometric tolerances applied to the components involve only translational deviations. The three proposed approaches modify the expression of the stack-up function to overcome the shortage of Jacobian model that the geometric error cannot be processed. Findings – The proposed approach has been applied to a case study. The results of the case study show how, when a statistical approach is implemented, the Jacobian model with the three developed methods gives results very similar to those due to other models of the literature, such as vector loop and variational. Research limitations/implications – In particular, the proposed approach may be applied only when the applied geometrical tolerances involve translational variations in 3D assemblies. Practical implications – Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease of the manufacturing costs. Originality/value – The original contribution of the paper is due to three methods to make a Jacobian model able to consider form and geometric deviations.

Study on Geometric Tolerances Information in Integrated Manufacturing Processes

2010 ◽  
Vol 37-38 ◽  
pp. 1292-1295
Author(s):  
Yan Chao ◽  
Hai Feng Zhang ◽  
Li Qun Wu
Keyword(s):  
Life Cycle ◽  
Data Model ◽  
Manufacturing Process ◽  
Product Life Cycle ◽  
Critical Role ◽  
Manufacturing Processes ◽  
Product Life ◽  
Internet Technologies ◽  
Geometric Tolerance ◽  
Geometric Tolerances

Tolerance information plays a critical role in many steps of the product life cycle. It is especially important due to the advances in Internet technologies and increasing integration requirements from industry. In this paper, geometric tolerances information in manufacturing process (IMP) is studied, and the layered conformance level of geometric tolerances is established according to ASME Y14.5-1994, STEP and DMIS. An EXPRESS-G data model of geometric tolerance information in IMP is established. The XML language is used to represent and program the geometric tolerances information in IMP.

scholarly journals Waste reduction of polypropylene bag manufacturing process using Six Sigma DMAIC approach: A case study

2021 ◽  
Vol 8 (1) ◽  
pp. 1896419
Author(s):  
Muhammad Hamad Sajjad ◽  
Khawar Naeem ◽  
Muhammad Zubair ◽  
Qazi Muhammad Usman Jan ◽  
Sikandar Bilal Khattak ◽  
...  
Keyword(s):  
Six Sigma ◽  
Manufacturing Process ◽  
Waste Reduction

Concurrent Engineering Assessment: A Proposed Framework

1996 ◽  
Vol 210 (4) ◽  
pp. 321-328 ◽  
Author(s):  
J Poolton ◽  
I Barclay
Keyword(s):  
Product Development ◽  
New Product Development ◽  
Concurrent Engineering ◽  
Research Study ◽  
New Product ◽  
Using Data ◽  
Past Experiences ◽  
Depth Interviews

There are few studies that have found an adequate means of assessing firms based on their specific needs for a concurrent engineering (CE) approach. Managers interested in introducing CE have little choice but to rely on their past experiences of introducing change. Using data gleaned from a nine month case study, a British-wide survey and a series of in-depth interviews, this paper summarizes the findings of a research study that examines how firms orientate themselves towards change and how they go about introducing CE to their operations. The data show that there are many benefits to introducing CE and that firms differ with respect to their needs for the CE approach. A tentative means to assess CE ‘needs’ is proposed which is based on the level of complexity of goods produced by firms. The method is currently being developed and extended to provide an applications-based framework to assist firms to improve their new product development performance.

EVOLUTIONARY APPROACH IN PROCESS IMPROVEMENT — A CASE STUDY IN AUTO ELECTRICAL ALTERNATOR MANUFACTURING

2012 ◽  
Vol 11 (01) ◽  
pp. 27-50 ◽  
Author(s):  
A. J. JEGADHEESON ◽  
L. KARUNAMOORTHY ◽  
N. ARUNKUMAR ◽  
A. BALAJI ◽  
M. RAJKAMAL
Keyword(s):  
Process Improvement ◽  
Manufacturing Process ◽  
Welding Process ◽  
Evolutionary Approach ◽  
Geometrical Analysis ◽  
Designed Experiments ◽  
Self Development ◽  
Riveting Process

Evolution is "understanding and overcoming current constraints in small steps toward optimum." "Understanding" requires elucidation of facts and corroborating theories that can explain those facts in a coherent manner. "Overcoming" requires self-development to suit the environment. In this paper, a case study about how a manufacturing process is improved in terms of productivity and quality using evolutionary improvements is explained. Here "Understanding" is achieved through use of Shainin Technique, PM analysis, Affinity Diagram, and the engineer's ingenuity, along with Relations diagram. "Overcoming" is achieved through Geometrical Analysis and Designed Experiments. The Study has set a new benchmark in the Stator riveting process by proving it can yield the desired results, and the need to adapt welding process is avoided.

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