Process Capability Based Tolerance Allocation in Pneumatic Percussive Riveting

2020 ◽  
Author(s):  
Hua Wang ◽  
Jialei Zhang ◽  
Junyang Yu
Keyword(s):  
High Efficiency ◽  
Load Transfer ◽  
Process Capability ◽  
Tolerance Analysis ◽  
Tolerance Allocation ◽  
Hole Drilling ◽  
Case Method ◽  
Pneumatic Hammer ◽  
Worst Case ◽  
Mating Conditions

Abstract Pneumatic percussive riveting is an important way to join the sheet metals. In order to ensure the load transfer and the fatigue performance of riveted joint, the interference of the rivet/hole is strictly specified. The interference of the rivet/hole is highly correlated with the process capability of the pneumatic hammer and the diameter of the pre-hole. It is a critical step to choose the appropriate pneumatic hammer to ensure the interference requirements. Energy per blow of the pneumatic hammer is a proclaimed parameter from the riveting hammer manufacturer. It is difficult for the designer to choose the riveting hammer in practical riveting scheme based on energy per blow. Tolerance analysis is an efficient way to model the manufacturing variation and implement process control. This paper presents the tolerance allocation of the pneumatic percussive riveting based on the process capability of the pneumatic hammer. In order to obtain the designed interferences of the rivet/hole, a tolerance chain is built with the process capability of the pneumatic hammer, the diameter of the pre-hole and the diameter of the rivet shank. The process capability of the pneumatic hammer is represented with the interferences of the rivet/hole after riveting. It is an intuitive parameter for the designer to choose the riveting hammer in practical riveting scheme. The process capability of the pneumatic hammer is obtained from the designed riveting experiments with the pneumatic percussive riveting platform. The diameter of the pre-hole affects the interference of the rivet/hole also. The tolerance for manual hole-drilling should be determined to assure the interference requirements and high drilling operation efficiency simultaneously. The variation of the pre-hole is obtained from the manual drilling experiments and diameter measurements. Different hole-drilling results in different mating conditions between the pre-hole and the rivet. The fit conditions of different pre-holes are modeled and the final interferences after riveting are analyzed. Worst case method and statistical analysis method are two common methods for tolerance analysis. For the manual hole-drilling and the pneumatic percussive riveting, worst case method is employed to analyze the constructed tolerance chain in order to accomplish the interferences of the rivet/hole. The different analyzed dimensions, rivet-hole clearances and pre-hole drilling variation, are investigated respectively. The reported work enhances the understanding of the tolerance allocation for the pneumatic percussive riveting. The interference based process capability of the pneumatic hammer provides good reference for pneumatic hammer choosing in riveting scheme. The reported tolerance chain of the interference could be used for the tolerance determination of manual hole-drilling with good quality and high efficiency.

scholarly journals Geometrical and dimensional tolerance analysis for the radial flux type of permanent magnet generator design

2021 ◽  
Vol 12 (2) ◽  
pp. 68-80
Author(s):  
Muhammad Fathul Hikmawan ◽  
Agung Wibowo ◽  
Muhammad Kasim
Keyword(s):  
Permanent Magnet ◽  
Manufacturing Process ◽  
Cumulative Effect ◽  
Tolerance Analysis ◽  
Air Gap ◽  
Tolerance Allocation ◽  
Design Stage ◽  
Worst Case ◽  
Radial Flux ◽  
Permanent Magnet Generator

Mechanical tolerance is something that should be carefully taken into consideration and cannot be avoided in a product for manufacturing and assembly needs, especially in the design stage, to avoid excessive dimensional and geometric deviations of the components made. This paper discusses how to determine and allocate dimensional and geometric tolerances in the design of a 10 kW, 500 rpm radial flux permanent magnet generator prototype components. The electrical and mechanical design results in the form of the detailed nominal dimensions of the generator components, and the allowable air gap range are used as input parameters for tolerance analysis. The values of tolerance allocation and re-allocation process are carried out by considering the capability of the production machine and the ease level of the manufacturing process. The tolerance stack-up analysis method based on the worst case (WC) scenario is used to determine the cumulative effect on the air gap distance due to the allocated tolerance and to ensure that the cumulative effect is acceptable so as to guarantee the generator's functionality. The calculations and simulations results show that with an air gap of 1 ± 0.2 mm, the maximum air gap value obtained is 1.1785 mm, and the minimum is 0.8 mm. The smallest tolerance value allocation is 1 µm on the shaft precisely on the FSBS/SRBS feature and the rotor on the RPMS feature. In addition, the manufacturing process required to achieve the smallest tolerance allocation value is grinding, lapping, and polishing processes.

scholarly journals Tolerance Analysis of Mechanical Parts

2020 ◽  
Vol 14 (3) ◽  
pp. 265-272
Author(s):  
Živko Kondić ◽  
Đuro Tunjić ◽  
Leon Maglić ◽  
Amalija Horvatić Novak
Keyword(s):  
Tolerance Analysis ◽  
Case Method ◽  
Worst Case ◽  
Mechanical Parts ◽  
Assembly Tolerance ◽  
Huge Impact ◽  
Quality Of Products ◽  
The One

The determination of tolerances has a huge impact on the price and quality of products. The objective of tolerance analysis is to provide the widest possible tolerance range of parts, without disturbing the functionality of the assembly. Tolerance analysis should be performed during the design process because then there is still the possibility for change. For the purpose of carrying out the analysis, three methods will be used: Worst Case method, Root Sum Square method and Monte Carlo Simulation. Methods are explained through simple examples and applied on the one-way clutch.

scholarly journals ANALYSIS OF GEOMETRICAL SPECIFICATION IN DECANTER CENTRIFUGE MACHINE

2018 ◽  
Vol 8 (2) ◽  
pp. 29-47
Author(s):  
Bagus Budiwantoro ◽  
Indra Djodikusumo ◽  
Ade Ramdan
Keyword(s):  
Statistical Method ◽  
Manufacturing Process ◽  
Tolerance Analysis ◽  
Mean Value ◽  
Case Method ◽  
3D Design ◽  
Worst Case ◽  
Production Phase ◽  
Performance Requirements ◽  
Decanter Centrifuge

A decanter centrifuge machine has been developed and currently at a complete stage of a preliminary 3D design layout. The next phase is a production phase. In the production phase, an ideal component that is identical with the 3D model will never be realized. Every manufacturing process has unavoidable variations. If they are accumulated, they can be immense and may cause serious problems. The machine may fail. Thus, the analysis of geometry specification is necessary to be conducted. The main objective of this study is to design the geometry specification which includes their tolerance to assure that the machine will work and achieve its performance, considering variation in manufacturing process. The study consists of four stages, they are: (1) reviewing the 3D design layout, (2) identifying functional key characteristics, (3) analyzing each requirement to determine the geometric dimensioning and tolerancing schemes and (4) allocating tolerances. Every scheme was built through six steps, establish the performance requirements, draw a loop diagram, converting dimension to mean dimension, calculate mean value with stack tolerance, determine the method of tolerance analysis and calculate the variation of performance requirements. The tolerance analysis uses the worst case and statistical methods. They involve 45 fixed tolerances and 38 variable tolerances. The calculated variation data output of every requirement is elaborated to finalize tolerance value that will meet all requirements. Finally, the final tolerance values are allocated and set to component geometry. This analysis concludes that every final tolerance of variable tolerance values must be tighter for the worst case method, and only 42% for statistical method. Probability of machine will work and achieve its performance is 100% for the worst case method and 99.73% for the statistical method.

Worst-case-based methodology for tolerance analysis and tolerance allocation of optical systems

2010 ◽  
Vol 49 (31) ◽  
pp. 6179 ◽  
Author(s):  
Chun-Che Hsueh ◽  
Psang Dain Lin ◽  
Jose Sasian
Keyword(s):  
Tolerance Analysis ◽  
Tolerance Allocation ◽  
Optical Systems ◽  
Worst Case ◽  
Case Based

Sensitivity characterization of polarization operating by embedded reflective grating

2021 ◽  
Author(s):  
Jiaman Hong ◽  
Bo Wang ◽  
Xiaoqing Zhu ◽  
Zhichao Xiong ◽  
Yusen Huang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Electric Field Intensity ◽  
High Efficiency ◽  
Transverse Electric ◽  
Tolerance Analysis ◽  
Transverse Magnetic ◽  
Infrared Band ◽  
Element Analysis ◽  
Field Intensity Distribution

In this paper, a novel embedded reflective grating (ERG) is presented to realize bi-function polarization operating at infrared band by finite element analysis (FEM). For transverse electric (TE) polarization, a two-port output (0th and −2nd orders) with an efficiency of more than 47% and excellent uniformity can be obtained. For transverse magnetic (TM) polarization, a high efficiency output of 94.72% can be achieved at the −2th order. The results of the analysis of the electric field intensity distribution, angular and wavelength bandwidths further demonstrate the advantages of the proposed grating. In addition, the tolerance analysis of period and duty cycle prove the feasibility of the grating in practical production.

Parametric Kinematic Tolerance Analysis of Planar Pairs With Multiple Contacts

1996 ◽  
Author(s):  
Elisha Sacks ◽  
Leo Joskowicz
Keyword(s):  
Efficient Algorithm ◽  
Tolerance Analysis ◽  
Parametric Model ◽  
Worst Case ◽  
Multiple Contacts ◽  
Work Cycle ◽  
Computer Aided ◽  
Kinematic Models ◽  
Range Of Variation ◽  
Different Parts

Abstract We present an efficient algorithm for worst-case limit kinematic tolerance analysis of planar kinematic pairs with multiple contacts. The algorithm extends computer-aided kinematic tolerance analysis from mechanisms in which parts interact through permanent contacts to mechanisms in which different parts or part features interact at different stages of the work cycle. Given a parametric model of a pair and the range of variation of the parameters, it constructs parametric kinematic models for the contacts, computes the configurations in which each contact occurs, and derives the sensitivity of the kinematic variation to the parameters. The algorithm also derives qualitative variations, such as under-cutting, interference, and jamming. We demonstrate the algorithm on a 26 parameter model of a Geneva mechanism.

Applications of Mating Conditions in Assembly Sequence Planning Task

1998 ◽  
Author(s):  
Pongsak Dulyapraphant ◽  
Tulga Ozsoy
Keyword(s):  
Degrees Of Freedom ◽  
Tolerance Analysis ◽  
Assembly Sequence Planning ◽  
Assembly Model ◽  
Assembly Sequence ◽  
Kinematics Analysis ◽  
Sequence Planning ◽  
Planning Task ◽  
Intuitive Interface ◽  
Mating Conditions

Abstract Because of their intuitive interface, mating conditions have been prevalently used in assembly modelling. Besides their use for modelling purposes, other type of information, such as spatial relationships between parts and local degrees of freedom, can be directly derived from mating conditions. This information in turn can be used in various engineering analysis applications, such as kinematics analysis or automatic tolerance chain generation for tolerance analysis. In this paper, application of mating conditions in an assembly sequence-planning task is investigated. The proposed approach mainly engages the mating information represented in the CAD assembly model to automatically generate sequence plans based on the minimization of the number of assembly directions.

Algebraic Representation of Geometric and Size Tolerances

1995 ◽  
Author(s):  
S. H. Mullins ◽  
D. C. Anderson
Keyword(s):  
Tolerance Analysis ◽  
Design Analysis ◽  
Algebraic Representation ◽  
Dimensional Metrology ◽  
Algebraic Form ◽  
Worst Case ◽  
Mechanical Component ◽  
Analysis And Synthesis ◽  
Statistical Tolerance ◽  
Statistical Tolerance Analysis

Abstract Presented is a method for mathematically modeling mechanical component tolerances. The method translates the semantics of ANSI Y14.5M tolerances into an algebraic form. This algebraic form is suitable for either worst-case or statistical tolerance analysis and seeks to satisfy the requirements of both dimensional metrology and design analysis and synthesis. The method is illustrated by application to datum systems, position tolerances, orientation tolerances, and size tolerances.

A New Tolerance Analysis Method for Designers and Manufacturers

1987 ◽  
Vol 109 (2) ◽  
pp. 112-116 ◽  
Author(s):  
W. H. Greenwood ◽  
K. W. Chase
Keyword(s):  
Tolerance Analysis ◽  
New Method ◽  
Analysis Method ◽  
Worst Case ◽  
Assembly Tolerance ◽  
Naturally Occurring ◽  
Methods Of Analysis

Even when all manufactured parts for an assembly are produced within limits, these parts still may not assemble properly if the assembly tolerance analysis was inadequately performed. Naturally occurring shifts in a process can produce biased distributions which can result in increased assembly problems and a greater number of rejects than anticipated. The most common methods of analysis of assembly tolerance buildup are worst case and root sum squares. The limitations of each of these methods are discussed and a simple new method is proposed which accounts for expected bias. This new method includes both worst case and root sum squares as extreme cases.

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