scholarly journals Tolerance analysis of annular surfaces considering form errors and local surface deformations

Procedia CIRP ◽  
2018 ◽  
Vol 75 ◽  
pp. 291-296 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Jianhua Liu ◽  
Xiaoyu Ding ◽  
Nan Shao
Keyword(s):  
Tolerance Analysis ◽  
Local Surface ◽  
Form Errors ◽  
Surface Deformations

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.

Variant Shape Model Applicable to Combined Geometric Tolerances

1996 ◽  
Author(s):  
Keisuke Inoue ◽  
Akira Okano
Keyword(s):  
Low Cost ◽  
Tolerance Analysis ◽  
Solid Model ◽  
Geometric Errors ◽  
Shape Model ◽  
Form Errors ◽  
Physical Conditions ◽  
Geometric Tolerances ◽  
Single Face ◽  
Manufacturing Errors

Abstract This paper describes a variant shape model and its application to tolerance analysis. To realize a high-precision mechanism at low cost, designers specify various types of tolerances selectively, often in combination on a single face. We propose a solid model that has attributes at points scattered over its faces. In this model, the macroscopic geometry is represented as a B-rep solid model, and the microscopic geometry (manufacturing errors and clearances) as attributes. The model can represent a wide variational class, such as shapes with form errors. We use it to present a method for generating a deviant shape model having a specified set of geometric errors. After deviant part shapes have been generated, they are assembled virtually in such a way that they do not interfere with each other and that the physical conditions of the attachment are satisfied. Through a large number of deviant assemblies, a product’s performance is analyzed statistically and quantitatively.

scholarly journals Tolerance Modeling and Analysis Considering Form Defects for Spaceborne Array Antenna

2020 ◽  
Vol 10 (8) ◽  
pp. 2840
Author(s):  
Guodong Sa ◽  
Zhenyu Liu ◽  
Chan Qiu ◽  
Jianrong Tan
Keyword(s):  
Tolerance Analysis ◽  
Simulation Method ◽  
Geometric Error ◽  
Array Antenna ◽  
Analysis Method ◽  
Phased Array Antenna ◽  
Modeling And Analysis ◽  
Form Errors ◽  
Assembly Simulation ◽  
Tolerance Modeling

Tolerance analysis is becoming increasingly important for tolerance design and optimization. When dealing with electromechanical products such as the array antenna, the form errors of the assembly must be considered. Traditional tolerance analysis with form errors relies on a double loop process, which is computationally expensive. A new tolerance analysis method is proposed in this paper, which can be achieved by a single loop process. First, a new tolerance modeling method considering form errors was proposed, it can represent the geometric error of a surface feature precisely. Then an effective sampling method was developed by introducing the variance separation method. An assembly simulation method was proposed to determine the final state of the whole assembly. Finally, the tolerance analysis was achieved based on the sufficient sample. The proposed analysis method was applied to an X-band spaceborne active-phased array antenna, numerical simulation results show the effectiveness of the method.

scholarly journals Integration of surface deformations into polytope-based tolerance analysis: application to an over-constrained mechanism

Procedia CIRP ◽  
2020 ◽  
Vol 92 ◽  
pp. 21-26
Author(s):  
Zhiqiang Zhang ◽  
Jianhua Liu ◽  
Nabil Anwer ◽  
Laurent Pierre ◽  
Nan Shao
Keyword(s):  
Tolerance Analysis ◽  
Surface Deformations ◽  
Analysis Application

A Method for Integrating Form Errors Into Geometric Tolerance Analysis

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Robert Scott Pierce ◽  
David Rosen
Keyword(s):  
High Speed ◽  
Tolerance Analysis ◽  
Manufacturing Processes ◽  
Analysis Model ◽  
Geometric Tolerance ◽  
Form Errors ◽  
Product Function ◽  
Computer Aided ◽  
Component Models

In this research, we describe a computer-aided approach to geometric tolerance analysis for assemblies and mechanisms. 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 are tested by simulating the assembly of imperfect-form component models and by measuring geometric attributes of the assembly that correspond to product functionality. A tolerance analysis model is constructed by generating and testing component variants that represent different manufacturing precision levels. The application of this approach to tolerance analysis is demonstrated using a case study that is based on a high-speed stapling mechanism.

scholarly journals To model bolted parts for tolerance analysis using variational model

2015 ◽  
Vol 4 (1) ◽  
pp. 139 ◽  
Author(s):  
Wilma Polini ◽  
Massimiliano Marziale
Keyword(s):  
Contact Surface ◽  
Tolerance Analysis ◽  
Variational Model ◽  
Solid Model ◽  
Functional Requirements ◽  
Form Errors ◽  
Proposed Model ◽  
Mechanical Products ◽  
Planar Contact

Mechanical products are usually made by assembling many parts. Among the different type of links, bolts are widely used to join the components of an assembly. In a bolting a clearance exists among the bolt and the holes of the parts to join. This clearance has to be modeled in order to define the possible movements agreed to the joined parts. The model of the clearance takes part to the global model that builds the stack-up functions by accumulating the tolerances applied to the assembly components. Then, the stack-up functions are solved to evaluate the influence of the tolerances assigned to the assembly components on the functional requirements of the assembly product.The aim of this work is to model the joining between two parts by a planar contact surface and two bolts inside the model that builds and solves the stack-up functions of the tolerance analysis. It adopts the variational solid model. The proposed model uses the simplified hypothesis that each surface maintains its nominal shape, i.e. the effects of the form errors are neglected. The proposed model has been applied to a case study where the holes have dimensional and positional tolerances in order to demonstrate its effectiveness.

Considerations of form defects and surface deformations for tolerance analysis of cylindrical components

2021 ◽  
pp. 095440542199141
Author(s):  
Zhiqiang Zhang ◽  
Jianhua Liu ◽  
Laurent Pierre ◽  
Nabil Anwer
Keyword(s):  
Tolerance Analysis ◽  
Iterative Closest Point ◽  
Simulation Methods ◽  
Skin Model ◽  
Icp Algorithm ◽  
Surface Deformations ◽  
Research Outcomes ◽  
Considerable Research ◽  
Computer Aided ◽  
External Forces

The modeling and simulation of cylindrical surfaces with consideration of form defects have led to considerable research outcomes in the field of Computer-Aided Tolerancing (CAT). However, further consideration of surface deformations caused by external forces still remains a challenge. To address this issue, this paper properly considers the form defects and surface deformations for tolerance analysis of cylindrical components. First, form defects are considered by modeling skin model shapes of cylindrical surfaces. Afterwards, the tight fit and loose fit of a pair of cylindrical surfaces are identified, and the simulation methods of their positioning are presented. Specifically, for tight fit situation, a k-d tree based Iterative Closest Point (ICP) algorithm is used, and for loose fit situation, the constrained registration approach is adopted. Moreover, a Conjugate Gradient-Fast Fourier Transform (CG-FFT) method is presented for the consideration of surface deformations. In addition, simulations of given examples are conducted, which show the considerable effects of form defects and surface deformations. The simulations may also help determine the best performance of the to-be-assembled cylindrical components.

Sign in / Sign up

Export Citation Format

Share Document