Improvement of location and orientation tolerances propagation control in cylindrical components assembly using stack-build assembly technique

Abstract

2015),"Auto-body assembly process fault diagnosis based on a dynamic variation modeling approach", Assembly Automation, Vol. 35 Iss 4 pp. 302-308 http://dx. Access to this document was granted through an Emerald subscription provided by emerald-srm:368933 [] For AuthorsIf you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -This paper aims to provide an assembly method to improve cylindrical components assembly quality. The proposed method not only could be applied to tolerance allocation, but also could guide the assembly of cylindrical components. Design/methodology/approach -The paper claims to provide a stack-build assembly method using a connective assembly model to take the location and orientation tolerances of a rotor stage into account. Through the separate analysis of the location and orientation tolerances propagation process in the assembly, the quality of the final assembly of the rotationally symmetric cylindrical components assembly could be improved by properly selecting component orientations to minimize the eccentric deviation in the assembly. Findings -The effectiveness of the proposed stack-build assembly technique in improving the tolerance propagation in the assembly of cylindrical components was verified through experiments run with a measuring machine. A real aero-engine rotor was assembly using the proposed method; compared to the direct-build assembly technique, which had the component orientations without consideration, the stack-build assembly technique could be used to reduce the eccentric deviation in cylindrical components assembly by nearly 50 per cent. Originality/value -Different with the old methods, the new method defined the tolerances in detail, such as perpendicularity and angle of the lowest point, and could guide the assembly by the features of surfaces on different components. Through measuring the special tolerances of surfaces on the components, the best assembly angle for each component could be obtained.

Experimental studies of robotic assembly of precision parts

“…The stated research results were obtained due to the formulation of a full factorial experiment to optimize technical solutions, that is, when the variation of the investigated parameters (in this case, assembly modes) is carried out at the extreme extreme levels: min and max, and their average value is in the center of the coordinate system of the parameter change. This method [24,25] allows obtaining target functions of technological parameters, for example, as a proposed function (13). For such functions, engineers can calculate, if not optimal values, then at least quasi-optimal values of optimization parameters.…”

“…For robotic assembly of cylindrical parts, studies [12] arose great interest, where the orientation of the part is determined using a vision system, and then a force or torque control algorithm is applied to perform assembly with tight tolerances. The angle of inclination of the part and the perpendicularity of one part relative to another are measured [13]. Both of the latter assembly methods are quite effective, but they require relatively expensive software and hardware in relation to simple robot manipulators.…”

“…The condition for the existence of an extremum of the objective function (13) at some point of the factor space with coordinates ( 0 0 0 , , P a ω ) has the form:…”

“…where: i a -scanning amplitude; α -is the central angle between rose petals; k -is the number of rose petals (see above). For a more accurate time calculation, it is recommended to use the formula (13), which allows us to determine the minimum assembly time depending on the parameters: assembly force, scanning amplitude and angular speed of rotation of the industrial robot gripper.…”

A method to control the amount of unbalance propagation in precise cylindrical components assembly

“…20–22 In order to control the variation propagation in the assembly, Yang et al 23 developed the straight-build assembly model for variation propagation control in an aero-engine assembly and used a transform matrix model to analyze variation propagation process. Wang et al 24 proposed a stack-build assembly technique and analyzed the location and orientation tolerances propagation process in the assembly, and the cumulative eccentric deviation can be minimized by controlling the assembly angle of component.…”