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Roller clinching is a variation of conventional clinching by using rotational tool movement. The joining quality of roller clinching is significantly affected by tooling geometries and motions. Considering the formation difference of joints at different locations, this paper investigated the deformation features of roller clinching of square joints and utilized multiple linear regression analysis to optimize the processing parameters. It was found that roller geometry has significant impact on the formation of interlocks of the front/rear sides of joints, while the impact on the formation of lateral sides is less. With the increase of roller diameters, the clearance variation of front/rear sides decreases; meanwhile, the separation clearance s at the front side after forming decreases. In the study, when the roller diameter is raised from 35 to 150 mm, the connection strength increases by 44%. If the diameter difference w of rollers increases, the squeezing degree of the front side decreases, and the joining quality increases; however, if the squeezing degree of the rear side increases, then the joining quality of the rear side and s decrease. In the sample, an increase in w by 3 mm enhanced the connection strength by 9%. When the clearance difference t between the rollers increases, the capability to contain metal increases in the rear side. When t increases by 0.6 mm, the connection strength augments by 12%. The separation clearance s of the front side is greatly affected by friction μ, roller diameter, w, and draft angle γ of the lower roller, while the effect of draft angle β of the upper roller on s is small. [ABSTRACT FROM AUTHOR]

As an important engineering material, aluminum alloy profile is widely used in each department of national economy. With polyurethane mandrel in the hollow of the profiles, equal channel angular pressing (ECAP) can be used to refine mechanical properties of these hollow materials with good shape control effects. However, based on existing researches, the hollow profiles are only limited to circular ones. In this paper, a mechanical analysis of a square tube in ECAP with polyurethane mandrel is provided. Through the slab method in different deformation planes, the mechanical mechanism of shape control effects is found. The thicknesses can be maintained as its initial ones after ECAP. Both simulations and experiments are used to verify the calculated results by the analysis. After calculating, most errors between the final and initial thicknesses in both simulations and experiments are less than 10%. [ABSTRACT FROM AUTHOR]

This paper focuses on the application of principal component analysis (PCA) to thoroughly analyse and interpret multidimensional data from a cold rolling process. The analysis includes the effects of variables on the final properties of strips in a cold rolling mill. Unscrambler software was used to analyse and identify hidden variables. Variable correlations were also used to derive correlations between the control parameters. The results of this research will be used to improve the selection of material in order to reduce the occurrence of defects in the cold rolling process and to improve the adjustment of the set points that are performed in every pass or section of the cold rolling process. The hot rolled strips that enter the cold rolling mill are made of different materials and are produced by different strip manufacturers. Some strips break during the thickness reduction process in the cold rolling mill. This paper focuses on two possible causes of breakage: non-uniform strip material properties and failures in the rolling mill process. Two types of rolled strips (those that break and those that do not break) were compared to identify causes of breakage. The results indicate that breakages are caused by material or process failures. PCA was applied to the dataset in order to identify and analyse the relationships between the variables in the process. This information was used to interpret and diagnose the process behaviour. Swarm analysis and relating observations to process behaviour were able to distinguish between different start-up conditions, and between desirable and undesirable process conditions. [ABSTRACT FROM AUTHOR]

In the processing of large and ultra-large forgings, the heated billets need to be properly placed on the lower forging die as quickly as possible before the plastic forming, or else the cooling of billets incurs enormous risks to the operation. This paper presents a novel methodology for examining the positioning status of billets on a forging die based on multi-body dynamics simulation and design of experiment (DOE). Using this method, the position and posture of a billet can be theoretically predicted after falling into the cavity of lower die from a manipulator with varying initial states. The method can also clarify the initial geometrical position parameters of the billet that should be strictly controlled in the operation of the manipulator above the lower die. Furthermore, finite element method (FEM) simulation can be used to analyze plastic deformations of the billets on the lower die surface with varying states, to attain in-depth understanding of the influence of the geometric states of billets in forming processes. A case study of forging with Al 7050 indicates that the method can provide a valuable reference for the rapid positioning of billets on the lower die. [ABSTRACT FROM AUTHOR]

The first step of a geometrical and dimensional tolerance analysis is to determine kinematic loops that affect the functional requirements and the tolerances that influence the relative positioning between two topological elements of a part. This process is called the interpretation of geometric and dimensional tolerances. The second step is a solution procedure to verify if the functional requirements will be met with the current tolerances. This paper presents the implementation of a C++ library for the interpretation of geometric and dimensional tolerances in order to accomplish the first step of the tolerance analysis process. First, the data structures that allow storing the tolerances, the toleranced part data model, and the assembly graph model are introduced. This is followed by the description of the algorithms for retrieving the relevant kinematic loops from the assembly graph and the tolerances that affect the relative positioning between any two topological elements. Finally, an example demonstrates how to use the interpretation data obtained from the library to calculate and verify the functional requirements. [ABSTRACT FROM AUTHOR]