Generic Relationships between Field Uses and Their Geographical Characteristics in Mountain-Area Dairy Cattle Farms

In mountain farms, challenges posed by the degree of land slope, altitude and harsh climate further compound multiple other possible constraints, particularly in relation to the distance of the farm from the farmstead. This study focused on how mountain-area dairy farmers factor the geographical characteristics of their fields into their field-use decisions. To that end, we surveyed 72 farmers who farm the traditional Salers breed of cattle and 28 specialised dairy system farmers in the central Massif region, France. Information was collected on the uses and geographical characteristics of all grassland fields (n = 2341) throughout the entire outdoor grazing season, without identifying farmers’ rationales for their field-use decisions. Field-use classes were constructed for the traditional Salers system per group of fields (grazed-only, cut-only, grazed-and-cut) and then used to classify fields in the specialized dairy system. The geographical characteristics, which were associated afterwards, were significantly different between the field groups and between field-use classes. Grazed-only fields were found to be more sloping and cut-only fields were smaller and further from the farmstead. Distance/area combinations were different according to field use (animal category, earliness of first cut, grazing and cutting sequence) and were decisive for all field-use classes. This study allowed the identification of generic relationships between field uses and their geographical characteristics in mountain-area dairy cattle farms.

Mitigating Cutting-Induced Plasticity Errors in the Determination of Residual Stress at Cold Expanded Holes Using the Contour Method

Background The split sleeve cold expansion process is widely used to improve the fatigue life of fastener holes in the civil and military aircraft industry. The process introduces beneficial compressive residual stresses around the processed hole, but uncertainties remain about the character of the stress field immediately adjacent to the bore of the hole. Objective The primary objective of this study was to implement the contour method with minimising error associated with cutting-induced plasticity to provide detailed and reliable characterisation of the residual stress introduced by the split sleeve cold expansion process. Methods A systematic FE study of plasticity effects by simulating different contour cutting strategies (a single cut, two sequential cuts and a 6-cut sequence) for a cold expanded hole in an aluminium alloy coupon was conducted. The identified ‘optimum’ cutting strategy was then applied experimentally on coupons containing a hole that had been processed to 3.16% applied expansion. Results The FE study of different cutting simulations show that the locations of the stress error is consistent with the location where cutting-induced plasticity accumulated and that the magnitude and locations of stress re-distribution plasticity can be controlled by an optimised cutting strategy. In order to validate this hypothesis a high quality contour measurement was performed, showing that accurate near bore stress results can be achieved by the proposed 6-cut approach that controls cutting induced plasticity. Conclusions The present work has demonstrated that detailed FE simulation analysis can be a very effective tool in supporting the development of an optimum cutting sequence and in making correct choices of boundary conditions. Through optimizing these key aspects of the cutting sequence one is much more likely to have a successful, low error contour residual stress result.

Improved Die Attribute Recognition via Colored Glass Wafer

The rise of various Wafer technologies has been developed based on industries and applications requirement. Highest quality of material characterization is complex and requires specialized process equipment and manufacturing procedures to meet defined design standards. The paper presents distinctive glass wafer-level fabrication technology that will enhance its properties with respect to pattern recognition system (PRS) at back-end manufacturing for industrial applications. Feasibility of colored glass wafer has been built into proposed conception to manufacture wafer-level packaging. The idea from transparent to colored glass wafer came from manufacturing key challenges that cutting sequence during pattern recognition cannot be distinguished. The proposed solution will mitigate high risk of misaligned cut at wafer sawing and its potential attachment on leadframe during die attach. glass wafer dice, transparent in nature, intermittently encountered multiple PRS assist during Wafer sawing and die attach as it hardly recognizes its cutting positions. Since dependent of machine capability limitations, misaligned cut is inevitable and usually happen occasionally. Addressing its unrecognizable characteristic, proposed colored glass wafer and with visible outline and saw lane fabrication was conceptualized instead of seeking ideal and high equipment model that can differentiate its opaque feature. The colored glass wafer and with visible outline and saw lane naturally creates segmentation visibly and will not be parameter dependent during manufacturing.

Rigidity Regulation Approach for Geometric Tolerance Optimization in End Milling of Thin-walled Components

The paper presents a novel approach to improve geometric tolerances (flatness and cylindricity) by manipulating the rigidity among finishing and roughing cutting sequences during end milling of thin-walled components. The proposed approach considers the design configuration of the thin-walled component as an input and aims to determine semi-finished geometry such that the geometric tolerances are optimized while performing finish cutting sequence. The objective is accomplished by combining Mechanistic force model, Finite Element (FE) analysis based workpiece deflection model and Particle Swarm Optimization (PSO) technique to determine optimal disposition of material along the length of component thereby regulating rigidity. The algorithm has been validated by determining rigidity regulated semi-finished geometries for thin-walled components having straight, concave and convex configurations. The outcomes of the proposed algorithm are substantiated further by conducting a set of end milling experiments for each of these cases. The results of the proposed strategy are compared with a traditional approach considering no change in the rigidity of component along length of the cut. It is demonstrated that the proposed approach can effectively optimize geometric tolerances for thin-walled components during end milling operation.

A cutting sequence optimization method based on tabu search algorithm for complex parts machining

Defining the cutting sequence of each cutter scientifically in the process of removing the allowance has an important influence on the machining efficiency for complex parts, which have multiple machining features. In order to satisfy the needs of high efficiency for rough machining, after determining the tool path of the machining region, a cutting sequence optimization method based on the tabu search algorithm is presented to define the cutting order in rough machining of complex parts. First, a cutting sequence optimization mathematical model is established, which relates to the shortest total length of the tool path. Second, through the problem analysis, the cutting sequence optimization model is converted into an open and constrained traveling salesman problem. And then, the optimization model is solved by dealing with an open and constrained traveling salesman problem using the tabu search algorithm. Finally, the optimal cutting sequence of machining a casing part is calculated, and a simulation and experiment are carried out. The result shows that the optimization approach presented in this article can optimize the cutting sequence and cutter position of advance and retract. Compared with the non-optimized cutting sequence method, the total length of tool path is reduced by 16.7%, the cutter lifting times are reduced to 26, and the efficiency is increased by 21.62%.