Study on Solidification Behavior of Aluminium alloy ( LM 6 ) Castings by using Computer aided Simulation software
Method layout of a casting is an important aspect of tooling development. It involves decisions regarding part orientation in mould, parting line, cores, cavity layout, feeders, neck and gating system. An improper method layout leads either poor quality or low yield, which affects the productivity. Method design is mostly carried out manually, using 2D drawing of the cast part. Then tooling is fabricated the sample castings are produced to 3-4 trials which involves lot of production cost in the from of wastage of manpower, time and hamper the day to day schedule of the particular production. Computer simulation provides a clear insight regarding the location and extent of internal defects, ensuring casting are right as first time and every time. In the present study plate castings were considered to study the solidification behavior of Aluminium Alloy (LM6) at different sizes of riser and riser neck. The VEM based casting simulation software is used to study the solidification behavior of above castings. The simulated results were compared with the experimental results. It is expected that this work will be of immense importance equally to the academicians as well as to the industrial methoding engineers.
Feedability Analysis and Optimisation Driven by Casting Simulation
Casting simulation programs can be used by foundry engineers for quality assurance and yield optimisation without shop-floor trials, as well as by product engineers for analysing and optimising the feedability of a casting during design phase itself. For widespread application, the simulation programs should require little domain experience, and they should be fast, reliable, easy-to-use, and economical. These goals can be achieved by automating some of the tasks involved: identifying the location of a feeder, calculating its minimum size, creating its solid model, attaching the feeder model to the casting, carrying out solidification simulation, predicting quality and estimating the yield. This paper describes the underlying algorithms, and their implementation in a software program. Two industrial cases of large steel castings show how simulation facilitates troubleshooting and elimination of defects by minor changes to part design coupled with improved methoding of casting.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.