The manufacture of cast metal components involves the use of cores to form the inside of shaped parts. These cores can be complex in shape and have to be of accurate dimensions and high quality. The cores are now commonly made by a process which blows sand into a shaped box and the sand is hardened by blowing through a catalyst gas. The manufacture of cores relies on past experience and there is no accurate computer simulation process currently in use. The project aims to develop a computer software programme to simulate sand filling and gassing of cores. This will be applied to the development of the blowing machine and the process extended to production of thin shaped contoured moulds. This will enable core design and manufacture to be improved and reduce time to market, costs and improve quality of casting manufacture.
-The partner requirements for the software have been defined and outlined to provide a software package which has an accuracy and operational time base to suit the industry in a practical way, i.e. not purely theoretical but giving indications of problem areas within the core blowing operation.
-A Laempe 10 litre core blower was specified, built, delivered, and made operational within the second and third quarters of the project. The machine was equipped to operate using the CO2 cured ‘Novanol’ sand system supplied by Ashland.
-Visualiation techniques have been developed and shown to operate with three sand systems, viz. Novanol, Cold Box (amine) and Betaset. These visualisation techniques have used the test component designs and a range of real time and rapid recording methods to show the progress of sand when blown into a core box with different configurations of shape and venting type and position. Similarly methods have been developed which show the progress and nature of the gassing/curing process.
-Valuable practical data on filling in ‘real time’ has already been derived and used by the modelling partners.
-The use of sands coloured with dyes seems to provide a possible means of identifying dead zones in shoot heads and complementary data on sand flow patterns in filled coreboxes.
-A method has been developed, based upon pH change indicators, to visualise the gassing process with the Cold Box, Betaset, and Novanol sand systems.-Abrasion marks on the Perspex front cover of the core boxes reveal sand flow patterns.
-Scratch hardness testing can be used to assess compaction levels. Surface measurements can be made, providing there is a flat test area. Hardness measurements on cut core sections have also been made.
-Models which can follow the blowing of sand and the gassing operations for the core blowing process have been developed using parameters which characterize the three sand systems used in the project.
-Software modules have been developed for the simulation of the gassing and blowing of the core making process, incorporating the developed models for the blowing process.
-The testing and development of the partner components has been conducted within the partner operational facilities.
-Examples from all three sand systems have been covered.
-The modelling and simulation of partner components have been completed and manufacture optimized.
-X-ray density measurements have been proven to be suitable for identifying poorly compacted regions of test case cores. There is a direct relationship between compaction density and radiographic density. Measurements have been carried out with all three core binder systems.The methods for blowing the test configurations have been evaluated and an optimised process determined. A ‘Best Practice’ guide has been produced.
-The concept of using contoured moulds with a reducing sand thickness has been developed and shown to achieve almost complete sand burnout whilst still retaining sufficient strength for casting.
Funding SchemeCSC - Cost-sharing contracts
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