scholarly journals Minimising Defect Formation in Sand Casting of Sheet Lead: A DoE Approach

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 252
Author(s):  
Arun Prabhakar ◽  
Michail Papanikolaou ◽  
Konstantinos Salonitis ◽  
Mark Jolly
Keyword(s):  
Process Parameters ◽  
Surface Defects ◽  
Defect Formation ◽  
Casting Process ◽  
Sand Casting ◽  
Sand Cast ◽  
Factors Affecting ◽  
Screening Experiments ◽  
Traditional Manufacturing ◽  
Lead Sheet

Sand casting of lead sheet is a traditional manufacturing process used up to the present due to the special features of sand cast sheet such as their attractive sheen. Similarly to any casting process, sand casting of lead sheet suffers from the presence of surface defects. In this study, a surface defect type, hereby referred to as ‘grooves’, has been investigated. The focus has been laid on the identification of the main factors affecting defect formation in this process. Based on a set of screening experiments performed using Scanning Electron Microscopy (SEM) as well as the existing literature, a number of factors affecting the formation of such defects was identified and their corresponding significance was estimated using the Analysis of Variance (ANOVA) technique. The obtained results suggest that the most significant factor affecting defect formation in sand casting of lead sheet is the composition of the moulding mixture. Defect formation was also proven to be dependent on the sand grain fineness, the quality of the melt and some of the interactions between the aforementioned process parameters. Finally, an optimal set of process parameters leading to the minimisation of surface defects was identified.

OPTIMISATION OF SAND CASTING PROCESS FOR IMPELLER USING TAGUCHI METHODOLOGY

2020 ◽  
Vol XVII (2) ◽  
pp. 23-33
Author(s):  
Faisal Hafeez ◽  
Salman Hussain ◽  
Wasim Ahmad ◽  
Mirza Jahanzaib
Keyword(s):  
Surface Roughness ◽  
Surface Defects ◽  
A356 Alloy ◽  
Casting Process ◽  
Sand Casting ◽  
Gate Length ◽  
Taguchi Methodology ◽  
Confirmatory Tests ◽  
Binder Ratio ◽  
Response Measures

This paper presents the study to investigate the effects of binder ratio, in-gate length and pouring height on hardness, surface roughness and casting defects of sand casting process. Taguchi methodology with L9 orthogonal array was employed to design the experimentation. Sand casting of six blade impeller using A356 alloy was performed and empirical models for all the above response measures were formulated. Confirmatory tests and analysis of variance results confirmed the accuracy of the model. Binder ratio was found to be the most significant parameter affecting casting surface defects and surface roughness. This was followed by pouring height and in-gate length.

Experimental Work on Possibilities to Predict Casting Defects in LPDC Brass Castings

2006 ◽  
Vol 508 ◽  
pp. 561-566 ◽  
Author(s):  
Arto Muikku ◽  
Jari Hartikainen ◽  
Sami Vapalahti ◽  
Tuomo Tiainen
Keyword(s):  
Process Parameters ◽  
Surface Defects ◽  
Defect Formation ◽  
Process Window ◽  
Process Conditions ◽  
Actual Process ◽  
Open Time ◽  
Die Castings ◽  
Pressure Die Casting

In water tap production 0.5 mm of material needs to be ground off from the surface of LPDC (Low Pressure Die Casting) brass castings in order to remove the defects deteriorating the quality of later applied coating. In order to minimize the amount of removed material the causes of these defects need to be discovered and properly connected with the process parameter window. At Oras Oy foundry in Finland, nearly 100 castings were produced under actual process conditions. To monitor the process seven thermocouples were inserted into the die. Thermal camera was also used for monitoring the die conditions during the open time of the die. Castings were divided into sets of ten pieces for statistical reasons. A few key process parameters were selected based on the basis of earlier knowledge and they were systematically varied during casting experiments. Each cast piece was marked and later analysed in order to find the dependencies between detected defects and process parameters. Computer simulations of the process were conducted to study the possibility to use numerical simulations for defect prediction. It was found that shrinkage defects could be reasonably well predicted and the influence of the process parameters on their formation was also apparent. The predictability of surface defects, however, was poor and only indirect conclusions could be made. Observations were made using as cast, ground and polished and cut surfaces from certain sections of the castings. It is very difficult to make any conclusions on surface defect formation based on parameter variation. One reason probably is the too narrow process window, but several promising ideas on the influence of e.g. mould shape, temperature and composition of the graphite coating on the defect formation was discovered.

Multi-objective optimization of western bentonite (Al2H2Na2O13Si4)-blended green sand casting process parameters to improve mould quality

2020 ◽  
pp. 1-10
Author(s):  
M. Nandagopal ◽  
K. Sivakumar ◽  
S. Velmurugan ◽  
R.B. Durairaj ◽  
G. Mageshwaran
Keyword(s):  
Process Parameters ◽  
Wall Thickness ◽  
Research Work ◽  
Casting Process ◽  
Rejection Rate ◽  
Sand Casting ◽  
Green Sand ◽  
Weight Percentage ◽  
Mould Wall

The quality of the mould in the green sand casting process plays a vital role in achieving good quality castings. In this research work, the mould properties permeability and hardness are focused on to improve the quality of the mould. These properties are improved by optimizing the process parameters such as degrees of ramming, mould wall thickness, and weight percentage of western bentonite using Taguchi-based grey relational analysis. The optimal level of these process parameters is experimentally validated by producing castings in a modern jobbing foundry. In the validation experiments, the moulds are produced with nominal hardness (92) and the mould wall thickness is reduced by creating cavities for storage of gases at a distance of 30 mm from the mould cavity. An interesting result found is that the nominal mould hardness and reduced wall thickness improve the quality of the mould by increasing the permeability value from 80 to 120. The improved mould quality reduces the mould-related casting rejection rate in pressure plate casting from 40% to 30%.

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