本文之主要目的在研究濕模砂的各種性質以及相關造模性質參數。本文中除對以往所重視的造模性質參數，如壓縮比，作深入的探討，又提出以形狀因數作為新的濕模砂結構參數。文中亦針對長久以來迭有爭議的造模性參數（moldability）提出一理論模型加以探討，並導出柱狀試片之最大密度差與強度差的理論方程式。
經實驗證明Shapiro與Kolthoff所提出之方程式極為擠製壓力和相對密度間的關係。Sheppard及McShane所提出的強度方程式與本文實驗所得的強度值配合極佳，誤差小於5%。本文所提出的一維模型是綜合S-M與S-K兩個方程式推導出試片相對密度差值以及壓縮強度差值。

本文之理論計算強度差值與實際測得的柱狀試片中心截面的硬度分佈平均差值相比較後顯示具有一致的趨勢，可以供評估濕模砂性質之參考。根據實驗結果顯示，當濕模砂水分在3％以上時正規化強度差（normalized strength difference）變化甚小，一般多在0.15-0.2之間。此值越小代表濕砂模均勻性越高，但是當此值低於0.15時多為缺水的乾砂狀態無法造模。

形狀因數是由Darcy定律中的流體傳導係數（hydraulic conductivity）導出的。實驗顯示形狀因數可以有效反應濕模砂結構的變化，是一個很好的指標參數。形狀因數的最大值可以有效的做為最佳水分添加量的控制依據。

本文所提出的指標性參數經實驗驗證可以正確靈敏的顯示濕模砂的性質變化並協助瞭解其原因。這些指標參數應可有效幫助研究人員進一步瞭解濕模砂的特性並找出正確的控制方式。

本文之主要目的在研究濕模砂的各種性質以及相關造模性質參數。本文中除對以往所重視的造模性質參數，如壓縮比，作深入的探討，又提出以形狀因數作為新的濕模砂結構參數。文中亦針對長久以來迭有爭議的造模性參數（moldability）提出一理論模型加以探討，並導出柱狀試片之最大密度差與強度差的理論方程式。

經實驗證明Shapiro與Kolthoff所提出之方程式極為擠製壓力和相對密度間的關係。Sheppard及McShane所提出的強度方程式與本文實驗所得的強度值配合極佳，誤差小於5%。本文所提出的一維模型是綜合S-M與S-K兩個方程式推導出試片相對密度差值以及壓縮強度差值。

本文之理論計算強度差值與實際測得的柱狀試片中心截面的硬度分佈平均差值相比較後顯示具有一致的趨勢，可以供評估濕模砂性質之參考。根據實驗結果顯示，當濕模砂水分在3％以上時正規化強度差（normalized strength difference）變化甚小，一般多在0.15-0.2之間。此值越小代表濕砂模均勻性越高，但是當此值低於0.15時多為缺水的乾砂狀態無法造模。

形狀因數是由Darcy定律中的流體傳導係數（hydraulic conductivity）導出的。實驗顯示形狀因數可以有效反應濕模砂結構的變化，是一個很好的指標參數。形狀因數的最大值可以有效的做為最佳水分添加量的控制依據。

本文所提出的指標性參數經實驗驗證可以正確靈敏的顯示濕模砂的性質變化並協助瞭解其原因。這些指標參數應可有效幫助研究人員進一步瞭解濕模砂的特性並找出正確的控制方式。

This paper investigates the properties of green molding sands, and new concepts for evaluating the molding properties are proposed. A new structure parameter called shape factor is introduced to measure the structure of sand compact. A new model to evaluate the flowability of sand compact is developed.
Controlling the water content, green strength, and flowability of the molding sand is very important in sand casting process. Although several indices for molding properties have been proposed to measure the state of the green sand, none of them has been universally adopted as a reliable indicator. In this study, experimental results are presented to show how the flowability of silica sand is affected by water content, bentonite and seacoal content. The equation proposed by Shapiro and Kolthoff can well fit the relationship between compacting pressure and relative density. The coefficients of S-K equation were substituted into the strength equation proposed by Sheppard and McShane. The S-M equation matches the green compression strength data, with error less than 5%. The model reported here correlates a one-dimensional compaction model with S-M and S-K equation, and derives relative density difference and compression strength difference of the compact. The hardness deviation on the central plane of the compact was taken as the reference to test the estimated strength difference. The trend of the estimated strength difference was consistent with the hardness data. The model can explain the experimental results and directly predicts the uniformity of the compact.

The structure parameter shape factor is derived from the hydraulic conductivity. The experimental results showed that the shape factor is very sensitive to the structure variation. The maximum shape factor can be a good index for the best water content.

This study also investigated the mulling effects and additive effects. The experiment data showed that the shape factor and the estimated strength difference can clearly reflect the cause of the variation. The researchers as well as the foundrymen can further improve the control of green sand properties.

REFRENCES
Barlow, T. E., Green, R. A., 1964, “ Pressure density relationships in high strength sands,” AFS Transactions, vol. 72, No. 26, pp. 169-192.
Bear, J., 1988, “Dynamics of fluids on porous media,” Dover Publications, New York.
Bowers, J., Galloway, H., Nooden, R., and Wendt, L., 1993, “ Significant factors affecting MB test values using experimental design,” AFS Transactions, vol. 101, No. 13, pp. 593-596.
Caine, J. B., King, E. H., Schumacher, J. S., 1975, “Steel foundry sand clay bonding,” AFS Transactions, vol. 67, No. 13, pp. 59-64.
Carman, P. C., 1937, “Fluid flow through a granular bed,” Trans. Inst. Chem. Eng. London, vol. 15, pp. 150-156.
Carroll, M. M., Kim, K. T., 1984, “Pressure- density equations for porous metals and metal Powers,” Powder Metallurgy, vol. 27, No. 3, pp. 153-159.
Chen, C. J., Shih, J. F., Liang, J. H., Tsai, J. F., Uen, C. H., Li, S. M., 1980a, “The study for the clay balls in green sand,” 鑄工, vol. 65, pp. 1-6.
Chen, C.J., 1980b, “The computerized operation system for green sand daily control,” 鑄工, vol. 67, pp. 20-29.
Collins, R. E., 1961, “Flow of fluids through porous materials,” Rhinhold Co., New York.
Dietert, H. W., Graham, A. L., and Schumacher, J. S., 1970, “A new methylene blue procedure for determination of clay in system sands,” AFS Transactions, vol. 78, pp.208-212.
Droper, A. B., Knappenberger, H. A., “Green sand properties- median grain size effect,” AFS Transactions, vol. 69, No. 31, pp. 345-351.
Graham, A. L., Praski, R. M., 1978, “Methylene blue testing of system sands and preblended additives,” AFS Transactions, vol. 89, pp. 313-321.
Green, R. A., Heine, R. W., 1990, “Clay activation and moisture in green sand system,” AFS Transactions, vol. 98, No. 32, pp.495-503.
Heine, R. W., Green, R. A., and Schumacher, J. S., 1957, “How to determine moisture requirements of molding sands,” AFS Transactions, vol. 65, No. 8, pp.118-122.
Heine, R. W., Schumacher, J. S., and Green, R. A., 1976, “Bentonite clay consumption in green sand,” AFS Transactions, vol. 84, No. 62, pp.97-100.
Heine, R. W., Green, R. A., 1992, “Properties of green sand bonded with mixtures of calcium and sodium bentonite,” AFS Transactions, vol. 100, No. 92, pp.499-508.
Heine, R. W., Green, R. A., 1988, “Sand-clay-compactibility-moisture control graphs,” AFS Transactions, vol. 96, No. 96, pp.197-208.
Hofmann, F., Dietert, H. W., Graham, A. L., 1969, “Compactability testing, a new approach in sand research,” AFS Transactions, vol. 77, pp.134-140.
Moore, W. H., 1950, “Flowability of molding sands,” AFS Transactions, vol. 58, No. 46, pp.650-660.
Moore, W. H., 1978, “Ramming characteristics of molding sand,” AFS Transactions, vol. 86, No. 62, pp.1-6.
Odom, I. E., 1992, “Chemical and physical factors that influence MB analysis of bentonites and system sands,” AFS Transactions, vol. 100, No. 32, pp. 313-321.
Odom, I. E., 1988, “Functional properties of Na and Ca bentonites in green sand systems,” AFS Transactions, vol. 96, No. 34, pp.229-236.
Phillips, D. R., 1964, “Measurement of true clay and its effect on sand properties,” AFS Transactions, vol. 75, No. 41, pp. 215-221.
Robertson, R. H. S., 1951, “Assay of pharmaceutical clays,” J. Pharm. Pharmacol., vol. 3, pp. 27-35.
Roshan, H. Md., Sambasivam, S. V., 1977, “Effect of high-temperature properties of synthetic molding sands on mold quality,” AFS Transections, vol.85, No. 26, pp.251-258.
Sambasivam, S. V., Roshan, H. Md., 1977a, “Expansion and deformation characteristics of synthetic molding sands at elevated temperatures,” AFS Transections, vol.85, No. 15, pp.259-264.
Sambasivam, S. V., Roshan, H. Md., 1977b, “Influence of composition on expansion defects in synthetic molding sands,” AFS Transections, vol.85, No. 16, pp. 265-270.
Sheppard T., Mcshane, H. B., 1980, “Strength of cold-pressed compacts, powder metallurgy,” No.3, pp. 120-125.
Shih, T. S., 1986, “Green sand control (I)- properties and test of green sand,” 鑄工, vol. 50, pp. 15-41.
Shih, T. S., Green, R. A., Heine, R. W., 1984, “Evaluation of green sand properties and clay behavior at 7-15% bentonite level,” AFS Transactions, vol. 92, No. 68, pp.476-473.
Shih, T. S., Green, R. A., Heine, R. W., 1985, “Evaluation of green sand properties and clay behavior at 8-15% bentonite level: part II,” AFS Transactions, vol. 93, No. 100, pp.689-698.
Shih, T. S., Green, R. A., Heine, R. W., 1986, “Evaluation of 8-15% bentonite content green sands properties and clay behavior: part III- mulling effect and dry properties,” AFS Transactions, vol. 94, No. 15, pp.71-84.
Shih, T. S., Green, R. A., Heine, R. W., 1987, “Evaluation of 8-15% bentonite content green sands properties and clay behavior: part IV- summary,” AFS Transactions, vol. 95, No. 102, pp.145-162.
Shih, T. S., Hsieh, C. S., Kao, F. Y., 1992, “Determination of clay consumption by geometric modeling,” AFS Transactions, vol. 100, No. 83, pp.631-637.
Shih, T. S., Chang, C. H., 1989, “Concept of green sand control and its application,” 鑄工, vol. 61, pp. 18-28.
Shyu, S. W., Yang, R. S., 1993, “The research of the effect of squeeze condition on the properties of the standard test specimen of the green sand,” 鑄工, vol. 19, No. 3, pp. 1-18.
Shyu, S. W., Yang, R. S., 1997, “The effects of accumulated mulling and aging treatment on the properties of green sand,” 鑄工, vol. 23, No. 4, pp. 96-109.
Smienow, G. A., Doheny, E. L., Kay, J. G., 1980, “Bonding mechanisms in sand aggregates,” AFS Transactions, vol. 88, No. 91, pp.659-682.
Strobl, S. M., Schuster, F. W., 1997, “Gauging Green Sand Flowability Helps Predict Mold Quality,” Modern Casting, February, pp. 48-50.
Wenninger, C. E., Volkmar, A. P., 1970, “a new control tool; a graph for evaluating effectiveness of available bentonite within foundry sand systems,” AFS Transactions, vol. 78, pp.134-140.
Wu, H. T., Chen, C. J., Liang, J. H., Tsai, J. F., Shih, J. F., Uen, C. H., Li, S. M., 1980, “The study of process parameters and their influence on green sand performance,” 鑄工, vol. 66, pp. 1-11.
Zrimsek, A. H., Heine, R. W., 1955, “Clay, fines, and water relationships for green strength in molding sands”, AFS Transactions, vol. 64, No. 112, pp.575-580.
Kupczuns S. K., J. Szreniawski, 1983, “Hardness as an indirect Measure of Physical Properties of Densified Molding Sand, ” AFS Transactions, vol. 915, pp. 191-198.
王祥生，1990，”鑄造實驗技術”，東南大學出版社。
翁震杰， 2001， “U.S. metal casting demand & supply trends-2001”，鑄造月刊，140期，民國90年5月，pp.2-6。
劉文海，2001，“1999年日本鑄件市場綜論”，鑄造月刊，140期，民國90年5月，pp.7-9。
謝明師，1992，“鑄造手冊”，第四卷，“造型材料”，中國機械工程學會鑄造專業學會編(中國大陸），機械工業出版社。
松浦 誠，1986，“生砂鋳型の造型機構に関する研究”，廣島大學工學博士論文。