Vibration molding of chamotte products of complex shapes

Abstract

The establishments of the refractories industry manufacture over 4000 different types and sizes of chamotte products of intricate shapes. A large proportion of these products are formed by hand from plastic compositions. Products of very intricate and special shapes are ordered in small batches and the orders are usually not repeated. The forming of the products by mechanical means on hydraulic and friction presses requires large outlays on the acquisition of equipment and the fabrication of heavy and expensive molds.The All-Union Institute of Refractories and the Borovich Refractories Combine have carried out experiments in the vibromolding of products of very intricate and special shapes on a vibration table designed at the All-Union Institute of Refractories [1 ] with a view to mechanizing the manufacture of these products.The vibration table contains 10 times less metal than a hydraulic or friction press. The power consumption is also lower [2]. Vibration tables permit the use of lightweight thin-walled molds because the pressure transmitted by the product being compacted to the wall of the mold as a result of the vibration and the static pressure does not exceed 10-15 kgf/cm 2.The choice of an example of a product of a special shape fell on the crucible (Fig. 1), which is a socalled multiheight product in which the difference in the height of the walls and bottom is large. The crucible weighs 10 kg. The products chosen for the manufacture of industrial batches weighed 34, 39, and 18 kg (Fig. 2).The crucibles were formed in a one-piece steel mold with 15-mm-thick wails, and the complex-shaped products of the experimental batches in sectional molds with wooden wails and steel dies.* Observations during the vibromolding process showed that the wear of the wooden wails reaches the permitted maximum after 20-25 moldings so that these walls can be used for the manufacture of a batch of 15-20 products.In order to match the technology of vibromolding to production conditions, the experiments were conducted with chamotte powders of the grain-size distribution used at the Borovich Combine (Table 1}. Tests were carried out with the standard chamotte powders used for the manufacture of complex-shaped *The molds for the products of the experimental batches were designed by M. M. Rusinskii.