This blog is part 1 of a six part series on the development, design and application of the Simpson Multi-Mull.
Successful foundry equipment companies are continuously acquiring or internally developing innovative products that provide new capabilities and value to their customers. Product innovation can be revolutionary where substantial advances in capability are realized or evolutionary where the continuous introduction of small improvements advance and improve a technology. Both revolutionary and evolutionary innovations are part of the Simpson history and are in our corporate DNA still today.
The early 1960’s was a period of abundant, revolutionary development in a variety of foundry equipment technologies that significantly changed the capabilities of green sand foundries and that remain an important part of modern foundries today. At the time, leading foundry equipment suppliers recognized the need to evolve from labor intensive, manual operations to increasingly automated, high speed, high performance systems that could produce larger volumes of complex, high value, high quality castings at a lower cost.
In green sand molding many significant innovations occurred in this period. In 1957, Mr. Vagn Aage Jeppesen, a professor at the Technical University of Denmark, patented for a device producing flaskless green sand molds with vertical parting lines. In 1960, the Danish company Dansk Industri Syndikat A/S (DISA) acquired the patent and in 1962, a half scale prototype of a DISAMATIC molding machine was introduced at the International Foundry Trade Fair (GIFA) in Düsseldorf, Germany. Also in 1962, at the American company Beardsley & Piper Inc. engineers developed the MATCHBLOMATIC as the world’s first blow, squeeze horizontally parted flaskless matchplate molding machine. So, in 1962 the world was introduced to the first vertically parted flaskless molding machine and the first horizontally parted flaskess matchplate molding machine. The DISAMATIC and the automated matchplate molding machines, in their current forms, are the heart of many green sand foundries around the world today and have evolved substantially from their 1962 origins.
Also at this time Simpson recognized the future would demand that molding sand preparation systems would need to keep pace with the developments of the molding machines. Modern molding technology could produce molds which were denser, more uniform and with greater dimensional accuracy at substantially increased molding speeds. Tolerances which used to be solely for small castings could now applied to medium and large size castings. Rising labor and energy costs together with the increased speed and quality of modern molding machines increased the demand for larger volumes of precisely controlled molding sand produced at the minimal amount of labor and energy. Prior to the development of the continuous Simpson Multi-Mull, if the demand for sand increased the installation of more or larger batch mixers was required. Simpson realized a more effective solution was needed that would match the demand of modern molding machines for large volumes of quality molding sand while reducing the total investment in sand preparation equipment, lowering the operating cost and reducing the installation complexity of traditional high capacity batch mixing systems.
Around the same time Mr. Jeppesen patented the DISAMATIC Simpson received US patent #9,943,801 in December, 1957 for the concept of a continuous muller. As the concept was refined several additional patents followed such as the 1963 patent pictured here. The muller would be called the “Simpson Multi-Mull” and the first developmental unit, a small model #205F, was installed for testing at the National Malleable Iron Foundry in Cicero, Illinois USA. Based on the successful testing at National Malleable the first production machine, a larger model #22F, was installed in 1959 at the Whitehead Brothers Company in Dorchester, New Jersey – USA to produce a manufactured “naturally bonded” molding sand. The first Simpson Multi-Mull for a foundry was delivered in 1959 to one of the most technologically advanced foundries of the time – the Danville, Illinois plant of the former Central Foundry Division of General Motors Corporation. It was an outstanding success and high volume, quality & cost conscious foundries increasingly turned to the Simpson Multi-Mull in the following years as they updated and expanded their molding operations. Over the next 12 years 174 more Simpson Multi-Mulls were delivered to foundries all over the world including 57 more machines just to General Motors foundries around the world. Other notable early adopters included the Ford Motor Company, International Harvester (Navistar), General Electric, J.I Case, John Deere, Caterpillar, CWC, Kohler and CIFUNSA in Mexico and TUPY in Brazil. Today, approximately 450 Simpson Multi-Mulls have been installed in foundries all over the world producing sand for all kinds of foundries and all kinds of molding lines. The Simpson Multi-Mull is available in eight sizes with productive capacity of up to 400 metric tons per hour, in some applications, from a single machine.
To further improve the performance of large sand systems, in 1963 Simpson developed a prototype of a continuous pre-mixer/cooler utilizing many of the same concepts developed for the Simpson Multi-Mull. The Simpson Multi-Cooler® was patented by Simpson in 1966 and has developed into the most popular technology in the world for cooling and pre-conditioning molding sand prior to mixing. Together, the Simpson Multi-Cooler and the Simpson Multi-Mull represent the only proven and widely accepted continuous bentonite bonded molding sand preparation technology in the world and are, by far, the most efficient, effective and lowest cost method for producing high volume, high quality molding sand for medium to large sized foundries.
Factors that lead to the original development of the Simpson Multi-Mull in the 1960’s are even more true today. For example, with a mold size of 535mm x 650mm x 150mm the DISAMATIC® 2013Mk5-B of the 1980’s could produce up to 360 uncored molds per hour. Today’s DISAMATIC D3B-555 with the same mold size can produce up to 555 uncored molds per hour – a 54% increase in productivity utilizing the same molding space and labor inputs. Replacing two 2013Mk5-B’s with two D3B-555’s would double the required sand plant capacity to keep pace with the potential of the molding machines. To meet the increased productivity and capacity requirements of modern molding machines a continuous sand plant based on the Simpson Multi-Cooler and Simpson Multi-Mull will deliver the large volumes of closely controlled molding sand at the minimal amount of investment, space, material handling complexity, operating energy and maintenance costs.
Just as the molding machines of today are dramatically more advanced than their original designs, so are the Simpson Multi-Mull’s of today far better than the first generation machines. At the 2019 GIFA exhibition in Dusseldorf, Germany Simpson will introduce the latest evolution of the Simpson Multi-Mull with many new, innovative features designed to improve mixing performance, reduce maintenance costs, reduce operating costs and integrate the muller with advanced controls including “Industry 4.0” features and an improved additive dosing systems.
Part 2 – How the Simpson Multi-Mull works