As a company specializing in custom-engineered systems for individual applications, Netzsch was able to manufacture a line of grinding mills to meet Deft’s requirements. To obtain a uniform particle size distribution in the micron and submicron particle size ranges, such as are necessary to produce Deft’s premium epoxy primer and topcoats, Netzsch proposed a variety of horizontal grinding mills, ranging from one-liter lab mills to 200-liter production mills.
Testing the Equipment
Before purchasing any Netzsch mills, a series of equipment tests were performed at Deft’s facility. Mahir Barkho, plant engineer at Deft, said, “In a laboratory testing, Netzsch’s technical people on the floor were experienced and knowledgeable about the equipment and the product line. They had great input during the test.” With all laboratory tests resulting in superior performance records, Deft expanded its manufacturing facility and purchased a variety of custom-built Netzsch horizontal mills to replace its current stock of vertical mills.
Custom Solutions
More specifically, Netzsch custom-manufactured a series of small Liegende Mühle Eccentric (LME) media mills capable of dispersing particles by shearing and impinging forces and attrition. In Deft’s application, these mills are equipped with an agitator design based on the epoxy primer needed to be processed. The rotation of this custom-built agitator imparts energy to the surrounding grinding media. These forces act on the solids suspended in a liquid as they are continuously pumped through the grinding chamber. The forces crush the solid particles, resulting in an overall reduction in the particle size.Compared to Deft’s original vertical mills, Netzsch’s horizontal configuration offers easier maintenance and operation, improved power consumption, cooling efficiency, and simple cleanup.
Each small media mill is designed with the LME disc milling system, the most successful disc grinding system in the world. In Deft’s case, Molinex discs are best suited for their application of discrete pass processes. The function of these discs is to accelerate the grinding media centrifugally from the outer edge and centripetally from the inner edge of the disc, creating shearing forces between the disc and the media. When the shaft is rotated with the media mill, the Molinex discs create an augering effect that pulses the grinding media against the product flow. This reduces hydraulic packing and results in an even distribution of the grinding media in the chamber. With this system, Deft is capable of processing low- to medium-viscosity (1–200 poise) formulations. Solid levels in paint applications for Deft’s industrial and aerospace paints have been as high as 85%, resulting in the ability to process very low-VOC formulations. This is necessary for compliance with California and national environmental regulations.
These LME mills were installed on a predesigned floor plan and are used in Deft’s research and development, as well as on the production floor. The Netzsch grinding mills assist in producing paint products for aerospace, farm equipment and general industrial use. According to Harry Way, Netzsch R&D manager, “Deft’s application of our mills is extremely precise. Working in the aircraft industry, the quality of our grind must be consistent and repeatable.”
Most recently, Deft upgraded one of its original Molinex mills to Netzsch’s new high-flow design of Trinex discs. The Trinex, or tri-globe disc milling system, applies the principles of the eccentric disc pulse grinding effect at a higher frequency. With this upgrade, Deft’s production increased over 200%.
In addition, Netzsch provided a series of flexible LME 1 lab mills for small-batch analysis, evaluation of dispersions, and determining process capability of larger mills.
Into the Future
Together with Netzsch’s technical sales and service and Deft’s team of chemists and formulators, the two growing manufacturers meet the needs of their end users. This is accomplished by establishing the ideal grinding system, which results in the formulation of the proper coating primer. Deft recognizes that all coating systems need proper support if they are to offer the true benefits they are designed to give.Today, the companies continue their commitment to the highest standards in their products, people and service. Barkho says, “As the need for superior products is required, I would expect Netzsch to lead us into the new era of dispersion and grinding. Netzsch’s role [in the future] is to design new technology, using the design inventions and development that will reflect enhanced performance and quality.”
With the creation of several new mills, and a new laboratory facility scheduled to be completed by October 2000, the company is committed to continuous success.
For more information on mixing equipment, contact Netzsch Inc., 119 Pickering Way, Exton, PA 19341-1393; phone 610/363.8010; fax 610/363.0971; visit www.netzschusa.com.
