For more than 10 years gravimetric dosing and blending units have started to capture market share within the Plastics Processing Industry.
For more than 10 years gravimetric dosing and blending units have started to capture market share within the Plastics Processing Industry. The basic process to blend ingredients in a hopper which stands on a weigh cell, in accordance with a preset recipe, was well known at the time and not only in the Plastics Industry. It was mainly used to prepare a larger quantity of the blend centrally, to move it to the production center and to feed it to the machine. A less expensive way, especially for the injection moulding industry rather than having a continuous, gravimetric system on each machine. The real innovation of the first batch dosing and blending units then was the compact design and the favorable price for a gravimetric unit. Machine mounted gravimetric blending in the injection moulding industry became more popular and replaced some of the volumetric blenders. The arguments for gravimetric batch blending have always been the repeatable blend accuracy, thus consistent product quality, automatic calibration even during the production process and reporting functions for quality management data recording. What has improved ever since? In addition to easier use and operation, better accuracy, reliability and a broader range of application opportunities, integration of Ethernet network technology contributes to today's success in the market. Higher performance controls through self-optimisation, intelligent process tuning, as well stainless steel parts. The production process would be unthinkable without gravimetric dosing and blending units in Injection Molding, Blow Molding and certainly Extrusion applications. GRAVICOLOR Sets New Standards To achieve optimum dosing accuracy and eliminating bridging problems, cone valves are used for all but the smallest quantities. The patented Motan Micro dosing technology is used for small amounts of additive. When separation of materials with different densities during conveying is not an issue, central blending sta-tions are the most cost effective solution. Sophisticated vibration management on the GRAVInet control, allows direct mounting, even on fast cycling injection molding machines. Speedy material changes, and easy cleaning are possible with either removable hoppers or windows. All controls can be operated through the webpanel, a full color and easy to use graphic touch screen. Set and actual process parameters, with the current throughput are all displayed on the screen. Stored recipes and documentation of process data for quality assurance can also be accessed via the touch screen. IntelliBlend – Intelligent Process Management The new generation GRAVInet control now qualifies as a self-learning and optimisation system. The focus is on achieving the highest possible mixing accuracy, within a running batch. Even before the batch is created, IntelliBlend applies the best start up conditions. The GRAVInet control automatically defines the most favourable sequence for all ingredients of the set recipe. During blending, every single dosing procedure is used for automatic throughput calibration. IntelliBlend immediately compensates for unavoidable dosing tolerances by exact adjustment of the following ingredients. After completing each batch, IntelliBlend corrects the remaining deviation in the following batch. GRAVInet controls also have an Ethernet interface and can be networked with other dosing and blending units as well as drying and conveying controls. Operation of all the controls can be from a local panel or central PC. IntelliBlend now meets all the different requirements of Injection molding and Extrusion applications, in regulating regrind. In a typical application for injection molding with regrind delivered from a granulator, any missing quantity of regrind will automatically be replaced in the batch by natural and color. With regrind, always available, as an important part of the blend which must not be missing, as is often the case with extrusion, then the regrind would be dosed after the masterbatch and natural. The GRAVIreport software is a Microsoft® Windows PC program, running under Windows XP, 2000 or NT. It is used for documentation, data acquisition and archiving of information for up to 252 GRAVICOLOR units. It gives an extended reporting capability for production and material data at local level and to higher level plant data management systems. All GRAVICOLOR units can be optionally equipped with an integrated conveying control, which allows the control of up to seven hopper loaders with blower stations.