Abstract (Technical Session)

Quality of casting shells is dependent on the viscosity of the shell-building slurry. This has two principal reasons: First, the viscosity is directly related to the solids content of the slurry and reflects shifts in its composition through evaporation of the liquid component. Second, the performance of the slurry is directly related to its flow characteristics. The thicker the slurry – the higher its viscosity – the slower it runs off the form and the thicker the layer that it deposits. If the viscosity is too low – the slurry is too thin – it flows off the form too quickly, and the deposited layer is too thin. Since shells are formed from multiple layers, any deviations of slurry viscosity can contribute to failures of quality and performance of the shells, which can, in turn, lead to defects in the parts cast in the shells.

In order to control viscosity, it is necessary to measure it. The accuracy of control – how well the viscosity of a slurry can be set and maintained throughout the casting process – depends on the accuracy and repeatability, but also the ease of use, of the chosen measurement. The traditional measurement method is the flow cup, which measures viscosity as the number of seconds required by the slurry to run out of the cup. This measurement is not suited for continuous, repetitive monitoring of viscosity, nor is it particularly accurate.

A robust balanced torsional resonator based inline viscometer brings accurate, repeatable and continuous monitoring of slurry viscosity during shell building. An integrated slurry viscosity tracking and control system is used to apply the viscometer’s measurements toward maintaining constant slurry viscosity during slurry preparation and shell building, despite evaporation losses, temperature changes and other influences that can cause unwanted changes to the shell quality. The inline viscometer and the integrated control system can, in addition, support the growing trend toward full shell-room automation, by reducing an important source of variability in the otherwise highly automated shell-building process.

Visit Us at Booth 222

Rheonics inline viscosity and density meters enable real-time monitoring and control of investment casting slurry properties to produce the best possible shell and casting quality. Viscosity and density of casting slurry are crucial to ensuring both the quality of the shell and the final castings for which it is used. Rheonics sensor put essential online quality control tools in the operators’ hands to optimize both the shell building and casting processes.

Realtime measurements give the operator valuable information about how the slurry will perform during the shell-building process, including factors like surface finish, strength, and ultimately, yield of top-quality castings.

Rheonics sensors let the operator adjust slurry parameters both during mixing and shell building, with individualized measurements for each layer as the shell is built up. In combination with the Rheonics SlurryTrack system, slurry properties can be automatically controlled without manual intervention, freeing operators to focus on their central job – to make the best shells and castings possible, despite variations in raw materials, mixing processes, and aging of the slurry. SlurryTrack is a standalone complete solution for ceramic slurry management that also integrates slurry measurement data into industrial SCADA systems thanks to a broad selection of built-in data interfaces. Full traceability of every shell is now at the fingertips of floor operators, production supervisors, and quality control personnel.

Highlights at WCIC

At the ICI world conference, Dr. Sunil Kumar and Dr. Joe Goodbread present a talk on the Realtime viscosity control for consistent shell building on Monday, August 22, 2022 in afternoon session.

During the EXPO, we invite you to come have an in-depth look at the underlying technology. At the exhibition, we will present the inline viscometer SRV, inline density and viscosity meter SRD and the SLURRYTRACK integrated system.

To learn more, visit us at Booth 222.

In investment casting slurry viscosity is an important process parameter. Keeping slurry viscosity within the proper range throughout the coating step is central to forming a uniform coating thickness and desirable shell properties, as well as avoiding some of the most common shell defects. Our technical presentation, will cover the following:

• • Overview of the shell building process
  • How are shell properties affected by ceramic slurry viscosity?
  • Why viscosity management is important in shell building?
  • Types of shell defects that can be alleviated with viscosity control during the mixing process
  • Process monitoring and control challenges – issues with traditional viscosity measurements
  • Why investment casters are embracing Industry 4.0, data-driven processes and digitalization
  • An inline sensor for simple integration in the slurry preparation drum
  • An overview of the SlurryTrack system: Data and insights from the sensor and a custom software
  • Unique advantages, technical specifications, and in-depth experimental analysis on the suitability of inline sensors for ceramic slurries