MONDAY, continued
11:00 a.m. - 11:40 a.m. Paper No. 4: An Investigation into Misrun Defects in Investment Cast Stainless Steel Castings Gerald Richard, MAGMA Foundry Technologies, Booth 204 The Investment Casting industry produces complex castings to near net shape. Regularly, these precision components either have thin walls or thin features that are challenging to fill, which result in misrun defects. Producing these defects is especially problematic because they will likely reduce scrap castings due to their inability to be repaired, leading to lost time and high cost. Methods used to mitigate this challenge such as increasing shell and pouring temperatures can be effective, however, changing those thermal conditions are subject to process variation or could even produce defects of their own. Understanding how the melt front cools as it flows through the investment shell cavities, analyzing the temperature and velocity profiles of the flow front while the shell is cooling, and knowing the fluidity of an alloy’s impact on the length it can flow given a section thickness will provide the tools needed to gain insight as to why these defects develop and how to eliminate them. In this paper, a case study will be used to demonstrate the root cause of misrun defects and include tips to eliminate them.
11:40 a.m. - 12:20 p.m. Paper No. 5: Analysis of Thermal Distortion Data to Detect Issues in Investment Shell Materials Dr. Sam Ramrattan, Western Michigan University The investment casting industry has been using shell molding materials to produce complex near-net-shape parts for centuries. Over this time period, significant process advancements have been made to increase overall quality, especially in the areas of melt and fill. Despite these advancements, the investment casting industry still suffers from high scrap/rejection rates due to shell quality. A key contributor to these less than ideal yield levels is the inability to effectively monitor and/or evaluate the quality of incoming shell molding materials.
Research has shown that measurements from a disc-shaped specimen tests are better able to discriminate between investment shell materials. The tests that were considered in this recent research were thermal distortion test (TDT) and retained strength. The results suggest that measurement taken from these tests may provide the means to effectively monitor incoming shell materials.
This paper investigates the capability of monitoring investment shell materials using TDT data. TDT is considered for this purpose because it provides coupled thermal-mechanical investment shell behavior at head pressures and temperatures that can be adjusted to represent actual casting scenarios. TDT produces a high-dimensional dataset, as it produces multiple time-series profiles, referred to as thermal distortion curves (TDCs). In order to effectively use this dataset, this paper will incorporate multivariate statistical analysis for process monitoring. The proposed monitoring scheme will be demonstrated through a case-study. The ability of the proposed monitoring scheme to detect the shift from one investment shell system to another will be determined.
12:20 p.m. - 1:00 p.m. LUNCH 1:00 p.m. - 1:40 p.m.
Paper No. 6: Optimization of an Aerospace Casting: A Case Study Tom Mueller, Mueller Additive Manufacturing Solutions Solidiform, an aluminum aerospace investment casting foundry in Fort Worth, Texas has been casting an aircraft instrument housing for a defense supplier customer. Solidiform’s customer was looking to reduce weight on the aircraft the housing was used on with the objective of reducing fuel consumption. Using topology optimization and printed patterns, the company was able to present a design that would bring the company annual fuel savings.
August 2021 ❘ 15 ®
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