10:30 a.m. - 10:50 a.m. 8:50 a.m. - 9:30 a.m. Paper No. 7
Investment Casting Bottom Pour Ladle Development Trials Dr. R.C. Voigt, Pennsylvania State University Nilesh Vanikar, Dr. Shantipal S. Ohol, College of Engineering, Pune Tanay Anjikar, Siddha Laxmi Engg. Pvt. Ltd. Bottom pour ladles and bottom pour stopper rod auto-pour systems
are commonly used in the metal casting industry. However, stopper rod bottom-pouring systems have not yet been developed for the smaller pouring ladles typical in use in the investment casting industry. The large thermal mass of these systems has typically limited the use of stopper rod bottom pour systems to ladles larger than 1500 lbs (700 kg). In this study, bottom pour ladle designs and low thermal mass refractory systems have been developed and evaluated in production foundry trials with 660 lb (300 kg) pouring ladles. The ladles systems and pouring practices used will be described along with the results from the pouring trials. The advantages and limitations of small ladle bottom pour systems will be described along with recommendations supporting the future development of small bottom-pour ladle systems for investment foundries.
9:30 a.m. - 10:10 a.m. Paper No. 8
A Comparison of Additive Manufacturing Technologies for Investment Casting Patterns Tom Mueller, Mueller Additive Manufacturing Solutions In the nearly 25 years since the first castings were made from QuickCast patterns, a number of additive manufacturing methods for creating IC patterns have come and gone and the use of printed patterns has become commonplace, especially for prototype castings. In North America, four technologies account for more than 98% of printed patterns used in industrial applications; QuickCast, Castform, ProJet Wax, and Voxeljet PMMA. While much has been published about the use of printed patterns in precision investment casting, to date there has been no detailed comparison of the capabilities of the four technologies.
This paper
attempts to do that. A detailed comparison must necessarily consist of three components:
1. Printer performance – this component compares the performance of the printers in areas such as accuracy, surface finish and build volume, and build speed.
2. Cost of Ownership – Cost of ownership includes not only the purchase price of the machine but cost of materials and the cost to build a given volume of patterns. It is a major concern to those considering the purchase of a machine and is the primary factor in determining the price of patterns for those planning to purchase printed patterns. This component details costs.
3. Pattern performance – Having a great printer is worthless if the pattern it creates cannot be reliably converted to an acceptable casting. This component details the cost and difficulty of converting printed patterns to castings.
Comparisons are based on measured performance as well as data and prices provided by the manufacturers.
10:10 a.m. - 10:30 a.m. Coffee Break sponsored by ALD Vacuum Technologies, Inc.
ICI/EICF Report: Process Control Standards, a Global Initiative Nipendra “Nip” Singh, S&A Consulting, ICI Director Our mission is to create a global standard for the use of process control methods to further enhance the investment casting industry while consistently meeting the customer’s expectations.
10:50 a.m. - 11:30 a.m. Paper No. 9
How It’s Made: Effects and Analysis of Thermal Stresses on Large Induction Furnace Refractory Linings for Molten Metal Applications Phil Geers, Blasch Precision Ceramics, Inc. Booth 223
One of the dominant factors which determine the life of refractory linings in large induction furnaces is the breakdown of the lining caused by various mechanical stresses caused by thermal expansion and contraction. While smaller induction furnace linings are inherently less prone to these issues due to the corresponding reduced scale, larger furnaces (300kg capacity and higher) will see a greater propensity for failure due to these compounding stresses. While improvements in the refractory materials to handle thermal shock are of course beneficial, the actual structure of the refractory lining can also have a great impact on how these stresses are handled. In this paper, furnace structures consisting of monolithic rammed, mortared brick, one piece, and segmented brick construction are all compared and analyzed using Finite Element Analysis techniques to determine where and why stresses are formed, and how they can be minimized.
Analysis is provided of various furnace lining systems, including a segmented design which avoids putting individual components into uneven tension, while providing unmortared engineered expansion gaps to provide room for thermal growth. In addition the incorporation of tensioned hold down system into the furnace structure is reviewed which provides a system to allow the refractory to expand and contract without the creation of large cumulative stresses.
11:30 a.m. - 12:00 p.m.
ICI/AFS Report: Update on the Collaborative Research Project on the MMPDS Project for 15-5 & 17-4 PH Stainless Steels Al Torok, Precision Propeller, Inc., ICI Director Jiten Shah, Product Development & Analysis (PDA), LLC Authors will present an update on the collaborative research project between AFS and ICI, funded by DLA/AMC(Defense Logistics Agency/ American Metalcasting Consortium) on the inclusion of 15-5 and 17-4 PH Investment cast steel properties into MMPDS (Metallic Materials Properties Development and Standardization, old MIL handbook 5). This is an effort to incorporate the static as well as fatigue properties derived statistically from test castings made in a production environment such that the design engineers can use the actual data off this handbook, rather than an ad-hoc “Casting Factor” traditionally being used. This will make casting competitive compared to its rivals – forged, wrought and fabricated & machined methods. There are fourteen foundries participating into this MMPDS project.
State of the art computer modeling was developed concurrently,
to predict the casting and wax injection (into the wax die), filling and solidification/curing processes with validations. Results of the simulation will be presented.
October 2016 ❘ 23 ®
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