Paper No. 12 continued... The use of microwave is also effective to dry plaster molds and ceramics in addition to lost wax molds. For example, a prototype maker who is using plaster mold is always pressed for time, and they are spending 20 to 45 hours to dry their plaster molds at the temperature of approximately 280C/536F. Our recent drying test achieved 90% reduction in dry time of plaster molds. This paper will present technical details of improved drying efficiency and reduced drying time of plaster molds.
3:00 p.m. - 6:00 p.m. EXPO 6:30 p.m. - 8:00 p.m. RECEPTION WEDNESDAY, OCTOBER 19, 2016
8:00 a.m. - 8:10 a.m. OPENING REMARKS 8:10 a.m. - 8:50 a.m.
Paper No. 13
How It’s Made: Recent Developments in Ceramic Raw Material Used for Producing Shell Moulds Thomas Krumrei, Clemens Lind, CARRD Scot Graddick, Imerys Many different alloys are being cast using the investment casting process. Some alloys require the use of ceramic materials with extreme inertness and chemical stability in the face coat of the mould, while other alloys have far less stringent requirements. The ceramic system for the face coat must be selected in accordance with the reactivity of the alloy. While aluminium parts can be produced using an alumino silicate-based face coat, titanium and other reactive alloys require much more “high- tech” materials (like zirconia or yttria) in the face coat. The requirements for backup coats are quite uniform. Sufficient mechanical strength, good dimensional stability throughout the IC process, and easy knock-out are needed, regardless of the alloy. Therefore, backup systems for various alloys can also be quite specific, from a technical point of view. Synthetic minerals are certainly used in the IC process to provide necessary refractoriness and resistance against molten alloy attack. But, they can also be used to build shells with exceptional hot dimensional stability. Synthetic minerals are used to build shells designed to withstand high temperatures for an extended period of time, in SX and DS castings, and can also be adapted to ensure the tightest possible dimensional control during the production of turbo charger wheels. In this paper we will review mould systems particularly suitable for steel and stainless steel, for equiaxed casting of Ni-based alloys, and for Ti and TiAl alloys. We will discuss the selection of appropriate materials for the face coat for each alloy type, speak about ways to increase the build-up speed of the backup, and present application examples and case studies.
63rd Technical Conference & Expo Sponsors:
Conference tote bags sponsored in partnership with Remet® Coffee break sponsors: Paramelt ALD Vacuum Technologies, Inc.
8:50 a.m. - 9:30 a.m.
Paper No. 14
Reclamation and Reuse of Shell Ceramics in Investment Casting Victor Okhuysen, Michael Landeros, Hardik Shah, Cal Poly Pomona A report on investigations on the reclamation and reuse of shell ceramics
in investment casting. Bars of ceramic (6 inches x 3/4 inch x 3/8 inch) were mixed using recipes based on Fused Silica and Alumino Silicates common to investment casting. The bars were tested for green strength and hot strength at two temperatures, 760°C and 1100°C.
All heated
specimens were then broken apart manually and then broken down particulates in a ball mill. The sieve size distribution of the milled material was compared to that of the virgin material. Then, the reclaimed material was remixed and retested, and the results were compared to the virgin mixes.
The more promising mixes were run for several cycles.
The
alumino-silicates were successfully reclaimed at the highest temperature while the fused silica materials were not successful at any temperature except for partial reclamation of flour at 760°C (aluminum processing temperatures).
9:30 a.m. - 10:10 a.m. Paper No. 15
Three Dimensional Heat Treating for Lean Part Design & Manufacture Joseph Powell, Akron Steel Treating Co. + IQ Technologies, Inc. When designing a new casting, the part end-user and their part design team need to be on the same page with their casting house to make sure the part will have ease of manufacturability and proper “fit and function” at the lowest cost. For hardened parts, the part design team should also collaborate with their heat treater to provide the needed mechanical properties in the hardened casting for a suitably long part life, with the lowest cost alloy. However, to make part manufacture as lean as possible, and as fast as possible, ALL the parties in the part manufacturing chain, including the steel maker, the casting house, the machinist, grinder, the plater, the heat treater and the end-user need to collaborate. From inception of CAD part design, to alloy selection, to pre-heat treat casting geometry, to final machining and grinding operations, every party plays an integral role in eliminating waste in each step of the lean part making value stream. The presentation will explain how the heat treater should become a “full partner” in the lean part design and manufacturing plan. By controlling all “Three Dimensions” of the heat treat hardening process: uniformity of heating, uniformity of cooling and uniformity of surface stress state, the part distortion from the hardening process becomes more “predictable.” Predictable distortion can be managed in the part green size (before heat treat). Managed distortion reduces waste by lessening the need for post-heat treat straightening, grinding and other corrective measures to achieve net part shape. In addition, the proper balance of “Hardness + Ductility” is enhanced with the Third Dimension of hardening: optimal compressive residual surface stresses. Beneficial compressive residual surface stress gives parts better wear resistance and provides longer cyclic fatigue life for a given alloy of steel.
Lean collaboration of all parties in the entire part manufacturing value stream means better hardened castings at a lower overall cost of manufacture.
10:10 a.m. - 10:15 a.m. CLOSING REMARKS 10:30 a.m. - 6:30 p.m. National Museum of the US Air Force
October 2016 ❘ 25 ®
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