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1–10 of about 331 matches for sand "dimensional accuracy" OR repeatability
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EFFECT OF SAND VARIABLES ON DIMENSIONAL ACCURACY OF Al-4%Cu ALLOY CASTINGS PRODUCED BY V-PROCESS (19850735)
Transactions of the American Foundrymen's Society V 93 Paper 85-41 P 303-306, 1985 (4 pages)
Authors review sources of variation from dimensional specifications that are frequently experienced in V-Process molding Al-4%Cu alloy castings. In this study, the molding sand and associated parameters have been investigated to determine their effect on as-cast dimensional accuracy. The authors determined that sand grain shape, size and distribution have a pronounced effect on dimensional accuracy. Also, that V- Process parameters such as vibration frequency, vibration time, etc., all significantly affect dimensional accuracy. They suggest a system through which these variables can be better controlled, and document results of its application.

CASTING QUALITY AND DIMENSIONAL ACCURACY USING A RESIN BONDED AIRSET-SAND SYSTEM (19770764)
The British Foundryman (June 1977) p. 168-180, 13 pages
This paper illustrate 13 years experience of using a resin bonded airset sand and show the basic method of approach to making castings with two major aims in view: 1) Casting quality and surface finish. 2) Dimensional accuracy and consistency. The paper is presented under the following headings: 1) the process 2) Pattern equipment 3) Molding techniques 4) Coremaking techniques 5) Core breakdown 6) The process in practice. An attempt is made to illustrate step by step how a chemically-bonded sand system has been adapted for use in one particular foundry and an example of the results which can be achieved by reference to one particular casting.

SAND QUALITY IN MODERN MOLDING LINES (19730867)
AFS Transactions 1973, p. 129-134, Preprint No. 73-22, $3.00
The authors devised unique tests to measure directly the stripping ability of sand; its flowability; tendency to form scabs; tendency to "water explosion" defects (principally metal penetration); tendency toward mold wall movement; and resistance to erosion. These are illustrated in this paper. It shows clearly how difficulties grow with regard to stripping properties, scabbing tendency and explosion tendency. Raising the clay content has a favorable influence only on stripping properties, scabbing tendency, erosion tendency and mold stability. The explosion tendency is increased, however, and the flowability drops somewhat. In many respect, a higher moisture content has adverse effects, and actually has a favorable influence only on stripping properties and erosion resistance.

PRECISION SAND CASTING (20040529)
Proceedings from the AFS International Conference on Structural Aluminum Casting, 2-4, November 2003, Orlando, FL P 149-161, 2003 (13 p)
The "Precision Sand Casting" process is capable of producing castings with optimum mechanical properties, good dimensional precision, and significant flexibility in producing various geometric shapes with good surface finishes. This presentation will point out the capabilities of several variations of the ôDry Sand Castingö process to include static pour, the ôCosworthö process, and the ôLevel Pourö process. The capabilities that will be discussed are generic characteristics of each process, alloy limitations, product integrity and relative product / process costs. In addition, a simple comparison of several other precision casting methods will be reviewed.

COMPARISON OF THE QUALITY CHARACTERISTICS OF AL-7%SI ALLOY CASTINGS PRODUCED BY V-PROCESS AND GREEN SAND MOLDING PROCESS (19940236)
Indian Foundry Journal V 39 N 5 P 13-16 May 1993 (4 p)
While V-process castings have better dimensional accuracy and surface finish than green sand mold castings, other characteristics such as volume porosity, mechanical properties, solidification times, etc., are compared in this paper. Briefly, the superior dimensional accuracy of V-process was confirmed, porosities were higher in green sand molding, green sand molding produced higher tensile strengths and elongation, there was no difference in impact strengths, heat treatments showed higher property results with the green sand molded samples. Metallurgical reasons for the observed differences are offered.

SAND FACTORS IN HIGH PRESSURE MOLDING (19710408)

Two important aspects of high pressure molding are considered: (a) Molding materials suitable for high pressure applications. (b) The dimensional accuracy of castings produced in molds compacted by high pressure squeezing. It is possible to summarize briefly the factors necessary for high pressure molding and the advantages that can be gained: 1. Sands of high clay content are necessary to obtain high strength molds, of high mold hardness and density. For desirable molding properties and also economy there are practical limits to this clay content and a maximum of 18 percent appears to be satisfactory. 2. A close control of water content is necessary if consistent bulk densities and hardness are to be obtained. Water contents should be lower relatively than those used for conventional molding. 3. It is necessary for some organic additions such as dextrine or starch to be made to the sand if its "brittleness" is not to be increased at high pressures. 4. Squeeze pressures in the range 200 - 400 p.s.i. are necessary to develop the full potential of the molding sand. Pressures above this range appear to offer little additional advantage. 5. Sharp definition is obtained on a high pressure mold and thus any imperfections in pattern equipment are reproduced. Good pattern equipment is absolutely essential. 6. By high pressure molding, molds of uniform hardness and density are obtained. This is difficult with other methods of molding. 7. Close dimensional accuracy can be maintained for a particular molding sand composition than is usually observed with normal molding machines. This accuracy increases as squeeze pressure is raised.

STABILITY, ABILITY, PROFITABILITY IN GREEN SAND MOLDING/AN INDUSTRY COMPARISON (19840538)
Transactions of the American Foundrymen's Society V 91 Paper 82-62 P 699-706, 1983 (8 pages)
Paper discusses the work of AFS Committee 4M in compiling data on the dimensional reproducibility of high density green sand molds. The data collected is stored in a computer system which provides a sophisticated means of determining dimensional reproducibility as well as providing an informational file. Data has been collected on castings ranging up to 30 inches with a mean dimension of 18 inches. Also covered is the history of high density high pressure molding and the future objectives of the 4-M Committee.

Rating Your Casting Supplier (20090431)
MetalCasting Design & Purchasing, Vol. 11, No. 6, P 34-39, November/December 2009
Is you sand casting supplier the cream of the crop? Using 25 specific criteria, the survey on the following pages will help you evaluate sand metalcasting facilities to determine their aptitude as a casting supplier.

CASTING TECHNOLOGIES TO IMPROVE THE DIMENSIONAL ACCURACY OF THIN-WALLED IRON CASTINGS (20020236)
Transactions of the American Foundry Society V 109 Paper No 01-113 P 1-10, 2001 (10 p)
When substantial numbers of parts are rejected, deliveries are delayed, machining time and costs are lost, and the product cost and lead-time is increased. The American Metalcasting Consortium (AMC), which is supported by The Defense Logistics Agency (DLA), the American Foundry Society (AFS), and selected foundries producing military castings has supported efforts to reduce foundry and machine shop scrap. In one of the project tasks, the University of Alabama at Birmingham (UAB) has worked with foundries producing military castings to implement casting technologies that will reduce casting rejects. Bulk density measurements and tests to measure mold binder content were performed on samples from fluidity spiral molds (70% silica/30% zircon), 100% zircon ring molds, and 70% silica/30% zircon ring molds.

EFFECT OF HEAD PRESSURE IN MEASURING GREEN SAND PERMEABILITY (19990417)
Transactions of the American Foundrymen's Society V 107 Paper No 99-86 P 43-50, 1999 (8 p)
A means to verify a traceable calibration of a permeability test machine was researched. A test fixture was built that would allow for the measurement of process variables that occur during a permeability test. The results show that the AFS standard equation for permeability will provide different permeability values for the same orifice if different head pressures are used. The inconsistency in head pressure between permeability test machines is the major contributor to the inconsistent indicated permeabilities.

1–10 of about 331 matches for sand "dimensional accuracy" OR repeatability
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