Breaking new barriers in solutions to porosity

Over the last 30 years Ultraseal has focused on ground breaking solutions to the ubiquitous problem of porosity in castings. This experience and knowledge has resulted in Ultraseal being recognised as the world leader in providing turn-key solutions through both equipment and sealant to a global customer base.By specialising on vacuum impregnation technology and associated processes and specifically focusing on the needs of its customers, Ultraseal is able to offer a wide range of services and products in the general field of fluid technology. The experience and knowledge that has been gained through combining mechanical and chemical engineering has enabled us to offer innovative solutions to the needs of industry.

Quality & Efficiency
With the relentless drive towards greater quality and efficiency, suppliers must continue to enhance their product range and develop innovative solutions to meet client demands.Ultraseal International has always been at the forefront of innovation in impregnation technology. Its success in researching and developing high-quality sealants is demonstrated by its strategic global partnership with leading companies across a diverse range of industry sectors.Ultraseal International maintains total control of the production and quality assurance processes by having all the resources from research and development through to manufacture and despatch at one centrally located site.The company is responsive to ever-changing legislative and environmental considerations, is registered to BS EN ISO 9001:2000, and is committed to achieving the highest global quality standards.

On-site Laboratory
An extensive on-site laboratory at Ultraseal’s UK headquarters performs two key functions: firstly, quality checks on raw materials as well as monitoring production (in addition to testing samples of customer’s sealants when required). Secondly, it concentrates on research and development work crucial to the implementation of new products to meet future requirements, and to maintaining Ultraseal’s world-leading position in the impregnation industry.

Research
Ultraseal’s research and development programme is supported by major universities in the UK who specialise in the filed. This synergic relationship brings together the combined resources of both parties, involving the theory and practical experience necessary for effective development. The results of these studies are invaluable tools, not only in the development of the next generation of sealants but also in fully exploring the future requirements of process equipment.

Ultraseal International: Providing Synergy to the IndustryFew companies worldwide can match Ultraseal’s experience and expertise in both machinery and sealant technology and it is this unique marriage which is not only maintaining, but enhancing the company’s position as a partner to household name global players in the automotive, aerospace and general manufacturing sectors.Backed by highly responsive, worldwide service support, and with a dedication to customer satisfaction second to none, Ultraseal’s position as the world’s leading provider of impregnation solutions remains unchallenged.

What can Ultraseal offer?
Equipment from simple top-load to sophisticated systems
Productivity through automation
Sealant and associated chemicals
Conversion packages for existing equipment
Engineering expertise
Product training
Process Knowledge
Laboratory support
After-sales back-up
A complete turnkey solution!

more

Porosity
Porosity is a measure of the void spaces in a material, and is measured as a fraction, between 0–1, or as a percentage between 0–100%. The term porosity is used in multiple fields including manufacturing, earth sciences and construction.
Contents
1 Porosity in earth sciences and construction
1.1 Porosity and hydraulic conductivity
1.2 Sorting and porosity
1.3 Porosity of rocks
1.4 Porosity of soil
1.5 Types of geologic porosities
2 Measuring porosity
3 See also
4 References

more

Foundry

A foundry is a factory which produces metal castings from either ferrous or non-ferrous alloys. Metals are turned into parts by melting the metal into a liquid, pouring the metal in a mold, and then removing the mold material or casting. The most common metal alloys produced are aluminum and cast iron. However, other metals, such as steel, magnesium, copper, tin, and zinc, can be processed.

The people who work in the foundry making molds and pouring castings traditionally worked moving sand extensively, and thus were affectionately called sandrats.

Contents

1 Melting
1.1 Furnace
2 Molding
3 Pouring
4 Shakeout
5 Degating
6 Surface Cleaning
7 Finishing
8 Advantages
9 References
10 See also
11 External links
//

more

Sand molded casting

A sand casting is a cast part, which is produced by forming a mold out of a sand mixture and pouring a casting liquid (often molten metal) into the mold. The mold is then air-cooled until the metal solidifies, and the mold is removed. Sand Casting is basically done in these steps:
1. Place a pattern in sand to create a mold2. Incorporate a gating system3. Remove the pattern4. Fill the mold cavity with molten metal5. Allow the metal to cool6. Break away the sand mold and remove the casting.

There are two main types of sand molding. "Green sand" is a mixture of silica sand, clay, moisture and some other additives. The "Air set" method uses dry sand that is bonded to other materials other than moist clay, using a fast curing adhesive. When these chemicals are used, they are collectively called "air set" sand castings to distinguish these from "green sand" castings. Many chemicals and mixtures have been designed for this use. Two general sand types are Natural bonded (bank sand) and synthetic (lake sand). And because synthetic sand's composition is more controllable it is preferred.

With both methods, the sand mixture is packed around a master "pattern" in order to form a mold cavity. If necessary, a temporary plug is placed to form a channel for pouring the fluid to be molded. Air-set molds often form a two-part mold having a top and bottom. The sand mixture is tamped-down as it is added, and the final mold assembly is sometimes vibrated in order to compact the sand and fill any unwanted voids in the mold. Then the pattern is withdrawn along with the channel plug.

Then the casting liquid (typically hot molten metal) is poured into the mold cavity left by the pattern. After the metal has solidified and cooled, the casting is separated from the sand mold. The mold is often designed to be single-use. There is typically no mold release agent, and the mold is generally destroyed in the removal process.[1]

The accuracy of the casting is limited by the type of sand and the molding process. Sand castings made from coarse green sand impart a rough texture on the surface of the casting, and this makes them easy to recognize. Air-set molds can produce castings with much smoother surfaces. Surfaces can also be ground and polished, for example when making a large bell.

After molding, the casting is covered in a residue of oxides, silicates and other compounds. This residue can be removed by various means, such as grinding, or shot blasting.

During casting, some of the components of the sand mixture are lost in the thermal casting process. Green sand can be reused after adjusting its composition to replenish the lost moisture and additives. The pattern itself can be reused indefinitely to produce new sand molds. The sand molding process has been used for many centuries to produce castings manually. Since 1950, partially-automated casting processes have been developed for production lines.

Contents
1 Simple manual sand casting process
1.1 Patterns
1.2 Molding box and materials
1.3 Chills
1.4 Cores
1.5 Design requirements
2 Types of Sand Castings
2.1 Green Sand
2.2 Cold Box
2.3 No Bake Molds
3 Essential improvements of the foundry technology
4 Fast molding & sand casting processes
4.1 Mechanized sand molding
4.2 Automatic high pressure sand molding lines
4.2.1 Horizontal sand flask molding
4.2.2 Vertical sand flaskless molding
4.2.3 Matchplate sand molding
5 Decorative use of wood patterns
6 Alternative casting methods
7 See also
8 References
9 External links
//

more



FOUNDRY SAND
Material Description
ORIGIN Foundry sand consists primarily of clean, uniformly sized, high-quality silica sand or lake sand that is bonded to form molds for ferrous (iron and steel) and nonferrous (copper, aluminum, brass) metal castings. Although these sands are clean prior to use, after casting they may contain Ferrous (iron and steel) industries account for approximately 95 percent of foundry sand used for castings. The automotive industry and its parts suppliers are the major generators of foundry sand.

The most common casting process used in the foundry industry is the sand cast system. Virtually all sand cast molds for ferrous castings are of the green sand type. Green sand consists of high-quality silica sand, about 10 percent bentonite clay (as the binder), 2 to 5 percent water and about 5 percent sea coal (a carbonaceous mold additive to improve casting finish). The type of metal being cast determines which additives and what gradation of sand is used.

The green sand used in the process constitutes upwards of 90 percent of the molding materials used.(1)

In addition to green sand molds, chemically bonded sand cast systems are also used. These systems involve the use of one or more organic binders (usually proprietary) in conjunction with catalysts and different hardening/setting procedures. Foundry sand makes up about 97 percent of this mixture. Chemically bonded systems are most often used for “cores” (used to produce cavities that are not practical to produce by normal molding operations) and for molds for nonferrous castings.

The annual generation of foundry waste (including dust and spent foundry sand) in the United States is believed to range from 9 to 13.6 million metric tons (10 to 15 million tons).(2) Typically, about 1 ton of foundry sand is required for each ton of iron or steel casting produced.

more

repair of Ex d enclosures

go here
the process of overhaul and repair

[DOC]
17060 Overhaul and repair explosion-protected electrical equipment ...
File Format: Microsoft Word - View as HTMLpurpose: This unit standard covers the overhaul and repair of explosion-protected equipment using the flameproof enclosure technique (Ex d) of protection ...www.nzqa.govt.nz/nqfdocs/units/doc/17060.doc - Similar pages

Overhaul & repair explosion-protected equipment (Ex d)
''''(Increased safety equipment Ex e) '' '''UTE NES215Z A''' Overhaul & repair explosion-protected equipment (''Flameproof enclosure Ex d)'' ...tpu.bluemountains.net/unit-wtf.php?recordID=23625&s=224 - 13k - Cached - Similar pages

[PDF]
2004 EX Digest 1.qxp
File Format: PDF/Adobe Acrobat - View as HTMLEx-d enclosures to be individually tested at 1.5 times ... The Ex-d non-metallic switch has a small internal volume. ..... user cannot repair them. ...www.crouse-hinds.com/crousehinds/sound_ideas/Chapter4.pdf - Similar pages

UTENES215ZA Overhaul & repair explosion-protected equipment (Ex d ...
UTENES215ZA Overhaul & repair explosion-protected equipment (Ex d) Overhaul and ... Flameproof enclosure Ex d) 1 Prepare for overhaul/repair of equipment 1 ...tpu.bluemountains.net/unit-xml.php?recordID=23625&s=224 - 15k - Cached - Similar pages

Computer simulation aids casting.

In the design of die casting dies, the object is to produce sound casting as cheaply and rapidly as possible. At the same time consideration must be given to suitable die size, locations of gating system, and selection of an appropriate die casting machine. Foundries in many cases encounter difficulties to ensure shortened lead-time in designing a new die for new product. A lot of estimations have to be done which use fundamentally based on previous experience and application of various mathematical and empirical equations.

In this work, main die design procedures and related equations are presented in a logical way. A computer program is developed to estimate main die elements based on the geometry input of casting shape. After initial inputs have been given, the system does full calculations, optimizes selections, and lists main die element sizes. The program can present die characteristics and casting machine characteristics. From both characteristics the optimum die elements were optimized. Optimum filling time and gating dimensions among other elements of die are estimated. Cooling time, cooling channel locations, and flow rates relations are estimated and presented.

more

By Karlsson, LarsPublication: Modern Casting Date: Thursday, February 1 1996Subject: Steel industry (Equipment and supplies), Steel casting (Process) (Equipment and supplies), Computer simulation (Usage), Steel castings, Applications softwareProduct: Steel Castings, Applications Software NEC
You are viewing page 1
Computer simulation of filling and solidification at this Swedish foundry cut lead times, reduced scrap and ensured quality.
Since 1980, Svedala-Arbra's steel foundry, located in southern Sweden, has been developing methods to produce heavy steel castings using the vacuum molding method - the V-process. The steel foundry produces about 6500 metric tons (7150 tons) annually - mainly machine and
google_ad_client = 'pub-2905054723170537'; // substitute your client_id (pub-number)
google_ad_channel = '6331884817';
google_ad_output = 'js';
google_max_num_ads = '3';
google_ad_type = 'text';
google_feedback = 'on';
Ads by GoogleMetal Injection MoldingMIM forms complex metal shapes without the need for machining.http://pagead2.googlesyndication.com/pagead/iclk?sa=l&ai=BYv2lfS0ASKDGC4LcvAP3ltH2DcWArx6TuYWXAcCNtwGQxywQARgBIM7jkQIoAzgAUIbVja37_____wFg5brmg7wOoAGlzuf-A7IBE3d3dy5hbGxidXNpbmVzcy5jb23IAQHaAUVodHRwOi8vd3d3LmFsbGJ1c2luZXNzLmNvbS90ZWNobm9sb2d5L2NvbXB1dGVyLXNvZnR3YXJlLzU0NjI5OC0xLmh0bWyAAgGoAwHoAwzoA58C6AMx9QMCBAAA&num=1&adurl=http://www.alberox.com/mim.htm&client=ca-pub-2905054723170537Bueno Technology Co., LtdSpecialized on investment castings, cf3m, Pctfe, Duplex, Monel, Peekhttp://pagead2.googlesyndication.com/pagead/iclk?sa=l&ai=BQNUSfS0ASKDGC4LcvAP3ltH2DfXF0EaFia65BMCNtwHwvvobEAIYAiDO45ECKAM4AFDb6cL1-f____8BYOW65oO8DrIBE3d3dy5hbGxidXNpbmVzcy5jb23IAQHaAUVodHRwOi8vd3d3LmFsbGJ1c2luZXNzLmNvbS90ZWNobm9sb2d5L2NvbXB1dGVyLXNvZnR3YXJlLzU0NjI5OC0xLmh0bWypAquAELe3uGE-qAMB6AMM6AOfAugDMfUDAgQAAA&num=2&adurl=http://www.pfalinedvalve.com/e-main.htm&client=ca-pub-2905054723170537Foundry and Process EquipUsed Foundry and Process Equipment Mullers, Melt, Blast, Pollutionhttp://pagead2.googlesyndication.com/pagead/iclk?sa=l&ai=BAoVKfS0ASKDGC4LcvAP3ltH2DYuDiibz38f2AcCNtwHgtg0QAxgDIM7jkQIoAzgAUKLf9Y34_____wFg5brmg7wOsgETd3d3LmFsbGJ1c2luZXNzLmNvbcgBAdoBRWh0dHA6Ly93d3cuYWxsYnVzaW5lc3MuY29tL3RlY2hub2xvZ3kvY29tcHV0ZXItc29mdHdhcmUvNTQ2Mjk4LTEuaHRtbKgDAegDDOgDnwLoAzH1AwIEAAA&num=3&adurl=http://www.morriseq.com&client=ca-pub-2905054723170537wear castings for crushers.
Compared to conventional sand molding, there are several benefits to using the V-process that result in a lower total production cost for the foundry and a high quality casting.
However, to obtain the desired casting results with the V-process, several precautions must be taken. The major cause of scrap is "mold collapses." As a mold fills with metal, the plastic melts and opens the mold up to the vacuum. If the air lost through the vacuum is not replaced with air from the atmosphere to equalize the pressure, the sand in the cope may fall in, causing a mold collapse. To prevent this from happening, air is drawn into the mold through a communicator, which could be a riser from the outside.
To minimize the risk of these defects, computer simulation can be used to analyze the filling sequences and optimize the casting and gating design. In this article, some examples of simulated and cast results of vacuum molded steel castings are presented.
Simulation Engineering
Simulation and calculation methods are used at Svedala for several different purposes. The development process can be described as a kind of simultaneous engineering. The design department is responsible for the coordination of the different activities during the process. The development work is carried out parallel in respect to time with the engineers from the involved departments. To avoid suboptimizing any part of the manufacturing process, engineers collaborate throughout the product development process.
Finite element-based software systems are used to analyze general solid mechanics and dynamic problems. When preparing the cast part for optimum castability, foundry engineers use a computer simulation program (MagmaSoft) based on the finite difference/finite volume method.
Simulation of Filling and Solidification
As a first step, a 3-D model of the cast part with gating and feeding system is created in a 3-D computer aided design (CAD) environment [ILLUSTRATION FOR FIGURE 1 OMITTED]. The CAD-model is then divided into elements [ILLUSTRATION FOR FIGURE 2 OMITTED]. The element mesh is generated automatically after setting a few parameters describing the mesh accuracy. Before starting the calculations, the operator sets different boundary conditions like heat transfer values, and initial conditions such as start temperatures for the appropriate materials, including the type of alloy and mold and core sands.
This article focuses mainly on the filling calculations needed to optimize the gating system to obtain calm filling. Filling calculations are often used primarily to find the right temperature distribution as start values to the solidification simulation. But with the V-process, a more detailed analysis of the filling calculations must be carried out to minimize the risk of the casting defects that might occur due to uncontrolled filling.
Filling Characteristics
When producing a vacuum mold, the pattern plate is mounted on a hollow patternbox connected to a vacuum system. A sheet of thin plastic is preheated and vacuum-formed to the contour of the pattern. After applying the mold coating, a special flask is positioned on the pattern plate and filled with dry, unbonded sand while vibrating the mold. The flask is then connected to the vacuum system. Following the separation of the pattern from the mold, the two half molds are set together with cores, insulating sleeves, etc. and transferred to the pouring station.
During filling of the mold cavity, three different "filling steps" occur with respect to the air flow in the cavity.
* When pouring begins, the air in the cavity is heated and escapes out of the cavity through the vents.
* After the filling gets more stable, air is drawn into the cavity through the vents as shown in Fig. 3. Because the plastic film becomes moist a few millimeters above the melt front, the underpressure causes the air to flow out of the cavity and into the mold. Air is drawn into the cavity through vents to prevent an underpressure in the cavity that could cause a mold to collapse.
* At the end of pouring, the airflow turns and the remaining air in the cavity and vents is pressed out through the vents. This part of the filling is critical and demands careful design of the venting system.
If the gating and venting design is incorrect, the scrap due to mold collapses and sand inclusions will increase. This unforgiving design is the major potential disadvantage with the V-process and must be treated with care.
Filling Simulation
All filling of V-process molds should be done smoothly. The metal should enter the lower part of the casting with a laminar flow, but with a higher flow rate than used in green sand molds. Three different castings of moderate complexity will be examined below. The examples focus mainly on how to analyze different types of filling problems.
Example 1: Pressurized or Unpressurized Gating System? - In general, an unpressurized gating system is preferable when using a bottom-pour ladle. However, for a vacuum-molded steel casting, the metal flow must never be turbulent. The casting in Fig. 4 is machined on all surfaces and experienced initial sand inclusions in its upper region. During filling with the original unpressurized gating system, the metal was flowing uncontrollably in a "wave-like fashion" next to the gate due to a pressure drop when the metal entered the cavity. By changing to a pressurized gating system, the flow is controlled and sand inclusions in the top of the casting were eliminated. Several hundred filler rings have been produced this way without any weld repair, resulting in shorter lead times and lower manufacturing costs.
Example 2: Multiple Filling - By controlling the pressure in the gating system for a multicavity mold, all the castings are filled simultaneously. This is necessary to prevent a mold collapse in the last-filled detailed. Figure 5 shows an example of a computer simulation designed to the dimensions of the different gates. The parting of the mold and other practical considerations determine the positions of the gates. Multiple-casting patterns are of course beneficial for the total capability of the vacuum molding plant.
Example 3: Velocity Drop in Curved Gating System - The often-used rule that a decreasing cross-section in a gating causes a proportionally related pressure drop is not necessarily true. For instance, a gating system with curved gatings [ILLUSTRATION FOR FIGURE 6 OMITTED] leads to frictional losses at the mold/metal interfaces. These losses cause a velocity drop that results in a longer filling time for the casting.
Originally, straight gates were used, but severe erosion at the steps of the mantle demanded a better solution. To prevent mold erosion or collapse due to high pressure, a refractory impact plate was placed at the lower end of the downspine. The new and improved design resulted in better surfaces and wear characteristics of the mantle.
Solidification Simulation
The simulation of casting solidification is an aid for foundryman to predict shrinkage and porosity in castings. Following are two examples of how solidification simulation can be used.
A simple, but important result of the collaboration between the design and foundry engineers is shown in Fig. 7. Computer simulated results of the original design indicated porosity in the area where the mantle is exposed to wear. Design changes were made, which allowed the part to be converted from hand to V-process molding. With the final design, no porosity was found.
In Fig. 8, a frame end with a casting weight of about 2.5 metric tons (2.75 tons), is shown at 50% solidification. When examining the internal cores (made from olivine sand) in Fig. 9, it can be seen that sintering occurs at the surfaces of the casting's center with accompanying surface defects on the casting. For this reason, chromite sand replaced olivine for the internal cores.
Conclusions
Computer simulation of the casting process gives the foundryman information on how to design the casting and gating system properly. The principle of the calculations can be generalized to more complex castings without any restrictions. A proper casting design results in lower scrap and less repair welding for the foundry. Using simulation, development times are decreased and the foundry gets as close as possible to a "right the first time solution."
1 2 3 4 5 Next Page
if (typeof floatingInterstitialAdHandlerObj == "undefined")
{
floatingInterstitialAdHandlerObj = new floatingInterstitialAdHandler('3',24,true,'546298');
}
if(typeof(adsObj) == "undefined")
{
adsObj = new Ads(true)
adsObj.setAdsRefreshTimestamp();
adsObj.setAdsRefreshPeriod(10000000);
}
function pageclick_4941716(pageNumIn)
{
// ab_click stuff --- --- ---
var configId = 4941716;
var pageNum = pageNumIn 1;
var leadingZeros = '000';
var componentParam = '';
if (pageNum >= 10 && pageNum = 100 && pageNum = 1000) { leadingZeros = ''; }
componentParam = configId + '_pg' + leadingZeros + pageNum;
ab_click(componentParam,546298);

// Ads stuff --- --- ---
adsObj.requestAdsRefresh();

// Request creation of floating interstitial ad --- --- ---
floatingInterstitialAdHandlerObj.requestAdCreation();
}
paginator_4941716 = new Paginator("paginator_4941716",800,"bodyWindow_4941716","bodyBox_4941716","navBox_4941716","pageIndWrap_4941716",
"pageIndNum_4941716", "#ffffcc",
'true','\nNext Page \n', '\n Previous Page\n',
'10', '\n__page_num__\n', '\n__page_num__\n',
pageclick_4941716, matchColumns);


=0) (navigator.userAgent.indexOf("WebTV") >= 0))
{
document.write('');
document.write('');
}
//-->


In addition, make sure to read these articles:
QUESTION: "What has been your greatest success story with...
Mathsoft and ANSYS Announce an Integrated Solution for Engineering...
MSC.Software and Kettering University Unite To Offer Master's Degree...
Sponsored Results
Investment Casting Supplier

more

This article presents an approach to making an aluminum automobile prototype by integrating numerical simulation and rapid prototyping into investment casting. Following the integrated prototype procedure, a sound aluminum (Al-Si-7Mg) manifold prototype with excellent contour and an acceptable surface finish was made with only one casting trial. This study indicated that the potential of the rapid prototyping-investment casting coupling could be more effective with the aid of integrated numerical simulation, and numerical optimization of the casting parameters aids in minimizing the risk of casting failure and avoiding the iterative casting trials.
For more information, contact M. Wu, Foundry Institute, Intzestrasse 5, Aachen, Germany D-52072; telephone 49 241 804067; fax 49 241 8888276; e-mail menghuai@gi.rwth-aachen.de.

more

Article Information
Parallelisation of a simulation tool for casting and solidification processes on Windows platformsClauss, C.; Schuch, S.; Finocchiaro, R.; Lankes, S.; Bemmerl, T.Parallel and Distributed Processing Symposium, 2006. IPDPS 2006. 20th InternationalVolume , Issue , 25-29 April 2006 Page(s): 8 pp. - Digital Object Identifier 10.1109/IPDPS.2006.1639606Summary: Since the beginning of computational engineering, the numerical simulation of physical processes is an essential element in the area of high performance computing. Thus, also the domain of metal foundry demands the computational simulation of casting and solidification processes. A popular software tool for this purpose has been developed by the RWP GmbH in Roetgen, Germany. This tool, named WinCast, is a complete software suite, which contains modules for pre-, main- and post-processing of simulation data sets. A core module of WinCast is TFB, which determines the chronological temperature distribution of a casting process based on a finite-element-method and a Gauss-Seidel solver. With the increasing demand for even higher precision of the simulation results on one hand, and a growing need for even larger data sets on the other hand, the parallelisation of this module became inevitable. In this paper, we present our work accomplished to parallelise the solving algorithm of this module. We have chosen an MPI based master-slave approach for compute clusters by using a self-developed MPI library for Windows platforms.» View citation and abstract

more

J Mater Sci Mater Med. 2002 Mar ;13 (3):301-6 15348628 (P,S,E,B)
Numerical simulation of the casting process of titanium removable partial denture frameworks.
[My paper] Menghuai Wu, Ingo Wagner, Peter R Sahm, Michael Augthun
Foundry Institute, University of Technology Aachen, Intzestr. 5, D-52072 Aachen, Germany. menghuai@gi.rwth-aachen.de
The objective of this work was to study the filling incompleteness and porosity defects in titanium removal partial denture frameworks by means of numerical simulation. Two frameworks, one for lower jaw and one for upper jaw, were chosen according to dentists' recommendation to be simulated. Geometry of the frameworks were laser-digitized and converted into a simulation software (MAGMASOFT). Both mold filling and solidification of the castings with different sprue designs (e.g. tree, ball, and runner-bar) were numerically calculated. The shrinkage porosity was quantitatively predicted by a feeding criterion, the potential filling defect and gas pore sensitivity were estimated based on the filling and solidification results. A satisfactory sprue design with process parameters was finally recommended for real casting trials (four replica for each frameworks). All the frameworks were successfully cast. Through X-ray radiographic inspections it was found that all the castings were acceptably sound except for only one case in which gas bubbles were detected in the grasp region of the frame. It is concluded that numerical simulation aids to achieve understanding of the casting process and defect formation in titanium frameworks, hence to minimize the risk of producing defect casting by improving the sprue design and process parameters.
J Mater Sci Mater Med. 2001 Jun ;12 (6):485-90 15348262 (P,S,E,B)
Numerical simulation of the casting process of titanium tooth crowns and bridges.
[My paper] M Wu, M Augthun, I Wagner, P R Sahm, H Spiekermann
Foundry Institute, University of Technology Aachen, Intzestr.5, D-52072 Aachen, Germany. menghuai@gi.rwth-aachen.de
The objectives of this paper were to simulate the casting process of titanium tooth crowns and bridges; to predict and control porosity defect. A casting simulation software, MAGMASOFT, was used. The geometry of the crowns with fine details of the occlusal surface were digitized by means of laser measuring technique, then converted and read in the simulation software. Both mold filling and solidification were simulated, the shrinkage porosity was predicted by a "feeding criterion", and the gas pore sensitivity was studied based on the mold filling and solidification simulations. Two types of dental prostheses (a single-crown casting and a three-unit-bridge) with various sprue designs were numerically "poured", and only one optimal design for each prosthesis was recommended for real casting trial. With the numerically optimized design, real titanium dental prostheses (five replicas for each) were made on a centrifugal casting machine. All the castings endured radiographic examination, and no porosity was detected in the cast prostheses. It indicates that the numerical simulation is an efficient tool for dental casting design and porosity control.
J Mater Sci Mater Med. 1999 Sep ;10 (9):519-25 15348102 (P,S,E,B)
Numerical study of porosity in titanium dental castings.
[My paper] M Wu, P R Sahm, M Augthun, H Spiekermann, J Schädlich-Stubenrauch
Foundry Institute, University of Technology Aachen, Intzestr. 5, D-52072 Aachen, Germany. menghuai@gi.rwth-aachen.de
A commercial software package, MAGMASOFT (MAGMA Giessereitechnologie GmbH, Aachen, Germany), was used to study shrinkage and gas porosity in titanium dental castings. A geometrical model for two simplified tooth crowns connected by a connector bar was created. Both mold filling and solidification of this casting model were numerically simulated. Shrinkage porosity was quantitatively predicted by means of a built-in feeding criterion. The risk of gas pore formation was investigated using the numerical filling and solidification results. The results of the numerical simulations were compared with experiments, which were carried out on a centrifugal casting machine with an investment block mold. The block mold was made of SiO2 based slurry with a 1 mm thick Zr2 face coat to reduce metal-mold reactions. Both melting and casting were carried out under protective argon (40 kPa). The finished castings were sectioned and the shrinkage porosity determined. The experimentally determined shrinkage porosity coincided with the predicted numerical simulation results. No apparent gas porosity was found in these model castings. Several running and gating systems for the above model casting were numerically simulated. An optimized running and gating system design was then experimentally cast, which resulted in porosity-free castings.
Adv Space Res. 1986 ;6 (12):85-99 11537847 (P,S,E,B)
Bioscience experiments in the German Spacelab mission D-1: introduction and summary.
[My paper] G Horneck, G Greger, P R Sahm
DFVLR, Institute for Aerospace Medicine, Koln, FRG.
The German Spacelab mission D-l was performed from 30 October through 6 November 1985. Payload operation in orbit was managed by DFVLR for the Federal Ministry of Research and Technology. The scientific program of the mission placed emphasis on microgravity research. In bioscience, the role of gravity in vital functions of biological systems was investigated, such as intracellular and intercellular interactions, developmental processes as well as regulation and adaptation in highly organized systems including human beings. In addition, the biological significance of cosmic radiation or altered zeitgeber within the complex matrix of all relevant spaceflight components were studied. Most of the experiments were accommodated in the following three payload elements: The Bioscience Experiment Package, and the ESA facilities Vestibular Sled and BIORACK. The information gained from the individual experiments will be compiled to help answer pending questions of space bioscience.
Mesh-terms: Adaptation, Physiological; Animals; Biological Sciences; Cell Physiology; Circadian Rhythm; Cosmic Radiation; Exobiology; Germany; Gravity Perception; Human; Laboratories; Research Design; Space Flight :: instrumentation; Space Flight :: organization & administration; Space Flight :: trends; Weightlessness;
Dent Mater. 2001 Mar ;17 (2):102-8 11163378 (P,S,E,B)
Application of laser measuring, numerical simulation and rapid prototyping to titanium dental castings.
[My paper] M Wu, J Tinschert, M Augthun, I Wagner, J Schädlich-Stubenrauch, P R Sahm, H Spiekermann
Foundry Institute, University of Technology Aachen, Intzestr.5, D-52072, Aachen, Germany. menghuai@gi.rwth-aachen.de
OBJECTIVES: This paper describes a method of making titanium dental crowns by means of integrating laser measuring, numerical simulation and rapid prototype (RP) manufacture of wax patterns for the investment casting process. METHODS: Four real tooth crowns (FDI No. 24, 25, 26, 27) were measured by means of 3D laser scanning. The laser digitized geometry of the crowns was processed and converted into standard CAD models in STL format, which is used by RP systems and numerical simulation software. Commercial software (MAGMASOFT) was used to simulate the casting process and optimize the runner and gating system (sprue) design. RP crowns were 'printed' directly on a ModelMaker II 3D Plotting System. A silicone negative mold (soft tool) was made from the RP crowns, then more than hundreds wax crowns were duplicated. The duplicated crowns were joined to the optimized runner and gating system. By using the investment casting process 20-25 replicas of each crown were made on a centrifugal casting machine. All castings were examined for porosity by X-ray radiographs. RESULTS: By using the integrated scanning, simulation, RP pattern and casting procedure, cast crowns, free of porosity, with excellent functional contour and a smooth surface finish, were obtained from the first casting trial. SIGNIFICANCE: The coupling of laser digitizing and RP indicates a potential to replace the traditional 'impression taking and waxing' procedure in dental laboratory, with the quality of the cast titanium prostheses also being improved by using the numerically optimized runner and gating system design.
Mesh-terms: Calcium Sulfate; Computer Simulation; Computer-Aided Design; Crowns; Dental Casting Investment :: chemistry; Dental Casting Technique :: instrumentation; Dental Materials; Dental Models; Dental Prosthesis Design; Human; Imaging, Three-Dimensional; Lasers; Porosity; Radiography; Silicones; Software; Support, Non-U.S. Gov't; Surface Properties; Titanium :: chemistry; Tooth Crown :: anatomy & histology; Waxes;
Eur J Oral Sci. 1999 Aug ;107 (4):307-15 10467947 (P,S,E,B)
Numerical simulation of porosity-free titanium dental castings.
[My paper] M Wu, M Augthun, J Schädlich-Stubenrauch, P R Sahm, H Spiekermann
Foundry Institute, University of Technology Aachen, Germany. menghuai@gi.rwth-aachen.de
The objective of this research was to analyse, predict and control the porosity in titanium dental castings by the use of numerical simulation. A commercial software package (MAGMASOFT) was used. In the first part of the study, a model casting (two simplified tooth crowns connected by a connector bar) was simulated to analyse shrinkage porosity. Secondly, gas pores were numerically examined by means of a ball specimen with a "snake" sprue. The numerical simulation results were compared with the experimental casting results, which were made on a centrifugal casting machine. The predicted shrinkage levels coincided well with the experimentally determined levels. Based on the above numerical analyses, an optimised running and gating system design for the crown model was proposed. The numerical filling and solidification results of the ball specimen showed that this simulation model could be helpful for the explanation of the experimentally indicated gas pores. It was concluded that shrinkage porosity in titanium dental casting was predictable, and it could be minimised by improving the running and gating system design. Entrapped gas pores can be explained from the simulation results of the mould filling and solidification.
Mesh-terms: Chemistry, Physical; Comparative Study; Computer Simulation; Crowns; Dental Casting Investment :: chemistry; Dental Casting Technique :: instrumentation; Dental Prosthesis Design; Forecasting; Gases; Human; Models, Chemical; Porosity; Software; Support, Non-U.S. Gov't; Surface Properties; Titanium :: chemistry;
Dent Mater. 1998 Sep ;14 (5):321-8 10379262 (P,S,E,B)
Computer aided prediction and control of shrinkage porosity in titanium dental castings.
[My paper] M Wu, J Schädlich-Stubenrauch, M Augthun, P R Sahm, H Spiekermann
Foundry Institute, Aachen, Germany. menghuai@gi.rwth-aachen.de
OBJECTIVES: The main objectives were to investigate the possibility and reliability of quantitative prediction and control of the concentrated shrinkage porosity (macroporosity) in titanium dental castings by means of a numerical simulation technique; and finally to optimize the filling and feeding system design for dental castings. METHODS: A commercial software, MAGMASOFT (Giessereitechnologie GmbH, Germany), was employed to simulate the mold filling and solidification process, and predict the shrinkage tendency in a sample dental casting, two simplified tooth crowns with a connector bar between them. The numerically predicted shrinkages were compared with the experimental results. The experiments were carried out on a centrifugal casting machine. The same geometric and processing parameters of the casting as in the simulations were strictly controlled. RESULTS: The computer predicted shrinkage porosity coincided with the performed experiments, demonstrating the reliability of the numerical model and the thermal physical data chosen for the calculations. Based on the above numerical model, several filling and feeding systems for the same casting were numerically simulated and compared. Finally an optimized design for this sample casting was proposed, and porosity-free castings were obtained. SIGNIFICANCE: It was expected that the numerical simulation technique could be further developed for dental laboratories to aid the real dental casting design.
Mesh-terms: Computer Simulation; Dental Alloys :: chemistry; Dental Casting Technique; Numerical Analysis, Computer-Assisted; Porosity; Support, Non-U.S. Gov't; Titanium :: chemistry;
Dtsch Zahnarztl Z. 1989 Nov ;44 (11):849-51 2700704 (P,S,E,B)
[Mathematical simulation of the cooling and solidifying process in improving the quality of dental castings]
[My paper] M Augthun, L Beckers, H Kreutzer, P R Sahm, W Schäfer, J Schädlich-Stubenrauch
CASTS-3D (Computer Aided Solidification Technologies) is a FEM software system for the simulation of heat transfer, melt flow and solidification problems for foundry purposes. This software system may basically be applied to dental castings as well--especially if the FEM software system is optimized and exact data on the thermophysical properties of the dental alloys are provided.
Mesh-terms: Computer Simulation; Crowns; Dental Alloys; Dental Casting Technique; English Abstract; Software;
Dent Labor (Munch). 1989 Jun ;37 (6):908-14 2676622 (P,S,E,B)
[Which sprue is best? Simulation of casting technic]
[My paper] H Kreutzer, W Schäfer, J Schädlich-Stubenrauch, P R Sahm
Mesh-terms: Dental Casting Technique :: instrument

more

repair of castings

APPLICATIONS:

Lab-metal fixes and protects virtually any worn or damaged surface. Lab-metal was developed as an economical, convenient way to repair, refurbish, seal, coat and protect equipment, machinery, vehicles, and industrial products. Some of the many industries using Lab-metal include:plants and factories foundries pattern shops powder coaters shipyards, marinas, boatyards public utilities garages and shops (automotive, equipment) processing and chemical industries appliance and electric industries welding, fabricating, metalworking and ornamental metal industries facility maintenance: hotels, schools, hospitals, office buildings construction: building, heavy equipment & machinery transportation: automotive, rail car, bus, truck, aircraft plumbing, heating, ventilation, air conditioning, refrigerationSuggested uses:Repair cracks and leaks:Pipes, boilers, tanks, water mains, valves, flanges Gutters, downspouts, metal roofs Castings, motor or engine blocks Gear housings Ducts and vents Heaters, radiators Oil and transmission lines Refrigerator/Heating coil lines Plastic piping Fill:Improperly or overbored holes, milled slots Surface defects, holes, rough and porous spots on castings Dents, gouges on wood or metal patterns, core boxes Damaged truck and auto bodies, rail cars Scored pistons and cylinders Coat and protect:Tanks and other large metal surfaces from rust attack Pipes and metal structures from salt spray and ground corrosion Wood surfaces from moisture damage/rot Patterns from gouging, denting, warping and checking Finish and repair:Rough welds Surfaces to be painted Worn machinery and equipment Seal:Seams and joints on sheet metal Rivets and riveted seams on fuel or water storage tanks and standpipes Leaks in radiators, valve seats, flanges Ducts and vents Important tips:Lab-metal and Hi-Temp Lab-metal repair putties are not designed for use as adhesives ("glues"). They are used for "cosmetic" repairs -- filling, finishing, sealing, patching, building up, and smoothing metal and non-metal surfaces.These products harden upon exposure to air, thus the user may need to keep the applicator wet with Lab-solvent in order to aid in smoothing the application (and reduce "pulling"). Lab-metal's workability may be enhanced by adding Lab-solvent until the desired consistency is achieved. (Lab-metal may be spread, brushed or sprayed on). Lab-solvent should always be added to Lab-metal and Hi-Temp Lab-metal just prior to closing the container. This prevents the metal repair compounds from hardening during extended storage. Simply stir the solvent in prior to the next use.Lab-metal has a guaranteed shelf-life of two years (in factory-sealed cans); Hi-Temp Lab-metal's shelf-life is one year. We urge Lab-metal users to test the suitability of the product for each application.
[Who Uses Lab-metal?] [Product Instructions] [Technical Data] [Lab-solvent (thinner for Lab-metal)] [Lab-metal or Hi-Temp Lab-metal?] [Lab-metal Drilled and Tapped] [Application Tips] [FAQs] [Testimonials]

more

...

Foundry Sand

A) PREPARED BINDERS FOR FOUNDRY MOULDS OR CORES
The heading covers foundry core binders based on natural resinous products (e.g. rosin) linseed oil vegetable mucilages dextrin molasses polymers of CHAPTER39 etc.
These are preparations for mixing with foundry sand to give it a consistency suitable for use in foundry moulds or cores and to facilitate the removal of the sand after the piece has been cast.
However dextrins and other modified starches and glues based on starches or on dextrins or other modified starches are classified in heading 35.05.

more

more

Molding-sand preparation

Ensuring the high quality of castings requires the use of automation solutions, also in the foundry sand preparation methods applied in sand casting shops.
Operational analyses and literature lead to the unanimous conclusion that approx. 45-55% of the casting rejects are to be attributed to the insufficient quality of the forming material, i.e. the core sand.
Gravimetric batching of all components is a must, just as is automated water batching.
Owing to the narrow tolerances required in terms of water content, highly accurate sensors (moisture and temperature), an electronic batching system, and a high-performance, sophisticated computer system is needed in order to ensure the compliance with the requirement of a full addition of the required water demand as early as at the beginning of the mixing cycle. This is the only way to ensure a high degree of efficiency of the preparation process. This requirement is particularly critical with today's high-performance mixers. When using a compactibility monitoring system in the prepared sand, the sand-mill operator can be sure to supply high-quality, homogenous forming material to the molding plant.
FRS Starline

Moisture control in sand preparation
High controlling accuracy
Simplified operator guidance via a visualized touch screen monitor
Upgradeable for up to three mixers/coolers of different makes, sizes and performance levels
Rapid integration in each sand control system -linkage involves only a few signals. [Read more...]
FS CC 6 PLC - Sandstar


The big solution in molding material management
Database connection
All functions visualised
Regulations of aggregats
Weighing technology can be integrated

[Read more...]

more

SPC II

For online quality supervision of prepared foundry sands by way of collection of the following measurement variables:
Compactibility
Shearing or compression resistance *
Moisture*
Temperature*
*optional
The SPC II is used in a downward sand flow, for instance, at the mixer exit or at a belt discharge point. Small quantities of molding sand will drop on a rotating plate edge where a stripper is used to select a uniform grain size.
The sand drops into an inspection beaker, where a sensor monitors the filling level. The molding sand is compacted by a compressive force, with the compacting process being recorded and evaluated, for instance by our FS-CC 6 PLC system. Subsequently, the test core will be ejected.
The system can be enhanced by measuring the shearing or compression resistance.

Technical data:
Supply voltage: 230 V AC Compressed-air supply: 5 to 10 bar / ¼” connector SPC II Download product sheet english (PDF 1,5 MB)

more