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89-461: The Etna Works was a failing small business when purchased by ironmolder John Roach and three partners in 1852. Roach soon gained full ownership of the business and quickly transformed it into a successful general-purpose ironworks. He took advantage of the civil war to transform the Etna Works into one of New York's leading manufacturers of marine steam engines. By the end of the war, he was in

178-449: A cleaner, quieter working environment with reduced operator exposure to safety risks or service-related problems. With automated mold manufacturing came additional workplace safety requirements. Different voluntary technical standards apply depending on the geopolitical jurisdiction where the machinery is to be used. Canada does not have a machine-specific voluntary technical standard for sand-mold making machinery. This type of machinery

267-571: A contract for the huge new ironclad USS  Dunderberg . Webb's usual engine suppliers, the Morgan Iron Works and Novelty Iron Works , were heavily inundated with orders and unable to meet his needs. Webb was so relieved to find an alternative source of supply, he not only awarded the Dunderberg 's engine contract to Roach, but also became guarantor for the higher line of credit Roach would need to re-equip his works for completing

356-407: A conveyor were accomplished either manually or automatically. In the late fifties hydraulically powered pistons or multi-piston systems were used for the sand compaction in the flasks. This method produced much more stable and accurate molds than it was possible manually or pneumatically . In the late sixties mold compaction by fast air pressure or gas pressure drop over the pre-compacted sand mold

445-489: A desire to become a builder of marine steam engines like his mentor James Allaire. Competition in the industry was fierce, and entry difficult due to high capital costs, but Roach believed that by utilization of the best tools, labor-saving devices and practices, he could compete successfully. Accordingly, through the late 1850s he sent engineers to the United Kingdom to study the latest in marine engine technology, and

534-551: A diversity of machinery contracts. The Navy through Benjamin Isherwood ordered three engines and six large boilers for the Guerriere class vessels, while shipbuilder William Webb contracted with Roach for the machinery for two large new sidewheel steamers , Bristol and Providence . The engines for the latter two ships, with their massive 110-inch (280 cm) cylinders, were the largest- bore ship engines ever produced in

623-423: A flask-less molding process by using vertically parted and poured molds. The first line could produce up to 240 complete sand molds per hour. Today molding lines can achieve a molding rate of 550 sand molds per hour and requires only one monitoring operator. Maximum mismatch of two mold halves is 0.1 mm (0.0039 in). Although very fast, vertically parted molds are not typically used by jobbing foundries due to

712-712: A large bell . After molding, the casting is covered with 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. Cold box uses organic and inorganic binders that strengthen

801-411: A number of anchors. In one ninety-day period, Roach made a profit from such sales of $ 8,000, giving his business a solid foundation. Roach was able to continue expanding the business through the sale of a variety of products, including Franklin stoves , firebacks, slats for iron shutters and other items. In 1856 he added a new steam boiler to the ironworks for driving a blower which forced a draft into

890-414: A position to acquire the businesses of some of his major New York competitors, which had run into financial difficulties. Roach subsequently consolidated his operations at the Morgan Iron Works , and some time afterward rented the Etna Works to the inventor Thomas Edison , who turned it into a dynamo factory. The Roach family sold the former Etna Works property in 1887. The Etna Works buildings, along with

979-601: A protest and the deal became the subject of an acrimonious government inquiry (see the John Roach article for details). Following the consolidation of his business at the Morgan Iron Works, Roach rented out his old Etna Iron Works property to various tenants. The Etna Works continued to operate as a general ironworks under new management until about 1881, when inventor Thomas Edison relocated production for his electrical illumination utility there. Edison renamed

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1068-487: A total of $ 10,000 ($ 366,240). In April 1852, Roach and his three partners purchased for the sum of $ 4,700 ($ 172,133) a small New York ironworks known as the Etna Iron Works, which had recently fallen into receivership. The ironworks, located at 102 Goerck Street, occupied a 40-by-100-foot (12 m × 30 m) property and consisted of a small foundry and some raw materials. Following their purchase, Roach

1157-449: A variety of AM-printed cores for a cavity derived from a traditional pattern. To control the solidification structure of the metal, it is possible to place metal plates, chills , in the mold. The associated rapid local cooling will form a finer-grained structure and may form a somewhat harder metal at these locations. In ferrous castings, the effect is similar to quenching metals in forge work. The inner diameter of an engine cylinder

1246-458: Is a metal casting process characterized by using sand —known as casting sand —as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries . In 2003, over 60% of all metal castings were produced via sand casting. Molds made of sand are relatively cheap, and sufficiently refractory even for steel foundry use. In addition to

1335-423: Is a factor, non-destructive testing methods may be applied before further work is performed. In general, we can distinguish between two methods of sand casting; the first one using green sand and the second being the air set method. These castings are made using sand molds formed from "wet" sand which contains water and organic bonding compounds, typically referred to as clay. The name "green sand" comes from

1424-441: Is a variation of the sand casting process for most ferrous and non-ferrous metals, in which unbonded sand is held in the flask with a vacuum . The pattern is specially vented so that a vacuum can be pulled through it. A heat-softened thin sheet (0.003 to 0.008 in (0.076 to 0.203 mm)) of plastic film is draped over the pattern and a vacuum is drawn (200 to 400 mmHg (27 to 53 kPa)). A special vacuum forming flask

1513-408: Is converted to illite , which is a non-expanding clay. Most foundries do not have the very expensive equipment to remove the burned out clay and substitute new clay, so instead, those that pour iron typically work with silica sand that is inexpensive compared to the other sands. As the clay is burned out, newly mixed sand is added and some of the old sand is discarded or recycled into other uses. Silica

1602-786: Is covered by: Safeguarding of machinery, CSA Z432. Canadian Standards Association. 2016. In addition, the electrical safety requirements are covered by: Industrial Electrical Machinery, CSA C22.2 No. 301. 2016. The primary standard for sand-mold manufacturing equipment in the EU is: Safety requirements for foundry moulding and coremaking machinery and plant associated equipment, EN 710. European Committee for Standardization (CEN). EN 710 will need to be used in conjunction with EN 60204-1 for electrical safety, and EN ISO 13849-1 and EN ISO 13849-2 or EN 62061 for functional safety. Additional type C standards may also be necessary for conveyors, robotics or other equipment that may be needed to support

1691-560: Is known for not requiring a draft because the plastic film has a certain degree of lubricity and it expands slightly when the vacuum is drawn in the flask. The process has high dimensional accuracy, with a tolerance of ±0.010 in for the first inch and ±0.002 in/in thereafter. Cross-sections as small as 0.090 in (2.3 mm) are possible. The surface finish is very good, usually between 150 and 125 rms . Other advantages include no moisture related defects, no cost for binders, excellent sand permeability, and no toxic fumes from burning

1780-491: Is made hard by a chilling core. In other metals, chills may be used to promote directional solidification of the casting. In controlling the way a casting freezes, it is possible to prevent internal voids or porosity inside castings. Cores are apparatus used to generate hollow cavities or internal features which cannot be formed using pattern alone in moulding, cores are usually made using sand, but some processes also use permanent cores made of metal. To produce cavities within

1869-416: Is made in the same way (without the sprue and pouring cup). Any cores are set in place and the mold is closed. The molten metal is poured while the cope and drag are still under a vacuum, because the plastic vaporizes but the vacuum keeps the shape of the sand while the metal solidifies. When the metal has solidified, the vacuum is turned off and the sand runs out freely, releasing the casting. The V-process

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1958-471: Is placed on the box and it is turned and unlatched, so that the halves of the mold may be parted and the pattern with its sprue and vent patterns removed. Additional sizing may be added and any defects introduced by the removal of the pattern are corrected. The box is closed again. This forms a "green" mold which must be dried to receive the hot metal. If the mold is not sufficiently dried a steam explosion can occur that can throw molten metal about. In some cases,

2047-414: Is placed over the plastic pattern and is filled with a free-flowing sand. The sand is vibrated to compact the sand and a sprue and pouring cup are formed in the cope. Another sheet of plastic is placed over the top of the sand in the flask and a vacuum is drawn through the special flask; this hardens and strengthens the unbonded sand. The vacuum is then released on the pattern and the cope is removed. The drag

2136-642: Is the ability of the sand to retain a given shape after the pattern is removed. Third Avenue Bridge (New York City) The Third Avenue Bridge is a swing bridge that carries southbound road traffic on Third Avenue over the Harlem River , connecting the boroughs of Manhattan and the Bronx in New York City . It once carried southbound New York State Route 1A . On the Manhattan side,

2225-482: Is the least desirable of the sands, since metamorphic grains of silica sand have a tendency to explode to form sub-micron sized particles when thermally shocked during pouring of the molds. These particles enter the air of the work area and can lead to silicosis in the workers. Iron foundries expend considerable effort on aggressive dust collection to capture this fine silica. Various types of respiratory-protective equipment are also used in foundries. The sand also has

2314-450: The CO created does not prevent oxidation. Green sand for aluminum typically uses olivine sand (a mixture of the minerals forsterite and fayalite , which is made by crushing dunite rock). The choice of sand has a lot to do with the temperature at which the metal is poured. At the temperatures that copper and iron are poured, the clay is inactivated by the heat, in that the montmorillonite

2403-713: The Delaware River Iron Ship Building and Engine Works , which became America's largest and most productive shipyard from its establishment in 1871 until the mid-1880s. At least 27 marine steam engines for 19 ships were produced by the Etna Iron Works. The following tables list those ships, together with basic details of the engines fitted to each. Table legend—Engine type: BA=back-acting, DA=direct acting, SB=simple beam; Horiz=horizontal, Vert=vertical, Inv=inverted. See marine steam engine for an explanation of engine types. Sand casting Sand casting , also known as sand molded casting ,

2492-404: The cope and drag . The sand mixture is tamped down as it is added around the pattern, and the final mold assembly is sometimes vibrated to compact the sand and fill any unwanted voids in the mold. Then the pattern is removed along with the channel plug, leaving the mold cavity. The casting liquid (typically molten metal) is then poured into the mold cavity. After the metal has solidified and cooled,

2581-635: The Civil War. Fortuitously for Roach, the proprietor, shipping magnate Charles Morgan , had recently experienced a setback in his own business dealings, as a result of which he was short of capital. Morgan quickly agreed to sell the premises along with all of its equipment for the sum of $ 450,000. At around the same time, two of Roach's former competitors, the Allaire Iron Works and the Franklin Forge, went bankrupt, and Roach purchased

2670-494: The United States up to that time. More importantly for Roach however, he realized that the government was planning to modernize its own shipyards, and he made a timely shift into the manufacture of machine tools in 1866. He was rewarded by the securing of almost a million dollars in government machine tool contracts between 1866 and 1868. At this point, Roach decided that his business had outgrown its original location. He

2759-467: The best of their equipment at firesale prices and also hired their best workers. To these he added the best workers and equipment from the Etna and Morgan establishments, and consolidated his operations at the latter, vacating his former premises at Goerck Street. Roach profited further at this time from the sale of his surplus equipment to the U.S. Navy, but on this occasion some rival business interests raised

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2848-404: The binders. Finally, the pattern does not wear out because the sand does not touch it. The main disadvantage is that the process is slower than traditional sand casting so it is only suitable for low to medium production volumes; approximately 10 to 15,000 pieces a year. However, this makes it perfect for prototype work, because the pattern can be easily modified as it is made from plastic. With

2937-414: The box containing the sand mold is then positioned for filling with molten metal—typically iron , steel , bronze , brass , aluminium , magnesium alloys, or various pot metal alloys, which often include lead , tin , and zinc . After being filled with liquid metal the box is set aside until the metal is sufficiently cool to be strong. The sand is then removed, revealing a rough casting that, in

3026-399: The box, closed at the bottom, will be filled with a molding sand. The sand is packed in through a vibratory process called ramming, and in this case, periodically screeded level. The surface of the sand may then be stabilized with a sizing compound. The pattern is placed on the sand and another molding box segment is added. Additional sand is rammed over and around the pattern. Finally a cover

3115-487: The bridge funnels traffic into three locations: East 128th Street; the intersection of East 129th Street and Lexington Avenue ; or FDR Drive in Manhattan. The bridge was formerly bidirectional, but converted to one-way operation southbound on August 5, 1941 on the same day the Willis Avenue Bridge was similarly converted to one-way northbound. In 1955, the original multi-truss bridge constructed in 1898

3204-606: The bridge on the Bronx side and off the bridge in Manhattan. As reconstructed, the Third Avenue Bridge carries five lanes of Manhattan-bound traffic from the Bronx, which split to three ramps in Manhattan: to East 128th Street and Second Avenue ; to Lexington Avenue and East 129th Street; and to FDR Drive . For 2011, the New York City Department of Transportation , which operates and maintains

3293-434: The bridge, reported an average daily traffic volume of 59,603; the bridge reached a peak ADT of 73,121 in 2000. Between 2000 and 2014, the bridge opened for vessels 93 times, including 60 times in 2007. On July 8, 2024, during the 2024 North America heat waves , the bridge suffered from heat expansion and got stuck in the open position, so vehicles could not cross it. The New York City Fire Department sprayed water onto

3382-512: The business, but his three partners voted to divide it into dividends of $ 250 each. Realizing that they had reached the limit of their ambition, Roach took out a mortgage on the property and used the loan to buy his partners out, thus becoming sole proprietor. Roach thereafter began canvassing the local shipyards for business. Although New York's shipbuilders were still at this time constructing mostly wooden sailing ships, each ship needed about forty pounds of iron fastenings and cables, in addition to

3471-409: The case of iron or steel, may still be glowing red. In the case of metals that are significantly heavier than the casting sand, such as iron or lead, the casting flask is often covered with a heavy plate to prevent a problem known as floating the mold. Floating the mold occurs when the pressure of the metal pushes the sand above the mold cavity out of shape, causing the casting to fail. After casting,

3560-424: The casting is separated from the sand mold. There is typically no mold release agent, and the mold is generally destroyed in the removal process. 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 to the surface, and this makes them easy to identify. Castings made from fine green sand can shine as cast but are limited by

3649-414: The casting—such as for liquid cooling in engine blocks and cylinder heads —negative forms are used to produce cores . Usually sand-molded, cores are inserted into the casting box after removal of the pattern. Whenever possible, designs are made that avoid the use of cores, due to the additional set-up time, mass and thus greater cost. With a completed mold at the appropriate moisture content,

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3738-403: The casting. Note that for each cubic centimeter (cc) of water added to the mold 1600 cc of steam is produced. Surface finish — The size and shape of the sand particles defines the best surface finish achievable, with finer particles producing a better finish. However, as the particles become finer (and surface finish improves) the permeability becomes worse. Cohesiveness (or bond ) — This

3827-408: The contract with the lowest bid. The contract called for a bridge with a pivoting center section which could be rotated to allow large ships to pass through one of two channels beneath. Roach had no prior experience of bridge building, so he hired an engineer with appropriate experience to design and oversee the project, and subcontracted out the masonry work. The bridge that was eventually constructed

3916-439: The cope and drag, such as the interior passages of valves or cooling passages in engine blocks. Paths for the entrance of metal into the mold cavity constitute the runner system and include the sprue , various feeders which maintain a good metal 'feed', and in-gates which attach the runner system to the casting cavity. Gas and steam generated during casting exit through the permeable sand or via risers , which are added either in

4005-468: The cores are broken up by rods or shot and removed from the casting. The metal from the sprue and risers is cut from the rough casting. Various heat treatments may be applied to relieve stresses from the initial cooling and to add hardness—in the case of steel or iron, by quenching in water or oil. The casting may be further strengthened by surface compression treatment—like shot peening —that adds resistance to tensile cracking and smooths

4094-505: The depth to width ratio of pockets in the pattern. Air-set molds can produce castings with smoother surfaces than coarse green sand but this method is primarily chosen when deep narrow pockets in the pattern are necessary, due to the expense of the plastic used in the process. Air-set castings can typically be easily identified by the burnt color on the surface. The castings are typically shot blasted to remove that burnt color. Surfaces can also be later ground and polished, for example when making

4183-459: The dimensional instability associated with the conversion of quartz from alpha quartz to beta quartz at 680 °C (1250 °F). Often, combustible additives such as wood flour are added to create spaces for the grains to expand without deforming the mold. Olivine , chromite , etc. are therefore used because they do not have a phase transition that causes rapid expansion of the grains. Olivine and chromite also offer greater density, which cools

4272-509: The early sixties the American company Hunter Automated Machinery Corporation launched its first automatic flaskless, horizontal molding line applying the matchplate technology. The method alike to the DISA's (DISAMATIC) vertical molding is flaskless, however horizontal. The matchplate molding technology is today used widely. Its great advantage is inexpensive pattern tooling, easiness of changing

4361-485: The engines for at least fifteen vessels, including return orders from the U.S. Navy and a dozen engines for the Van Deusen Brothers . At its wartime peak, the Etna Iron Works employed almost 2,000 workers and was valued at $ 150,000, putting it in the front rank of New York's engine builders. Shortly after the war, the U.S. Navy auctioned off hundreds of ships it had requisitioned for the war effort, flooding

4450-432: The fact that the sand mold is not "set", it is still in the "green" or uncured state even when the metal is poured in the mould. Green sand is not green in color, but "green" in the sense that it is used in a wet state (akin to green wood). Contrary to what the name suggests , "green sand" is not a type of sand on its own (that is, not greensand in the geologic sense), but is rather a mixture of: There are many recipes for

4539-517: The fast development of the car and machine building industry the casting consuming areas called for steady higher productivity . The basic process stages of the mechanical molding and casting process are similar to those described under the manual sand casting process. The technical and mental development however was so rapid and profound that the character of the sand casting process changed radically. The first mechanized molding lines consisted of sand slingers and/or jolt-squeeze devices that compacted

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4628-464: The foundry would be forced to close without steam power. Undeterred, Roach negotiated the use of a boiler in a neighbouring factory, ran 200 feet of pipe from their boiler to his workshop, and was back in production within 48 hours. In 1859, one of Roach's closest friends, a lawyer named John Baker, died and left Roach the trustee of his estate. The estate, worth $ 70,000, was entrusted to Roach for investment until Baker's four children came of age. Since

4717-615: The job. Roach next travelled to Washington to meet the U.S. Navy's Chief of the Bureau of Steam Engineering, Benjamin Franklin Isherwood . On October 24, 1862, Isherwood awarded Roach a contract to supply the machinery for the Navy's new gunboat Peoria —the first of a number of such contracts Roach would fulfill for the Navy in coming years. Roach also secured the engine contracts for two new merchant steamships recently ordered by

4806-630: The largest marine engines then built in the United States . John Roach emigrated from Ireland to the United States in 1832 at the age of sixteen, eventually obtaining employment as a common laborer at the Howell Works of James P. Allaire at an initial wage of 25c a day. After securing an apprenticeship as an ironmolder at Howell Works, Roach later transferred to Allaire's other plant, the Allaire Iron Works in New York, where he learned

4895-422: The latter is generally preferred due to its more consistent composition. With both methods, the sand mixture is packed around a pattern , forming a mold cavity. If necessary, a temporary plug is placed in the sand and touching the pattern in order to later form a channel into which the casting fluid can be poured. Air-set molds are often formed with the help of a casting flask having a top and bottom part, termed

4984-590: The manufacturing method for marine steam engines . Roach would remain an employee of Allaire's for twenty years. By the 1850s, Roach, concerned about the needs of a growing family and anxious to obtain a more secure financial future, began to consider starting his own business. He had been unable to save much money of his own—only $ 1,000 (equivalent to $ 36,624 in 2023)—but was able to persuade three of his co-workers at Allaire, including his brother-in-law Joseph Johnstone, who had savings of $ 8,000 ($ 292,992), to join him. The four partners mustered between them

5073-431: The market and seriously depressing prices. The resulting slump in the U.S. shipping industry sent many long-established American shipyards and marine engineers to the wall, and New York was one of the worst affected locations, with its maritime industry all but wiped out by the slump. By 1867, most of Roach's marine engine competitors had gone bankrupt. Roach himself, however, was able to prosper during this time by securing

5162-412: The melting furnace, thus obtaining a higher temperature and melting the iron faster, which saved valuable man-hours. He also purchased the adjoining property at 104–106 Goerck St., upon which stood a small three-storey building. Roach used the third floor as a pattern shop, while renting out the first and second floors to an iron shutter manufacturer. By 1859, Roach was employing forty men and his property

5251-426: The metal being cast. This is especially important with highly reactive metals, such as magnesium and titanium . Permeability — This refers to the sand's ability to exhaust gases. This is important because during the pouring process many gases are produced, such as hydrogen , nitrogen , carbon dioxide , and steam , which must leave the mold otherwise casting defects , such as blow holes and gas holes, occur in

5340-618: The metal faster, thereby producing finer grain structures in the metal. Since they are not metamorphic minerals , they do not have the polycrystals found in silica , and subsequently they do not form hazardous sub-micron sized particles. The air set method uses dry sand bonded with materials other than clay, using a fast curing adhesive . The latter may also be referred to as no bake mold casting . When these are used, they are collectively called "air set" sand castings to distinguish them from "green sand" castings. Two types of molding sand are natural bonded (bank sand) and synthetic (lake sand);

5429-458: The mold by chemically adhering to the sand. This type of mold gets its name from not being baked in an oven like other sand mold types. This type of mold is more accurate dimensionally than green-sand molds but is more expensive. Thus it is used only in applications that necessitate it. No-bake molds are expendable sand molds, similar to typical sand molds, except they also contain a quick-setting liquid resin and catalyst. Rather than being rammed,

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5518-402: The mold in order to avoid an incomplete casting. Should a piece of core or mold become dislodged it may be embedded in the final casting, forming a sand pit , which may render the casting unusable. Gas pockets can cause internal voids. These may be immediately visible or may only be revealed after extensive machining has been performed. For critical applications, or where the cost of wasted effort

5607-427: The molding sand and to have proper locations to receive and position the cores. A slight taper, known as draft , must be used on surfaces perpendicular to the parting line, in order to be able to remove the pattern from the mold. This requirement also applies to cores, as they must be removed from the core box in which they are formed. The sprue and risers must be arranged to allow a proper flow of metal and gasses within

5696-457: The molding sand is poured into the flask and held until the resin solidifies, which occurs at room temperature. This type of molding also produces a better surface finish than other types of sand molds. Because no heat is involved it is called a cold-setting process. Common flask materials that are used are wood, metal, and plastic. Common metals cast into no-bake molds are brass, iron ( ferrous ), and aluminum alloys. Vacuum molding ( V-process )

5785-418: The molding tooling, thus suitability for manufacturing castings in short series so typical for the jobbing foundries. Modern matchplate molding machine is capable of high molding quality, less casting shift due to machine-mold mismatch (in some cases less than 0.15 mm (0.0059 in)), consistently stable molds for less grinding and improved parting line definition. In addition, the machines are enclosed for

5874-541: The money could not be claimed until 1881, it was as good as a long-term interest-free loan to Roach, who was soon to take advantage of it to expand his business. One of the largest projects undertaken by the Etna Iron Works was for construction of the Third Avenue Harlem Bridge over the Harlem River , New York. The project was submitted to public tender by the City of New York in 1860 and Roach secured

5963-499: The newly-established Neptune Steamship Company, Electra and Galatea . Having secured these contracts, Roach set about equipping the Etna Iron Works for its new role. He began by hiring Thomas Main, a leading engineer with experience in a number of the world's most advanced engine works, as the plant's superintendent. Roach then began reorganizing the Works, adding a boilershop, machine shop, coppersmith shop and blacksmith, and equipping

6052-646: The operation of the mold-making equipment. There is no machine-specific standard for sand-mold manufacturing equipment. The ANSI B11 family of standards includes some generic machine-tool standards that could be applied to this type of machinery, including: There are four main components for making a sand casting mold: base sand , a binder , additives , and a parting compound . Molding sands , also known as foundry sands , are defined by eight characteristics: refractoriness, chemical inertness, permeability, surface finish, cohesiveness, flowability, collapsibility, and availability/cost. Refractoriness — This refers to

6141-459: The pattern itself, or as separate pieces. In addition to patterns, the sand molder could also use tools to create the holes. A multi-part molding box (known as a casting flask , the top and bottom halves of which are known respectively as the cope and drag) is prepared to receive the pattern. Molding boxes are made in segments that may be latched to each other and to end closures. For a simple object—flat on one side—the lower portion of

6230-469: The pattern must be slightly larger than the finished product, a difference known as contraction allowance . Different scaled rules are used for different metals, because each metal and alloy contracts by an amount distinct from all others. Patterns also have core prints that create registers within the molds into which are placed sand cores . Such cores, sometimes reinforced by wires, are used to create under-cut profiles and cavities which cannot be molded with

6319-715: The plant the Edison Machine Works , using it to build DC dynamos until 1887. In that year, the Roach family business sold the premises, the Edison having moved their expanding Machine Works to a much larger site in Schenectady, NY . The property, along with the street in which it was situated, was later liquidated in a 1940s redevelopment. Roach himself went on to establish his own shipyard in Chester, Pennsylvania ,

6408-439: The plant with a host of new machines including traveling and swing cranes and the steam engines to power them, along with planers, lathes, boring mills, punches, shears and rollers. Amongst the new equipment was a planer capable of finishing 100-ton iron plates, and a lathe capable of boring a 112-inch-diameter (280 cm) cylinder—the two largest machine tools in the entire country. Over the next two years, Roach's plant produced

6497-424: The proportion of clay, but they all strike different balances between moldability, surface finish, and ability of the hot molten metal to degas . Coal, typically referred to in foundries as sea-coal , which is present at a ratio of less than 5%, partially combusts in the presence of the molten metal, leading to offgassing of organic vapors. Green sand casting for non-ferrous metals does not use coal additives, since

6586-426: The rough surface. And when high precision is required, various machining operations (such as milling or boring) are made to finish critical areas of the casting. Examples of this would include the boring of cylinders and milling of the deck on a cast engine block. The part to be made and its pattern must be designed to accommodate each stage of the process, as it must be possible to remove the pattern without disturbing

6675-491: The sand around models called patterns , by carving directly into the sand, or via 3D printing . There are five steps in this process: From the design, provided by a designer, a skilled pattern maker builds a pattern of the object to be produced, using wood, metal, or a plastic such as expanded polystyrene. Sand can be ground, swept or strickled into shape. The metal to be cast will contract during solidification, and this may be non-uniform due to uneven cooling. Therefore,

6764-529: The sand in the flasks. In early fifties the high pressure molding was developed and applied in mechanical and later automatic flask lines. The first lines were using jolting and vibrations to pre-compact the sand in the flasks and compressed air powered pistons to compact the molds. In the first automatic horizontal flask lines the sand was shot or slung down on the pattern in a flask and squeezed with hydraulic pressure of up to 140 bars . The subsequent mold handling including turn-over, assembling, pushing-out on

6853-443: The sand in the flasks. Subsequent mold handling was mechanical using cranes, hoists and straps. After core setting the copes and drags were coupled using guide pins and clamped for closer accuracy. The molds were manually pushed off on a roller conveyor for casting and cooling. Increasing quality requirements made it necessary to increase the mold stability by applying steadily higher squeeze pressure and modern compaction methods for

6942-544: The sand may be oiled instead of moistened, which makes casting possible without waiting for the sand to dry. Sand may also be bonded by chemical binders, such as furane resins or amine-hardened resins. Additive manufacturing (AM) can be used in the sand mold preparation, so that instead of the sand mold being formed via packing sand around a pattern, it is 3D-printed. This can reduce lead times for casting by obviating patternmaking. Besides replacing older methods, additive can also complement them in hybrid models, such as making

7031-405: The sand's ability to withstand the temperature of the liquid metal being cast without breaking down. For example, some sands only need to withstand 650 °C (1,202 °F) if casting aluminum alloys, whereas steel needs a sand that will withstand 1,500 °C (2,730 °F). Sand with too low refractoriness will melt and fuse to the casting. Chemical inertness — The sand must not react with

7120-421: The sand, a suitable bonding agent (usually clay) is mixed or occurs with the sand. The mixture is moistened, typically with water, but sometimes with other substances, to develop the strength and plasticity of the clay and to make the aggregate suitable for molding. The sand is typically contained in a system of frames or mold boxes known as a flask . The mold cavities and gate system are created by compacting

7209-413: The specialized tooling needed to run on these machines. Cores need to be set with a core mask as opposed to by hand and must hang in the mold as opposed to being set on parting surface. The principle of the matchplate, meaning pattern plates with two patterns on each side of the same plate, was developed and patented in 1910, fostering the perspectives for future sand molding improvements. However, first in

7298-404: The street on which they were located, were later liquidated in a city redevelopment. Notable achievements of the Etna Iron Works include the building of the steam-operated Third Avenue Harlem Bridge in the 1860s, and the manufacture in the 1860s of the engines for the giant ironclad USS  Dunderberg and for the passenger steamers Bristol and Providence , the latter two of which were

7387-480: Was 526 feet (160 m) long, with masonry foundations, a cast-and-wrought iron superstructure, and a 216-foot (66 m) steam-powered pivoting center section spanning two 80-foot-long (24 m) ship channels. The bridge opened for traffic in 1868, and operated reliably for about thirty years until increasing maintenance costs and traffic persuaded the city fathers to construct a new bridge with faster operation and higher and wider dimensions. Roach had long nurtured

7476-538: Was developed (sand-impulse and gas-impact). The general working principle for most of the horizontal flask line systems is shown on the sketch below. Today there are many manufacturers of the automatic horizontal flask molding lines. The major disadvantages of these systems is high spare parts consumption due to multitude of movable parts, need of storing, transporting and maintaining the flasks and productivity limited to approximately 90–120 molds per hour. In 1962, Dansk Industri Syndikat A/S (DISA- DISAMATIC ) invented

7565-410: Was given the task of promoting the business while his three partners attended to management of the shop floor. Roach began by touting for custom piecework, his first sale being for cast grate bars for a Brooklyn distillery. By the end of the first year of operations, the partners had made a modest profit of $ 1,000, but now a dispute broke out over how to employ the money. Roach wanted to use it to expand

7654-471: Was keen to establish a plant with direct water frontage, which would both save him the cost of transporting his engines to the docks, and also enable him to move into the potentially lucrative business of ship repair. The obvious target for acquisition was the Morgan Iron Works, a leading ironworks with frontage on the East River, and which like most other marine engineering plants had lain mostly idle since

7743-468: Was not above hiring himself out as a mechanic to New York's leading engine builders of the day to spy on their organization, technology and practices. When the American Civil War broke out in 1861, Roach was thus already well prepared to take advantage of the huge demand for marine engines generated by the conflict. He began by contacting the shipbuilder William H. Webb , who had just secured

7832-471: Was removed and sold. A rebuilt bridge reopened in December 1956. As part of a major NYCDOT reconstruction project from 2001-2005, a new swing span was floated into place on October 29, 2004. Two lanes of Manhattan-bound traffic opened on December 6, 2004, and the remaining three lanes opened in 2005. In addition to replacing the swing span and its machinery, the project included redesigned approach ramps to

7921-413: Was valued at $ 15,000. A contemporary evaluator noted that Roach was "getting along well" and deemed him "safe for a fair amount of credit". On September 2, 1859, the forced-draft boiler for the Etna Works' furnace exploded after accidentally being allowed to run dry, killing one man and seriously injuring two others, and gutting the building in which it stood. The $ 5,000 damage was covered by insurance, but

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