Low-Pressure Permanent Mold Casting Machines Offer Benefits.Hayes Lemmerz Equipment & Engineering, AuGres, Michigan, offers a new line of low-pressure permanent mold mold, name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. casting machines (LPPM LPPM Low-Pressure Permanent Mold (aluminum alloy casting process) ) and production cells. The production cells contain two casting units, each with its own 1500-Ib, resistance-heated holding furnace furnace, enclosed space for the burning of fuel. There are many kinds of furnaces, the type depending upon the fuel and the use to which the heat produced within it is put. Most familiar are the furnaces used in the heating of buildings. and an optional quench quench, v to cool a hot object rapidly by plunging it into water or oil. quench to put out, extinguish, or suppress; to cool (as hot metal) by immersing in water. tank serving both units. The holding furnaces include rails for convenient rollout for servicing and are heated by 36 kw of rod-type heaters. Air pressure applied to the sealed holding furnace forces molten aluminum through a fill tube extending from the bottom of the holding tank into the mold. A single, proportional valve controls the air pressure applied to the furnace. Software provides smooth, stepless control and virtually eliminates surface waves in the molten metal while ensuring complete filling. The software includes a Proportional Integral Derivative-type control loop for controlling actual rate of change (psi/sec) vs. the desired psi/sec filling profile. The software's acceleration and deceleration deceleration /de·cel·er·a·tion/ (de-sel?er-a´shun) decrease in rate or speed. early deceleration sections further reduce surge/slow-down whenever the fill rate is changed. Each casting's ideal filling profile may be retrieved for future runs of the same casting. Another feature of the cells and individual casting units is the dual-purpose platform for the system's control panels. Virtually all of the system's control devices, piping and wiring are housed below the platform with access provided through removable steel floor panels in the platform's deck. Snap-fit and plug-in connectors below the platform deck permit quick connections during on-site system assembly. Benefits of the LPPM process include: * increased yield, resulting from reduced need for gates and risers; * easy placement of odd casting configurations and tooling points for machining due to reduction in gates and risers; * less need for, and lower cost of, subsequent machining; * clean metal filling from the bottom of holding furnace; * improved and more consistent casting quality due to precise control of filling pressure and precise directional solidification Directional solidification is a series of measures applied to control the feeding of castings. As most metals and alloys solidify, changing from the liquid state to the solid state they will undergo an appreciable volume contraction. of the castings using the water and/or air channels for cooling; * normal shrinkage Shrinkage The amount by which inventory on hand is shorter than the amount of inventory recorded. Notes: The missing inventory could be due to theft, damage, or book keeping errors. problems eliminatged by pressure filling of the mold feeds; * good to excellent as-cast surface finish; * excellent dimensional tolerances because the molds are made of metal rather than sand. |
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