Hydraulic 2-platen machine innovates diecasting operations.Most diecasting machines utilize a mechanical linkages-tyle (toggle To alternate back and forth between two states. toggle - To change a bit from whatever state it is in to the other state; to change from 1 to 0 or from 0 to 1. This comes from "toggle switches", such as standard light switches, though the word "toggle" actually refers to ) clamp clamp (klamp) a surgical device for compressing a part or structure. rubber dam clamp a metallic device used to retain the dam on a tooth. clamp n. because they are well-known for their robustness and repeatable mechanism for creating tonnage TONNAGE, mar. law. The capacity of a ship or vessel. 2. The act of congress of March 2, 1799, s. 64, 1 Story's L. U. S. 630, directs that to ascertain the tonnage of any ship or vessel, the surveyor, &c. . The linkage linkage In mechanical engineering, a system of solid, usually metallic, links (bars) connected to two or more other links by pin joints (hinges), sliding joints, or ball-and-socket joints to form a closed chain or a series of closed chains. is the main contributor to a "stiff" diecasting machine (high spring rate), and this is essential for maintaining distributed force on a die. The technology's success has made it possible to produce engine blocks, instrument panels and transmission cases with cycle times that are typically 60-90 sec. However, there are inherent limitations to the technology that prevent dramatic productivity and operational cost improvements: * size of the machine (floor footprint The amount of geographic space covered by an object. A computer footprint is the desk or floor surface it occupies. A satellite's footprint is the earth area covered by its downlink. See form factor. 1. ); * maintenance and operation costs related to the linkage; * lack of die closing stroke flexibility; * tie bar tonnage control that requires mechanical adjustment of the diecasting machine to vary tonnage. Engineers at IdraPrince Inc., Holland, Mich., designed a clamp-system that maintains the advantages of the linkage style machine (stiffness, robustness, reliability and cycle time) while eliminating the disadvantages. The new machine utilizes hydraulic cylinders Hydraulic cylinders (also called linear hydraulic motors) are mechanical actuators that are used to give a linear force through a linear stroke. Operation Hydraulic cylinders get their power from pressurized hydraulic fluid, which is typically oil. located on each tie bar behind the moving plate to establish tonnage (Fig. 1). While the use of hydraulic cylinders is not a new development in machine technology, the current design improves on their use to increase the machine's stiffness and operational performance. [FIGURE 1 OMITTED] As shown in Fig. 1, the new design eliminates the third plate and locates the split locking nut with the hydraulic cylinder behind the moving plate. The much shorter tie bar improves machine stiffness, and the location of the split nuts A split nut is a nut that consists of two pieces which can be clamped together to engage the thread of the nut with the bolt, or released, to allow the nut to move along the bolt without turning the bolt. eliminates the need to pull the tie bar thread area into the die space each cycle. Advantages of the new machine compared with current linkage machines include: * smaller machine footprint--the 1,200-ton Model 44 2-Platen machine is the same length as a 900-ton linkage machine with an extra 8 in. (20.32 cm) of space between tie bars; * one machine can operate over a wide tonnage range, which is useful for scheduling work that had to be performed on different size linkage machines; * elimination of the linkage as a maintenance item and lubrication lubrication, introduction of a substance between the contact surfaces of moving parts to reduce friction and to dissipate heat. A lubricant may be oil, grease, graphite, or any substance—gas, liquid, semisolid, or solid—that permits free action of point; * increased die stroke flexibility--only opens the machine as far as necessary to remove the casting; * real-time tonnage of tie bars is individually and automatically controlled. While most of the advantages reduce operational costs compared with a linkage machine, the most remarkable benefits to date have been related to the actual diecasting process. Modeling has shown the machine to be 15% stiffer than a comparable linkage machine. In addition, because force on the tie bar is controlled through pressure regulation in the cylinder, tonnage is the same every cycle, regardless of die thermal expansion thermal expansion Increase in volume of a material as its temperature is increased, usually expressed as a fractional change in dimensions per unit temperature change. of non-uniformity. The combination of improved stiffness and closed-loop tonnage control improves parting line management of the die and therefore increased productivity. Select No. 002 at www.moderncasting.com/info |
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