Abstract: A die casting system includes a die, a shot tube, a melting system and a vacuum system. The die includes a plurality of die components that define a die cavity. The shot tube is in fluid communication with the die cavity and is operable to deliver a charge of material to the die cavity. The melting system is positioned adjacent to the die and includes an alloy loader, a melting unit and a crucible. The vacuum system defines a first chamber and a second chamber separated from the first chamber by an isolation valve. The melting system is disposed within the first chamber, and the die is disposed within the second chamber.

Abstract: Various embodiments provide apparatus and methods for injection molding. In one embodiment, a constraining plunger may be configured in-line with an injection plunger to transfer a molten material from a melt zone and into a mold. The constraining and injection plungers are configured to constrain the molten material there-between while moving. The constrained molten material can be controlled to have an optimum surface area to volume ratio to provide minimized heat loss during the injection molding process. The system can be configured in a longitudinal direction (e.g., horizontally) for movement between the melt zone and mold along a longitudinal axis. A molded bulk amorphous object can be ejected from the mold.

Abstract: A die casting apparatus (100) for amorphous alloy comprises a stationary die (1) and a movable die (2); a sealed cabin (4) difining a sealing chamber (40); a protecting gas supplying device connected with the sealed cabin (4) for supplying the protecting gas into the sealing chamber (40); a melting device (5) for receiving and melting amorphous alloy; a feed sleeve (6) having a molten material inlet (60), with a plunger (7) positioned therein for injecting the molted amorphous alloy from the melting device (5) into a die chamber via the molten material inlet (60); a driving device (8) connected with the plunger (7) for driving the plunger (7) in the feed sleeve (6); and a gas purifying device (10) communicated with the sealed cabin (4) for purifying the gas from the sealed cabin (4).

Abstract: Disclosed is an injection molding system including a plunger rod and a melt zone that are provided in-line and on a horizontal axis. The plunger rod is moved in a horizontal direction through the melt zone to move molten material into a mold. The melt zone can have a vessel that is configured to receive the plunger therethrough. A transfer sleeve provided between the vessel and the mold and/or an inlet into a mold can also be horizontally in line with the plunger. The injection molding system can perform the melting and molding processes under a vacuum.

Abstract: Described herein is a plunger of an injection molding machine, comprising a plunger body; a plunger tip that is a separate element from the plunger body and comprises an end surface configured to directly contact a molten material used in injection molding in the injection molding machine; wherein thermal conductance across the end surface of the plunger tip may be adjustable by moving the plunger tip relative to the plunger body such that temperature of the plunger tip may be adjusted during injection molding. When this plunger is used to injection molding of a BMG, it allows reduction of formation of crystalline phases near the plunger tip and allows replacement of the plunger tip without replacement of the plunger body.

Abstract: Exemplary embodiments described herein relate to methods and systems for casting metal alloys into articles such as BMG articles. In one embodiment, processes involved for storing, pre-treating, alloying, melting, injecting, molding, etc. can be combined as desired and conducted in different chambers. During these processes, each chamber can be independently, separately controlled to have desired chamber environment, e.g., under vacuum, in an inert gas environment, or open to the surrounding environment. Due to the flexible, independent control of each chamber, the casting cycle time can be reduced and the production throughput can be increased. Contaminations of the molten materials and thus the final products are reduced or eliminated.

Abstract: A high-vacuum die-casting method includes an injecting step of moving a plunger in a sleeve so that a molten metal fed to the sleeve is pushed by the plunger to be injected into a cavity formed by a fixed mold and a movable mold, a cavity vacuumizing step of vacuum absorbing a gas in the cavity to discharge the vacuum-absorbed gas to the outside through a first path, and a sealed space vacuumizing step of vacuum absorbing a gas in a sealed space in which an eject plate and one ends of eject pins are arranged to discharge the vacuum-absorbed gas to the outside through a second path while the injecting step is performed. The sealed space vacuumizing step is started prior to the cavity vacuumizing step.

Abstract: Various embodiments provide apparatus and methods for injection molding. In one embodiment, a constraining plunger may be configured in-line with an injection plunger to transfer a molten material from a melt zone and into a mold. The constraining and injection plungers are configured to constrain the molten material there-between while moving. The constrained molten material can be controlled to have an optimum surface area to volume ratio to provide minimized heat loss during the injection molding process. The system can be configured in a longitudinal direction (e.g., horizontally) for movement between the melt zone and mold along a longitudinal axis. A molded bulk amorphous object can be ejected from the mold.

Abstract: The invention relates to a vacuum die-casting system and a method for operating a vacuum die-casting system.

Abstract: Various embodiments provide systems and methods for casting amorphous alloys. Exemplary casting system may include an insertable and rotatable vessel configured in a non-movable induction heating structure for melting amorphous alloys to form molten materials in the vessel. While the molten materials remain heated, the vessel may be rotated to pour the molten materials into a casting device for casting them into articles.

Abstract: Various embodiments provide apparatus and methods for melting and introducing alloy feedstock for molding by using a hollow branch having a constraint mechanism therein. In one embodiment, a hollow branch can extend upward from a cold chamber that is substantially horizontally configured. The hollow branch including a constraint mechanism can be capable of containing an alloy feedstock for melting into the molten alloy in the hollow branch and introducing the molten alloy to the cold chamber for molding.

Abstract: The invention is provided with a first injection electric motor used for low-speed injection and increasing pressure, a second injection electric motor used for high-speed injection, first and second power transmission mechanisms for transmitting rotary motion of the injection electric motors to a screw shaft, first and second clutch mechanisms provided in the power transmission mechanisms, an injection plunger advanced and withdrawn integrally with respect to a nut threaded on the screw shaft, and a controller for controlling the driving of the injection electric motors and the clutch mechanisms. The controller starts the second injection electric motor from a stopped state before the point in time where the high-speed injection step is to commence; and switches the second clutch mechanism from a disengaged state to an engaged state at the point in time where the high-speed injection step is to commence, or at a requisite timing prior thereto.

Abstract: A method for controlling a temperature of a portion of a die casting system having a shot tube plunger, according to an exemplary aspect of the present disclosure includes, among other things, communicating a fluid through a fluid inlet of a fluid passageway of a thermal control scheme of the shot tube plunger. The fluid circulates through the fluid passageway of the thermal control scheme to selectively adjust a temperature of the shot tube plunger. The fluid is discharged through a fluid outlet of the fluid passageway.

Abstract: Metal alloy injection molding techniques are described. In one or more implementations, these techniques may also include adjustment of injection pressure, configuration of runners, and/or use of vacuum pressure, and so on to encourage flow of the metal alloy through a mold. Techniques are also described that utilize protrusions to counteract thermal expansion and subsequent contraction of the metal alloy upon cooling. Further, techniques are described in which a radius of edges of a feature is configured to encourage flow and reduce voids. A variety of other techniques are also described herein.

Abstract: The invention relates to a valve device for a pressure injection or die-casting machine, said device comprising a body (18) with a valve chamber (21) including a suction chamber and a control chamber, and a sliding valve (20) mounted in the valve chamber, said sliding valve comprising a first portion (34) with a valve head (44) that co-operates with a valve seat (22) on the body in order to open and close the valve and a second portion (35) comprising a piston (38) mounted in the control chamber (21a). The control chamber is connected to fluid control connections (26a, 26b) in order to exert a pressure on the piston (38) so as to control the opening and closing of the valve. The second valve portion and the first valve portion re aligned on the same axis in the direction of movement of the sliding valve and said first and second portions of the sliding valve can be separated from one another and secured to one another using a removable securing member (36, 36?).

Abstract: Various embodiments provide apparatus and methods for injection molding. In one embodiment, a constraining plunger may be configured in-line with an injection plunger to transfer a molten material from a melt zone and into a mold. The constraining and injection plungers are configured to constrain the molten material there-between while moving. The constrained molten material can be controlled to have an optimum surface area to volume ratio to provide minimized heat loss during the injection molding process. The system can be configured in a longitudinal direction (e.g., horizontally) for movement between the melt zone and mold along a longitudinal axis. A molded bulk amorphous object can be ejected from the mold.

Abstract: Various embodiments provide apparatus and methods for melting and introducing alloy feedstock for molding by using a hollow branch having a constraint mechanism therein. In one embodiment, a hollow branch can extend upward from a cold chamber that is substantially horizontally configured. The hollow branch including a constraint mechanism can be capable of containing an alloy feedstock for melting into the molten alloy in the hollow branch and introducing the molten alloy to the cold chamber for molding.

Abstract: A casting machine includes a processing cylinder formed in a thermally conductive block. The cylinder has a processing chamber, a first end configured to receive the metal feed stock and a second end. An injector cylinder formed in the thermally conductive block has a shooting pot coupled to the second end of the processing cylinder by a passage configured to permit feed stock to pass from the processing cylinder into the shooting pot. A nozzle is coupled to the injector cylinder and to the mold. A processing drive drives the feed stock from the first end of the processing cylinder through the passage into the shooting pot. A heater is thermally coupled to the processing cylinder to heat the feed stock. An injector plunger coupled to an injector actuator for driving the plunger sufficiently to force the metal from the shooting pot through the nozzle and into the mold.

Abstract: A molded article includes a flat plate portion and a projected portion. A molding method includes filling a cavity with the semimolten or semisolid metal in plate thickness directions of the flat plate portion starting from a surface on an opposite side of the flat plate portion from the surface from which the projected portion projects. The cavity is a casting space of the molded article formed inside a forming mold. A molding apparatus for casting the molded article includes a forming mold having the cavity, and a separate insert or slide mold disposed between the cavity and a runner in order to form the runner in plate thickness directions of the flat plate portion starting from the other surface. The runner is used to fill the cavity.

Abstract: A die casting system according to an exemplary embodiment of this disclosure can include a shot tube plunger and a tip portion connected to the shot tube plunger. The tip portion can include an inner flange and a lip portion circumferentially disposed about the inner flange. A recess can be circumferentially disposed between the lip portion and the inner flange.

Abstract: Some embodiments provide methods and systems for casting articles. One example of a method includes providing and positioning a thermal blanket within a mold cavity and then introducing a molten material into the mold cavity and into contact with the thermal blanket. The method allows the molten material to remain in a molten state during a dwell time that extends from the introduction of the molten material at least until the mold cavity is filled. In another example, a method of using a thermal blanket includes keeping a molten material in a molten state during a dwell time extending from first introduction of the molten material until pressurization. Systems including a variety of mold types, one or more thermal blankets, and in some cases preforms and/or inserts are also provided. Also described is a novel thermal blanket and method of manufacturing the same.

Abstract: The die casting machine comprises a mold closing actuator capable of selectively inducing a closing pressure on first and second platens for forcing them towards a closed position in which their mold portions are pressed against each other along a parting line. An injection sleeve is movable relative to the mold portions between a distal position in which the injection sleeve and the mold portions are spaced apart; and an injection position in which the injection sleeve engages the mold portions at an inlet opening when the first and second platens are in their closed position. The injection sleeve applies a transverse contact pressure when it engages the mold portions. The closing pressure is unevenly distributed on the platens so as to compensate the transverse contact pressure to have a resulting effective molding pressure on the mold portions that is substantially evenly distributed across the parting line.

Abstract: The injection chamber (CI) includes a tubular body formed by a supply portion, having a radial supply window to receive a charge of molten metal (MF) and in which is incorporated an injection portion provided with an outlet end opened to the interior of a molding cavity. A piston is provided to be displaced in the interior of the tubular body to inject the molten metal (MF) in the molding cavity. The supply portion has its inner region, which receives the pouring impact of the charge of molten metal (MF), lined by an insert formed in a high melting point material and presenting an inner contour in the form of a circle arc coinciding with that of the supply and injection portions.

Abstract: A ladle (100) for a casting apparatus (1) includes a cylindrical melt pouring spout (120) through which a melt (M) is poured from an accommodation portion (110). Protrusions (121, 122) are formed on opposite sides along the inner circumference of the melt pouring spout (120) along the lower side and upper side in the vertical direction of the melt pouring spout (120). The cross sectional area of the protrusions (121, 122) in the axial section of the melt pouring spout (120) gradually increase, while the phase of the protrusions varies gradually in one circumferential direction of the melt pouring spout (120) from the upstream side towards the downstream side in the flow direction of the melt (M). In addition, the protrusions (121, 122) become gradually thinner and curve gradually in the respective phase variation direction towards the inside in the radial direction of the melt pouring spout (120).

Abstract: Four cavities are arranged on a concentric circle “C” with respect to the center “O” of a flow divider and a gate sleeve. Each of the cavities is connected to a sleeve stamp portion through each of four die side runners and each of four stamp side runners formed in a radial direction and separated from the neighboring runners. A semicircular arc-shaped reservoir is provided between the lower half side of the flow divider and the lower half side of the gate sleeve. This reservoir is connected to the sleeve stamp portion. A semi-solidified layer formed by pouring the molten metal into a sleeve is filled into the reservoir, so that the molten metal from which the semi-solidified layer is separated can be filled directly from each of the stamp side runners via the die side runners into each of the cavities evenly and simultaneously.

Abstract: An outer panel mold and method of constructing a piston and forming an undercut cooling gallery of a piston therewith is provided. The outer panel mold is operably attachable to a conventional piston mold machine. The outer panel mold has a pair of gudgeon core members and a pair of gudgeon guide blocks. The gudgeon core members are moveable toward and away from one another along an axis that is substantially perpendicular to a longitudinal central axis of a piston. Each of the gudgeon guide blocks have an opening receiving a separate one of the gudgeon core members. A pair of outer panels are moveable into a closed position between the pair of gudgeon guide blocks to form an undercut cooling gallery of the piston and an open position to allow extraction of the piston vertically along the longitudinal central axis in response to movement of the gudgeon guide blocks.

Abstract: The present invention provides a casting die that can achieve the improved fluidity of molten metal and the improved ease release of castings from die. The casting die 10 comprises area of dimples D where a plurality of first dimples are formed in semispherical shape on the surface of the cavity 11 with no particular indication of direction and in a dispersed manner and where the ratio of communication is 80% or more, which ratio of communication is defined by the ratio of the number of the first dimples 12 that constitute the bound dimples 12b, which each comprise one or more of the dimples, to the total number of the first dimples 12. So, in the area of dimples D a number of bound dimples 12b that work as short flow-channels that have no particular indication of direction are randomly formed, thus improving the fluidity of the molten metal.

Abstract: A method for die casting a hybrid component includes defining a cavity within a die element of a die and inserting a spar into the cavity. Molten metal is injected into the die element. The molten metal is solidified within the cavity to cast the hybrid component. The spar establishes an internal structure of the hybrid component. The spar includes a high melting temperature material that defines a first melting temperature greater than a second melting temperature of the molten metal.

Abstract: A mold for molding a green body for manufacturing a zirconium oxide dental implant includes a first molding part and a second molding part. The first and second molding parts each has a first imprinting inner surface and two none-thread inner surfaces for forming the external of the green body with two external thread sections and two none-thread sections. The mold may also include a driving mechanism, a polygonal conical slider and a screw thread forming rod. The polygonal conical slider can be driven for axially sliding into the mold cavity without rotation. The screw thread forming rod is coaxially and slidably penetrated the polygonal conical slider and driven by the driving mechanism for screwing into the mold cavity and unscrewing out of the mold cavity thereby forming the inner of the green body with an internal thread and a polygonal tapering section.

Abstract: A reduced size vacuum die-casting machine wherein an amount of powder release agent which is fed to a mold cavity each time is stable and loss of velocity of the air flow for sucking out the powder release agent is difficult, the apparatus provided with a powder control valve which has a powder release agent passage through which a powder release agent passes and which moves back and forth inside of a sleeve to switch between a state communicating a discharge hole with a molten metal holding chamber and a state communicating a discharge hole with a powder release agent passage, the powder release agent passage of the powder control valve formed inside of the powder control valve, the inlet and outlet of the powder release agent passage being formed at the outer surface of the powder control valve.

Abstract: A casting machine system includes a first casting machine and a separate second casting machine, wherein the first casting machine is a metal-casting machine and the second casting machine is a plastic-casting machine, or the first casting machine is a plastic-casting machine and the second casting machine is a metal-casting machine. An associated process produces hybrid metal/plastic articles. The casting machine includes a transfer device for transferring a precursor product, produced by a first casting process in the first casting machine, to the second casting machine, in which a hybrid metal/plastic component is formed from the precursor product by a second casting process, and a temperature-regulating device for regulating the temperature of the precursor product in a controllable manner after its removal from the first casting machine, and before starting the second casting process.

Abstract: By blocking an angular extent of an annular skimming trap used for semi-solid injection, a notable reduction in lenticular defects and porosity are observed. The blocking can be performed by a ring having dimensions to completely occlude a prior art annular skimming trap throughout the angular extent, and providing complete and/or partial flow across the ring throughout the rest of the angular extent. Preferably an outlet to the ring trap includes a chamfered edge and/or a deflector for encouraging flow of the contaminated semi-solid material into the trap.

Abstract: A die casting system includes a die having a plurality of die elements that define a die cavity. A charge of material is received in the die cavity. The charge of material may comprises a refractory metal intermetallic composite based material system. The charge of material may also comprise a composite material.

Abstract: A shot tube plunger of a die casting system includes a tip portion and a thermal control scheme at least partially disposed within the shot tube plunger. The thermal control scheme includes a fluid passageway having at least one coiled portion that receives a fluid to adjust a temperature of the shot tube plunger.

Abstract: A molten metal is fed from a distributor provided in a molten metal introduction portion of a casting die to a cavity of the casting die so as to perform a casting operation. A portion of the distributor to be in contact with the molten metal is made of a copper or a copper alloy. The casting is performed while setting a cavity temperature of the casting die in an initial stage of casting to a predetermined temperature and setting a temperature of the distributor in the initial stage of casting to 65° C. or lower.

Abstract: The casting device (1) comprises a die (3) consisting of two die halves (3a, 3b) forming in their interior a die cavity (4). In addition, the casting device (1) comprises connected to the die cavity (4) a casting chamber (6), the outlet (9) of which can be closed off at least partially by means of a closure member (18,26). At least the one die half (3a) is provided with a vent passage (13) for evacuating the die cavity (4) and/or the casting chamber (6). The vent passage (13) ports into the die parting (12) of the one die half (3a) such that it can be closed off by the other die half (3b) when locking the die (3).

Abstract: A semi-solid metal alloy injection feed system for reduced inclusion injection molding comprises a substantially closed injection chamber for containing a billet of semi-solid metal alloy, and thrusting the billet through the injection chamber into a mold, wherein the injection chamber has a first section defined by a wall with an inner contour for mating with a bearing surface for reciprocating motion of the bearing surface within the first section, along a center axis of the injection chamber; and the injection chamber has an outlet in fluid communication with the mold, the outlet provided at an opening in the injection chamber that is offset with respect to the center axis, and is disposed at an angle of 90° to 125° from the center axis. There is no neck or throttling between the chamber and the outlet. A butt end trap is preferably formed that requires inclusions that are principally on a bottom side of the injector to travel a relatively long ways to enter the outlet.

Abstract: A die casting machine provided with an electric servomotor and a hydraulic cylinder as drive sources for injection is enhanced in operation stability in an injection step. In the injection step, the rotational speed of an injection electric servomotor (3) is pattern-controlled to follow a preset speed command pattern while the forward speed of a piston (5a) caused by driving of an injection hydraulic cylinder (5) is feedback-controlled with an addition signal of the forward speed of the piston (5a) caused by driving of the injection electric servomotor (3) and the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5). Alternatively, the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5) may be pattern-controlled to follow a preset speed command pattern while the rotational speed of the injection electric servomotor (3) is feedback-controlled with the addition signal.

Abstract: A ladle (100) for a casting apparatus (1) includes a cylindrical melt pouring spout (120) through which a melt (M) is poured from an accommodation portion (110). Protrusions (121, 122) are formed on opposite sides along the inner circumference of the melt pouring spout (120) along the lower side and upper side in the vertical direction of the melt pouring spout (120). The cross sectional area of the protrusions (121, 122) in the axial section of the melt pouring spout (120) gradually increase, while the phase of the protrusions varies gradually in one circumferential direction of the melt pouring spout (120) from the upstream side towards the downstream side in the flow direction of the melt (M). In addition, the protrusions (121, 122) become gradually thinner and curve gradually in the respective phase variation direction towards the inside in the radial direction of the melt pouring spout (120).

Abstract: A mold including a product cavity that is to be filled with a molten metal to mold a product; a supply cavity that connects to one side of the product cavity to supply the product cavity with the molten metal that is poured from a casting port; and a cooling cavity that connects to the other side of the product cavity and in which the molten metal filling the cooling cavity is cooled before the molten metal filling the product cavity and the supply cavity is cooled. A modulus M (=V/S) as a ratio of a volume V to a cooling surface area S in each of the cavities has a relation of Ms>Mp>Mc, where Mp is a modulus of the product cavity, Ms is a modulus of the supply cavity, and Mc is a modulus of the cooling cavity.

Abstract: A method of processing metal, metallic alloys, and metal matrix composites in a plastics injection molding machine is disclosed. The method includes the steps of providing a plastics injection molding machine having a screw. A step of removing the screw is included in the method. A step of replacing the screw with a modified screw configured and arranged for processing metals is also included. Alternatively, a step of removing the flights from the middle portion of the original screw shaft may be included.

Abstract: A shot tube plunger of a die casting system includes a tip portion and a thermal control scheme at least partially disposed within the shot tube plunger. The thermal control scheme includes a fluid passageway having at least one coiled portion that receives a fluid to adjust a temperature of the shot tube plunger.

Abstract: Provided is an electric die casting machine capable of achieving high injection speed and high boost pressure. An injection unit (100) is provided with an electric servomotor (104) for injection in a first stage, a ball screw mechanism (110) (motion converting mechanism in the first stage) for converting rotational motion of the electric servomotor for injection in the first stage into rectilinear motion of a linear motion body (106), electric servomotors (111 and 112) for injection in a second stage, mounted on the linear motion body, a crank mechanism (113 and 116) (motion converting mechanism in the second stage) for converting rotational motion of the electric motor servomotor for injection in the second stage into rectilinear motion of an injection plunger (118), and a control unit (400) for controlling driving of each electric servomotor for injection.

Abstract: A method of die casting a component having an integral seal includes defining a first portion of a die cavity of a die to include an open cell structure. A second portion of the die is defined without the open cell structure. Molten metal is injected into the die cavity, and the molten metal is solidified within the die cavity to form the component having the integral seal.

Abstract: A die casting system includes a die, a shot tube and a shot tube plunger. The die casting system is positioned relative to a surface. The die includes a plurality of die components that define a die cavity. The shot tube is in fluid communication with the die cavity. The shot tube plunger is moveable within the shot tube to communicate molten metal into the die cavity. Each of the die, the shot tube and the shot tube plunger are inclined at an angle relative to the surface during injection of the molten metal into the die cavity.

Abstract: A shot tube plunger for a die casting system includes a first face, an opposing second face and an outer surface disposed between said first face and said opposing second face. A channel circumferentially extends about the outer surface. The channel is operable to receive a portion of a charge of material introduced into the die casting system.

Abstract: A multi-piece piston (1) is disclosed, for fixing to the high pressure side end (3) of a piston rod (5) running axially in a casting cylinder (7) of a cold chamber casting machine. The piston comprises a piston crown (9) forming a piston front face (13) on the high pressure side and a piston body (15) in the form of a bush connected to the piston crown (9) on the low pressure side. The piston body (15) can be connected to the piston crown (9) by means of fixing screws (23) to form a module. Complementary bayonet looking means (25, 27) are provided, for axial fixing of the piston (1) to the end (3) of the piston rod (5), on the piston crown (9) and the end (3).

Abstract: The invention relates to a die casting piston (20) and a respective support (2). The piston has a wall (21) in which channels for a coolant flow are obtained: this improves the thermal exchange between the piston and the coolant, leading to greater cooling efficiency.

Abstract: A vacuum die casting method according to the present invention solves the problems relating to seal performance, differential pressure, and the stability of the degree of vacuum. The method carries out the casting with a casting cavity evacuated. In the method, a molten metal is poured from a molten metal inlet of a plunger sleeve, followed by forming a vacuum chamber surrounding the inlet and an open end of the plunger sleeve located on the opposite side of the die, and an evacuation of the vacuum chamber and the cavity starts before starting an operation of a plunger tip. When the evacuation starts, the plunger tip is positioned between the open end of the plunger sleeve and the inlet so that the vacuum chamber is communicated to the inside of the plunger sleeve through the inlet.

Abstract: An injection sleeve or shot sleeve for a die-casting machine includes an elongated plunger passage and a container supporting portion configured to support an elongated container containing a charge of semi-solid metal alloy. The charge can be axially aligned with the plunger passage, and an interior surface of the container can be axially aligned with an interior surface of the plunger passage.