Patent Application
20080079202
A better understanding of the exemplary embodiments of the present invention (including alternatives and/or variations thereof) may be obtained with reference to the detailed description of the exemplary embodiments of the present invention along with the following drawings, in which:
The drawings are not necessarily to scale and are sometimes illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details that are not necessary for an understanding of the embodiments or that render other details difficult to perceive may have been omitted.
Preferably, the sub-system 100 includes, amongst other things, a dryer 108 that is positionable relative to the system 1, and the dryer 108 is configured to dry, at least in part, metal chips 2 such as chips of magnesium, aluminum and/or zinc, etc. The metal chips 2 are receivable by the system 1. The sub-system 100 and the system 1 may be sold separately or together. A metallic molded article 90 is manufactured or molded by the system 1. The metallic molded article 90, includes, amongst other things, a solidified molding material 91 having been made from metal chips 2, the metal chips 2 being receivable by the system 1, and the metal chips 2 were dried, at least in part, by the dryer 108.
A technical effect, amongst other technical effects, is that, since trapped gas porosity degrades quality of the article 90, by removing moisture and driving wet gases away from the metal chips 2, a reduction of and/or entrapment of such gases, at least in part, in the melt (that is, a metallic molding material manufactured by the system 1) when the system 1 processes the metal chips 2. Removal of moisture and/or driving of wet gases away from the metal chips 2 may be accomplished, for example, by applying or directing relatively dry air toward the metal chips 2 or by heating the metal chips 2. A technical effect of conditioning the metal chips 2 is reduction of water vapor and/or wet gases in the metal chips 2 so that the extruder of the system 1 is not subjected to premature corrosion from such gases. The conditioning of the metal chips 2 is, preferably, performed in-line (the conditioning is performed proximate of a feed throat of the extruder); alternatively, the conditioning may be performed off-line (that is, the metal chips 2 are conditioned at a location remote of the system 1, and then the metal chips 2 are delivered to and feed into the system 1).
A molding material 91 of the system 1, includes, amongst other things, the metal chips 2 receivable by the system 1, and the metal chips 2 were dried, at least in part, by the dryer 108 positionable relative to the system 1. A molten molding material 92 of the system 1, includes, amongst other things, a molten metallic melt 93 being made from metal chips 2, and the metal chips 2 are receivable by the system 1, and the metal chips 2 were dried, at least in part, by the dryer 108.
Preferably, the dryer 108 includes, amongst other things, a blower 110 that is configured to blow air toward, at least in part, the metal chips 2. The blower 110 includes a pipe 112 that is positionable, at least in part, at (or “in”) the metal chips 2. The air dries, at least in part, the metal chips 2 (that is, the air removes moister contained in the metal chips 2). The pipe 112 has a perforation configured to pass the air toward, at least in part, to the metal chips 2. The pipe 112 is configured to direct the air upwardly toward, at least in part, through the metal chips 2. The blower 110 also includes an aerating bubbler 114 (also called a diffuser) that is attached to the pipe 112.
According to a variant, the blower 110 is configured to blow, at least in part, relatively dehumidified air (the air is dehumidified at least in part), toward the metal chips 2. By blowing the dehumidified air toward the metal chips 2, the following technical effects may be obtained: (i) final part quality of the article 90 may be improved, and/or (ii) molding process of the system 1 may be improved (the molding process may be more repeatable and more independent of ambient humidity conditions as may be experienced in different countries or at different times of the day or year, etc).
According to another variant, the blower 110 is configured to blow, at least in part, heated air (the air is heated at least in part), toward the metal chips 2. By blowing heated air toward the metal chips 2 (that is, before the metal chips 2 enter the extruder 3), the following technical effects may be obtained: (i) throughput rate of the system 1 may be increased or improved since the chips are preheated at least in part, (ii) duty cycle of extruder heaters (not depicted) that are coupled to the extruder 3 may be decreased thereby extending the life of the extruder 3 and of the extruder heaters, (iii) noise pollution may be reduced by providing preheated metal chips 2 that reduce friction between screw flights of a processing screw 4 and the extruder 3, and/or (iv) increased throughput rate of the system 1 by allowing faster screw recovery (of the screw 4). Feeding preheated and/or dry metal chips 2 (to the extruder 3) increases repeatability of the screw 4 (and hence recovery rate as well) from shot to shot (that is, shot weight repeatability). Moreover, when the (metallic) molding material is required to be maintained at a high temperature and melted relatively quickly (that is, quicker than the extruder heaters may provide), preheating the metal chips 2 may prevent slugging by preventing freezing of the metallic molding material near a feed throat 7 of the extruder 3. The feed throat 7 is sometimes called a throat connection. Slugging is the inadvertent (that is, unwanted) freezing of metallic molding material in the barrel of the extruder 3.
Preferably, the metal chips 2 are receivable in a hopper 102 of the system 1. The hopper 102 includes, amongst other things: (i) an inlet 104 that is configured to receive the metal chips 2, and (ii) an outlet 106 that is configured to expel the metal chips 2 to the extruder 3 of the system 1 (that is, after the metal chips 2 have been dried at least in part). Preferably, the hopper 102 is thermally insulated. The extruder 3 includes, amongst other things: (i) the screw 4 that is driven by a drive unit 5, and (ii) a barrel 6 that receives the screw 4 in which the barrel 6 is coupled to the hopper 102 via the feed throat 7. A material-delivery assembly 95 delivers the metal chips 2, such as by venturi action or vacuum to the hopper 102 (that is, a chip-receiving compartment, etc).
The heating, dehumidifying and gas expulsion is accomplished by air flowing from the dryer 108 through the pipe 112 (that is, a conduit) with a perforation (or more than one perforation) of the pipe 112. Preferably, the perforation of the pipe is positioned near a bottom of the hopper 102, after which the air flows upwardly toward, at least in part, through the metal chips 2. The dryer 108 may be mounted above the feed throat 7 of the extruder 3 so that loss of heat may be avoided to the surrounding environment before the metal chips 2 enter the extruder 3. According to other variants, drying of the metal chips 2 is achieved by conduction heating and/or radiation heating, induction heating, etc. The dryer 108 improves the throughput rate of the system 1, amongst other things, by providing dry (at least in part) metal chips 2. Gas or vapor or gas-producing liquid water is driven away, at least in part (but preferably substantially) from the metal chips 2 by air flow. Preferably, the treated metal chips 2 have an elevated temperature.
The system 1 also includes, amongst other things, (i) a machine nozzle 8, (ii) a stationary platen 9 and (iii) a movable platen 10. A mold 12 includes: (i) a stationary mold portion 13 (that is mounted to the stationary platen 9), and (ii) a movable mold portion 14 (that is mounted to the movable platen 10). The system 1 further includes, amongst other things, tangible subsystems, components, sub-assemblies, etc, that are known to persons skilled in the art. These items are not depicted and not described in detail since they are known. These other things may include (for example): (i) tie bars (not depicted) that operatively couple the platens 9, 10 together, and/or (ii) a clamping mechanism (not depicted) coupled to the tie bars and used to generate a clamping force that is transmitted to the platens 9, 10 via the tie bars (so that the mold 12 may be forced to remain together while a molding material is being injected in to the mold 12). These other things may include: (iii) a mold break force actuator (not depicted) coupled to the tie bars and used to generate a mold break force that is transmitted to the platens 9, 10 via the tie bars (so as to break apart the mold 12 once the molded article 90 has been molded in the mold 12), and/or (iv) a platen stroking actuator (not depicted) coupled to the movable platen 10 and is used to move the movable platen 10 away from the stationary platen 9 so that the molded article 90 may be removed from the mold 12, and (vi) hydraulic and/or electrical control equipment, etc.
A controller (not depicted) may be coupled to the dryer 108, and the controller is used to automatically adjust the dryer 108 under an open loop and/or closed loop feedback control scheme, etc.
According to a variant, the conditioner 107 includes the dryer 108 and the hopper 102 includes a mixer 111 configured to mix the metal chips 2 received in the hopper 102.
The metal chips 2 include, for example, chips of a magnesium alloy and/or chips of a zinc alloy and/or chips of an aluminum alloy, and/or other alloys, and/or impurities, and/or reinforcements (such as ceramic particles), etc.
The description of the exemplary embodiments provides examples of the present invention, and these examples do not limit the scope of the present invention. It is understood that the scope of the present invention is limited by the claims. The exemplary embodiments described above may be adapted for specific conditions and/or functions, and may be further extended to a variety of other applications that are within the scope of the present invention. Having thus described the exemplary embodiments, it will be apparent that modifications and enhancements are possible without departing from the concepts as described. It is to be understood that the exemplary embodiments illustrate the aspects of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims. The claims themselves recite those features regarded as essential to the present invention. Preferable embodiments of the present invention are subject of the dependent claims. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims:
