Abstract:
In accordance with one aspect of the present embodiment, disclosed is a system and method of processing sand mold castings including the steps of placing a mold on a translation surface of a first conveyor at a first position, the mold including a sand housing having compacted sand that encapsulates a casting. The mold is translated along the translation surface of the first conveyor from the first position towards a second position. Air is directed against the casting and temperature of the air and or casting is measured after the casting is being removed from the sand mold.

Description:
[0001]    This application claims priority to U.S. Provisional Application No. 61/692,972 filed Aug. 24, 2012 by inventor Jeffrey D. Eagens. This provisional application is also incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present exemplary embodiment relates to a manufacturing process and system. It finds particular application in conjunction with processing sand type molds, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications. 
         [0003]    Many types of manufacturing processes utilize sand molds to assist with the heat transfer required to manufacture work pieces from molten material such as iron. The basic steps of a sand molding process include placing a desired pattern in the sand to create a mold half, compress the sand and pattern into a gating system, remove the pattern, align the mold halves together to create a mold cavity, fill the mold cavity with molten material, and allow the material to cool and break away the sand mold to remove the casting. 
         [0004]    More particularly, the known processes manufacture particular types of castings and various processes with particular features are employed depending on the requirements of the finished part or workpiece. For instance, vertical flaskless molding processes are employed to generate round and geometric shaped workpieces. Vertical flaskless molding is the process whereby sand molds are generated and stacked together horizontally along an elongated in-line process. Contact surfaces of each mold are vertically aligned and abut one another. Molten material, such as iron, is poured into a vertical joint of the mold halves whereby the material is allowed to harden, the sand mold is removed, and the workpiece is generated. A table or surface supports the molds on a common horizontal plane as a machine makes each mold half. The table includes particular features that are configured to allow the contact surfaces of each mold to maintain mold-to-mold contact pressure of each mold along the entire line such that molten material does not leak therefrom and until the material solidifies as intended. 
         [0005]    Additionally, horizontal tight flask molding is utilized for thin longer and flatter work pieces. The horizontal tight flask molding process utilizes sand molds that are created and designed to stack together horizontally in a signal set. The contact surfaces of the mold halves align and abut horizontally in this process. Molten material is poured into the top mold half as the mold halves are formed in and maintained in a housing such as a steel “flask”. 
         [0006]    Many types of conveyors are used to heat or cool the sand molds and work pieces. Conventional conveyors of different lengths and configurations translate the workpieces while directing air across the workpieces. Other foundry type conveyors that are generally known include U.S. Pat. No. 7,296,951 to Kraus et al., as well as U.S. Pat. Nos. 6,827,201, 7,037,048 and 7,377,728 to Markowski et al. each of which are incorporated herein by reference. 
         [0007]    However, these processes address covered transporting molds with castings, and castings only, but have not addressed the problematic issue of actually measuring the temperature of the castings after being removed from the sand mold and applying a cooling method that automatically adjusts the amount of air, or high velocity air, that is applied to efficiently lower the temperature of the casting to a desired temperature for subsequent processing, e.g., de-gating and shot blast cleaning. 
       BRIEF DESCRIPTION 
       [0008]    One aspect of the present exemplary embodiment is a method of processing sand mold castings including the steps of placing a mold on a translation surface of a first conveyor at a first position (e.g., an upstream position), the mold including a sand housing having compacted sand that encapsulates a casting. The mold is translated along the translation surface of the first conveyor from the first position towards a second position (e.g., a downstream position). Air is directed against the casting and a temperature of the air and/or temperature of the casting is (are) measured after the casting is removed from the sand mold. 
         [0009]    Still other features and benefits of the present disclosure will become apparent from the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic plan view of a preferred method and system for processing sand mold castings according to the present disclosure; 
           [0011]      FIG. 2  is a schematic plan view of an embodiment of the method and system method of processing sand mold castings according to the present disclosure; 
           [0012]      FIG. 3  is a perspective view of the system for processing sand mold castings according to the present disclosure; 
           [0013]      FIG. 4  a perspective view of the system for processing sand mold castings according to the present disclosure; 
           [0014]      FIG. 5  is a perspective view of air velocity modeling within a hood of the system for processing sand mold castings according to the present disclosure; 
           [0015]      FIG. 6  is a cross-sectional view of air velocity modeling within a hood of the system for processing sand mold castings according to the present disclosure; and 
           [0016]      FIG. 7  is a cross-sectional view of the hood over a conveyor of the system for processing sand mold castings according to the present disclosure; 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    A method and system is provided for a transportation of a mold casting while the casting is still in a sand mold, and as the sand mold is subsequently removed from the external surface of the cast component. Additionally, a process for transporting and cooling mold castings with high velocity air flow is provided. 
         [0018]    The method and apparatus used for this disclosure uses a series of conveyors to transport the molds for the duration required for cooling of the casting in the sand mold. The use of a series of conveyors produces maximum heat transfer from the casting to the molding sand. A unique feature of this process is that the system and process combine the transportation of the casting in the mold and also allows for the sand that is shed from the mold (due to thermal degradation and vibratory friction) to be maintained as a carrying media for the casting. The system also incorporates means for removal of the sand from the mold at a temperature below the eutectic state of the casting solidification and then subsequent high velocity controlled air cooling of the castings in the same process line system. 
         [0019]    This method uses conveyors of specific calculated lengths and flow rates to transport the castings and molds to maximize the amount of heat transfer from the casting to the sand from the mold. Initially, molds are formed, aligned and filled with molten material. As illustrated by  FIG. 1 , the molds are translated along a conveyor  20  until the molten material is sufficiently solid. 
         [0020]    Once this is accomplished the molds are transferred to a vibration conveyor at location  40  to begin imposing a vibration force to the mold to impose shedding of loose sand from the mold. The molds extend along the conveyor and are subject to vibration along all or a part of this accumulating mold conveyor  50 . The accumulating mold conveyor  50  translates the molds through a series of high velocity exhaust hoods  102  that are adapted to receive a pressurized air flow or velocity of air from a casting cooling conveyor  100  downstream of the accumulating mold conveyor  50 . Preferably, the sand is further shed and removed from the mold along the accumulating mold conveyor  50  wherein the sand is collected in a sand transfer conveyor  60  and transported to a sand hopper  65  via a sand return conveyor  70 . The sand is then sent from the hopper  65  to a reprocessing center (not shown) via a sand return conveyor  80 . In one embodiment, the molds can be conveyed over a shakeout deck or frequency conveyor  85  that is configured to further shed sand from the casting and collect sand on the sand transfer conveyor  60 . The accumulating mold conveyor  50  terminates in a housing  95  that preferably contains the frequency conveyor  85  and sand transfer conveyor  60 . The sand return conveyor  70  extends from the housing unit  95 . 
         [0021]    The castings (once free of the molding sand) are then conveyed along a first casting transfer conveyor  90  to the high velocity casting cooling conveyor  100 . As also illustrated by  FIG. 2 , this conveyor section  100  includes high velocity exhaust hoods  102  to blow air on the castings at a controlled rate in specific zoned sections. The hoods  102  include inlet connections  104  and exhaust connections  106  located at spaced intervals along a process direction that are connected to an air duct system. In one embodiment, inlet  104  and exhaust connections  106  are provided along five meter intervals, although other intervals or spacings may be used without departing from the scope and intent of the present disclosure. 
         [0022]    Air is provided by a commercial blower or fan  108  that produces high volumes of air through a primary duct line  110  ( FIGS. 2-3 ) that is sectioned off along particular branch lines  112  and into the exhaust hoods  102  through the inlet connections  104 . In one embodiment, as illustrated by  FIG. 2 , five branch lines  112   a - 112   e  supply five exhaust hoods  102   a - 102   e  along the casting cooling conveyor  100 . The casting cooling conveyor section  100  includes specific air zones applying the air to the castings along the conveyor  100 . The primary line  110  and branch lines  112  can include various cross sectional areas to allow various amount of air into each hood section  102   a - 102   e . In one embodiment, the fan  108  is located on top of the housing  95 . 
         [0023]    Each air zone defined by each hood  102   a - 102   e  includes an exhaust air line  116  that extends from the associated exhaust connection  106 . In one embodiment, the exhaust lines  116   a - 116   e  include a temperature measuring unit  122  to provide a signal to a controller  124  that is configured to adjust the blower  108  to provide a desired volume of air input by the blower to the casting cooling conveyor  100 . Optionally, each branch line  112   a - 112   e  and each exhaust line  116   a - 116   e  can include a manual volume damper or an automatically adjustable volume damper that can be adjusted to modulate air volume control. 
         [0024]      FIG. 3  illustrates a perspective plan view of one embodiment of the cooling system. The process reduces time for thermal break down of the molding sand and reduces the amount of moisture and temperature in its exhaust air. Directional arrows indicate the direction in which molds and castings travel along the conveyors  50 ,  100 . Also, directional arrows indicate the direction that air is exhausted from the hoods  102  of the cooling conveyor  100  to the hoods  102  of the accumulating mold conveyor  50 . 
         [0025]    An electronic temperature sensor  118  for measuring a casting temperature is placed in close proximity to a discharge end  120  of the housing  95 . Inputs from this sensor  118  will also be tied into the controller  124  to control the input air volume from the blower  108  to ensure the desired casting temperature is maintained. The casting cooling conveyor  100  can optionally include a curtain system  114  to prevent the unwanted exhaust of air along a discharge end of the cooling conveyor  100 . 
         [0026]    Exhaust air from the casting cooling conveyor  100  is regenerated in this system. The exhaust air from the casting cooling conveyor is dry hot air that is advantageously transferred into the hoods  102  that cover the accumulating mold conveyor  50  to absorb the moisture in the displaced air when the molds, still with the castings inside, are translated along the accumulating mold conveyor  50 . Notably, air that has excessive moisture and/or heat cannot effectively be sent to a dust collection system. The high temperature dry recycled air as provided by the present arrangement will allow improved efficiency in moisture absorption and also the addition of the moist air will drop the temperature of the hot air. Air from the accumulating mold conveyor  50  is exhausted from a series of exhaust ports  126  located thereon. The exhaust ports  126  can be coupled to a series of ducts that are port of a buildings dust control and exhaust system (not shown for ease of illustration). The regeneration of the air will reduce the total air to be exhausted and thus reduce operational costs. 
         [0027]    Stated another way, the fan  95  is used to produce high volumes of air that reduces the cooling time of cast metal parts once they are removed from the sand/molding media. The fan  95  injects ambient air into hoods  102  that cover the casting cooling conveyor  100  that are designed with an internal plenum that stores and accelerates the flow of the air to the surface of the conveyor that is transporting the cast parts.  FIG. 7  illustrates a cross-sectional view of the hood  102  along the cooling conveyor  100 . 
         [0028]      FIGS. 5 and 6  illustrate airflow modeling examples that identify vector stream lines through an inlet  104  and within a hood  102  of the disclosed system. As illustrated by  FIG. 6 , the cross sectional geometry of the hood  102  and the conveyor cause a dual wind tunnel cyclone effect at a location about the conveyor  100 . The concentrated airflow includes rebounding and counter-flowing air across surfaces of the castings that cause rapid cooling of the cast components. Once the ambient air crosses the cast workpiece along the conveyor  100 , the ambient air becomes a warm dry air that is exhausted through exhaust outlets  106  and through branch pipes  116  positioned along the conveyors  100 . 
         [0029]    Optionally, the hoods can be located at spaced intervals that are not continuous along the conveyor. The hoods  102  can have a staggered orientation such that each pressure reducing hood sections is spaced to allow exhausting of the air that has absorbed heat from the castings. 
         [0030]    The exhaust air from the casting cooling conveyor  100  is warm and dry and is transferred via branch tube-pipes  116   a - 116   e  by its own thermal expansion and negative pressure from the casting cooling conveyor  100  to the mold accumulating conveyor  50 . The air can optionally be transferred to the housing unit  95  or transport device that is downstream of the mold accumulating conveyor  50  or exhausted directly from the mold accumulating conveyor  50 . 
         [0031]    Notably, green sand molding processes utilize sand with natural binders that are activated by water. When the mold derogates and or is broken open after the molten material solidifies, there is a release of steam from the water/moisture in the sand due to the high temperature of the molten material. This wet, hot air causes a problem for dust collection and exhausting systems. However, by recirculating the hot dry air from the casting cooling conveyor  100  into the mold accumulation conveyor  50 , the mold media/sand breaks down faster and the hot, wet exhaust air is mixed with warm dry air from the casting cooler conveyor  100  thus making the accumulation conveyor exhaust air acceptable for being processed by an exhaust system. 
         [0032]    The disclosure has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiments be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.