Abstract:
An injection molding system includes a mold with a mold cavity, an injection device, and a temperature control device. The injection device is capable of injecting a molten material into the mold cavity. The temperature control device includes a heating system and a cooling system. The heating system utilizes hot fluid to increase a temperature of the mold to a predetermined upper temperature when the injection device starting to inject the material. The cooling system utilizes cool fluid to decrease the temperature of the mold to a predetermined low temperature when the material is being solidified in the mold cavity.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to an injection molding system and method. 
         [0003]    2. Description of Related Art 
         [0004]    Injection molding is a well-known process which may be used for the fabrication of complexly shaped plastic or metal objects or parts. In the injection molding process, a molten thermoplastic or metal material is introduced into a mold and allowed to set or cure by cooling. Once the plastic or metal is set or cured, the mold is opened, and the molded object is released. The temperature of the injection mold is preferably controlled so that the mold is at the proper temperature when the molten material is injected into the mold and such that the object formed in the mold is set or cured at an optimal rate to both maintain the quality of the molded object while minimizing the setting or curing time to maximize production rates. 
         [0005]    A typical injection molding system and method usually utilizes a temperature sensor to sense a temperature of the mold and a cooler to cool the mold. The mold is heated by the molten material injected thereto, then cooled by the cooler to solidify the molten material. However, the typical injection molding system and method cannot maintain the mold at an optimal temperature throughout the injection molding process. 
         [0006]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  a block diagram of an injection molding system according to an embodiment of the present disclosure. 
           [0008]      FIG. 2  is a drawing that shows an arrangement of a heating system of the injection molding system in  FIG. 1 . 
           [0009]      FIG. 3  is a drawing that shows an arrangement of a cooling system of the injection molding system in  FIG. 1 . 
           [0010]      FIG. 4  is a flowchart of an embodiment of an injection molding method. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The disclosure is illustrated by way of example and not by way of limitation. In the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
         [0012]    Referring to  FIG. 1 , an embodiment of an injection molding system includes a mold  10 , a temperature controlling device  20 , an injection device  30 , and an air blower  40 , and a pressure maintaining device  50 . 
         [0013]    The mold  10  includes a fluid channel  12  and a mold cavity  14 . The injection device  30  can inject a molten material into the mold cavity  14 . The mold cavity  14  determines the size and shape of the article molded by the mold  10 . The mold  10  includes male and female mold parts. The mold cavity  14  is formed between the male and female mold parts. 
         [0014]    The temperature control device  20  includes a heating system  22  and a cooling system  24 . The heating system  22  can output hot fluid (e.g., hot water) to the fluid channel  12  of the mold  10  for heating up the mold  10 . The cooling system  24  can output cold fluid (e.g., ice water) to the fluid channel  12  of the mold  10  for cooling the mold  10 . Both the hot fluid and the cold fluid can be reclaimed after flowing through the fluid channel  12 . 
         [0015]    Referring to  FIG. 2 , the heating system  22  includes a fluid storage barrel  221 , a first pump  222 , a heating module  224 , a first valve K 1 , and a second valve K 2 . The first pump  222  is connected to the fluid storage barrel  221  to pump fluid from the fluid storage barrel  221  to the heating module  224 . The heating module  224  includes a plurality heating tubes  223  connected in series. In one embodiment there are four heating tubes  223 . The heating tubes  223  can heat up the fluid flowing from the fluid storage barrel  221  to a predetermined upper temperature (e.g. 90° C.). The first valve K 1  is connected between an output port of the heating module  224  and an input port of the fluid channel  12  of the mold  10 . The second valve K 2  is connected between an output port of the fluid channel  12  and the fluid storage barrel  221 . 
         [0016]    To heat up the mold  10 , the first valve K 1  and the second valve K 2  are both open. The first valve K 1  allows hot fluid heated by the heating tubes  223  to be pumped into the fluid channel  12  of the mold  10 . The hot fluid then flows out from the fluid channel  12  and flows back to the fluid storage barrel  221 . 
         [0017]    Referring to  FIG. 3 , the cooling system  24  includes a cold fluid container  241 , a second pump  242 , a cold fluid source  243 , a third valve K 3 , a fourth valve K 4 , a fifth valve K 5 , and a recycling container  244 . The second pump  242  is connected between the fluid container  241  and the fluid channel  12  for pumping cold fluid to the fluid channel  12 . The cold fluid source  243  provides cold fluid to the cold fluid container  241 . The third valve K 3  is connected between the second pump  242  and the input port of the fluid channel  12  of the mold  10 . The fourth valve K 4  is connected between the output port of the fluid channel  12  and the cold fluid container  241 . One port of the fifth valve K 5  is connected to the output port of the fluid channel  12 , and another port of the fifth valve K 5  is connected to the recycling container  244 . To cool the mold  10 , the third valve K 3  is opened to allow cold fluid to be pumped into the fluid channel  12  of the mold  10 . One of the fourth valve K 4  and the fifth valve K 5  is opened to allow fluid to flow out from the fluid channel  12  into either the cold fluid container  241  or the recycling container  244 . 
         [0018]    Referring to  FIG. 4 , an injection molding method based upon above injection molding system includes following blocks. 
         [0019]    S 01 : the mold  10  is closed and the mold cavity  14  is defined in the mold  10 . 
         [0020]    S 02 : the heating system  22  causes hot fluid to flow through the fluid channel  12  to heat up the mold  10 . In this block, the first valve K 1  and the second valve K 2  are open. The first pump  222  pumps fluid from the fluid storage barrel  221  to the heating tubes  223 . The heating tubes  223  heat up the fluid and outputs the heated fluid to the fluid channel  12  to heat up the mold  10  to the predetermined upper temperature. The heated fluid then flows back to the fluid storage barrel  221 . 
         [0021]    S 03 : Whether the temperature of the mold  10  reaches the predetermined upper temperature is determined. If yes, go to block S 04 ; if not, go back to block S 02  to continue heating the mold  10 . 
         [0022]    S 04 : the injection device  30  injects a molten material into the mold cavity  14  of the mold  10 . 
         [0023]    S 05 : the pressure maintaining device  50  regulates air pressure in the mold cavity  14  to maintain pressure at a predetermined value to compensate for material shrinkage. 
         [0024]    S 06 : the cooling system  24  causes cold fluid to flow through the fluid channel  12  to cool the mold  10 . In this block, the third valve K 3  is open to allow cold fluid to flow into the fluid channel  12  to the mold  10 . The second pump  242  pumps the cold fluid from the cold fluid container  241  to the fluid channel  12  to cool down the mold  10  to a predetermined low temperature (e.g. 0° C.). One of the fourth valve K 4  and the fifth valve K 5  is open to let fluid flow into either the cold fluid container  241  or the recycling container  244 . 
         [0025]    S 07 : The air blower  40  blows air into the fluid channel  12  of the mold  10  to dry the channel  12 . 
         [0026]    S 08 : The material in the mold cavity  14  is solidified to form the article. 
         [0027]    S 09 : the mold  10  is open and the article is ejected. 
         [0028]    In one embodiment, the heating system  22  and the cooling system  24  of the temperature control device  20  work in turn to heat or cool the mold  10  at appropriate time during the injection molding process. The temperature of the mold  10  is increased to the predetermined high value just prior to or when the material starts to be injected into the mold cavity  14  of the mold  10 . The temperature of the mold  10  is decreased to the predetermined low value during solidifying the material in the mold  10 . This temperature control manner can improve the quality of the molded article. 
         [0029]    While the present disclosure has been illustrated by the description of preferred embodiments thereof, and while the preferred embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications within the spirit and scope of the present disclosure will readily appear to those skilled in the art. Therefore, the present disclosure is not limited to the specific details and illustrative examples shown and described. 
         [0030]    Depending on the embodiment, certain of the steps of methods described may be removed, others may be added, and the sequence of steps may be altered. It is also to be understood that the description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps.