Patent Application
20140087017
The present invention is on injection mold with cooling and heating passage which can form cooling and heating passage close to forming space in the inside of mold body and easily design cooling and heating passage in forming space with complicated trajectory.
Injection molding is a manufacturing process for producing parts from polymer resins which are melted and plasticized by injecting them into an injection mold using hydraulic power. Injection molding has the advantage of mass-producing a variety of parts, from the smallest component to very large one.
However, general polymer resin molding is poor in appearance due to weld line created by melted resin fed into the inside of injection mold and has an inferior luster on the surface.
In order to improve these problems, heating molding has been widely used, which sets the temperature of injection mold higher than the melting point of polymer resin. For example, Japan Open Patent So 45-22020, Japan Open Patent So 51-22759, Japan Open Patent So 55-109639, Japan Open Patent So 57-165229, Japan Open Patent So 61-79614, and Japan Open Patent Pyong 4-265720 are the patents for heating molding.
If polymer resin is formed at the higher temperature of mold than the melting point of resin, the product has improved appearance and quality such as no weld line and good luster on the one hand, but it also has a longer cooling time and in turn, a longer total forming cycle, which lowers production, on the other.
In order to resolve these problems, an injection molding temperature auto-control system is disclosed in the Korea Registration Patent No. 10-0081909 and a mold cooling system is disclosed in the Korea Registration Patent No. 10-0167711 and a mold temperature control system is disclosed in the Korea Registration Patent No. 10-0470835. In addition, the Korea Registration Patent No. 10-0701229 presents a structure in which quick heating and freezing of a mold is carried out from 100 to 200° C./min.
However, these structures could not be a fundamental solution for the abovementioned problems, for an injection mold can not be cooled or heated in a short time, and have many cooling lines and hot water supply lines for cooling and heating, causing the mold to be deformed in repeated forming jobs due to the relatively weak structure of mold. In particular, the existing injection molds have an inlet at the bottom of the molds corresponding to cavity so as to reduce thermal capacity for cooling and heating. However, if an inlet is formed at the bottom of the mold, the mold becomes relatively weak and may have cracks due to external impact or repeated injection molding.
Meanwhile, for the existing weld-less injection molding, a method to form cooling and heating passage (60) in the body of the injection mold so as to close to this forming trajectory along the trajectory of forming space (13) was presented.
This method could not maximize cooling and heating effect if cooling and heating passage (60) installed in upper and lower mold or core which constitute the forming space are not formed close to forming space, despite of good performance of the cooling and heating system of weld less molding or injection molding. In particular, if forming space is complicated in structure, passage for cooling water and hot water could not be formed in uniform thickness along forming space, which caused cooling efficiency to be lowered.
Therefore, it is necessary to develop an injection mold by which it is easy to form cooling and heating passage of injection mold close to forming space of said mold.
(Patent Literature 0001) Japan Open Patent JP 2009-34695 (Disclosure No.) 2009.02.19
(Patent Literature 0002) Korea Open Patent KR 10-2011-0055956 (Disclosure No.) 2011.05.26
(Patent Literature 0003) U.S. Open Pat. No. 7,172,405 (Registration No.) 2007.02.06
The purpose of the present invention is to provide an injection mold with cooling and heating passage, which can form cooling and heating passage (60) close to forming space (13) in the inside of mold body (31) of upper mold (20) and lower mold (30).
The present invention also aims to provide an injection mold with cooling and heating passage which can design cooling and heating passage (60) suitable for forming space (13) with complicated trajectory.
The present invention consists of the lower mold and the upper mold which forms the blown forming space combined with said lower mold at the top of said lower mold, wherein said lower mold or said upper mold consist of mold body which has the forming space on one side such that melted resin may be injected and formed; connecting groove which is depressed towards said forming space from the opposite side of the side with said forming space of said mold body; and sealing kit which is inserted into said connecting groove by standing off the end of forming space of said connecting groove and forms cooling and heating passage (60) in said stand-off space.
Also, the present invention features that connecting groove is formed by overlapping multiple vertical holes formed close to the floor surface of said forming space and said sealing kit is formed by overlapping multiple columns.
The present invention can form cooling and heating passage (60) close to forming space (13) in the inside of mold body (31) of upper mold (20) and lower mold (30) and reduce cooling and heating time of resin upon injection molding of the product. Therefore, the present invention has an effect of promoting production efficiency by reducing cycle time for injection molding.
Also, the present invention can process each of vertical holes (41) by mechanical processing wherein overlapping vertical holes (41) forms channel and has an effect of easily designing cooling and heating passage (60) suitable for forming space (13) with complicated trajectory.
Hereinafter, injection mold with cooling and heating passage according to the embodiment of the present invention is described in detail with reference to attached drawings.
According to
Lower fixation plate (11) serves as a conventional support base and fixes lower mold (30) so that a stable molding process may be carried out. For this, the lower base may be made in a form of plate or frame and only has only to fix and support lower mold (30) in a stable manner, so the present invention does not limit the form.
Upper fixation plate (12) is removable and allows upper mold (20) fixed at the bottom to be combined with or separated from lower mold (30). For this, upper fixation plate (12) goes up and down by rack gear (not shown) and hydraulic piston (not shown) and goes down upon forming of injection products and makes upper mold (20) and lower mold (30) combined and sealed and goes up upon completion of injection products and separates upper mold (20) and lower mold (30) so as to collect completed injection products. This upper fixation plate (12), likewise lower fixation plate (11), may be created in a form of plate of frame, and is not limited in form by the present invention. Also, a means to move upper fixation plate (12) is not limited in type by the present invention, and of course, it is easy to use power transfer unit in separating or combining upper mold (20) and lower mold (30) by moving upper fixation plate (12).
As upper mold (20) and lower mold (30) are same in configuration according to the embodiment of the present invention as shown in
Lower mold (30) consists of mold body (31) in which forming space (13) is formed on the top so that melted resin is injected and formed, connecting groove (40) depressed so as to separate at regular intervals from the bottom surface of forming space (13) at the lower side of mold body (31), and sealing kit (50) which is inserted into connecting groove (40) and forms cooling and heating passage (60) between connecting groove (40) and the end part.
To elaborate more detail, connecting groove (40) is formed by multiple overlapping vertical holes (41) in mold body (31) of lower mold (30) so as to close to forming space (13) from the lower side of mold body (31). That is, connecting groove (40) is formed by depression in a form of vertical holes (41) overlapping to the direction of forming space (13) from the opposite side of the side on which the forming space (13) of mold body (31) is formed, and these vertical holes (41) can be made through drilling processing at the lower side of mold body (31), and the side end of forming space (13) of continuous vertical holes (41) is separated from the side end of forming space (13) of sealing kit (50) to be described in the following and forms cooling and heating passage (60).
Sealing kit (50) is made in a form of the same section as the section of connecting groove (40) and inserted in separation from the side end of forming space (13) of connecting groove (40) and serves to form cooling and heating passage in a separated space. That is, the external circumference of sealing kit (50) and the internal circumference in which sealing kit (50) of connecting groove (40) is inserted are fit to each other and sealed, and the space surrounded by the side end of forming space (13) of connecting groove (40), the internal circumference with no sealing kit (50) of connecting groove (40) inserted, and the side end of forming space (13) of sealing kit (50) becomes cooling and heating passage (60). For this, sealing kit (50) is formed by overlapping multiple columns (51) as shown in
The end part of forming space (14) of sealing kit (50) has trajectory in a line with the trajectory of said forming space (13) or is formed along the trajectory same as the end part of forming space (13) of connecting groove (40), and forms cooling and heating passage (60) separated in a prescribed distance from the end part of forming space (13) of said connecting groove (40).
At this time, if the formation depth of one vertical hole (41) and subsequent vertical hole (41) of connecting groove (40) is bigger than the separation distance between connecting groove (40) and the end part of forming space (13) of sealing kit (50) due to the very complicated form of the floor surface of forming space (13), the channel created by connecting groove (40) and sealing kit (50) may be blocked. In this case, it is possible to form cooling and heating passage (60) as a continuous channel by adjusting the formation depth of connecting groove (40) and vertical hole (41) or the height of each column of sealing kit (50).
In addition, sealing kit (50) can make at least one sealing protrusion (53) along the external circumference to improve airtight force with the side of connecting groove (40), that is mold body (31), and this sealing protrusion (53) can be created in numbers top and bottom direction.
Meanwhile, each of vertical holes (41) may be formed at regular intervals from one another, not overlapping each other. At this time, connecting hole (42) can be made by processing vertical hole (41) as shown in
At this time, columns (51) which have the same sectional form as the horizontal sectional form of vertical hole (41) are interconnected by connecting part (52) which has the same sectional form as the section of said connecting hole (42).
Meanwhile, in a case where lower mold (30) and mold body (31) are relatively thick, a prescribed depth of inlet (32) can be formed by depression at the bottom of mold body (31) as shown in
And on both sides of lower mold (30), supply hole (43) and discharge hole (44) to supply and discharge cooling fluid and heating fluid to and from cooling and heating passage (60) are formed to be connected to more than one vertical hole (41).
Meanwhile, cooling and heating unit (100) supplies cooling or hot water to cooling and heating passage (60) so as to cool or heat mold and consists of heating part (110) and cooling part (120).
Heating part (110) consists of boiler (111), first circulation pipe (112) which joins boiler (111) and supply hole (43) together to supply steam or hot water from boiler (111) to cooling and heating passage (60), and second circulation pipe (113) which joins boiler (111) and discharge hole (44) together to recover steam or hot water which are discharged through cooling and heating passage (60) to boiler (111).
At this time, first control valve (115) may be installed in first circulation pipe to lock the supply of steam or hot water from cooling and heating passage (60) and condensate tank (114) may be installed in second circulation pipe (113) to store condensed water.
Heating part (110) is not limited to the abovementioned embodiment but consists of heater which is installed on the side close to forming space (13). In this case, a separate first fluid passage (not shown) may be formed around the heater. The heater may be supported by sealing kit (50) and installed close to forming space (13).
Cooling part (120) is used to cool forming products completed by forming space (13) and injection mold. It discharges hot water supplied to cooling and heating passage (60) using coolant as well as cools injection mold.
Cooling part (120) consists of cooling media tank (121) in which cooling media such as cooling water or cooling oil is stored, third circulation pipe (123) which joins said cooling media tank (12) and supply hole (43) together so as to supply cooling media from cooling media tank (121) to said cooling and heating passage (60), and fourth circulation pipe (125) which joins cooling media tank (121) and discharge hole (44) together so as to recover cooling media discharged through cooling and heating passage (60). At this time, third circulation pipe (123) may include cooling media supply pump (124). Meanwhile, cooling media tank (121) is connected to water supply tank (126) to make up for loss of cooling media. In addition, cooling system (122) may be installed to cool cooling media in cooling media tank (121). Although this cooling system (122) is not shown in drawings, it may consist of a system which is operated by common cooling cycle with evaporator, condenser and compressor.
Cooling part (120) is not limited to the abovementioned embodiment but available for any structure which can quickly cool mold in a short time. For example, nitrogen may be supplied to cooling and heating passage (60) to be cooled, and for this purpose, nitrogen tank and valve may be furnished to lock nitrogen.
The present invention configured as abovementioned can make cooling and heating passage (60) close to forming space (13) in the inside of mold body (31) of upper mold (20) and lower mold (30) and shorten heating and cooling time for resins upon injection molding of products and reduce cycle time for injection molding of products so as to increase production efficiency.
Also, the present invention processes each of vertical holes (41) by mechanical processing and forms channels by overlapping vertical holes (41), such that cooling and heating passage (60) may be easily designed even in forming space (13) of complicated trajectory.
11: lower fixation plate; 12: upper fixation plate; 13: forming space; 20: lower mold; 21: mold body; 30: upper mold; 40: connecting groove; 41: vertical hole; 42: connecting hole; 50: sealing kit; 60: cooling and heating passage
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0108123 | Sep 2012 | KR | national |
