This document relates to a variety of applications involving injection molding.
Injection molding is a common process for manufacturing plastic parts. Manufacturers can produce large quantities of parts having complex geometries in a single production step. In many instances, finishing operations are not be necessary. Thermosets and/or thermoplastics can be used.
In injection molding, molten plastic is injected at high pressure into a mold, which is the inverse of the desired shape of the articles to be molded. The mold may be made by a moldmaker (or toolmaker) from metal (e.g., steel or aluminum) and precision-machined to form the features of the desired parts. After the plastic is injected, it cools until hardened, thereby forming the desired molded parts. The parts can then be ejected, and, commonly, the process is repeated several times.
Parts produced by injection molding pervade modern life. Examples include automotive parts, appliances, toys, components used in medical devices, consumer electronic goods, household goods, and communication and industrial equipment.
Some injection molding applications employ multiple processing stations. Examples of such applications include in-mold assembly operations, insert loading, over-molding, part transfer, providing additional cooling time for certain parts, in-mold decorating, in-mold labeling, and in-mold assembly stations. Increasing the speed and/or accuracy associated with such applications can provide substantial benefits.
In one aspect, the invention involves an injection molding mold for use in injection molding applications. The injection molding mold can include first and second mold plates. The first mold plate can be configured to be connected to a stationary platen of an injection molding machine. The second mold plate can be configured to be connected to a movable platen of an injection molding machine. The injection molding mold can include a mold cavity that includes a slide. The injection molding mold can include a slide-eject mechanism, which can be configured to eject a finished part from the mold cavity by removing the slide from the mold cavity. The injection molding mold can include an actuator coupled to one of the mold plates. The actuator can be configured to actuate the slide-eject mechanism.
In a second aspect, the invention involves an injection molding mold for use in injection molding applications. The injection molding mold can include first and second mold plates. The first mold plate can be configured to be connected to a stationary platen of an injection molding machine. The second mold plate can be configured to be connected to a movable platen of an injection molding machine. The injection molding mold can include a rotatable turret having a mold cavity that comprises a slide. The injection molding mold can include slide-eject means for removing the slide from the mold cavity or ejecting a finished part from the mold cavity. The injection molding mold can include an actuator coupled to one of the mold plates. The actuator can be configured to actuate the slide-eject means. The rotatable turret can be rotatable relative to the actuator.
In a third aspect, the invention involves an injection molding method. The injection molding method can include injecting a first quantity of resin into a first mold cavity. The first mold cavity can include a first slide. The injection molding method can include allowing the first quantity of resin to cool, thereby creating a first finished part. The injection molding method can include removing the first slide from the first mold cavity. The injection molding method can include ejecting the first finished part as a result of removing the first slide from the first mold cavity.
In a fourth aspect, the invention involves a slide-eject mechanism. The slide-eject mechanism can include means for withdrawing a slide from a mold cavity. The slide-eject mechanism can include means for ejecting a part from the mold cavity in response to removing the slide from the mold cavity.
Embodiments can include one or more of the following features. The slide-eject mechanism can include a slide driver. The actuator can be configured to move the slide driver in a first direction. The slide driver can be configured to remove the slide from the mold cavity by moving the slide in a second direction that differs from the first direction. The second direction is substantially perpendicular to the first direction. The slide-eject mechanism can include a rocker and ejection equipment. The rocker can be configured to trigger the ejection equipment in response to being contacted by the slide. The injection molding mold can include a rotatable turret. The rotatable turret can be positioned between, and coupled to, the first and second mold plates. A portion of the mold cavity can be coupled to the rotatable turret. The rotatable turret can include an injection processing station on a first turret face and an ejection processing station on a second turret face. The rotatable turret can be configured to allow a first part to be formed at the injection processing station and ejected at the ejection processing station. The rotatable turret can be rotatable relative to the actuator. In some embodiments, the rotatable turret can have exactly two turret faces. The slide-eject mechanism can be configured to eject a finished part when the injection molding mold is in a closed position.
In some embodiments, the slide-eject mechanism can include several features. The slide driver can be coupled to one of the mold plates and can be movable by the actuator in a first direction. The slide-eject mechanism can include a slide engagement block coupled to the one of the mold plates. The slide engagement block being can be movable by the slide driver in a second direction that differs from the first direction. The slide engagement block can be configured to engage the slide and move the slide in the second direction. The slide-eject mechanism can include ejection equipment coupled to the rotatable turret. The ejection equipment can be configured to eject the finished part from the mold cavity. The slide-eject mechanism can include a rocker coupled to the rotatable turret. The rocker can be configured to make use of energy from movement of the slide in the second direction by triggering the ejection equipment to eject the finished part from the mold cavity.
In some embodiments, an injection molding method can include several steps. Some embodiments can include moving the first quantity of resin and the first slide from an injection processing station to an ejection processing station. Some embodiments can include injecting a second quantity of resin into a second mold cavity that comprises a second slide at the injection processing station while the first quantity of resin is cooling at the ejection processing station. Some embodiments can include performing an injection molding process on the first quantity of resin. The injection molding process can be selected from a group consisting of: overmolding, labeling, decorating, transferring, and combinations thereof. In some embodiments, removing the first slide from the first mold cavity can include actuating a slide driver to move in a first direction, thereby causing the first slide to move out of the first mold cavity in a second direction that differs from the first direction. In some embodiments, ejecting the first finished part can include causing a rocker to trigger ejection equipment in response to being contacted by the first slide.
Certain embodiments may have one or more of the following advantages. Some embodiments substantially improve injection molding throughput, which is an important factor in injection molding. In such embodiments, performing processes in one part of an injection molding mold while molded parts cool at a different part of the injection molding mold can substantially improve injection molding throughput. This is especially so for parts that involve significant cooling for part features that are formed with slide blocks due to undercuts in their part geometry. Some embodiments improve efficiency in that they do not require a separate energy input to eject finished parts. In some embodiments, parts can be ejected without using the injection molding machine's ejection mechanism. Some embodiments can make use of the mechanical energy of slide blocks to eject finished parts. In some embodiments, the opening of slides causes ejection of parts. Some embodiments avoid difficulties associated with having the actuator that controls the slide blocks rotate with a rotatable turret. In such embodiments, the actuator that controls the slide blocks can be separate from, and need not rotate with, the rotatable turret. In some embodiments, ejection can occur while the injection molding mold is in the closed position, which can improve injection molding throughput.
The following detailed description of illustrative embodiments should be read with reference to the drawings, in which like elements in different drawings are numbered identically. The drawings depict illustrative embodiments and are not intended to limit the scope of the invention.
Rather, the present invention is defined solely by the claims.
Some embodiments of the invention include the features shown in
The injection molding mold 10 of
Many injection molding mold features may supplement and/or replace those discussed in connection with
In some injection molding applications, slides are used. Slides often include a slide block and a mold component that is held by the slide block. The slide mold components, along with mold components such as cavities and cores, combine to form mold cavities in which parts can be injection molded. Slide blocks typically move their mold components in a direction that is different from the direction that the movable plate 20 moves relative to the stationary plate 15. In many instances, the direction of the slide movement is perpendicular to that of the movable plate 20, though such a relationship between the directions is not necessary. In other words, if cavities and cores make up the front and back of mold cavities, slide mold components can play a role in forming the sides of mold cavities. Often, slides are used when parts require undercuts (e.g., threads, holes on the side of the part, latch features, etc.).
In injection molding, throughput can be critical. Because parts are typically molded in high volumes, it is often desirable to minimize the amount of time spent molding each part. At the same time, however, parts often need to remain in the injection molding mold for a duration that is long enough to allow the resin to cool and harden into the finished part. One way to address these conflicting factors—the desire to increase speed and the necessity of allowing the part to cool sufficiently—is to perform other functions while parts are cooling.
Some embodiments of the invention include the features shown in
Many injection molding mold features may supplement and/or replace those discussed in connection with
In use, the injection molding mold can be moved into a closed position (as shown in
With the injection molding mold in the closed position, a first mold cavity can be formed by mold component 705, mold component 732, and core pins 755, and a second mold cavity can be formed by mold component 710, mold component 734, and core pins 756. Resin can be injected into the two mold cavities to create two parts. The injection molding mold of
After the resin has cooled sufficiently, the injection molding mold can move to an open position. To open the injection molding mold, the resin should be cool enough to open the injection molding mold, though it need not yet be cool enough to eject the part. As shown in
The injection molding mold can then move back into the closed position (as shown in
The parts that had previously been molded can now be positioned adjacent the movable plate 20. Those parts can remain in contact with mold components 732, 734 and the core pins 755, 756, respectively. But the parts can be otherwise exposed. That is, the movable plate 20 of
In this orientation, two new mold cavities can be formed-one by mold component 705, mold component 735, and core pins 758, and the other by mold component 710, mold component 733, and core pins 757. Resin can then be injected into the new mold cavities to create two more parts. The new parts cool long enough to allow the injection molding mold to be opened (though they need not cool as long as is necessary for ejection).
At a predetermined time, (e.g., just before the injection molding mold moves back to the open position, just after the injection molding mold moves back to the open position, etc.), the slide-eject mechanism 700 can eject the previously molded parts.
Moving the slide engagement blocks 720 outwardly to withdraw the core pins 756, 755 from the mold cavities and to eject finished parts provides several advantages. For example, in typical applications, the injection molding machine includes an ejection actuator to trigger ejection of finished parts. But in such embodiments, the parts are ejected toward the injection molding machine's stationary platen. In injection molding molds that use turrets, ejecting parts away from the turret rather than into it is desirable. Thus, using some of the ejection actuators discussed herein allows ejection of finished parts away from the turret. Moreover, making use of the mechanical movement of the slide blocks 744, 742, 740, 738 to eject parts can improve the efficiency of the injection molding mold.
After the previously molded parts are ejected, the slide-eject mechanism 700 can prepare the injection molding mold to perform the process again. The slide engagement blocks 720 can move back to their original positions, thereby causing the rockers 770 to rotate about pivot 778 back to their original positions and the ejection equipment to move back to its original positions. The injection molding mold can move to the open position, the turret 25 can rotate, the injection molding mold can move back to the closed position, and the process can begin again.
Some embodiments of the invention include the features shown in
Each slide engagement block 720 (only four of which are shown, though this embodiment would include eight) is coupled to a slide driver 725. The slide drivers 725 include rails 1005 along which the slide engagement blocks 720 are configured to travel. The slide drivers 725 can be moved by actuators 40, 45 along a line of travel L-L. The actuators 40, 45 can be any suitable type of linear actuator (e.g., pneumatic, servo, hydraulic, etc.). A controller can control the movement of the actuators 40, 45. In some embodiments, the actuators 40, 45 are separate from the turret and do not rotate with the turret. In such embodiments, the turret is rotatable relative to the actuators 40, 45. As the slide drivers 725 move in the L-L direction, the tapered surfaces 1010 of the slide drivers 725 cause the slide engagement blocks 720 to move along a line of travel M-M. In the embodiment of
The slide-eject mechanism 700 of
Some embodiments of the invention include the features shown in
After the quantity of resin is moved (1210), two operations can proceed concurrently. The first involves further processing of the aforementioned quantity of resin. An injection molding process can be performed on the quantity of resin (1215). Examples of injection molding processes include over molding, labeling, decorating, transferring, and combinations thereof. The quantity of resin can be allowed to cool (1220), as is discussed elsewhere herein. After the quantity of resin has cooled and become a finished part, the slide can be removed from the mold cavity (1225). The finished part can be ejected from the mold cavity (1230). In some embodiments, removing the slide from the mold cavity (1225) can cause the finished part to be ejected from the mold cavity (1230).
The second operation involves a second quantity of resin. While the injection molding process is being performed on the quantity of resin (1220), the slide is removed (1225), and the finished part is ejected (1230), a second quantity of resin can be injected into a second mold cavity (1235). The second quantity of resin can be injected into the second mold cavity (1235) at the same location that the previously mentioned quantity of resin was injected into the previously mentioned mold cavity (1205). Performing these two operations concurrently can save a substantial amount of time, which can significantly improve injection molding throughput.
When the two aforementioned operations are completed, a determination can be made whether to continue the exemplary injection molding method (1240). If it is determined that the method should be continued, the second quantity of resin can be moved and the same or similar way that the first quantity of resin was moved (1210). If it is determined that the method should not be continued, the method can come to an and (1245).
The method provided in
Certain embodiments of the slide-ejector actuator are disclosed. One skilled in the art will appreciate that the present invention can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present invention is limited only by the claims that follow.
This application claims priority under 35 U.S.C. §119(e) to U.S. provisional application 60/680,089, filed May 12, 2005, which is hereby incorporated by reference in relevant part.
Number | Date | Country | |
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60680089 | May 2005 | US |