WO2009079197A1

WO2009079197A1 - Multi-cube, stack-turning, injection-molding system for in-mold assembly

Info

Publication number: WO2009079197A1
Application number: PCT/US2008/085227
Authority: WO
Inventors: Richard La Torre
Original assignee: Siemens Heathcare Diagnostics Inc.
Priority date: 2007-12-17
Filing date: 2008-12-02
Publication date: 2009-06-25

Abstract

A system for in-mold assembly of two mold halves using a multi-cube, injection-molding system is disclosed. The system includes a first mold cube that is adapted to rotate in a first (clockwise) direction, a second mold cube that is adapted to rotate in a second, opposite (counter-clockwise) direction, and a rotating device for rotating the first and the second mold cubes through a predetermined angle of rotation. An extruding device injects heated plasticizer material into the first and second mold cubes to provide, respectively, a first mold half and a second mold half. The mold halves are allowed to cool before a joining device mechanically joins, adhesively joins or solvent bonds the exposed edges of the first mold half to the exposed edges of the second mold half.

Description

TITLE OF THE INVENTION

MULTI -CUBE, STACK-TURNING, INJECTION-MOLDING SYSTEM FOR IN-MOLD

ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR

DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

Stack-turning technologies and injection-molding systems employing stack-turning are well known in the art. For example, Foboha GmbH of Haslach, Germany manufactures stack-turning systems that simultaneously perform injection, cooling, and assembly steps in a continuous cycle by rotating a stack ("cube") about an axis of rotation. With each 90-degrees of rotation, the cube, for example, undergoes a primary injection step, a primary cooling step, a secondary injection step, and a final cooling and ejection step. Manufacturing cycle times have been reduced by as much as 25 percent using stack-turning technologies.

Advancements in stack-turning have increased the number of rotating cubes in the system. However, stack- turning technologies have not yet been able to perform in-mold assembly of hermetically- sealed products. Indeed, currently, when plural molded parts need to be combined to produce an end product, the molded parts are assembled after ejection from a mold. This adds additional steps to the process and a corresponding increase in cost and a decrease in throughput. Accordingly, an in-mold assembly, injection-molding system using stack-turning is desirable.

BRIEF SUMMARY OF THE INVENTION

A system for in-mold assembly of two mold halves using a multi-cube injection-molding system is disclosed. The system includes a first mold cube that is adapted to rotate in a first (clockwise) direction and a second mold cube that is adapted to rotate in a second, opposite (counter-clockwise) direction. A rotating means rotates the first and the second mold cubes through a predetermined angle of rotation. An injection or extruding means injects heated plasticizer material into the first and second mold cubes to provide, respectively, a first mold half and a second mold half . The first and second mold halves are allowed to cool before they are re-heated or an adhesive is applied for joining purposes. A joining means mechanically- or adhesively- joins exposed edges of the first mold half to exposed edges of the second mold half. The joined first and second mold halves are then ejected from the mold.

Further disclosed is a method of in-mold assembly of two mold halves using a multi-cube i,nj ection-molding system. The method includes rotating a mold cube through a pre-determined angle of rotation to each stage of manufacture. In a first stage, a heated plasticizer material is injected or extruded into each of the two mold halves. The plasticizer material is then allowed to cool. In a second stage, each of the two mold halves is re-heated or an adhesive is applied to exposed edges. In a third stage, the two mold halves are joined at the exposed edges. Finally, in a fourth stage, the joined end product is ejected. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be more fully understood by reference to the following Detailed Description of the invention in conjunction with the Drawing, in which common elements share the same reference number.

FIG. 1 shows a diagrammatic view of a multi-cube, stack- turning, injection-molding system in accordance with the present invention;

FIG. 2 shows a diagrammatic view of a mold cube in accordance with the present invention; and

FIG. 3 shows a plan view of twin-cubes with individual joining systems in accordance with the present invention; and

FIG. 4 shows a plan view of twin-cubes with a common, shared joining system in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A multi-cube, stack-turning, injection-molding system for producing plasticized end products such as sealed or hermetically- sealed containers, e.g., a reagent pack, is disclosed. Although the invention will be described as a twin-cube system, those skilled in the art can appreciate that the system can be adapted to accommodate any even number of cube pairs.

Referring to FIG. 1 and FIG. 2, the system 10 includes a pair of rotating mold cubes 15a and 15b that are each adapted to produce respective mold halves . Each of the cubes 15a and 15b includes a plurality of faces 31-34 that are oriented 90 degrees from each other. Although the molds of the invention will be described as cubes, those skilled in the art can appreciate that the system can be adapted for any polygonal or cylindrical shape.

The upper face 35 of each cube 15a or 15b is structured and arranged for releasably attaching the cube 15a or 15b to a rotatable shaft (not shown) operatively coupled to a stepper motor 12 and 14. Each stepper motor 12 and 14 is supported between upper supporting rods 18 and 19 of a frame 20 by a support portion 11 and 13. The support portions 11 and 13 are translatable along the longitudinal axes of the upper supporting rods 18 and 19 for the purpose of positioning the stepper motors 12 and 14. Each support portion 11 and 13 includes end portions through which the upper support rods 18 and 19 can translate and locking portions (not shown) for releasably locking the support portions 11 and 13 at a desired location along the upper supporting rods 18 and 19. The lower face 36 of each cube 15a and 15b is structured and arranged to transfer all or some portion of the weight of the cube 15a and 15b to a supporting substrate (s) 21. The supporting substrate (s) 21 is translatable along the longitudinal axes of the lower supporting rods 16 and 17 of the frame 20. The supporting substrate 21 includes end portions through which the lower support rods 16 and 17 can translate and locking portions (not shown) for releasably locking the supporting substrate (s) 21 at a desired location along the lower supporting rods 16 and 17.

The lower face 36 of each cube 15a and 15b is also structured and arranged to include an axis about which each cube 15a and 15b rotates, including- means for reducing frictional resistance to rotation of the cubes 15a and 15b. The axis can be, for example, a rotary coupling, a shaft, a rod, a projection, a protuberance, and the like 38. The supporting substrate (s) 21 is further adapted to include slots 39 that are oriented in the longitudinal axes of the lower supporting rods 16 and 17, to enable the rotary couplings, shafts, rods, projections, protuberances, and the like 38 of each cube 15a and 15b to translate in the longitudinal axes of the lower supporting rods 16 and 17. More particularly, the slots 39 are structured and arranged to allow the cubes 15a and 15b to mover towards and away from each other. As shown in FIG. 1, a first stepper motor 12 is structured and arranged to rotate the first cube 15a in a clockwise direction and a second stepper motor 14 is structured and arranged to rotate the second cube 15b in a counter-clockwise direction. The directions of rotation can be reversed. Although the invention has been described with the stepper motors 12 and 14 operating from above the cubes 15a and 15b, those skilled in the art can appreciate that the stepper motors 12 and 14 can operate just as well from beneath the cubes 15a and 15b.

The frame 20 of the system 10 includes end portions 27 and 29 that are fixedly or releasably_t attached to each of the proximal and distal ends of the upper 18 and 19 and lower supporting rods 16 and 17. Each of the end portions 27 and 29 supports respective injection-molding extruders 26 and 28, plasticizer material injection units 22 and 24, e.g., thermocouplers , and ball screws or pistons 23 and 25. The function of and interplay between injection-molding extruders 26 and 28, plasticizer material injection units 22 and 24, and the ball screws or pistons 23 and 25 will be described in greater detail below.

As shown in FIG. 3 and FIG. 4, heating units 40 are disposed proximate to the frame 20 and/or are incorporated into the frame 20. The heating units 40 are adapted to re-heat, e.g., using infrared heating and the like, discrete portions of the first and second mold halves for the purpose of joining together the mold halves. Although FIG. 3 and FIG. 4 show heating units 40, alternatively, the units can include means for applying an adhesive, epoxy, solvent, and the like to discrete portions of the first and second mold halves for the purpose of joining together the mold halves . Heating units 40 can be dedicated to each of the cubes 15a and 15b (FIG. 3) or a common heating unit 40 can be shared between the two cubes 15a and 15b (FIG. 4) . When a common heating unit 40 is shared as shown in FIG. 4, the heating unit 40 must be structured and arranged as a shuttling system by which the heating units 40 can be continuously moved into and out of the location shown.

Having described a multi-cube, injection-molding system, a method of in-mold manufacturing a sealed, sealable or hermetically sealed end product, e.g., a reagent pack, from two mold halves will now be described. As shown illustratively in FIG. 3 and FIG. 4, the molding device is a cube 15a and 15b. As a result, each molding device has four faces 31-34 and the stepper motors are adapted to rotate each cube 90 degrees between successive process steps.

Although the actual faces 31-34 of the cube 15a and 15b are identical, the faces 31-34 will rotate through each of the four orientations associated with each process step. For ease of description, the face of the cube 15a or 15b undergoing the injection and cooling steps will be designated "face 32", the face of the cube 15a and 15b undergoing re-heating will be designated "face 33", the face of the cube 15a and 15b during the joining step will be designated "face 34", and the face of the cube 15a and 15b at the ejection step will be designated "face 31". Optionally, as shown in FIG. 4, the system 10 can be adapted so that the cooling step occurs at face 33, prior to the re-heating step, and/or the re-heating step occurs at face 34, immediately prior to the joining step. Furthermore, although the manufacturing process will be described beginning at the injection step and ending with ejection, those skilled in the art can appreciate that the process steps are occurring at each face of the cube simultaneously. In a first step, a heated plasticizer material is injected into the mold cavities of the first face 32 by a method or methods that are well-known to the art. For example, plasticizer material can be stored in a heated reservoir i that is fluidly coupled to an injection-molding extruder 26 and, 28, e.g., via a conduit 30 in the frame 20. The injection unit can include a piston or rotary- screw (not shown) that forces the plasticizer material through the conduit 30 into an injection-molding extruder 26 and 28. The injection-molding extruder 26 and 28 is structured and arranged to interface with each mold cavity (ies) of the first face 32 so that conduits disposed in the extruder 26 and 28 deliver sufficient plasticizer material into each mold cavity (ies) . The injected plasticizer material is then allowed to cool.

Once the heated plasticizer material has been introduced into the mold cavity (ies) of the first face 32 and allowed to cool, and the face is opened and the cubes 15a and 15b can be rotated 90 degrees to the second face 33. At the second face 33, portions of the cubes 15a and 15b., e.g., the portions of the cubes 15a and 15b that will be joined, are re-heated, using a heating element 40.

Optionally, at the second face 33, the mold halves are allowed to cool further before re-heating. For example, after cooling sufficiently, the exposed edges of each mold half to be joined can be subject to infrared heating. Alternatively, an adhesive or solvent for adhesively joining the mold halves can be applied to the exposed edges of each mold half .

After the next 90 -degree rotation of the cube 15a and 15b, the two mold halves to be joined are facing each other at the third face 34. The two mold halves are then brought together do that the exposed edges are mechanically-, e.g., by infrared welding, or adhesively- joined. ., Although this description describes re-heating occurring at the second face 33, the exposed edges of each mold half to be joined can be subject to infrared heating at any location between the second face 33 orientation and the third face 34 orientation. Hence, the heating unit 40 can also be disposed between the third faces 34 of the two cubes 15a and 15b. When so structured, the heating unit 40 must be brought between the two cubes 15a and 15b to heat the exposed edges of each mold half to be joined and, then, removed so that the two exposed edges can be forced together. Shuttling system to introduce and remove the heating unit 40 are well known to the art and will not be described in detail . Once the exposed edges of each mold half have been sufficiently heated or an adhesive or solvent has been applied, the mold cubes 15a and 15b are brought or forced together and the exposed edges of the mold halves are joined. For example, the mold cubes 15a and 15b can be brought together using the servo- electric motors, balls screws, pistons 23 and 25, and the like. More specifically, the motors, ball screws or pistons 23 and 25 press their respective extruders 26 and 28 into the first faces 32 and continue to press the mold cubes 15a and 15b until the exposed edges of the mold halves are in contact with one another. Finally, during the next 90-degree rotation, or, more specifically, between the third 34 and fourth faces 31, the mechanically- or adhesively- joined end product is ejected from the mold cubes 15a and 15b. As a result, once the cube 15a and 15b is at the fourth face 31, it is empty and ready for the intrusion step after the next 90-degree rotation.

It will be apparent to those skilled in the art that modifications to and variations of the disclosed method and system are possible without departing from the inventive concepts disclosed herein, and therefore the invention should not be viewed as limited except to the full scope and spirit of the appended claims .

Claims

CLAIMS What may be claimed is:

1. A method of in-mold assembly of two mold halves using a multi-cube injection-molding system, the method comprising: rotating a mold cube through a pre-determined angle of rotation prior to each of the following steps : extruding a heated plasticizer material into each of the two mold halves, cooling each of the two mold halves, joining the two mold halves at an exposed edge; and ejecting a joined end product.

2. The method as recited in claim 1, wherein the two mold haves are mechanically-joined, adhesively- joined or solvent-bonded.

3. The method as recited in claim 2, wherein the two mold halves are mechanically- joined by infrared welding.

4. A system for in-mold assembly of two mold halves using a multi-cube injection-molding system, the system comprising: a first mold cube that is adapted to rotate in a first direction; a second mold cube that is adapted to rotate in a second direction; rotating means for rotating the first and the second mold cubes through a predetermined angle of rotation; extruding means for injecting heated plasticizer material into the first and second mold cubes to provide, respectively, a first mold half and a second mold half; joining means for mechanically- or adhesively-joining exposed edges of the first mold half to exposed edges of the second mold half; and ejecting means for ejecting the joined mold halves.

5. The system as recited in claim 4, wherein the joining means includes infrared welding.

6. The system as recited in claim 4, wherein the rotating means includes a plurality of stepper motors .