The present disclosure relates to a system and method for manufacturing an article, and more specifically to a system and method for manufacturing an article comprising a high viscosity composite.
High viscosity materials, such as thermoset plastics, thermoset elastomers, pre-heated thermoplastics, cementitious composites, and the like exhibit properties which may provide benefits and advantages as a compositional substance for a variety of articles. For example, cementitious composites in the class of macro-defect-free (MDF) cements can be characterized by high stiffness as compared to other cementitious materials and as a result may be desirable for use in various applications. However, other material properties, such as, for example, the high degree of adhesiveness of high viscosity materials may present difficulties and may render such materials impracticable for numerous fabrication processes. Additional properties and characteristics may present challenges and limitations in terms of the utilization of these materials for certain applications. For example, the hydrophilic properties of MDF cements can cause these cements to be susceptible to the tendency to absorb moisture, which, in turn, can reduce the strength and stiffness of the material. Furthermore, MDF cements may be brittle and susceptible to surface defects, such as cracks, which may resultantly cause premature failure of products made of MDF cements. These and other challenges and limitations may serve as impediments to the use of high viscosity materials, such as thermoset plastics, thermoset elastomers, pre-heated thermoplastics, and cementitious composites, and the beneficial characteristics thereof. Consequently, present methods have been substantially limited to casting low-viscosity cement products into plastic or steel forms to create articles with less risk of surface cracking or abrasion.
U.S. Pat. No. 6,722,009 B2 (the '009 patent) to Kojima et al. discloses a sheet hydroforming method. According to the hydroforming method disclosed by the '009 patent, two stacked metallic sheets are clamped between a pair of upper and lower dies. A fluid is introduced and pressurized between mating surfaces of the metallic sheets, causing the metallic sheets to bulge into a space defined by die cavities. A thru-hole for introducing the fluid is formed in one of the dies so as to lead to a holding surface of the die, and a pierced hole for introducing the fluid is formed in one of the metallic sheets in a portion of the one metallic sheet which portion is in contact with a holding surface of one of the dies. The pierced hole is positioned with the thru-hole, and then the fluid is introduced in a pressurized state between mating surfaces of the metallic sheets from the thru-hole through the pierced hole, thereby causing the metallic sheets to bulge.
The present disclosure is directed to mitigating or eliminating one or more of the drawbacks discussed above.
In one aspect of the present disclosure, a system for manufacturing an article is disclosed. The system includes a first mold half and a second mold half. The first mold half and the second mold half define a molding cavity therebetween. The molding cavity is configured to receive two outer layers and a high viscosity material provided between the two outer layers. The system also includes an actuator configured to move at least one of the first mold half and the second mold half towards the other. The first mold half and the second mold half are configured to deform the high viscosity material in conformation with a shape of the article. The high viscosity material fills a space between the two outer layers such that the two outer layers encase the high viscosity material therebetween.
In another aspect, a method of manufacturing an article is disclosed. The method includes providing a molding cavity between a first mold half and a second mold half. The method also includes receiving two outer layers containing a high viscosity material therebetween in the molding cavity. The method further includes moving at least one of the first mold half and the second mold half towards the other. The method includes deforming the high viscosity material by the first mold half and the second mold half in conformation with a shape of the article. The high viscosity material deforms the two outer layers such that the two outer layers encase the high viscosity material therebetween.
In yet another aspect, an article is disclosed. The article includes a cementitious composite formed in a shape of the article. The article also includes two metal sheets encasing the cementitious composite therebetween.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Referring to
The first mold half 102 includes one or more spring biased members 112 positioned at, along, or within ends 114 of the first mold half 102. The ends 114 can be straight surfaces on outer sides of the first molding surface 108. Each of the spring biased members 112 can be biased by a spring 116 towards the hollow molding cavity 106. Further, the spring biased members 112 and the springs 116 can be at least partly received within a recesses 118 of the first mold half 102. The spring biased members 112 extend from the recesses 118 into the hollow molding cavity 106. Similarly, the second mold half 104 includes one or more spring biased members 120 positioned at, along, or within ends 122 of the second mold half 104. The two ends 122 can be straight surfaces on outer sides of the second molding surface 110. Each of the spring biased members 120 can be biased by a spring 124 towards the hollow molding cavity 106. Further, the spring biased members 120 and the springs 124 are received within recesses 126 of the second mold half 104. The spring biased members 120 extend from the recesses 126 into the hollow molding cavity 106. The spring biased members 112, 120 can be movable between fully extended positions (illustrated in
The system 100 further includes an actuator 128. The actuator 128 can be configured to actuate the relative movement and position of first mold half 102 and the second mold half 104 to retract and advance along the direction D depending on various stages of manufacturing of the article 300. For example, the first mold half 102 may move towards the second mold half 104, along the direction D, during molding. Further, the first mold half 102 may move away from the second mold half 104 during de-molding. De-molding may include one or more processes and/or devices which are used for removing the article 300 from the hollow molding cavity 106 after molding. The actuator 128 can include a drive (not shown) configured to move the first and second mold halves 102, 104. The drive can be embodied as any suitable drive mechanism, including but not limited to, a mechanical drive, a hydraulic drive, an electric drive, a pneumatic drive, or a combination thereof. The actuator 128 can further include a control module 129. The control module can be communicably coupled to the drive, one or more sensors (e.g., weight sensors, thickness sensors, pressure sensors, displacement sensors etc.), and the like. The control module 129 can be connected in electronic and controllable communication with the actuator 128 to regulate the movements of the first and second mold halves 102, 104 based on the one or more parameters, stored lookup tables, algorithms, and the like. The parameters can include any one or more of molding or de-molding movement values of the first and second mold halves 102, 104, molding pressure or force, weight of molding material, dimensions of the article 300, and the like. The control module 129 can also be configured to receive inputs from an operator via a user interface (not shown). The control module 129 can also have any other functions within the scope of the present disclosure.
The system 100, as described above, is exemplary in nature, and variations are possible within the scope of the present disclosure. For example, depending upon the variables, parameters, or requirements of a particular application, the spring biased members 112, 120 may be removed or eliminated. In an additional or alternative example, one or more separate holders may be provided adjacent to the first and/or second mold halves 102, 104.
In an embodiment, the first and second outer layers 202, 204 can be in the form of metal sheets. The metal sheets can be plates or foils depending on the thicknesses T2 and T3 of the first and second outer layers 202, 204, respectively. For example, the first and second outer layers 202, 204 can be metal foils if the thickness T2 and T3 are less than 1 mm. Further, the first and second outer layers 202, 204 can be made of any metal or metal alloy, for example, but not limited to, various grades of steel, aluminum, magnesium, copper, or alloys thereof. The first and second outer layers 202, 204 can have similar or different dimensions. In a particular embodiment, the first and second outer layers 202, 204 can be ferrous materials with thickness between 0.1 and 1.0 mm. In another embodiment, the first and second outer layers 202, 204 can be stainless steel with thickness between 0.1 and 0.5 mm.
In an embodiment, the high viscosity material 206 can be a thermoset plastic, a thermoset elastomer, a pre-heated thermoplastic, a cementitious composite, and the like. The high viscosity material 206 can have a viscosity equal to or above 10,000,000 centipoise; this can be measured using a Mooney Viscometer and would have a viscosity above 50 Mooney Units. In another embodiment, the high viscosity material 206 can be a macro-defect-free (MDF) cement. The MDF cement can include any MDF cement known in the art. For example, the MDF cement can include a cement material, water and one or more polymers. Further, MDF cements can be made in one or more processes known in the art. For example, the cement material, water and the polymers can be pre-mixed, and then subjected to shear mixing and/or calendaring in roll mills. Further, the MDF cement can be formulated to bond to metallic foils during curing without the use of an additional adhesive. A person ordinarily skilled in the art may appreciate that MDF cements can have a high viscosity in uncured state, for example, equal to or above 10,000,000 centipoise or 50 Mooney Units as measured on a Mooney Viscometer.
In an embodiment, an adhesive 207 may be utilized to bond the high viscosity material 206 with the first and second outer layers 202, 204, wherein the adhesive 207 may be applied to an inner surface of each of the first and second outer layers 202, 204 facing the high viscosity material 206, and in one example may be pre-coated on the inner surface of each of the first and second outer layers 202, 204. Alternatively, the adhesive 207 may be applied to the high viscosity material 206. The adhesive 207 may be a heat activated adhesive. In an embodiment, the adhesive 207 may be Chemlok® 213 from Lord Corporation.
The molding material 200, as illustrated in
Further, the springs 116, 124 can bias the spring biased members 112, 120 to contact the first and second outer layers 202, 204, respectively. The spring biased members 112, 120 can retain the first and second outer layers 202, 204 at the ends 114, 122 of the first and second mold halves 102, 104, respectively. The spring biased members 112, 120 can therefore prevent any movement of the first and second outer layers 202, 204 relative to the first and second mold halves 102, 104, along a direction perpendicular to the direction D.
The spring biased members 112, 120 can move the first and second outer layers 202, 204 further closer to each other. Further, the first and second outer layers 202, 204, respectively, can contact each other at the between the ends 114, 122 of the first and second mold halves 102, 104, respectively. The high viscosity material 206 can also deform the first and second outer layers 202, 204 in conformation with the shapes of the first and second molding surfaces 108, 110, respectively. Therefore, the first and second outer layers 202, 204 can encase the high viscosity material 206 between them. In an embodiment, the adhesive 207, which is pre-coated on the first and second outer layers 202, 204, can bond the first and second outer layers 202, 204 to each other at the ends 302, 304 of the article 300. Moreover, the first and second outer layers 202, 204 can encase the high viscosity material 206 between them. Further, the article 300 is formed in
The various process steps, as described above, are exemplary in nature, the process steps may vary according to specifications and/or parameters of the system 100 and the article 300. Deformations of the first and second outer layers 202, 204, and the high viscosity material 206 may also vary in intermediate process steps, as described in
Additional processing can also be performed to the article 300 formed in
High viscosity materials, such as thermoset plastics, thermoset elastomers, pre-heated thermoplastics, cementitious composites, and the like are known in the art. Molding of such high viscosity materials may be difficult. Further, MDF cements are an example of a type of cementitious composite. MDF cements may tend to absorb moisture and are susceptible to surface defects, such as cracks.
The present disclosure is related to the system 100 for molding high viscosity materials, such as thermoset plastics, thermoset elastomers, pre-heated thermoplastics, cementitious composites, and the like. The present disclosure is also related to a method for manufacturing an article (For example, the articles 300 and 400).
At step 502, the method 500 includes providing the hollow molding cavity 106 between the first and second mold halves 102, 104. The system 100 includes the first and second mold haves 102, 104. At step 504, the method 500 includes receiving the first and second outer layers 202, 204 containing the high viscosity material 206 between them in the hollow molding cavity 106. Any manual or automatic processes and/or devices may place the first and second outer layers 202, 204 and the high viscosity material 206 in the hollow molding cavity 106. Further, the spring biased members 112, 120 may retain the first and second outer layers 202, 204 between them in the hollow molding cavity 106. The first and second outer layers 202, 204 may be pre-coated with the adhesive 207. At step 506, the method 500 includes moving at least one of the first and second mold halves 102, 104 towards the other. The actuator 128 may move the first mold half 102 towards the second mold half 104.
At step 508, the method 500 includes deforming the high viscosity material 206 by the first and second mold halves 102, 104 in conformation with the shape of the article 300. The shape of the article 300 is defined by the first and second molding surfaces 108, 110 of the first and second mold halves 102, 104, respectively. In an embodiment, the heating module associated with the first and/or second mold halves 102, 104 may heat the first and second molding surfaces 108, 110 during the molding process. This may at least partially cure the high viscosity material 206. Further, in case the adhesive 207 is heat activated, the adhesive 207 may bond the first and second outer layers 202, 204 to the high viscosity material 206 during the molding process.
The first and second outer layers 202, 204 may prevent the high viscosity material 206 from sticking to the first and second molding surfaces 108, 110. The high viscosity material 206 may deform the first and second outer layers 202, 204 against the first and second molding surfaces 108, 110, respectively, during molding. Therefore, a separate pressure source (for example, a high pressure fluid) may not be required to form the first and second outer layers 202, 204. Further, deformation by the high viscosity material 206 may provide accurate forming of the first and second outer layers 202, 204 in conformation with the first and second molding surfaces 108, 110, respectively. The system 100 and the method 500 may thus enable cost efficient and accurate manufacture of the article 300.
Further, the first and second outer layers 202, 204 encase the high viscosity material 206 between them. The first and second outer layers 202, 204 may therefore prevent the high viscosity material 206, such as an MDF cement, from absorbing moisture. Further, the first and second outer layers 202, 204 may substantially prevent formation of any surface defects, such as cracks on the MDF cement. Moreover, the first and second outer layers 202, 204 may also increase a stiffness of the article 300. The article 300 may therefore have improved stiffness and long life.
After step 508, the actuator 128 may move the first mold half 102 away from the second mold half 104. Further, any de-molding processes and/or devices may remove the article 300 from the hollow molding cavity 106. In an embodiment, the article 300 may then undergo a post-curing process. The post-curing may complete the curing of the high viscosity material 206.
Though the method 500 was described above with respect to the article 300, the method 500 may be used for manufacturing any article having two outer layers encasing a high viscosity material between them. For example, the method 500 may be used to manufacture the article 400 (shown in
The present disclosure may provide a system and method for manufacturing which effectively incorporates macro-defect free cements as well as other high viscosity materials in the formation of articles which exhibit the beneficial properties of these materials while overcoming the difficulties which may have traditionally limited their use. As provided herein, while MDF cements and other high viscosity materials exhibit high stiffness as compared to conventional cementitious materials and lower cost, traditional manufacturing methods may be ineffective or impracticable for utilizing these materials in the formation of articles.
Although some known methods of releasing materials from molds include coating a steel mold with chrome-based coatings, applying mold release chemicals based on wax, silicone, or fluoropolymers, or using a release film, these methods do not provide any benefit to the function of the article being molded. In particular, employing such methods to fabricate articles out of macro-defect free cements as well as other high viscosity materials may facilitate the release of these adhesive materials, but would result in a formed article which has reduced strength and stiffness and is susceptible to surface defects, moisture absorption, and thus premature failure.
Other known methods include sandwich panel construction and hydroforming. Sandwich panel construction typically involves manufacturing an article with top and bottom panels or skins with a high modulus and high strength material and including a low density and/or low cost core material in the center of the article. If metal panels are used in such construction, it is customary to preform or prefabricate such panels prior to filling the center cavity with the low density core material. Such core material may be a two-part polyurethane (designed to be solid or foamed) or other reactive polymer system. Yet another known method of preforming metal panels is hydroforming. If two panels are needed in a structure, double-blank hydroforming is a method that may be utilized. In such method, two panels are concurrently deformed to the shape of a mold cavity by the hydraulic pressure exerted by a working fluid, typically water-based although hydraulic oils can also be used. In the double-blank hydroforming method, the working fluid does not remain with the preformed metal panels as an integral component of the final article. If only one panel is needed, a method called rubber pad forming may be used. This process uses the high resistance of the rubber to flow as the force required to deform the sheet metal. Additionally, neither of the known sandwich panel construction nor double-blank hydroforming are suited for the utilization of macro-defect free cements or other high viscosity materials. In particular, neither method provides a high viscosity material as an integral component of the final article and which adheres to and forms the shape of outer layers against interior mold surfaces while being pressurized within a mold cavity to provide a unitary article, as sandwich panel construction is characterized by low density core material and double blank hydroforming requires low viscosity working fluids such as water-based fluids or hydraulic oils.
Thus, and unlike any known methods, the present disclosure can provide a system and method for manufacturing which effectively incorporates macro-defect free cements or other high viscosity materials in the formation of articles wherein the high viscosity material adheres to and forms the shape of outer layers against interior mold surfaces while being pressurized within a mold cavity such that the high viscosity material not only remains with the outer layers as an integral component of the final article, but also is adhesively bonded with, encapsulated within, and protected by the outer layers.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
Number | Date | Country | |
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Parent | 14179621 | Feb 2014 | US |
Child | 15360322 | US |