Patent Application
20160046038
1. Field of the Invention
This invention relates to an apparatus for solving manufacturing issues related to casting panels for use in the fields of industrial design and architecture. A reconfigurable and reusable flexible membrane mold is disclosed that can be selectively and accurately configured for casting panels and the like into a variety of different sizes and shapes.
2. Background Art
Software today has enabled designers to develop virtually any surface regardless of complexity and variability of curvature. Moreover, manufacturing has, for all intents and purposes, allowed the designer to realize these designs in physical artifact while presenting few limitations other than cost. We live in an age where population will exceed nine billion by 2050. Resources are becoming scarce and expensive, energy consumption is rising, and jobs are a welcome commodity globally. The building industry accounts for about half the world's consumption of energy which mandates that architects and engineers design sustainably. One of the most notable groups pushing for high performance sustainable design is the 2030 Challenge which asks the building industry to cut energy use in buildings by 50% by 2030. The program has since extended this challenge not only to the performance of buildings but the manufacturing and construction of buildings.
Computer Numeric Control (CNC) routing or hot wire foam cutting is the current industry standard for producing molds for casting objects that display smooth variable geometry. This method uses stock material that comes in sheet or block units and removes material until the final part is revealed in a process commonly known as subtractive manufacturing. This process typically utilizes a routing bit of various sizes and shapes or a hot wire to cut down the material. The resulting parts are precise, accurate, and relatively smooth. However, the process is both time consuming and wasteful with respect to material. A typical process for producing one panel would start with a three dimensional Computer Aided Drawing (CAD) surface that is exported into a Computer Aided Manufacturing (CAM) program. The CAM program will then write G-Code which is a series of movements and cut commands encoded as a computer language that the CNC tool understands as its series of steps to realize the final part. Once the G-Code is produced, it is uploaded to the post-processing program of the CNC machine. The machine will then complete a series of cutting steps during which it removes one layer of material at a time until a rough form emerges to produce the part. This rough part is then subjected to a finishing cut process that reveals the final part. As the machine cuts down the stock material, the excess is turned into dust, flakes, or smaller particles which are collected via vacuum and disposed of as waste. Upwards of 90% of a stock material can be cut away as waste to reveal the final part depending on the relief depth of the part. The process of producing the G-Code, loading up stock material, cutting down the material, and finishing the part is very time consuming and wasteful.
Another process for manufacturing panels is Pin-Point forming (PPF) which was invented in 1923 by C. J. Williams and T. Skinner. This process uses a two-dimensional former to produce manually-adjustable automobile leaf springs. About twenty years thereafter, this method of forming was expanded to three dimensions by adding multiple rows with the intent of forming sheet metal. These types of forming devices are referred to in the art as reconfigurable discrete dies. Such devices were not capable of being digitally actuated until the mid-1970's following work performed by Professor David Hardt at the Massachusetts Institute of Technology (MIT). Professor Hardt's original design was a press that configured itself by adjusting a matrix of densely packed quarter inch pins with rounded heads via servo actuators. The configuration of the pins is actuated into its final position via input from a CAD surface whose typography is broken down into a height-field of lines where length is translated into servo motor rotational degrees or stepper motor steps. These machines are referred to as digitally reconfigurable formers which allow molds to be produced in one step by turning CAD data into physical form. This technique requires no stock material and no CAM programming or G-Code production which advantageously creates no waste. Once the panel is produced, the pins reconfigure to their original rest state and the process can be repeated for any other configuration. Various types of pin point formers have been developed throughout the years aimed at pressing sheet metal or thermoforming panels directly onto the array of pins.
The disadvantage of these conventional formers and processes is that one cannot cast materials against an open array of pins, because the casting material will destroy the mechanism. Therefore, it would be desirable to be able to overcome this disadvantage by attaching a flexible impervious membrane onto the ends of these pins that allow one to cast objects of variable geometry and depth.
In general terms, a reconfigurable and reusable flexible membrane mold is disclosed which has particular use in the fields of industrial design and architecture to enable a variety of panels, tiles and other objects to be accurately cast. Each of a pair of opposing, mirrored sides of the membrane mold includes a flexible (e.g., rubber) forming membrane having a plurality of ball joint receiving cup extending therefrom. An arrayed grid of actuating pins is coupled to the flexible forming membrane of each mirrored side to apply pushing and/or pulling forces thereto to selectively change the geometry of the forming membrane depending upon the object to be cast. The actuating pins are attached to respective pin sleeves, each of which having a spherical ball joint standing upwardly therefrom. Each ball joint is received within a ball joint connector head so as to lie against and be capable of moving around a correspondingly shaped swivel cavity in response to a movement of an actuating pin to which the ball joint is connected. The ball joint connector heads are located inwardly of and embedded within respective ones of the ball joint receiving cups which extend from the flexible forming membrane.
As an important detail of this invention, the receiving cups are molded around and bonded to the connector heads to prevent the connector heads from pulling out of the receiving cups and becoming separated from the forming membrane. In this regard, each ball joint connector head has a ring-shaped armature located above the top thereof. A series of casting slots are formed through the armature. The casting slots communicate with casting channels that run along the outside of the connector head below the armature. During the process of molding the flexible forming membrane, molding material from the membrane flows into the casting slots and casting channels of each ball joint connector head. At the conclusion of the molding process, the molding material fills the casting slots and channels to create anchors for holding the ball joint connector heads in place within the ball joint receiving cups.
By virtue of the foregoing, the flexible forming membrane at each of the mirrored sides of the membrane mold will be continuously responsive to both back and forth, pushing and pulling, and rotational forces applied thereto by way of the arrayed grid of actuating pins. A pair of such forming membranes are arranged in spaced and opposing, face-to-face alignment to form a variety of shapes depending upon the direction of the forces being selectively applied to the arrayed grid of actuating pins by means of, for example, a stepper or servo-motor or by hand. A space between the opposing forming membranes is filled with casting material after which the forming membranes may be reused and reshaped.
Referring to the drawings,
The flexible forming membrane 3 of the one side 1 of the mold shown in
Hollow, cylindrical pin sleeves 16 are coupled to respective ball joint connector heads 5. The arrayed grid of actuating pins 7 is received inwardly of and mated (e.g., adhesively bonded) to the hollow pin sleeves 16. As will be described in greater detail when referring to
The perimeter 12 of the membrane 3 can be polygonal or spline-like having any number of edges depending upon the arrangement of the actuating pins 7. Additionally, the forming face 9 can be customized to integrate a variety of grooves, patterns, or relief designs. The plurality of ball joint receiving cups 14 are initially axially aligned with the arrayed grid of actuation pins 7 by way of the ball joint connector heads 5 and the pin sleeves 16 attached thereto. The thickness of the perimeter 12 between the front forming face 9 and the back face 10 of the forming membrane 3 is variable and dependent on the spacing of the grid of the actuating pins 7. As the pins 7 become less densely packed, the thickness of the perimeter 12 increases proportionately, and vice versa. The length and geometry of the ball joint receiving cups 7 are chosen to buckle or stiffen to accentuate deformity of the membrane 3.
As earlier explained, the ball joint receiving cups 14 which extend from the back face 10 of the flexible forming membrane 3 form cavities that are sized and shaped to accommodate the ball joint connector heads 5 therewithin. During manufacture of the membrane mold 1, the cups 14 of the forming membrane 3 are cast around and bonded to each of the connector heads 5. Thus, the ball joint connector heads 5 will be embedded within the ball joint receiving cups 14 so as to prevent a separation of heads 5 from cups 14 as the forming membrane 3 is shaped by the actuating pins 7.
As was previously explained while referring to
In this regard, during the manufacture of the flexible membrane mold side (designated 1 in
At the conclusion of the molding process, the casting slots 28 and the casting channels 32 will be filled with molding material to create a reliable anchor by which to hold the ball joint connector head 5 inside the respective ball joint receiving cups 14 of membrane 3. Hence, and as is best illustrated in
Turning now to
As an advantage of the membrane mold 50 having the pair of mirrored sides 1-1 and 1-2 herein disclosed, at the conclusion of the casting process, pulling forces can be applied to the actuating pins 7 in order to separate the opposing flexible forming membranes 3-1 and 3-2 from one another so that the casting can be removed from the gap 40. The mirrored sides 1-1 and 1-2 of mold 50 may then be reused and reconfigured to form different shapes as needed in the architectural and industrial communities.
As was previously explained, the ball joint connector heads 5 that are embedded within the ball joint receiving cups 14 of the flexible forming membranes 3-1 and 3-2 are adapted to freely swivel around respective ball joints 20. More particularly, as the arrayed grids of actuating pins 7 apply back and forth, pushing and pulling forces along the membranes to impart a corresponding curvature thereto, the ball joint receiving cups 5 will swivel relative to pins 7. That is, while the back and forth moving actuating pins 7 remain parallel to each other during the shaping of the flexible forming membranes 3-1 and 3-2 at the mirrored sides 1-1 and 1-2 of the membrane mold 50, any number of the ball joint connector heads 5 can swivel out of their initial axial alignment with the actuating pins 7 depending upon the curvature imparted to the membranes. Thus, pinpoint shaping of the flexible forming membrane 3-1 and 3-2 can be achieved to produce smooth, high resolution topographical surfaces. What is more, the discrete pin pressures being applied by actuating pins 7 act to smooth out undesirable dimples and thereby permit a continuous curvature of the flexible forming membranes 3-1 and 3-2 in three dimensions.
