Patent Application
20050288807
1. Field of the Invention
One aspect of the present invention relates to a semi-automated computer-assisted method and system for designing manifold assemblies, and more specifically, hot runner manifold assemblies.
2. Background Art
Hot runner manifold assemblies are used to deliver molten plastic into injection molds. A hot runner manifold can be comprised of a steel casing that distributes molten plastic, wood or steel, or mixtures thereof, from the outlet of a molding machine to the mold. Examples of steel casings include, but are not limited to, cast round, square, or rectangular; and machined round, square, or rectangular. Plastic enters the manifold through one or more sprue bushings and exits to the mold through one or more drops. One or more valve gates may be used to control the flow through the one or more drops. The manifold is typically retained by compression between the molding machine and the mold steel. The manifold seals to the one or more sprues and one or more drops, which is commonly referred to as the preload step. Pressure pads and preload plates are mounted on the manifold opposite from the sprue and drops.
Conventionally, hot runner manifold assemblies are designed using computer aided design (“CAD”) applications. Typically, the design process begins with a customer order. The customer provides drawings of the injection mold to the manifold designer. Optionally, mold flow analysis can be conducted on the mold. Based on the mold drawings, a manifold designer designs a pattern drawing of the manifold in a CAD system, which usually takes about a week.
Once the customer approves the pattern drawing, the design process proceeds down two paths—pattern building and preliminary drawing completion. Pattern building includes pattern checking, pattern construction, pattern verification, foundry work for producing the cast manifold, and cast making. Preliminary drawing completion includes detailing for the preliminary drawing package, drawing checking, and drawing completion. The pattern building and preliminary drawing completion processes are executed in parallel and usually take about three to four weeks to complete. Once the customer signs off on the completed drawing, which usually takes about a week, the rest of the design process is completed, which includes final detailing, final package drawing, release to manufacturing, manufacture manifold from machined round, rectangular or square casting, and shipping. The rest of the process typically takes about four days. Overall, the conventional design process takes about six to seven weeks to complete.
The conventional process outlined above does not utilize automation. Although some legacy data is used for layout, the process utilizes manual two-dimensional drawing with CAD. Two-dimensional views for blueprints are prepared by converting a three-dimensional solid, via CAD software. This conversion consumes a substantial amount of man-hours. Further, the conventional process leads to bottlenecking at the detailing for preliminary design and checking steps.
In light of the foregoing, what is needed is a semi-automated computer-implemented method and system for designing manifold assemblies, which shortens the conventional design cycle. What is also needed is a computer-implemented method and system for automatically generating two-dimensional layouts based on three-dimensional solids.
One aspect of the present invention relates to a semi-automated computer-implemented method and system for designing manifold assemblies for shortening the conventional design cycle. The present invention also includes a computer-implemented method and system for automatically generating two-dimensional layouts based on three-dimensional solids. One advantage of the present invention is design cost savings. Another advantage of the present invention is increased design capacity that may lead to business growth. Other advantages over the conventional system can include, but are not limited to, decreased preliminary detailing, decreased final detailing, increased sales, elimination of manual creation of bill of materials, increased quality, and lower product development costs.
According to a first embodiment of the present invention, a semi-automated computer-implemented method for designing manifold assemblies is disclosed. The method includes receiving a number of design parameters for the design of a manifold assembly and applying the number of design parameters to a heater and zoning logic to generate a manifold assembly design. The method can further include generating two-dimensional data for the manifold assembly based on the number of design parameters and the heater and zoning logic. The method can further include automatically generating a blueprint based on the two-dimensional data for the manifold assembly. In certain embodiments, the manifold assembly design includes a three-dimensional rendering of the manifold assembly. The method can further include automatically generating a bill of materials based on the two-dimensional data for the manifold assembly. The number of design parameters can include manifold size, sprue coordinates, and drop coordinates. The heater and zoning logic can include minimizing overall heater gap, minimize number of zones, and minimize number of heaters. The manifold assembly design can include a manifold, one or more drops, one or more heaters, one or more thermocouples, and one or more plugs.
According to a second embodiment of the present invention, a semi-automated computer-implemented system for designing manifold assemblies is disclosed. The system can include one or more computers. The one or more computers can be configured to receive a number of design parameters for the design of a manifold assembly and apply the number of design parameters to a heater and zoning logic to generate a manifold assembly design. The one or more computers can be further configured to generate two-dimensional data for the manifold assembly based on the number of design parameters and the heater and zoning logic. The one or more computers can be further configured to automatically generate a blueprint based on the two-dimensional data for the manifold assembly. The manifold assembly design can include a three-dimensional rendering of the manifold assembly. The one or more computers can be further configured to automatically generate a bill of materials based on the two-dimensional data for the manifold assembly. The number of design parameters can include manifold size, sprue coordinates, and drops. The heater and zoning logic can include minimizing overall, heater gap, minimize number of zones, and minimize number of heaters. The manifold assembly design can include a manifold, one or more drops, one or more heaters, one or more thermocouples, and one or more plugs.
According to a third embodiment of the present invention, a semi-automated computer-implemented apparatus for designing manifold assemblies is disclosed. The apparatus includes means for receiving a number of design parameters for the design of a manifold assembly and means for applying the number of design parameters to a heater and zoning logic to generate a manifold assembly design. The apparatus can further include means for generating two-dimensional data for the manifold assembly based on the number of design parameters and the heater and zoning logic. The apparatus can further include means for automatically generating a blueprint based on the two-dimensional data for the manifold assembly and/or means for automatically generating a bill of materials based on the two-dimensional data for the manifold assembly.
These and other objects of the present invention will become more apparent from a reading of the specification in conjunction with the drawings.
The methods and systems of the present invention operate in the environment of manifold assembly design. Elements of a manifold assembly, include, but are not limited to, manifolds, heaters, thermocouples, pressure pads/preload plates, plugs, location rings, and drops. Manifolds are usually sand castings with raised bosses on both sides for drops, sprue, and pressure pads. Manifold types, include, but are not limited to, round manifolds (either two inch or three inch) and square manifolds. The pattern for the manifold can be a group of straight-line segments joining the sprue to each drop, or joining the sprue to an intermediate branch point that is joined to one or more drops. Straight segments are gun drilled to allow flow through the manifold. In certain embodiments, there can between about 1 to 120 drops per manifold.
Heaters are flat metal pads bent into a substantially circular form (for round castings, round stainless steel P-20 or H-13, or any other mold steel) to fit around the manifold and drops. The heaters contain electrical resistance elements and are wired together in zones. H-shaped units are used around bosses and straight units are used basically everywhere else on the manifold. Straight units may be used near bosses where no available H unit can fit. Full circle heaters are used around drops. Heaters are separated by standard gaps. The objective for heater use is to cover as much of the manifold and drops as possible for good thermal control. For square or rectangular shaped manifolds, heaters are usually tubular round or square in shape.
Thermocouples are placed in standard locations among the heaters to provide temperature feedback to the controller. For round and rectangular shaped castings, pressure pads and preload plates are used on top of bosses opposite sprue and drops. The pressure pads and preload plates are held in place by screws. Plugs seal ends of gun drilled passages and may include the plug itself, a set screw, and a bracket. Locating rings are circular plates that fit around sprue and drops for location. Drops can be of various diameters, various lengths, various bores, and various tip configuration and can include, but are not limited to, locating rings and retention screws and keys.
Having described in detail the elements of a manifold assembly,
With respect to block 28, the user can input one or more design parameters into the design module 14. Design module 14 provides rapid design and manufacture of molding assemblies. The user can enter the following non-limiting parameters: manifold size (two inch round or three inch round), coordinates of sprue, drops and reference point (if different from sprue), intermediate points (if any), interconnection pattern, bore sizes, special heaters and lengths and tip style(s) for drops. According to logic described in detail below, the design module selects the following non-limiting design features based on the user input and contents of library 16: pattern model and drawing with tolerances, bosses/spacers (for preload pads, drops, and sprue), heaters (H-shaped around bosses, straight as fillers between Hs, straight as alternative to H where space restricted, thermocouples, tapped holes (pressure pads and plugs), drops (size, length, tip, and attachment to manifold), pressure pads and screws, other details, and desired outputs (standard drawing format, bill of materials, and isometric view).
According to one embodiment of the present invention, heater and zoning logic is used to aid the design of manifold assemblies. In general terms, the heater and zoning logic accounts for the placement of intersection heaters, body heaters, and drop heaters and the definition of zones, including the placement of thermocouples in each zone. In doing so, the following optimization rules are followed: (1) minimize overall heater gap; (2) minimize number of zones; and (3) minimize number of heaters. More specifically, the following optimization rules are followed: (1) only one drop may be defined in any heater zone; (2) two intersections may be combined into a single zone if the number of intersections excess number of available zones; (3) segment heaters are added in a circular fashion around an intersection if required; and (4) segment heaters are added to intersection zones, if required, in an even pattern to all intersections until a zone solution is found. The objective of these optimization rules is to (1) minimize overall gap between manifold heaters; (2) ensure maximum number of zones is not exceeded; (3) ensure maximum zone power is not exceeded; and (4) ensure that maximum/minimum clearance is not violated.
In certain embodiments, the heater and zoning logic is implemented in the following process by the design module. First, the total number of zones is estimated as the sum of the drop zones and intersections. If this sum is greater than the maximum number of allowable zone, then intersections are combined where possible. The process ends if the value of drop zones plus number of intersections minus intersection combinations exceeds maximum number of zones. In certain embodiments, the ability to fit an intersection heater is not analyzed during the process. Second, drops, including sprue, heater zones are reserved according to drop length. Third, intersection heaters are placed in the following order: (1) drops; (2) sprue; and (3) other intersections. Intersection H-heater(s) are replaced with smaller H-heater(s) if required to fit a segment heater. Fourth, segment heaters are placed. Fifth, an optimization routine searches available heater patterns until a solution is found which best meets optimization objectives. If the maximum number of optimization iterations is exceeded, the routine ends with no valid solution. Sixth, drop heaters and zones are defined.
The process also includes accounting for manifold intersections. Drop intersections can be two legs and linear. H-heaters can be placed on all intersections if space allows using largest H-heater available. If a standard H-heater will not fit, fitting an offset H-heater is attempted. If a intersection leg is a plug, then no minimum gap is required when placing a H-heater. If intersections are too close together to allow standard H-heaters, intersection H-heaters can be replaced with smaller H-heaters on all intersections. Non-drop intersections can be two legs and angled or three legs and two linear. In the first case, a split-heater can be placed on an outside angle of each leg. In the latter case, a split heater can be placed on the outside of an intersection with two linear legs. Sprue intersections can have two legs that are linear. The largest H-heater fitting the available space can be placed on an intersection. For manifold leg segments, all possible heater patterns are determined that fit defined segments which meet minimum and maximum clearance requirements. Heater patterns are first sorted by minimum clearance then by minimum number of heaters, that is, all possible permutations of heaters, which equal each possible coverage length, are determined. The logic optimizes the heater pattern placement to meet optimization objective.
The process also includes steps for placing thermocouples on the manifold. The tolerance between two thermocouples is about 2.5 inches at minimum. If two thermocouples are closer, then the process moves one relative to the other so that there is a minimum distance of about 2.5 inches. In certain embodiments, every zone needs a thermocouple. Zones on manifold legs with only one H-band heater need the thermocouple under the H-band. The location can be about 0.25 inches from the end of the H-band heater towards the drop. Zones on manifold leg with H-band and multiple solid heaters in the same zone can have the thermocouple located between the H-band and solid heater, regardless of the number of extra heaters in the zone. For main leg zones with two solid heater bands, the thermocouple can be between two heaters. For main leg zones with three solid heater bands, the thermocouple can be under the middle heater. For main leg zones with four heater bands, the thermocouple can be in the four heaters. This logic is true, as the number of heaters per zone increase. For heaters in a cross-section of main leg and drop leg, the thermocouple can be under the longest heater about 0.50 inches away from the edge of the heater. For heaters in a cross-section of main leg and drop leg, if there is another heater the same size in the same zone, then the thermocouple can be between the two larger heaters. To install a manifold thermocouple, drill a hole with a #27 bit, then drill and tap a one-fourth-20 thread perpendicular to the thermocouple opening.
The process also includes steps for thermocouple and heater placement. For tip heaters, an about 1.5 inch by about 2.0 inch heater is put on the following full size tip styles: standard sprue tips, all valve gate tip, and all guardian tips. The tip zone, thermocouple location can be about 0.25 inches away from shoulder. For down size drops, an about 1.0 inches by about 1.5 inches tip heater is used. For full size low vestige style, an about 1.0 inches by about 1.5 inches is placed on the threaded insert. For body heaters, there is up to three heaters per zone. Each heater has the same length. The body heater is placed directly under the drop head, in the undercut section. The rest of the heaters are placed with the gap tolerance. In certain embodiments, the gap tolerance between heaters is about 0.25 inches to about 0.75 inches. If one body heater is used for the body zone, then the thermocouple can be placed in the center of the heater. If two body heaters are used for the body zone, then the thermocouple can be placed between the two heaters. If three body heaters are used for the body zone, then the thermocouple can be placed in the middle of the center heater. If four body heaters are used, then the heaters are split equally. Two heaters for body zone one and the other two. heaters for body zone two. In certain embodiments, there are an equal number of heaters and equal lengths for each body zone. In certain embodiments, there is a limit of three zones per drop, that is, body zone one, body zone two, and tip zone. In other situations, there are two zones per drop, that is, body zone and tip zone. A drop thermocouple can be installed by drilling a hole with a #27 bit, then drilling and tapping a 8-32 thread in the middle and perpendicular to the #27 hole.
Having described the user inputs and one system logic of the design module, following is a description of a user interface for providing a semi-automated system according to one embodiment of the present invention. In certain embodiments, the user interface is a web-enabled collection of graphic user interfaces (GUIs).
Referring back to
It should be understood that post-processing step(s) can be carried out on the two-dimensional blueprints. For example, post-processing step(s) can include refining dimensions, cutting sections, updating charts (i.e. hot and cold numbers), updating the title block on all drawing sheets, placing balloons on ISO for bill of materials, and/or updating an electrical chart.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
