Patent Application
20080039969
A better understanding of the exemplary embodiments of the present invention (including alternatives and/or variations thereof) may be obtained with reference to the detailed description of the exemplary embodiments of the present invention along with the following drawings, in which:
The drawings are not necessarily to scale and are sometimes illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details that are not necessary for an understanding of the embodiments or that render other details difficult to perceive may have been omitted.
For example, the molding system 100 is operating in automatic control mode (under the directions of a controller or equivalent). When a random change in a process of the system 100 occurs, the controller is to continue automatic control of the process in a slow approach so as to not upset the process too much. However, when the controller senses or detects an operator request to change the process, the controller then selects another control schema (from amongst several—that is the control schema the controller is currently executing or another control schema that the controller can begin using in order to quickly respond to the request of the operator of the system 100).
Preferably, the system 100 includes an extruder 120 (such as an injection unit with either single screw feed or twin screw feed). Thermal condition of zones 122, 124 (any one zone or both zones) are measured by way of thermal sensors 123, 125 respectively that are placed proximate of the zones 122, 124. The sensors 123, 125 are operatively coupled to the controller 102. By way of example, the process is control of heaters 136, 138, 140, 142 that are coupled to the extruder 120; the heaters 136, 138, 140, 142 are used for applying heat to molding material held in the extruder 120. The molding system 100 also includes a melt passageway 126 formed by any one of: (i) a machine nozzle 127, (ii) a sprue, (iii) a manifold of a hot runner 128 and (iv) any combination and permutation thereof.
The machine nozzle 127 connects the extruder 120 to the hot runner 128. According to a variant (not depicted), the hot runner 128 is not used. The hot runner 128 is attached to a stationary platen 130. The machine nozzle 127 passes through the stationary platen 130. A mold 132 includes (i) a stationary mold portion 132B that is attached to the hot runner 128 and (ii) a movable mold portion 132A that is attached to a movable platen 134. The mold 132 defines mold cavities 133A, 133B.
Preferably, the molding system 100 also includes (i) a clamping mechanism (not depicted) used to generate a clamping force, (ii) a mold-break force applicator (not depicted) used to generate a mold break force and (iii) tie bars (not depicted) that couple the clamping mechanism and the mold-break mechanism to the mold 132 and the tie bars are used to transfer the clamping force and the mold-break force from the clamping mechanism and from the mold-break applicator, respectively, to the mold 132. Since the structure and operation of the clamping mechanism and the mold-break applicator are known to persons skilled in the art of molding systems, these mechanisms will not be described in detail and will not be illustrated.
Extruder heaters 136, 138, 140, 142 are coupled to the extruder 120. Preferably, the extruder 120 includes a reciprocating screw (not depicted) that is used to (i) process or convert chips (or larger portions) of magnesium (or other types of metal, such as aluminum, zinc, etc) or (ii) process plastic material (such as PET—polyethylene terephthalate, thermoplastic resin, etc). The extruder heaters 136, 138, 140, 142 are used to keep the molten metallic molding material hot before it is injected into the mold cavities 133A, 133B defined by the mold 132. The melt passageway 126 extends from the extruder 120 through the machine nozzle 127 and through the hot runner 128 and leading up to the gate (the gate is the entrance to the cavities defined by the mold 132). The controller 102 is used to control or change the thermal condition (a process) of an extruder 120 by controlling the extruder heaters 136, 138, 140, 142 (that is, turning the extruder heaters 136 to 142 on or off in combination or individually according to programmed instructions that are used to direct the controller 102 to control the extruder heaters 136 to 142).
The controller 102 is programmable and includes a controller-usable medium 104 (such as a hard disk, floppy disk, compact disk, optical disk, flash memory, random-access memory, etc) that embodies programmed instructions 106 (hereafter referred to as the “instructions 106”). The instructions 106 are executable by the controller 102. The instructions 106 include executable instructions for directing the controller 102 to select a control schema from amongst several control schemas usable for controlling a process of the system 100. Operation of the controller 102 is described below in connection with
The instructions 106 may be delivered to the controller 102 via several approaches. An article of manufacture 108 may be used to deliver the instructions 106 to the controller 102. The article of manufacture 108 includes a controller-usable medium 104 (such as a hard disk, floppy disk, compact disk, optical disk, flash memory, etc) that is enclosed in a housing unit. The controller-usable medium 104 embodies the instructions 106. The article of manufacture 108 is interfacable with the controller 102 (such as via a floppy disk drive reader, etc). A network-transmittable signal 110 may also be used (separately or in conjunction with the article of manufacture 108) to deliver the instructions 106 to the controller 102. The network-transmittable signal 110 includes a carrier signal 112 modulatable to carry the instructions 106. The network-transmittable signal 110 is transmitted via a network (such as the Internet) and the network is interfacable with the controller 102 (such as via a modem, etc).
The controller 102 includes interface modules 150 to 159 (all known to persons skilled in the art) inclusive that are used to interface the controller 102 to: (i) the thermal sensors 125, 123, (ii) the extruder heaters 136 to 142 inclusive, (iii) the network-transmittable signal 110 and (iv) the article of manufacture 108 respectively, amongst other things. The interface modules 150, 151 are temperature-sensor interface modules. The interface modules 152 to 155 are heater-interface modules. The interface module 156 is a modem. The interface module 157 is a controller-usable medium reader (such as a floppy disk, etc).
Preferably, a display 164 (such as a flat panel screen, etc) is used as a human-machine interface; the display 164 is interfaced to the controller 102 via an interface module 158 that connects the display 164 to a bus 162. A keyboard and/or mouse 166 (that is, operator control equipment) are interfaced to the controller 102 via an interface module 159 that connects the keyboard and/or mouse 166 to the bus 162 (as known to those skilled in the art).
The controller 102 also includes a CPU (Central Processing Unit) 160 that is used to execute the instructions 106. The bus 162 is used to interface the interface modules 150 to 157, the CPU 160 and the controller-usable medium 104. The controller-usable medium 104 also includes an operating system (such as the Linux operating system) that is used to coordinate automated processing functions related to maintaining the controller 102 in operational condition. A database (not depicted) is coupled to the bus 162 so that the CPU 160 may keep data records pertaining to the operational parameters of the system 100.
Operation 180 includes starting of the instructions 106; control is then transferred to operation 182. Operation 182 includes directing the controller 102 to determine a difference between a setpoint 176 of the process 101 of the system 100 and a measured output 172 of the process 101. Operation 184 includes directing the controller 102 to determine whether the determined difference is greater than the threshold 178. If the determined difference is greater than the threshold 178, control is then transferred to operation 186. If the determined difference is less than (or equal to) the threshold 178, control is then transferred to operation 188.
Operation 186 includes directing the controller 102 to select a first control schema and then to use the selected first control schema that is then in turn used to generate a value of a manipulatable input of the process 101.
Operation 188 includes directing the controller 102 to select a second control schema and then to use the selected second control schema to generate a value of a manipulatable input of the process 101.
Preferably, the first control schema urges the process 101 to respond quickly (aggressively), and the second control schema urges the process 101 to respond slowly. The first control schema is enabled or used (in favor of using the second control schema) because it is likely that an operator of the system 100 has imposed a change to the process 101, and it would be prudent to have the system 100 respond to such a change request quickly (or fast); however, the second control schema is enabled or used (in favor of using then first control schema) because it is likely that the system 100 has imposed a random change to the process 101, and it would be prudent to have the system 100 respond to such a random change slowly (so that the process 101 may settle down without disrupting the overall performance of the system 100.
The instructions 106 may also include other executable instructions, such as: (i) selecting the control schema from amongst several control schemas based on a reading of a measurement of a sensor 123, 125 that are associated with the process 101 of the system 100, (ii) selecting the control schema from amongst several control schemas is based on a comparison between a measurement of a sensor 123, 12 and a value of the setpoint of the process 101, (iii) determining the comparison between the measurement of the sensor 123, 125 and the value of setpoint of the process parameter includes: comparing a threshold against the comparison between the measurement of the sensor 123, 125 and the value of setpoint of the process parameter, (iv) determining the comparison between the measurement of the sensor 123, 125 and the value of setpoint of the process parameter includes: comparing a threshold against the measurement, (v) determining a degree of change to be imposed to the process 101 in which the degree of change is based on the determined comparison made between the process measurement and a threshold, (vi) reading the value of the setpoint of the process 101 of the system 100, (vii) reading the measurement of the sensor 123, 125, (viii) controlling the process 101 of the system 100 using the selected control schema, and/or (ix) selecting the control schema usable for imposing any one of a quicker degree of change to the process 101 and a slower degree of change to the process 101.
The description of the exemplary embodiments provides examples of the present invention, and these examples do not limit the scope of the present invention. It is understood that the scope of the present invention is limited by the claims. The exemplary embodiments described above may be adapted for specific conditions and/or functions, and may be further extended to a variety of other applications that are within the scope of the present invention. Having thus described the exemplary embodiments, it will be apparent that modifications and enhancements are possible without departing from the concepts as described. It is to be understood that the exemplary embodiments illustrate the aspects of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims. The claims themselves recite those features regarded as essential to the present invention. Preferable embodiments of the present invention are subject of the dependent claims. Therefore, what is to be protected by way of letters patent are limited only by the scope of the following claims:
