Claims:1. A heat treatment oven comprising:
a Programmed Logic Controller (PLC) based control system configured to control operation of heaters and fans of the oven and precisely implement a heat treatment process by interlocking with a design process data sheet; and
a pneumatic lock operatively coupled to the control system and configured to lock door of the oven;
Wherein the control system keeps the door of the oven locked till temperature inside the oven falls near to ambient temperature.

2. The oven of claim 1, wherein the control system is configured so as to prevent unlocking of the pneumatic lock on occurrence of power failure or power switch off conditions.

3. The oven of claim 1, wherein the oven incorporates a thermistor to sense the ambient temperature and the control system unlocks the pneumatic lock based on the sensed ambient temperature.

4. The oven of claim 2, wherein the control system stores last settings on the occurrenceof power failure or power switch off conditions and restarts the heat treatment process with reference to last stop.

5. The oven of claim 1, wherein the oven further incorporates a camera configured to capture at least one image of part/component loaded in the oven.

6. The oven of claim 4, wherein the at least one captured image of the part/component loaded in the oven is used to select the design process data sheet for heat treatment of the loaded component/part.

7. The oven of claim 4, wherein the control system is configured to log data pertaining to the heat treatment process, wherein for each heat treatment cycle, details pertaining to the component/part loaded in the oven, set temperature, rise time, hold time, fall time, cycle completion time and like are stored.

8. The oven of claim 1, wherein the control system further incorporates a Graphical User Interface for retrieval of the logged data.

9. The oven of claim 8, wherein the GUI is further configured for inputting and storing reference images of the components/parts, their part/cat. Numbers and corresponding design process data sheets.

10. The oven of claim 1, wherein the control system is configured to send a message on completion of the heat treatment process.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of ovens/furnaces. More particularly, it pertains to a computer aided oven for fully automated heat treatment of bimetallic and like materials.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Heat treatment plays an important role in manufacturing as it enables materials to attain their optimum physical properties. Heat treatment involves use of heating or cooling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, normalizing and quenching. It is noteworthy that while the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occurs incidentally during other manufacturing processes such as hot forming or welding. Since such incidental heating and cooling is governed by considerations other than physical properties of the material involved, subsequent heat treatment becomes essential to bring the properties to a desired optimum level.
[0004] Heating of material requiring heat treatment is typically done in an oven or a furnace (one of the two terms is used depending on operating temperature). Depending on nature of heat treatment, the oven/furnace may be required to heat the material to a desired elevated temperature over a defined time period, hold it at the elevated temperature for certain time period and cool back at a desired rate. Combination of these periods and their respective temperatures is known in the art as heat treatment cycle. The heat treatment cycle defers from material to material, and also for same material depending on nature of treatment i.e. stress relieving, normalizing, hardening, grain refinement etc. The cycle for a given material and heat treatment process may also vary depending on requirement of end properties.
[0005] To achieve the desired properties and to have consistency in results, it is of utmost importance that the heat treatment cycle is strictly followed. Any deviation from the desired cycle shall result in non-attainment and inconsistency of the properties of the material which may lead to non-performance of the system where the material is used and/or premature failures.
[0006] One material that critically controls performance of MCCBs is bimetal and is subjected to stress relieving heat treatment operation to reduce residual internal stresses for dimensional stability or reduced risk of premature failure. These stresses may be caused in a number of ways, ranging from cold working to non-uniform cooling. Proper stress relieving requires precise control over temperature, hold time at specific temperature and cooling.
[0007] FIG. 1 illustrates a typical arrangement used for manual inputting/selection of temperature during the heat treatment process and FIG. 2 illustrates a typical bimetal used in MCCBs. FIG. 3 illustrates a typical temperature-time cure required to be followed during stress relieving of a bimetal pertaining to MCCBs.
[0008] In conventional methods, the heat treatment cycle for bimetals is implemented on manually controlled furnaces/ovens. In manual process, setting of the heat treatment cycle before starting is manual, which often leads to error. Furthermore, many a time operators remove the material from the oven even before the Heat treatment cycle is complete or before the oven has cooled down to a temperature close to ambient leading to degradation of material quality due to unwanted quenching. Even when an automated selection of the heat treatment cycle is provided based on selection of material/component through software recipe, operator may select a wrong material/component.
[0009] Thus the manually controlled heat treatment process has direct effect on MCCB Performance resulting in variations from lot to lot and resultant rejections and reworks with corresponding cost implications. As highlighted above this is due to reasons such as i) manual selection of temperature and material, b) Material removal before completion of the heat treatment process resulting in quality degradation, c) deviation from desired temperature time curve and d) cooling of the bimetal not followed strictly. These reasons either individually or in combination result in inconsistent yield and increased rework.
[0010] Prior art references have tried to overcome at least some of these drawbacks of the conventional system. For example, United States patent number 6175103 discloses a furnace that consistently controls heat treating a metallic target according to a heat treatment recipe including a cycle temperature and a cycle exposure time. An automated heat treatment controller includes an operator interface for prompting an operator to load or remove a heat treated target. The controller further provides for commanding furnace door locks and for monitoring system performance. However, such electronic locks can be circumvented either by operators by intentionally switching off the entire system to remove the material or when power supply fails in which case removal of material even if at a temperature higher than ambient is possible.
[0011] There is, therefore, need in the art to provide improved furnaces/ovens that can implement the desired heat treatment cycles without any human interventions, maintain record of treatment cycle actually followed and isolate the system during process from unintended human interference.
[0012] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0013] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0014] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0015] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0016] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0017] A general object of the present disclosure is to provide an oven for heat treatment.
[0018] An object of the present disclosure is to provide a heat treatment oven that eliminates human intervention during the heat treatment process.
[0019] Another object of the present disclosure is to provide a heat treatment oven that does not allow the oven to be opened by premature switching off the power supply or during power off situation.
[0020] Yet another object of the present disclosure is to provide an oven that does not require manual selection of already fed recipe for heat treatment cycle to be followed.
[0021] Another object of the present disclosure is to provide a heat treatment oven that does not require manual feeding of ambient temperature.
[0022] Still another object of the present disclosure is to provide an oven that incorporates a camera to identify component placed for heat treatment and select corresponding heat treatment cycle without human intervention.
[0023] Still yet another object of the present disclosure is to provide an oven that in case of power failure during heat treatment cycle, restarts the process with reference to last stop.

SUMMARY
[0024] Aspects of the present disclosure relate to a computer aided automated oven that can prevent intended or unintended manual interventions during process of heat treatment thus ensuring quality and consistency by adherence to the specified heat treatment cycle.
[0025] In an aspect, the disclosed oven incorporates a PLC based Control system configured to interlock with design process data sheet and execute heat treatment operation precisely in accordance with the design process data sheet.
[0026] In an aspect, the disclosed oven further incorporates a Pneumatic Door lock operatively coupled to the Control system and configured to lock door of the oven to prevent unintended human intervention when the heat treatment cycle is on. In an aspect the lock is configured to keep the oven locked till the heat treatment process is completed i.e. temperature in oven falls near to ambient temperature. This can ensure that the oven door cannot be opened in the event of power switch off or power failure and thus prevents premature removal of material from the furnace without completion of the process and resultant air quenching of the material.
[0027] In an aspect, in case of intermittent power failure or switch off condition during the heat treatment cycle, the oven stores its last settings and restarts the process with reference to last stop thus preventing deviation from the prescribed heat treatment cycle.
[0028] In an aspect, the oven can incorporate a camera to capture image of component loaded in the oven for heat treatment and the oven can further incorporate means to process and identify the component image and select corresponding heat treatment cycle from the stored recipes. Thus manual loading or selection of preloaded heat treatment cycles is eliminated along with corresponding chances of error. In an alternate embodiment, the required heat treatment cycle can be selected by entering part/cat. Number of the material loaded in the oven.
[0029] In an aspect, the oven can incorporate feature of data logging of heat treatment process wherein for each heat treatment cycle details pertaining to the material loaded in the oven, set temperature, rise time, hold time, fall time, cycle completion time etc. can be stored for retrieval for the purpose of traceability.Any intended or unintended intermittent tempering with the heat treatment cycle such as due to loss of power supply also gets recorded which can be helpful during subsequent defect analysis.
[0030] In an aspect, the disclosed oven can be configured to send a message to a preset mobile telephone number or email address on completion of the heat treatment cycle or on any other occurrence such as power loss.
[0031] In an aspect, the disclosed oven can further incorporate a Graphical User Interface configured to carry out various functions like inputting the heat treatment recipes and their corresponding part/cat, numbers or images, selection of material, event recording and online traceability of cycle to name a few.
[0032] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0034] FIG. 1 illustrates a typical arrangement used for manual inputting/selection of temperature during the heat treatment process.
[0035] FIG. 2 illustrates a typical bimetal used in MCCBs.
[0036] FIG. 3 illustrates a typical temperature-time cure required to be followed during stress relieving of a bimetal pertaining to MCCBs.
[0037] FIG. 4 illustrates an exemplary Programmable Logic Controller (PLC) used with system for executing programmed heat treatment cycle in accordance with an embodiment of the present disclosure.
[0038] FIG. 4 illustrates an exemplary image of a computer aided automatic oven in accordance with an embodiment of the present disclosure.
[0039] FIG. 5 illustrates an exemplary Programmable Logic Controller (PLC) used with system for executing programmed heat treatment cycle in accordance with an embodiment of the present disclosure.
[0040] FIG. 6 illustrates an exemplary screen shot of Lab View graphical development programme in accordance with an embodiment of the present disclosure.
[0041] FIG. 7 illustrates an exemplary image of Graphical User Interface screen developed in Lab View in accordance with an embodiment of the present disclosure.
[0042] FIG. 8 illustrates an exemplary screen shot of event and data recorder in accordance with an embodiment of the present disclosure.
[0043] FIG. 9 illustrates an exemplary image of door lock with pneumatic actuator in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0044] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0045] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0046] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0047] Aspects of the present disclosure relate to a computer aided automated oven that can prevent intended or unintended manual interventions during process of heat treatment thus ensuring quality and consistency by adherence to the specified heat treatment cycle.
[0048] In an aspect, the disclosed oven incorporates a PLC based control system configured to interlock with design process data sheet and execute heat treatment operation precisely in accordance with the design process data sheet.
[0049] In an aspect, the disclosed oven further incorporates a Pneumatic Door lock operatively coupled to the control system and configured to lock door of the oven to prevent intended or unintended human intervention when the heat treatment cycle is on. In an aspect the lock is configured to keep the oven locked till temperature in oven falls near to ambient temperature. This can ensure that the oven door cannot be opened in the event of power switch off or power failure and thus prevents premature removal of material from the furnace without completion of the process and resultant air quenching of the material.
[0050] In an aspect, in case of intermittent power failure or switch off condition during the heat treatment cycle, the control system of the oven can store last settings and restart the process with reference to last stop thus preventing deviation from the prescribed heat treatment cycle.
[0051] In an aspect, the oven can incorporate a camera to capture image of component loaded in the oven for heat treatment and the oven can further incorporate means to process and identify the component image and select corresponding heat treatment cycle from the stored recipes. Thus manual loading or selection of preloaded heat treatment cycles is eliminated along with corresponding chances of error. In an alternate embodiment, the required heat treatment cycle can be selected by entering part/cat. Number of the material loaded in the oven.
[0052] In an aspect, the oven can incorporate feature of data logging of heat treatment process wherein for each heat treatment cycle details pertaining to the material loaded in the oven, set temperature, rise time, hold time, fall time, cycle completion time etc. can be stored for retrieval for the purpose of traceability.
[0053] In an aspect, the disclosed oven can be configured to send a message to a preset mobile telephone number on completion of the heat treatment cycle.
[0054] In an aspect, the disclosed oven can further incorporate a Graphical User Interface configured to carry out various functions like inputting the heat treatment recipes and their corresponding part/cat, numbers or images, selection of material, event recording and online traceability of cycle to name a few.
[0055] FIG. 4 illustrates an exemplary image of a computer aided automated oven 400 in accordance with an embodiment of the present disclosure. As shown the computer aided automated oven 400 can incorporate a PLC 402, a GUI 404 and a pneumatic door lock 406. In an aspect, the oven 400 can also incorporate a camera (not shown here) configured to capture image of parts/components placed inside the oven 400. The captured image can be analysed to identify the component/part loaded in the furnace.
[0056] FIG. 5 illustrates an exemplary Programmable Logic Controller (PLC) 402used with system for executing programmed heat treatment cycle in accordance with an embodiment of the present disclosure. PLCs, such as PLC 402are digital computers, typically used for automation of industrial electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, light fixtures etc. PLCs are programmed using application software on personal computers, which now represent the logic in graphic form instead of character symbols. A computer is connected to the PLC 402 through Ethernet, RS-232, RS-485 or RS-422 cabling. The programming software allows entry and editing of the ladder-style logic. Generally the software provides functions for debugging and troubleshooting the PLC software.
[0057] In an aspect, the PLC 402 can be configured to store last settings and restart the process with reference to last stop in case of any intermittent power failure or switch off condition during the heat treatment cycle, thus preventing deviation from the prescribed heat treatment cycle.
[0058] In an aspect, the computer can also be connected to the camera of the oven 400 and receive the captured image of the component/part loaded in the oven. It can further incorporate image processing software to compare the captured image with images of known parts stored in a library and identify the component. The computer can further locate corresponding heat treatment cycle pertaining to the loaded component and communicate relevant details pertaining to the heat treatment cycle to the PLC 402. Thus the oven 402 does not require any human intervention for feeding or selection from recipes of the required heat treatment cycle thus avoiding any possible errors.
[0059] FIG. 6 illustrates an exemplary screen shot 600 of Lab View graphical development programme in accordance with an embodiment of the present disclosure. The Lab View is a system-design platform and development environment for a programming language from National Instruments. Lab View is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various versions of UNIX, Linux, and Mac OS X. The Graphical User Interface 404 developed in Lab View can enable selection of material, event traceability of process through GUI. Temperature parameter and Hold time can be controlled through master database to meet the heat treatment cycle requirements. GUI software is interfaced with PLC 402 for electro-mechanical sequential operation. GUI 404 makes it easy to add temperature and Hold time for new materials. Further, all events of the heat treatment process are recorded for future references with respective to material and these records can be helpful in traceability.
[0060] FIG. 7 illustrates an exemplary image 700 of the Graphical User Interface screen developed in Lab View in accordance with an embodiment of the present disclosure. The exemplary image 700 shows display of a typical temperature time curve (also referred to as design process data sheets) for a heat treatment cycle to be executed by the oven 400. The curves such as one shown in image 700 corresponding to different materials or components/parts along with their reference images, part/cat. Number can be inputted and stored in the PLC by means of GUI. If required, these details can be later selected using the GUI for execution. Alternatively these can be automatically selected based on image of the loaded component/part captured by the camera for execution by the PLC.
[0061] In an embodiment, the GUI can also enable viewing of data relating to batches of material previously processed in the oven 400. The data can be displayed in tabular form listing all relevant information such as those relating to the heat treatment cycle, material/component subjected to heat treatment etc.
[0062] FIG. 8 illustrates an exemplary screen shot 800 of event and data recorder in accordance with an embodiment of the present disclosure. The recorded data can help in traceability or investigating the failures and other such applications.
[0063] In an aspect, the disclosed oven 400 further incorporates a pneumatic lock 406 to lock the door of the oven to prevent an unintentional opening/removal of the material before the heat treatment cycle is complete.FIG. 9 illustrates an exemplary image of door lock with pneumatic actuator in accordance with an embodiment of the present disclosure In an embodiment the pneumatic lock 406 is controlled by the PLC 402 controlling its opening and closing based on the heat treatment cycle.
[0064] In an aspect, the PLC 402 can be configured to open the lock 406 only when the temperature inside the oven 400 drops down close to ambient temperature. It thus, prevents premature opening of the oven and prevents quenching of material on account of temperature difference that may take place due to difference in temperature of the material and ambient temperature.
[0065] In an aspect, the PLC 402 is configured such that the lock 406 remains locked under condition of power outage or power switch off. Thus intended or unintended human intervention i.e. opening of the oven 400 is prevented.
[0066] In an aspect, the oven 400 can incorporate a thermistor to sense the ambient temperature doing away with requirement of entering/feeding of the ambient temperature. As can be appreciated the thermistor further eliminates any chance of intended or unintended human mistakes that may result in deviation from the prescribed heat treatment cycle.
[0067] Thus the disclosed oven 400 ensures a PLC control system based interlocked heat treatment process in which all elements of the process are controlled by PLC system including temperature controlling, heater On-Off, fan On-Off, operation of pneumatic door lock system and Alarm system. System also gets resumed after abnormal power failures but maintains record of such failures and their effect on the process in terms of temperature and other parameters.
[0068] The disclosed computer aided oven can ensure exact replication of required heat treatment cycle, eliminates manual intervention, provides a faithful event recording, provides ease of entering/selecting heat treatment parameters based on material code or component number.
[0069] The disclosed computer aided oven makes it possible to trace intentional/unintentional tempering of the material due to deviations from the prescribed heat treatment cycle.
[0070] The disclosed computer aided oven results in improved quality of the end product by providing components such as bimetals, with consistent physical properties thus reducing failures, rejections and reworks such as secondary stress relieving at MCCB level.
[0071] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0072] The present disclosure provides a heat treatment oven that eliminates human intervention during the heat treatment process.
[0073] The present disclosure provides a heat treatment oven that does not allow the oven to be opened by premature switching off the power supply or during power off situation.
[0074] The present disclosure provides an oven that does not require manual selection of already fed recipe for heat treatment cycle to be followed.
[0075] The present disclosure provides a heat treatment oven that does not require manual feeding of ambient temperature.
[0076] The present disclosure provides an oven that incorporates a camera to identify component placed for heat treatment and select corresponding heat treatment cycle without human intervention.
[0077] The present disclosure provides an oven that in case of power failure during heat treatment cycle restarts the process with reference to last stop.