Automated pyrometer tracking

Abstract

This document describes components, systems, assemblies, and related methods for automatically aligning a temperature measuring device with a die cavity during a sintering process. These include monitoring the temperature at a location on the die and include a pyrometer, a laser measuring device attached to the pyrometer, projecting a laser beam, and measuring the distance from the laser measuring device to the location from which the laser beam is projected. Each laser device outputs a signal, and an actuator adjusts the position of the pyrometer according to these signals.

Description

Technical Field

[0001] The present invention relates to methods and systems for spark plasma sintering, also known as direct current sintering, in which a temperature measuring device is used to monitor the temperature at specific locations on a die that is subject to movement during processing, such as vertical, horizontal, or a combination thereof.

Background Art

[0002] Spark plasma sintering (“SPS”), also known as direct current sintering (“DCS”) and field assisted sintering technique (“FAST”), is a pressure-assisted sintering technique capable of processing both conductive and non-conductive materials. SPS / DCS provides more rapid densification and improvement of material properties, and its mechanism is still under investigation. However, the most commonly accepted mechanisms are the possibility of a faster heating rate, Joule heating, and the influence of an electric field on densification.

[0003] During a typical SPS / DCS process, either ON-OFF DC pulses, generally square wave DC pulses or continuous direct current, is applied to the powder contained within a punch and die tool set in order to generate Joule heat and contain the pressure. The punch and die tool set is typically composed of graphite, although metals, ceramics or composite materials are not excluded. Graphite is the most common material because it is a good conductor and stable at extremely high temperatures. The abbreviation DCS may be used to denote a system that supplies non-pulsed direct current to the die. However, SPS and DCS are frequently used to mean the same type of apparatus and are used interchangeably herein. In an SPS / DCS apparatus, heat is transferred to the powder by heat conduction from the die, and when the powder is conductive, current can flow through the powder to directly generate Joule heat within the material being sintered.

[0004] The operating or monitoring temperature in the SPS apparatus is in the range of 200°C to 2400°C. Material processing (pressure and temperature rise and holding time) is typically completed in the SPS apparatus in a shorter period compared to conventional techniques. Faster processing times provide better control over particle growth and microstructure, thereby improving material properties directly related to microstructure, such as strength, toughness, electrical properties, thermal properties, optical properties, and corrosion and erosion resistance.

[0005] The temperature during sintering is typically monitored using either a thermocouple or pyrometer positioned within the die. Thermocouples are less preferred due to their sensitivity to stray voltages, which are caused by the electric field present within the tool. To ensure optimal sintering conditions, it is crucial to identify a consistent control point and monitor the temperature at that point throughout the process. However, during sintering, compression and compaction of the powder occur, requiring dynamic positioning of the pyrometer when the sintered product is formed. More specifically, the pyrometer must move because the die case itself moves during compression and compaction. Repositioning the pyrometer relative to the die is typically done manually, but this is often difficult to do consistently and in a timely manner, as the optimal position changes over the sintering time. Inaccuracies lead to variations in product quality, especially from run to run.

[0006] Components and methods for automatic pyrometer tracking in sintering are known, as can be seen in the following background patents, patent publications and (if any) non-patent literature, which are found in the appendix, incorporated in whole by reference, disclosed solely for background purposes, relating to state-of-the-art technology but not including one or more elements of the present invention, for example, found in U.S. Patent Application Publication No. 2016 / 0325353 and U.S. Patent No. 4,936,765, as can be seen in the appendix.

[0007] In fact, a basic block diagram of a typical SPS / DCS apparatus can be found in U.S. Patent Publication 2016 / 0325353 (see Appendix), which includes the SPS / DCS system of the present invention. As shown in Figure 1 of U.S. Patent Publication 2016 / 0325353, the sintering apparatus 100 includes a vacuum chamber 102 located within a load frame 104, and further includes an observation window 106 and a temperature measuring device 108, both of which are incorporated into the vacuum chamber 102. The material to be sintered (typically a powder material) is loaded into a die set 111 and placed in the vacuum chamber 102 of the sintering apparatus 100 on which the process is carried out. More specifically, as shown, the die set 111 includes a casing 112 and two opposing rams, namely a lower ram 120 and an upper ram 122, which form a die cavity 110 in which the material to be sintered is placed. The sintering apparatus 100 further includes a hydraulic power unit 116 and a hydraulic press cylinder 118. A hydraulic power unit supplies power to a hydraulic press cylinder, which is then used to manipulate the applied mechanical force (or pressure) by moving the lower and upper rams up and down, thereby compressing the easily sinterable material during the process. The force can be measured and monitored using a load cell or the like. In addition, a DC power supply 114 supplies the necessary current into the vacuum chamber 102 during compression. As shown in the figure, the sintering apparatus 100 also includes a vacuum pump 124, which allows the apparatus to operate under negative atmospheric pressure. Gas 126 can also be injected into the vacuum chamber 102 during the process if desired. A central control system 128 can be used to control different aspects of the sintering apparatus during use. For example, the control system can be used to control the DC power supply, the hydraulic power unit, the vacuum pump, and the amount of any inert gas introduced into the vacuum chamber during use.

[0008] Additionally, as shown in Figure 2 of U.S. Patent Application Publication No. 2016 / 0325353 (see Appendix), the die set 211 includes a casing 212 and two opposing rams, a lower ram 220 and an upper ram 222, which form a die cavity in which the material 205 (powder) to be sintered is placed. As shown, the die cavity is vertically symmetrical, but other shapes are possible. In this example, a target position of the die cavity is identified, which is the geometric centerline of the material. Assuming that the density is constant throughout the sample, particularly vertically, when heated, this will be the position of the highest measurable temperature relative to the powder. As seen in Figure 2 of U.S. Patent Application Publication No. 2016 / 0325353 (see Appendix), the position of the centerline changes as the powder is sintered to form the desired sintered part 295.

[0009] The prior art does not disclose a method or system with sufficient accuracy to provide unmanned tracking of pyrometer holes or recesses in the die of an electric field-assisted sintering apparatus.

[0010] Therefore, although spark plasma methods and systems are known, there is a need to provide sintering systems and methods that improve process consistency both during and between cycles. [Overview of the project]

[0011] To satisfy these and other needs, and in consideration of that purpose, the present disclosure relates to components and related methods for aligning a temperature measuring device with a die cavity in a sintering process.

[0012] In one embodiment, the present disclosure describes a system for monitoring the temperature of a location on a die. The system includes a pyrometer having ends, which is configured to measure temperature based on the intensity of thermal radiation received at the ends of the pyrometer, and the pyrometer has sides opposite to each other.

[0013] The system also includes first and second laser measuring devices attached to a pyrometer, one of which is mounted close to one side of the pyrometer and the other close to the opposite side of the pyrometer, each laser measuring device projects a laser beam, measures the distance from the laser measuring device to the point from which the laser beam is projected, and outputs a signal indicating whether the measured distance is less than or equal to a minimum distance. The system includes actuators connected to communicate with each laser measuring device and to receive signals output from each laser measuring device, the actuators supporting the pyrometer and moving the pyrometer in the first and second opposite directions according to the signals received from the laser measuring devices until each received signal indicates that the measured distance is not less than or equal to a minimum distance.

[0014] When each received signal indicates that the measured distance is greater than the minimum distance, the end of the pyrometer is positioned opposite the position on the die, receiving thermal radiation from there and outputting a temperature signal based on the intensity of the thermal radiation.

[0015] The pyrometer includes an upper and lower section, with one laser measuring device mounted close to the upper section of the pyrometer and the other laser measuring device mounted close to the bottom of the die, and an actuator moves the pyrometer up and down. When the actuator receives a signal from one of the laser measuring devices, the actuator moves the pyrometer downward, and when the actuator receives a signal from the other laser measuring device, the actuator moves the pyrometer upward. However, if the system receives signals from both laser measuring devices, the actuator does not adjust the position of the pyrometer.

[0016] The die has height, and the actuator moves the pyrometer parallel to the height of the die. In another embodiment, the laser measuring device is positioned vertically along the height of the die. In yet another embodiment, each laser measuring device is mounted equidistant from the die, and on that die, the distance is measured from the point on the outer wall of the die closest to the laser measuring device. Furthermore, the actuator is programmable.

[0017] In another aspect, the Disclosure describes a method for tracking a recess in a die using a temperature measuring device. The method includes mounting a first laser and a second laser facing each other in a temperature measuring device to fabricate a pyrometer assembly; aligning the temperature measuring device with the recess to measure a first laser beam distance by projecting a laser beam into the recess using the first laser and a second laser beam distance by projecting a laser beam into the recess and a second laser beam distance; and realigning the temperature measuring device with the recess by moving the pyrometer assembly so that the first laser beam and the second laser beam are projected into the recess when a decrease in the first laser beam distance or the second laser beam distance is detected.

[0018] The die includes height, and the mounting process includes mounting the first and second lasers opposite each other along the height of the die. When a decrease in the first laser beam distance is detected, the pyrometer assembly is moved in a first direction, and when a decrease in the second laser beam distance is detected, the pyrometer assembly is moved in a second direction opposite to the first direction.

[0019] Each laser is integrated with a laser measuring device, which detects a decrease in the laser beam distance and provides a signal. The method further includes mounting the pyrometer assembly to an actuator, using the actuator to receive the signal, and repositioning the pyrometer assembly by moving it using the actuator according to the received signal.

[0020] The method further includes mounting the pyrometer assembly to an actuator and performing alignment and realignment steps using the actuator. The mounting step includes mounting each laser at an equidistant distance from the point on the die closest to it.

[0021] In yet another aspect, the disclosure provides a method for forming a sintered product, which in any order includes: i) loading material to be sintered into a die cavity of a die set including a casing and opposing rams configured to compress the material; ii) positioning the die set in a vacuum chamber of a sintering apparatus, wherein the sintering apparatus includes a temperature measuring device configured to determine the temperature of the material in the die cavity during sintering, and a control system configured to move the temperature measuring device during sintering; and iii) positioning the temperature measuring device relative to a target position in the die cavity using a first laser and a second laser on the temperature measuring device to produce a pyrometer assembly; and projecting a laser beam into the die cavity using the first laser. The present invention describes a method comprising the steps of: iv) aligning a temperature measuring device with a die cavity to generate a first laser beam distance and project a second laser beam into the die cavity to generate a second laser beam distance; automatically realigning the temperature measuring device with the die cavity by moving a pyrometer assembly so that the first and second laser beams are projected into the die cavity when a decrease in the first or second laser beam distance is detected; and iv) compressing and sintering the material in the die cavity to form a sintered product, wherein during the compression and sintering, the temperature measuring device is moved using a control system to maintain relative positioning of the die cavity with respect to a target position.

[0022] In a more detailed embodiment of the method described above, the sintering apparatus further includes a repositioning device that communicates with a temperature measuring device and a control system, the temperature measuring device being moved by the repositioning device using the control system. In further detail of this method, the die set includes an outer casing, an upper ram, and a lower ram, and the step of moving the temperature measuring device includes determining the position of the upper ram, the lower ram, or both. In further detail, the temperature measuring device is moved continuously during compression sintering. In further detail, the movement of the temperature measuring device is automated, and the sintering apparatus is a discharge plasma sintering apparatus or a DC sintering apparatus.

[0023] In another aspect, the disclosure describes a control system for automated pyrometer tracking comprising: a die having a die cavity having a temperature measuring device opening having a first edge portion and a second edge portion having a target depth; a first laser having a first laser beam; a second laser having a second laser beam; a temperature measuring device for observing the temperature of the die through the temperature measuring device opening; and at least one sensor for measuring the distance of the first laser beam to the target depth and the distance of the second laser beam to the target depth, wherein the first and second lasers are mounted on either side of the temperature measuring device to form a pyrometer assembly, and the first laser beam The first laser beam is positioned near the first edge portion and the second laser beam is positioned near the second edge portion such that the first and second laser beams contact the target depth to generate the first and second laser beam distances, and at least one sensor detects the first and second laser beam distances, and if at least one sensor detects a decrease in the first or second laser beam distance, the sensor provides a signal to readjust the pyrometer assembly so that at least one sensor can detect the first and second laser beam distances to the target.

[0024] The structure, overall operation, and technical features of the present invention will become apparent from the detailed description of preferred embodiments herein and the illustrations in the relevant drawings.

[0025] Both the foregoing general description and the following detailed description are exemplary and explanatory only, and it is to be understood that they are intended to provide a further description of the present invention as claimed.

Brief Description of the Drawings

[0026] This disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that the various features of the drawings are not to scale in accordance with general practice. On the contrary, the dimensions of the various features are arbitrarily enlarged or reduced for clarity. The drawings include the following figures: [Figure 1] Showing prior art from U.S. Patent Application Publication No. 2016 / 0325353. [Figure 2] Showing prior art from U.S. Patent Application Publication No. 2016 / 0325353. [Figure 3] Showing a side view of an embodiment of the present invention. [Figure 4] Showing a perspective view of a part of the embodiment shown in FIG. 3. [Figure 5] Showing a simplified schematic view of the embodiment of FIG. 3. [Figure 6] Showing a logical flow diagram of the embodiment of FIG. 3.

Modes for Carrying Out the Invention

[0027] The present invention relates to a method and a system / apparatus for sintering a material under compression.

[0028] Generally, compression sintering processes such as hot pressing and spark plasma sintering (SPS) (also known as direct current sintering (DCS)) involve the use of pressure and high temperatures to transform the material being sintered, particularly in the form of particles or powder (fine particles), into a higher-density product. SPS is a pressure-assisted DC heating sintering process that utilizes uniaxial force and DC to compact powder material. Specifically, DC voltage and current are applied to a conductive die assembly (die set). Due to the heat generated within the die set and potentially within the powder, high heating rates are achievable, in contrast to conventional hot pressing where heat must be transferred to the die set from the outside by a radiant heating element. During SPS sintering, heat is generated within and around the material in the die, the material is rapidly heated, and particle / grain growth is limited due to the speed of the process. The entire process from powder to final sintered sample is completed faster and with higher uniformity.

[0029] In the SPS process, the current flowing between particles is thought to help remove fine impurities and gases from the particle surface and between particle surfaces, due to dielectric breakdown and localized heating of the surface oxide. In addition, the higher heating rates that can be achieved allow the fine powder to be heated to high temperatures before particle coarsening can occur, allowing the powder to retain a high surface area and contribute to a more rapidly progressing sintering process.

[0030] Force (pressure) also plays a crucial and predictable role in SPS systems, inhibiting particle growth and influencing overall density. For example, force increases diffusion throughout the sample as the material moves under pressure, particularly during the initial sintering phase. Both excessively high and low pressure can negatively impact the process. In large samples requiring high density, force is generally increased stepwise to enhance gas release at lower temperatures and sintering diffusion at higher temperatures. Therefore, precise control of force can improve the process.

[0031] In compression sintering systems, precise temperature determination is required to monitor and control the process and thereby consistently produce sintered products with desired predictable properties. As the material is compacted and compressed, the temperature profile of the entire product changes. For example, the position of the highest temperature throughout the material changes, and as a result, temperature measuring devices such as pyrometers must be repositioned during the sintering process to track and maintain monitoring of this position in order to provide accurate process control. This is typically done manually and is time-consuming to do accurately, especially in the case of sintering projections that take several hours. Therefore, in the process and apparatus of the present invention, a control system is used to evaluate the relative position of the temperature measuring device with respect to a target position in the die cavity of the die set, and the control system repositions the temperature measuring device to maintain a constant relative position.

[0032] Specific examples are shown in Figures 3 and 4. However, it will be apparent to those skilled in the art that these are merely illustrative and not limiting, and are presented only as examples. Numerous modifications and other embodiments are within the scope of those skilled in the art and are considered to fall within the scope of the present invention. In addition, those skilled in the art should understand that certain conditions and configurations are illustrative and that actual conditions and configurations depend on the specific system. Those skilled in the art will also be able to recognize and identify equivalents of the specific elements shown simply by using ordinary experiments.

[0033] In this example, a pyrometer is positioned relative to the die set to monitor the temperature at a target location in the die cavity, which is a recess in the outer wall of the die near the centerline of the die cavity. Once compression sintering begins, the position of the recess relative to the pyrometer is monitored and adjusted.

[0034] For example, a motor-driven stage can be used to reposition the pyrometer. This repositioning method can be repeated as frequently as necessary, either stepwise (semi-continuously) or continuously, throughout the compression sintering process. This automated process improves process consistency by eliminating human error that occurs during manual adjustment of the pyrometer position and maintaining the same pyrometer position throughout each process cycle. In addition, the process and system include a control system configured to move a temperature measuring device during sintering based on a real-time measurement system.

[0035] As shown in Figure 3, one embodiment of the present invention relates to a system for monitoring the temperature of position 10 on a die 12. Figure 3 shows a portion of an exaggerated side view of the die 12 to facilitate its explanation. The die 12 is placed in the chamber of an SPS machine for sintering the material (not shown) contained in the die 12. The SPS machine is a conventional type, commercially available from suppliers such as Thermal Technology LLC in Minden, Nevada, USA.

[0036] The die 12 is surrounded by chamber walls, one of which, 14, is shown in Figure 3. Chamber walls like wall 14 enclose the interior of the chamber, isolating it from the external environment. Typically, the chamber is evacuated during sintering as the material constituting the die ignites and burns in the presence of oxygen at temperatures typically reached during the sintering process.

[0037] During the sintering process, the temperature is monitored to ensure that it reaches and is maintained at the appropriate temperature for sintering the material within the die. Figure 3 shows a pyrometer 16 positioned at the aforementioned position 10 on the die 12 to monitor the temperature. The pyrometer 16 is a conventional design and is commercially available from suppliers such as Fluke Process Instruments in Everett, Washington, USA.

[0038] The pyrometer 16 is a type of remote sensing thermometer that measures temperature based on the intensity of thermal radiation received at one end 18 of the pyrometer 16. To allow the pyrometer 16 to receive thermal radiation emitted from the die 12, the chamber wall 14 includes a window 20 (see Figure 4) made of a material that is substantially transparent to thermal radiation and can withstand high temperatures, such as quartz.

[0039] Referring to Figure 4, the window 20 is elongated and has a height substantially greater than its width. The long height of the window 20 allows the position of the pyrometer 16 to be adjusted to face position 10 on the die 12. In particular, position 10 is at the bottom of a recess 22 formed on the side of the die 12. Due to being at the bottom or end of the recess 22, position 10 is closer to the material being sintered than other positions along the side of 10. Furthermore, the recess 22 tends to direct thermal radiation outward along the central axis 23 of the recess 22. Therefore, adjusting the end 18 of the pyrometer to face position 10 at the end of the recess 22 is the optimal position for the most reliable and accurate measurement of the die 12 temperature, i.e., facing approximately along the central axis of the recess towards position 10 at the end of the recess 22 within the die 12.

[0040] The system for monitoring the temperature at position 10 at the end of the recess 22 includes first and second laser measuring devices 24 mounted on a pyrometer 16. One laser measuring device 24 is mounted close to one side of the pyrometer 16, and the other laser measuring device is mounted close to the opposite side of the pyrometer. During operation, each laser measuring device 24 projects a laser beam 26 and measures the distance from the laser measuring device to the position from which the laser beam is projected. For clarity, Figure 3 shows only the upper laser measuring device 24 that projects the laser beam 26. However, during operation, each laser measuring device 24 projects a laser beam. The laser measuring devices 24 are of a conventional design and are commercially available from suppliers such as Keyence Corporation of America in Itasca, Illinois, USA.

[0041] Each laser measuring device 24 projects a laser beam 26 and measures the distance from the laser measuring device to the position from which the laser beam was projected. Figure 3 shows the laser 26 projected onto the end position 10 of the recess 22 on the side of the die 12. However, as can be understood, if the pyrometer 16 is positioned slightly upward along the chamber wall 14, the laser beam 26 will hit the outer side wall of the die 12 and will not be projected into the recess 22. The distance from each laser measuring device 24 to the outer side wall of the die 12 is defined herein as the minimum distance 28 (see Figure 5) and should be the same or close to the same value for each laser measuring device 24.

[0042] Each laser measuring device 24 outputs a signal indicating whether the measured distance is less than or equal to the minimum distance 28. Figure 5 shows a simplified geometric shape of the monitoring system 12, omitting the chamber wall 14, and schematically illustrating the minimum distance 28. In Figure 5, the pyrometer 16 is positioned higher relative to the recess 22 compared to the pyrometer position in Figure 4. Therefore, the distance measured by the upper laser measuring device is the same as (not greater than) the minimum distance 28, and thus the upper laser measuring device outputs a signal indicating that the measured distance is less than or equal to the minimum distance 28. In contrast, the lower measuring device 24 is positioned so that its laser beam is projected into the recess 22. Therefore, the lower measuring device 24 outputs a signal indicating that the measured distance is not less than or equal to the minimum distance. In other words, each laser measuring device outputs a signal indicating whether its laser beam is projected into the recess 22. If the measured distance is less than or equal to the minimum distance, the laser beam is projected onto the side of the die 12 and not into the recess 22.

[0043] In this regard, the laser measuring device is programmable to adjust the minimum distance 28 to accommodate SPS devices in which a temperature monitoring system is used. For example, if a particular SPS device has a larger and thicker chamber wall 14, the minimum distance 28 may be programmed to a larger value. In addition, the signal may be modified to output a signal indicating that the measured distance is greater than the minimum distance 28. Alternatively, the signal may output the measured distance instead of a binary signal.

[0044] Returning to Figure 3, the temperature monitoring system includes an actuator 32 connected to communicate with each laser measuring device 24 and receiving signals output from each laser measuring device. The actuator 32 supports the pyrometer 16 and moves the pyrometer in first and second opposite directions according to the signals received from the laser measuring devices until each received signal indicates that the measured distance is not less than or equal to a minimum distance. The actuator is of a conventional type, including a stepping motor with an onboard programmable motion controller and drive electronics. Such actuators include those commercially available under the trademark MDRIVE from Schneider Electric in Andover, Massachusetts, USA.

[0045] First, the pyrometer's position is manually adjusted by the operator to position it facing the recess 22. At this position, the laser beams 26 from each device 24 are projected into the recess 22 of the die 12, and the temperature monitoring system is activated. As the material in the device 12 sintersects, the die 12 moves up and down, as well as the recess 22, since the recess 22 is formed integrally with the die. When any of the laser measuring devices 24 measures a distance of a minimum distance 28 or less, the laser measuring device outputs a signal to the actuator 23. The actuator 23 moves the pyrometer 16 according to the received signal. If the received signal is from the upper laser measuring device 24, the actuator 23 moves the pyrometer downward until there is no longer a signal from the upper laser measuring device indicating a measurement distance of a minimum distance 28 or less.

[0046] Conversely, if the actuator receives a signal from the second measuring device 24 (the lower measuring device), the actuator 23 moves the pyrometer 16 upward until no signal is received. If the actuator 23 has removed signals from both laser measuring devices 24, this indicates an error condition requiring intervention by the operator to manually reposition the pyrometer 16. In the error condition, the actuator 23 does not move the pyrometer 16 in any direction.

[0047] Figure 6 shows a flowchart of the logic of the temperature monitoring system. The system starts in block 32 after the operator positions the pyrometer 16 opposite a recess 22 where no signal has been received from the laser measuring device 24 indicating that the measured distance is less than or equal to the minimum distance. The logic then proceeds to block 34, where the actuator 23 monitors for signal reception. If a signal is received, the logic determines in block 36 whether a signal indicating that the measured distance is less than the minimum distance 28 has been received from only one of the laser measuring devices 24. If the determination is affirmative, the actuator 23 moves the pyrometer according to the signal received in block 38. Specifically, if the signal is from the upper laser measuring device 24, the upper laser device 24 is too high, and the actuator 23 moves the pyrometer 16 downward. If the signal is from the lower measuring device 24, the lower laser measuring device 24 is too low, and the actuator 23 moves the pyrometer 16 upward. When the laser measuring device is attached to the pyrometer 16, the laser measuring device 24 moves together with the pyrometer 16.

[0048] If the determination in block 36 is negative, the logic flow proceeds to block 40, where actuator 23 does nothing, i.e., pyrometer 16 does not move, and then the logic returns to monitoring the signal in block 34.

[0049] For the sake of clarity, the terms "upper" and "lower" have been used in the above description to distinguish the laser measuring devices 24 from one another. However, the terms "first" and "second" or "one" and "the other" may also be used and are defined herein as synonymous with "upper" and "lower." In this regard, some sintering devices may not be vertically positioned and may have orientations other than up and down.

[0050] When the laser measuring device 24 does not output a signal indicating that the measured distance is less than or equal to the minimum distance, the end of the pyrometer is positioned opposite the position 10 in the recess 22 of the die 12, receives thermal radiation from there, and outputs a temperature signal based on the intensity of the received thermal radiation.

[0051] The above description of preferred embodiments of the present invention is presented for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the invention to the exact forms disclosed. Modifications and variations are possible in light of the above teachings, or modifications and variations can be obtained from practices of the present invention. The embodiments have been selected and described to illustrate the principles of the present invention and their practical applications, so that those skilled in the art may utilize the invention in various embodiments and with various modifications suitable for the specific use intended. The scope of the present invention is intended to be defined by the claims and equivalents appended herein.

Claims

1. A system for monitoring the temperature at a location on the die, A pyrometer having an end, configured to measure temperature based on the intensity of thermal radiation received at the end of the pyrometer, and having sides opposite to each other, A first and second laser measuring device attached to the pyrometer, wherein one of the laser measuring devices is mounted close to one side of the pyrometer, and the other laser measuring device is mounted close to the opposite side of the pyrometer, each laser measuring device projects a laser beam, measures the distance from the laser measuring device to the position from which the laser beam is projected, and each laser measuring device outputs a signal indicating whether the measured distance is less than or equal to a minimum distance, An actuator connected to communicate with each laser measuring device and receiving the signal output from each laser measuring device, the actuator supporting the pyrometer and moving the pyrometer in first and second opposite directions according to the signals received from the laser measuring device until each received signal indicates that the measured distance is not less than or equal to the minimum distance, A system in which, when each received signal indicates that the measured distance is greater than the minimum distance, the end of the pyrometer is positioned opposite the position on the die, receives thermal radiation from there, and outputs a temperature signal based on the intensity of the thermal radiation.

2. The system according to claim 1, wherein the actuator moves the pyrometer up and down, the pyrometer includes an upper and a bottom, one of the laser measuring devices is mounted close to the upper part of the pyrometer, and the other laser measuring device is mounted close to the bottom of the die, and when the actuator receives a signal from the one of the laser measuring devices, the actuator moves the pyrometer downward, and when the actuator receives a signal from the other laser measuring device, the actuator moves the pyrometer upward.

3. The system according to claim 1 or 2, wherein the actuator receives signals from both of the laser measuring devices, and the actuator does not adjust the position of the pyrometer.

4. The system according to claim 1, 2, or 3, wherein the die includes height, and the actuator moves the pyrometer parallel to the height of the die.

5. The system according to claim 1, 2, 3, or 4, wherein the laser measuring device is positioned vertically along the height of the die.

6. The system according to claim 1, 2, 3, 4, or 5, wherein each laser measuring device is mounted equidistant from the die, and in the die, the distance is measured from the point on the outer wall of the die closest to the laser measuring device.

7. The system according to claim 1, 2, 3, 4, 5, or 6, wherein the actuator is programmable.

8. A method for tracking recesses in a die using a temperature measuring device, To fabricate a pyrometer assembly, the process involves mounting a first laser and a second laser facing each other in a temperature measuring device, The process involves aligning the temperature measuring device with the recess in order to project a laser beam into the recess using the first laser to measure the first laser beam distance, and to project a second laser beam into the recess to measure the second laser beam distance. When a decrease in the first laser beam distance or the second laser beam distance is detected, the temperature measuring device is repositioned with respect to the recess by moving the pyrometer assembly so that the first laser beam and the second laser beam are projected into the recess. Methods that include...

9. The method according to claim 8, wherein the die has height, and the mounting step includes mounting the first laser and the second laser facing each other along the height of the die.

10. The method according to claim 8 or 9, wherein when a decrease in the first laser beam distance is detected, the pyrometer assembly is moved in a first direction, and when a decrease in the second laser beam distance is detected, the pyrometer assembly is moved in a second direction opposite to the first direction.

11. The method according to claim 8, 9, or 10, wherein each laser is integrated with a laser measuring device, the laser measuring device detects when there is a decrease in laser beam distance and provides a signal.

12. The method according to claim 11, further comprising the steps of attaching the pyrometer assembly to an actuator, receiving the signal using the actuator, and repositioning the pyrometer assembly by moving it using the actuator according to the received signal.

13. The method according to claim 8, 9, 10, or 11, further comprising the steps of attaching the pyrometer assembly to an actuator and performing the steps of aligning and realigning using the actuator.

14. The method according to claim 8, 9, 10, 11, 12, or 13, wherein the mounting step includes mounting each laser at an equidistant distance from the point on the die closest to each laser.

15. A method for forming a sintered product, in any order, i) A step of loading the material to be sintered into the die cavity of a die set, which includes a casing and opposing rams configured to compress the material; ii) A step of placing the die set in a vacuum chamber of a sintering apparatus which includes a temperature measuring device configured to determine the temperature of the material in the die cavity during sintering, and a control system configured to move the temperature measuring device during sintering, iii) To manufacture a pyrometer assembly, the steps include: positioning the temperature measuring device relative to a target position in the die cavity using a first laser and a second laser in the temperature measuring device; aligning the temperature measuring device with the die cavity in order to project a laser beam into the die cavity using the first laser to generate a first laser beam distance and project a second laser beam into the die cavity to generate a second laser beam distance; and automatically realigning the temperature measuring device with the die cavity by moving the pyrometer assembly so that the first laser beam and the second laser beam are projected into the die cavity when a decrease in the first laser beam distance or the second laser beam distance is detected. iv) a method comprising the step of compressing and sintering the material in the die cavity to form the sintered product, wherein during the compression and sintering, the temperature measuring device is moved using the control system to maintain the relative positioning of the die cavity with respect to the target position.

16. The method according to claim 15, wherein the sintering apparatus further includes a repositioning device that communicates with the temperature measuring device and the control system, and the temperature measuring device is moved by the repositioning device using the control system.

17. The method according to claim 15 or 16, wherein the die set includes an outer casing, an upper ram, and a lower ram, and the step of moving the temperature measuring device includes determining the position of the upper ram, the lower ram, or both.

18. The method according to claim 15, 16, or 17, wherein the temperature measuring device is continuously moved during the compression sintering.

19. The method according to claim 15, 16, 17, or 18, wherein the movement of the temperature measuring device is automated.

20. The method according to claim 15, 16, 17, 18, or 19, wherein the sintering apparatus is a discharge plasma sintering apparatus or a DC sintering apparatus.

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