TECHNICAL FIELD

The disclosed embodiments are generally directed to injection molding machines, and more particularly to systems for post-mold alignment and alignment monitoring.

BACKGROUND

Injection molding machines are used to produce plastic molded parts. Post-mold conditioners are known for use with injection molding machines to handle and condition the molded parts. The post- mold conditioner are known to include various post-mold devices that are coupled to the platens of a mold clamp of the injection molding machine. For example, a cooling plate coupled to a moving platen may be configured to cool the molded parts retained within a take-off plate that is coupled to a stationary platen whenever the platens are arranged to clamp a mold in a molding configuration. In such systems, having proper alignment between the take-off plate and the cooling plate may be important for equipment life and for part handling. Known structures used to align these parts do not provide a satisfactory solution.

SUMMARY

According to one aspect, a post-mold conditioner of an injection molding machine for conditioning molded articles is disclosed. The post-mold conditioner includes first and second post-mold devices. The first and second post-mold devices are moveable toward and away from one another, and the first post-mold device has a first side in facing relationship with a corresponding second side of the second post-mold device. The post-mold conditioner further includes two or more parallel alignment sensors located on one of the first and second sides and two or more corresponding parallel alignment sensor receivers located on the other of the first and second side, and two or more angular alignment sensors located on one of the first and second sides and two or more corresponding angular alignment sensor receivers located on the other of the first and second side.

According to another aspect, a post-mold conditioner of an injection molding machine for conditioning molded articles is disclosed. The post-mold conditioner includes first and second post- mold device. The first post-mold device has a first side in facing relationship with a corresponding second side of the second post-mold device. The post-mold conditioner further includes first and second parallel alignment sensors located on the first side and first and second corresponding parallel alignment sensor receivers located on the second side, and first and second angular alignment sensors located on the first side and first and second corresponding angular alignment sensor receivers located the second side. The first and second parallel alignment sensors are located at first and second corners of the first side, respectively, and the first and second angular alignment sensors are located at third and fourth corners of the first side, respectively. The first corner is one of the top right corner and top left corner and the third corner is the other of the top right corner and top left corner. When the first corner is the top right corner, the second corner is the bottom left corner and the fourth corner is the bottom right corner. When the first corner is the top left corner, the second corner is the bottom right corner and the fourth corner is the bottom left corner.

According to still another aspect, a method of monitoring the alignment of a post-mold conditioner having first and second post-mold devices is disclosed. The method includes evaluating a parallel alignment of the first and second post-mold devices via first and second parallel alignment sensors and corresponding first and second parallel alignment sensor receiver, evaluating an angular alignment of the first and second post-mold devices via first and second angular alignment sensors and corresponding first and second angular alignment sensor receivers, and alerting an operator when the first and second post-mold devices are not parallel or when the first and second-post mold devices are angularly misaligned.

It should be appreciated that the foregoing aspects, and additional aspects discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect.

The foregoing and other aspects, embodiments, and features of the present teachings can be more fully understood from the following description in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

FIG. 1A is a side view of aligned post-mold devices according to one aspect; FIG. IB is a bottom view of the post-mold devices of FIG. 1 A;

FIG. 1C is a front view of the post-mold devices of FIG. 1A;

FIG. ID is an enlarged view of an aligned receptacle and cooling pin of FIG. 1C.

FIG. 2A is a top view of an injection molding machine according to the prior art; FIG. 2B is a top view of a conditioning device of the injection molding machine of FIG. 2A;

FIG. 3A is a side view of an alignment device according to the prior art, in an partially engaged position;

FIG. 3B is a side view of the alignment device of FIG. 3A, in a fully engaged position;

FIG. 4A is a side view of a post-mold alignment system according to one aspect, in a closed position;

FIG. 4B is a side view of the post mold-alignment system of FIG. 4A, in an open position;

FIGS. 5A-5C are front, side and bottom views, respectively, of post-mold devices with vertical misalignment;

FIGS. 6A-6C are front, side and bottom views, respectively, of post-mold devices with horizontal misalignment; FIGS. 7A-7C are front, side and bottom views of post-mold devices with angular misalignment; FIG. 8 is a rear view of a conditioning device of a post-mold cooling plate; and FIG. 9 is a perspective view of the post- mold devices of FIG. 1 C.

DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENTS

Injection molding machines are used to produce plastic molded parts, and typically, such machines include platens onto which a mold, also referred to as a tool, is fastened. In some known injection molding machines, a conditioning device such as a cooling device is attached to a moveable platen to condition (e.g., cool) the molded parts. As will be appreciated, maintaining proper alignment between the conditioning device and a take-off plate attached to a stationary platen may be important for equipment life and for part handling. Typically, alignment is accomplished via a physical device, such as a pin or plug, that is attachable between the cooling device and the take-off plate during an alignment protocol but that is otherwise removable. Applicant has realized that by providing no-contact, real-time alignment and alignment monitoring between post-mold devices (e.g., the cooling plate and the take-off plate), various advantages may be realized. Applicant has further realized that advantages may be realized by monitoring the alignment of these post-mold devices while the machine is in use, such that any discovered misalignments may be corrected. As such, embodiments disclosed herein include a no-contact alignment and alignment monitoring system with a post-mold conditioner having a plurality of parallel alignment sensors and receivers on corresponding sides of first and second post-mold devices, respectively. The conditioner further includes a plurality of angular alignment sensors and corresponding receivers located on the corresponding sides. Feedback from the sensors is sent to a controller, which may monitor alignment of the devices while in-use and provide alarms to an operator when there are misalignments. As will be described, the controller evaluates parallel alignment and angular alignment of the post-mold devices.

For purposes herein, alignment of the post-mold conditioner may include vertical-parallel alignment, horizontal-parallel alignment and angular alignment. As shown in FIGS. 1A and 9, for example, vertical-parallel alignment may mean the vertical axes A3a, A3b of the post-mold devices 102, 104 are parallel to one another. Horizontal-parallel alignment is illustrated in FIGS. IB and 9, in which the longitudinal axes Ala, Alb of the post-mold devices 102, 104 are parallel to one another. FIGS. 1C and 9 illustrate angular alignment, in which the sensors are in an overlapping relationship with the corresponding receivers. As shown in FIG. 9, in angular alignment, a surface plane defined by axes Ala and A3a of the plenum/cooling plate may be parallel to a surface plane defined by axes Alb and A3b of the take-off plate. As also shown in FIG. 9, in angular alignment, the rotational axes A4a, A4b of the cooling plate and the take-off plate may be parallel to one another. In some embodiments, the axes Alb, A2b, A3b, A4b of the take-off plate 437 remain constant while the axes Ala, A2a, A3a, A4a of the cooling plate 443 may change with respect thereto. That is, the take-off plate, in some embodiments, may be relatively fixed whereas the cooling plate may be more susceptible to misalignment during use.

As will be appreciated, the conditioner may have multiple points of alignment, or misalignment, as the case may be. For example, the conditioner may have both vertical-parallel alignment and angular alignment, but have horizontal-parallel misalignment. The conditioner also may be completely aligned, having vertical-parallel alignment, horizontal-parallel alignment and angular alignment or may be completely misaligned, having vertical-parallel misalignment, horizontal-parallel misalignment and angular misalignment. According to one aspect, providing no-contact alignment reduces the likelihood of human errors, and any resulting equipment damage and/or mechanical failure. For example, a no-contact system eliminates the chance that an operator will forget to install and/or remove alignment plugs before and after each alignment procedure is performed, respectively. Accordingly, if the system does not use traditional alignment plugs, there is no chance that a collision between the alignment plugs and the take-off plate will occur. A no-contact alignment system will also reduce the chance that an operator will improperly install the plenum/plate and take-off plate (e.g., not aligning them or not fastening to the specific torque). According to another aspect, real-time alignment monitoring may allow for earlier detection of an improper installation and/or mechanical failure from the improper installation. Without wishing to be bound by theory, even a small angular misalignment may be exacerbated and may cause an interference between parts (e.g., between the receptacle and the cooling pin). For example, as shown in FIG. 8, a rear view of a plenum 810 attached to a moving platen 841 , a one-degree rotation is sufficient to cause a cooling pin 844 located about 600 mm away from a mounting joint 860 to move, such as relative to the line labeled M, and cause interference between the pin 844 and the preform 852. In some embodiments, the rotation may cause the blow pin 844 to move about 10 mm. In extreme cases, when using the prior art alignment pins with installed plugs, the alignment pins might crash into the opposing plate causing the plate to crack. Without wishing to be bound by theory, equipment damage (e.g., tooling collisions, servo drive overloading, and motor over-temperature) may be prevented and machine downtime and/or cycle interruption may be minimized or even prevented by earlier detection when using the alignment and alignment monitoring system described herein. FIGS. 2A and 2B illustrate a prior art injection molding machine 200 having a treatment device 239 (e.g., a cooling device) attached to a moving platen 241 , and a take-off plate 237 attached to a fixed platen 232. As shown in FIG. 2B, the treatment device 239 is mounted on a hollow cylinder 240 on a side of the moveable platen 241 such that a cylinder/actuator 242 causes the treatment device 239 to rotate about a horizontal axis through 90 degrees. The cylinder is pivotably mounted on an extension arm 250 that is fastened to the moveable platen 241. The cylinder 240 is hollow to allow air to flow to the cooling pins.

The treatment device 239 has a plurality of cooling/transfer pins 244 (attached via a plenum and plate, such as cooling plate 243), and the take-off plate 237 has a plurality of preform carriers 238. In use, when the moveable platen 241 is moved to the open a mold, the take-off plate 237 moves linearly along arrow S in between the mold halves to extract the freshly molded preforms from the mold cores and onto a set of preform carriers 238. The take-off plate 237 is then moved linearly to a position outboard of the mold halves. When the moveable platen 241 moves in a direction towards the fixed platen to close the mold and mold a new set of preforms, the treatment device 239 (i.e., the cooling plate) moves simultaneously to engage the take-off plate carriers 238 via the cooling/transfer pins 244. In this engaged positon, a cooling fluid (such as air) may be discharged from the cooling pins 244 into the interior of the preform. As will be appreciated, all of the pins 244 need not discharge cooling fluid into the preform. In some embodiments, one or more of the pins (e.g., every third or fourth pin in the set) may be an extracting pin. For example, when the moving platen 241 moves to open the mold, the preforms from the carriers 238 may be extracted by a vacuum means onto the cooling/transfer pins 244. By the time the moving platen 241 has reached its fully open position, the treatment device 239 has rotated about a horizontal axis to drop the molded and cooled parts onto a conveyor (not shown).

As shown in FIG. 3A, in some known systems, alignment of the take-off plate and cooling plate is accomplished via alignment plugs 302 that engage with corresponding openings 304 on the take-off plate 337. In such embodiments, the alignment plugs 302 are first installed on one or more alignment pins 306 of a cooling plate (e.g., plate 343). When the take-off plate and cooling plate are moved towards one another, the alignment plugs 302 may be engaged with the openings 304 to align the cooling plate in a desired position with respect to the take-off plate. Once the plates have been aligned, they may be moved away from one another so that the plugs 302 may be removed from the pins 306. As previously noted, human error in installing/removing the plugs may occur, which may have a detrimental effect on the post-mold conditioner and on the molded parts.

FIGS. 4A and 4B illustrate a post-mold conditioner 400 according to one aspect. As is shown, the post-mold conditioner 400 has a plenum 410 and plate 443 (e.g., a cooling plate), which are attached to a moveable platen (not shown), and a take-off plate 437 that is attached to the stationary platen (not shown). As will be appreciated, the plenum 410 may include a blow motor to blow cooling fluid (e.g., air) to the cooling pins 444 and into the interior of the preforms carried by the carriers 438. Also attached to the cooling plate 443 are alignment pins 406.

As shown in FIG. 4A, in one embodiment, a parallel alignment sensor 412a, 412b is attached to a distal end of the alignment pin 406. A corresponding receiver 414a, 414b is located on the take-off plate 437 and in facing relationship to the parallel alignment sensor 412a, 412b, respectively. As will be appreciated, although the parallel alignment sensor 412a, 412b is located on the alignment pin 406 and the corresponding receiver 414a, 414b is located on the take-off plate, in other embodiments, this orientation may be reversed. That is, the sensor may be positioned on the take-off plate with the corresponding receiver on the alignment pin. As will be further appreciated, in some embodiments, the parallel alignment sensor or receiver may be attached directly to the cooling plate. In such embodiments, the alignment pin may not be used. The conditioner 400 may have two parallel alignment sensors 412a, 412b, one on each of the two shown alignment pins 406. As will be appreciated, in other embodiments, the conditioner may have more than two sensors.

As shown in FIG. 9, a perspective view of the conditioner of FIG. 1C, the sensors 412a, 412b and corresponding receivers 414a, 414b are positioned diagonally across from one another and on opposite corners of the cooling plate 443. For example, a first parallel alignment sensor 412a is located on the alignment pin 406 at a top, left corner 486a of an interior side 482 of the cooling plate 443, and the second parallel alignment sensor 412b is located on the alignment pin 406 at a bottom right corner 486b of the interior side 482 of the cooling plate 443. The corresponding first parallel alignment sensor receiver 414a is located on a corresponding top, right corner 488a of an interior side 487 of the take-off plate 437 and the corresponding second parallel alignment sensor receiver 414b is located on a corresponding bottom left corner 488b of the interior side 487 of the take-off plate 437. FIG. 1C shows a front view of the conditioning device of FIG. 9, with the diagonally placed sensors on the cooling plate shown superimposed over the diagonally placed corresponding receivers on the take-off plate. As will be appreciated, the parallel alignment sensors also may be located on the top right corner and bottom left corners of the cooling plate 443 in other embodiments.

According to one aspect, by having sensors positioned diagonally across from one another and on opposite corners of the cooling plate, the alignment of the cooling plate and take-off place can be properly measured and the cooling plate and the take-off plate also can be properly aligned. That is, by having one sensor located on the top corner of the cooling plate and a second sensor located on the bottom corner of the cooling plate, the alignment measuring system can determine when the bottom of the cooling plate is closer to the take-off plate than the top of the plate, for example. In a similar fashion, by having one sensor located on the left corner of the cooling plates and a second sensor located on the right corner of the cooling plate, the alignment measuring system can determine when one of the sides of the cooling plate is closer to the take-off plate than the other side.

In some embodiments, the parallel alignment sensors are position sensors, such as distance- measuring sensors. The position sensors may be lasers, inductive distance measurement sensors, or other suitable sensors. In such embodiments, the sensor and corresponding receiver measure the distance between one another, noted as Dl and D2 in FIGS. 4A and 9. Without wishing to be bound by theory, the distances Dl and D2 correspond to specific gaps between the alignment pins 406 and the tooling plate 437 when the mold is in a fully closed position (e.g., a distance from the alignment pins 406 to the interior side 487 of the take-off plate 437). The gaps Dl and D2 may be monitored in real-time, with the no-contact alignment being performed so that the distances between each sensor and corresponding receiver is equal (D1=D2) or within a tolerance range. Without wishing to be bound by theory, if the distance between each of the sensors and corresponding receivers is the same (e.g., D1=D2) or within the tolerance range, the axis labeled A2a (e.g., the axis through the parallel alignment sensors 412a, 412b) is parallel to the take-off plate. In embodiments in which the cooling plate and take-off plate are misaligned, the distances between the sensors and corresponding receivers will differ (e.g., Dl ≠ D2) or be outside of the tolerance range. In such embodiments, the axis labeled A2a will not be parallel to the interior side of the takeoff plate. Thus, according to one aspect, alignment of the cooling plate and take-off plate is monitored by measuring and comparing the first and second distances.

FIGS. 5B and 6C illustrate embodiments in which there is parallel misalignment. In these embodiments, the distances between the post mold devices and, thus, the distance between the parallel alignment sensors and corresponding receivers, differ or are outside of a tolerance range. In FIG. 5B, which is a right-side end view of the post-mold device of FIG. 5A, an example of vertical-parallel misalignment is shown where tops 546, 548 of the plates 543, 537 are further away from one another than the bottoms 562, 564 of the plates. In this example, the distance Dl between the first sensor and corresponding receiver 512a, 514a is greater than the distance D2 between the second sensor and corresponding receiver (not shown, because they are located behind the shown angular alignment sensor 518b and receiver 520b). As will be appreciated, vertical -parallel misalignment also may occur if the second distance is greater than the first distance (e.g., when the bottoms of the plates are further away from one another than the tops of the plates). In these examples, because the cooling plate rotates with respect to the longitudinal axis Ala, such misalignments may be corrected by rotating the plate 543, which may be performed automatically or manually.

In FIG. 6C, which is a bottom end view of FIG. 6A, an example of horizontal parallel misalignment is shown. As illustrated in this figure, the left sides 670, 672 of the plates 643, 637 are closer together than the right sides 674, 676, and the distance D2 between the second parallel alignment sensor 612b and corresponding receiver 614b is smaller than the distance Dl between the first parallel alignment sensor and corresponding receiver (not shown, because they are located behind the angular alignment sensor 618b and receiver 620b). In embodiments in which the cooling plate rotates with respect to axis Ala, horizontal-parallel misalignments may be corrected by manual adjustment such as manual mechanical adjustment. Referring again to FIG. 4B, the conditioner also includes angular alignment sensors 418a, 418b. In some embodiments, the angular alignment sensors are photoelectric or laser sensors, although other suitable sensors also may be used. Similar to the parallel alignment sensors, while the angular alignment sensors 418a, 418b are shown on the alignment pins 406, with corresponding receivers 420a, 420b located on the take-off plate 437, this orientation may be reversed in other embodiments. Also, while two angular alignment sensors 418a, 418b are shown in this embodiment, the conditioner 400 may have more than two sensors 418a, 418b in other embodiments.

As illustrated in FIG. 9, the angular alignment sensors 418a, 418b are located diagonally across from one another and on opposite corners of the cooling plate 443. As with the parallel alignment sensors, the diagonally placed angular alignment sensors may allow the angular alignment (e.g., the relative position) of the cooling plate and take-off plate to be measured and properly aligned. As will be appreciated, the corresponding sensors may be located on opposite corners and diagonally across from one another on the take-off plate 437. In some embodiments, a first angular alignment sensor 418a is located on the alignment pin 406 at a top, right corner 480a of the interior side 482 of the cooling plate 443, and the second angular alignment sensor 418b is located on the alignment pin 406 at a bottom left corner 480b of the interior side 482 of the cooling plate 443. The corresponding first angular alignment sensor receiver 420a is located on a corresponding top, left corner 484a of an interior side 487 of the take-off plate 437 and the corresponding second angular alignment sensor receiver 420b is located on a corresponding bottom right corner 484b of the interior side 487 of the take-off plate 437. As will be appreciated, in other embodiments, the first angular alignment sensor may be located on the alignment pin at the top left corner of the interior side of the cooling plate, with the second angular alignment sensor being located on the bottom right corner of the interior side. Although both the angular alignment sensors and the parallel alignment sensors are located on the cooling plate in FIG. 1C (with corresponding receivers on the take-off plate), all the alignment sensors need not be located on the same post-mold device. For example, the cooling plate may include both parallel alignment sensors while the take-off plate includes both angular alignment sensors. The cooling plate also may include one parallel alignment sensor and one angular alignment sensor, with the other parallel alignment sensor and angular alignment sensor located on the take-off plate. FIG. 7A shows an example of angular misalignment. The angular alignment sensors 718a, 718b monitor the position of the cooling plate 743 with respect to the position of the take-off plate 737. That is, an angular misalignment is identified when the angular alignment sensor 718a, 718b is not in an overlapping relationship with the corresponding receiver 720a, 720b. In some embodiments, when the angular alignment sensors and corresponding receivers are offset from one another, the receiver is unable to receive a signal from the sensor. In examples having angular misalignment, though the plane of the cooling plate (e.g., the plane defined by axis Ala and A3 a) may be parallel to the plane of the take-off plate (e.g., the plane defined by axis Alb and A3b), the axes through the sensors A2a, A2b are offset from one another. In situations with angular misalignment, manual or automatic adjustment can be used to properly align the plates.

As shown in FIG. ID, when the plates have proper angular alignment, the axes of the pins 144 and preform carrier 238 are coaxial within a tolerance range. Accordingly, the pin 144 can engage with the preform 152 without damaging the preform or another tool component. As shown in FIG. 7 A, when the cooling plate and take-off plate are angularly misalignment, at least some, if not all, of the cooling pins 144 can interfere with the preform and/or carriers 238.

According to another aspect, a method of monitoring the alignment of a post-mold conditioner is disclosed. In some embodiments, the method involves measuring the gaps between the cooling plate and the take-off plate that is the distances Dl, D2 between the first and second parallel alignment sensors and their corresponding receiver, when the mold is closed. In some embodiments, this monitoring may be done in real time. If the gaps are not within a specified tolerance or threshold, (e.g., the gaps are different sizes and the difference between the gaps is larger than the threshold) and the plates have parallel misalignment, an alarm is reported and/or the machine cycle is interrupted. The method further involves verifying the angular alignment between the plates with the angular alignment sensors when the mold is opened. If the plates are angularly misaligned, an alarm is reported and/or the machine cycle is also interrupted. In some embodiments, data from the parallel alignment sensors and angular alignment sensors is first sent to a controller, which triggers the alarm when a misalignment is identified and/or which interrupts the machine cycle.

As shown in FIG. 9, in some embodiment, the post-mold conditioner is operatively coupled to a controller 990. The controller 990 may receive feedback from the parallel alignment sensors 412a, 412b regarding the distance between the cooling plate 443 and the take-off plate 437. The controller 990 also may receive feedback from the angular alignment sensors 418a, 418b regarding the angular alignment of the cooling plate 443 and the take-off plate 437 (e.g., the relative position between the cooling plate 443 and the take-off plate 437). The controller 990 processes the information received from the sensors and alerts the user when a misalignment and/or machine failure is identified. The alarm may be a visual alarm (e.g., a light or a notification on a control panel), an audible alarm, another suitable alarm or any combination thereof. The controller 990 also may stop a mold cycle upon identification of the misalignment and/or machine failure.

Although embodiments have been shown and described has using the alignment system on the takeoff plate and cooling plate, it will be appreciated that such a system may be used in other parts of the injection molding machine. For example, parallel alignment sensors and angular alignment sensors may also be used on corresponding faces of the mold halves to monitor alignment.

While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. Accordingly, the foregoing description and drawings are by way of example only.