JP7108523B2 - Press molding device, press molding method and press molding program - Google Patents

Description

The present invention relates to a press molding apparatus, a press molding method and a press molding program.

Patent Literature 1 discloses an optical element molding apparatus and a molding method for pressing and molding an optical element material by moving a press shaft. In Patent Document 1, the acceleration of the press shaft during pressure molding is monitored, and the press pressure is changed when the press shaft reaches a predetermined acceleration.

JP 2008-115022 A

However, in the optical element molding apparatus and molding method disclosed in Patent Document 1, the optical element molding accuracy may be insufficient. For example, there is a risk that radiation scratches, uneven interference fringes, lens foaming, and surface imperfections (cracks and chips) may occur in optical elements.

The present invention was completed based on the awareness of the above problems, and an object of the present invention is to provide a press forming apparatus, a press forming method, and a press forming program capable of obtaining high-quality and stable-quality press-formed products. do.

The press molding apparatus of this embodiment includes a pair of molding dies for pressing a preform to obtain a lens , and a schedule from an initial position where the pair of molding dies are spaced apart to a press-cut position where the pair of molding dies are close to each other. a control unit that controls press molding parameters by the pair of molds based on the movement time and the planned movement position, and the control unit controls, at a plurality of points from the initial position to the press cutting position, The press molding parameters are varied so that the current movement time and the current movement position follow the planned movement time and the planned movement position, and the plurality of points are set at the start of pressing the preform with the pair of molds. Alternatively, it includes a first point that is the press start position and a second point that is the time or position at which the pair of molds reach the press-cutting position, and the plurality of points include the first point from the initial position to the first point. The area up to the point contains relatively few temporal/positional points, and the area from the first point to the second point contains relatively many temporal/positional points. It is characterized by

The press forming parameters may include at least one of press load, press speed and press acceleration.

The press molding method of the present embodiment is a press molding method for obtaining a lens by pressing a preform with a pair of molding dies. A step of controlling the press molding parameters by the pair of molds based on the scheduled movement time and the scheduled movement position until reaching the position, and in the controlling step, the time from the initial position to the press cutting position At a plurality of points, the press molding parameters are varied so that the current movement time and the current movement position follow the planned movement time and the planned movement position, and the plurality of points are the preform by the pair of molds. and a second point that is the time or position at which the pair of molds reach the press cutting position, and the plurality of points include the initial position to the first point contains relatively few temporal and positional points, and the area from the first point to the second point contains relatively many temporal and positional points is characterized by containing

The press-molding program of the present embodiment is a press-molding program for obtaining a lens by pressing a preform with a pair of molds. Based on the planned movement time and the planned movement position until reaching the position, the computer executes the step of controlling the press molding parameters by the pair of molds, and in the controlling step, the press cutting position is reached from the initial position. The press-forming parameters are varied so that the current movement time and the current movement position follow the planned movement time and the planned movement position at the plurality of points up to, and the plurality of points are obtained by the pair of molds. It includes a first point that is the press start time or press start position of the preform, and a second point that is the time or position at which the pair of molds reach the press cut position, and the plurality of points include the The area from the initial position to the first point includes relatively few temporal/positional points, and the area from the first point to the second point includes relatively many temporal/positional points. It is characterized in that it contains important points .

ADVANTAGE OF THE INVENTION According to this invention, the press molding apparatus, the press molding method, and the press molding program which can obtain a press-molded article of high quality and stable quality can be provided.

It is a figure which shows an example of a structure of the press molding apparatus by this embodiment. FIG. 10 is a diagram showing an example of a lens with good quality and a lens with degraded quality; FIG. 10 is a diagram showing an example of optimal trajectory data including planned travel time and planned travel position; It is a functional block diagram showing an example of composition of a press forming device by this embodiment. FIG. 4 is a first diagram showing an example of variation control of press-forming parameters by a control unit; FIG. 5 is a second diagram showing an example of variation control of press-forming parameters by the control unit; It is a figure which shows an example of the relationship between the movement time of four samples using the press molding apparatus by this embodiment, and a movement position. It is a figure which shows an example of the relationship of the movement time of five samples using the press molding apparatus by a comparative example, and a movement position.

A press molding apparatus, a press molding method, and a press molding program according to the present embodiment will be described in detail with reference to FIGS. 1 to 8. FIG.

As shown in FIGS. 1A and 1B, a press molding apparatus 1 according to the present embodiment has an upper mold 10 and a lower mold 20 that form a pair of molds, and presses are placed above and below the upper mold 10 and the lower mold 20, respectively. It has an upper part 11 and a press lower part 21 . The press upper portion 11 has an upper base portion 12 and a press head 13 formed below the upper base portion 12 . The press lower part 21 has a lower base part 22 and a pedestal 23 provided above the lower base part 22 , and the upper die 10 and the lower die 20 are placed on the pedestal 23 . A body mold 15 surrounding the upper mold 10 and the lower mold 20 is provided on the side of the upper mold 10 and the lower mold 20 .

The press molding device 1 has a servo motor unit 30 . The servo motor unit 30 lifts the press lower part 21 toward the press upper part 11 to press the preform (press material) placed on the molding surface of the lower die 20 with the upper die 10 to form a lens (press material). molding). FIG. 1A depicts a preform (press material) P before being pressed by an upper die 10 and a lower die 20, and FIG. 1B depicts a lens (press-molded product) L after being pressed by an upper die 10 and a lower die 20. drawing.

In the above example, the press lower part 21 is raised to bring the upper die 10 and the lower die 20 closer, but the press upper part 11 may be lowered to bring the upper die 10 and the lower die 20 closer. . Furthermore, in order to bring the upper mold 10 and the lower mold 20 closer together, the press upper part 11 may be lowered and the press lower part 21 may be raised.

FIG. 1A corresponds to the "initial position" in which the upper mold 10 and the lower mold 20 (a pair of molds) are separated, and FIG. It corresponds to "position". The initial position and the press-cut position are defined by, for example, a mechanical stopper mechanism. The "push-off position" of this embodiment is defined by the lower end of the press head 13 coming into contact with the upper end of the barrel mold 15 . The mechanical stopper mechanism for defining the "push-off position" is not limited to this, and various design changes are possible.

As a result of intensive research, the inventors of the present invention have found that from the initial position where the upper mold 10 and the lower mold 20 (a pair of molds) are spaced apart, to the press cutting position where the upper mold 10 and the lower mold 20 (a pair of molds) are close to each other. If the movement time and movement position vary, the molding accuracy of the lens (press-molded product) L may deteriorate (radiation scratches, uneven interference fringes, lens foaming, surface imperfections (cracks and chips) may occur). I found something.

That is, when the movement time and movement position at the initial positions of the upper mold 10 and the lower mold 20 (a pair of molding dies) are set to zero, the time required for the upper mold 10 and the lower mold 20 (a pair of molding dies) to reach the press-off position is If the movement time to reach an arbitrary position is too fast or too slow, it will adversely affect the lens molding, and the upper mold 10 and the lower mold 20 (a pair of molds) will not reach the press-cut position at any time. It has been found that the lens molding is adversely affected if the moving position is too forward or too backward.

Variations in the movement time and movement position from the initial position to the press-off position are caused by, for example, the size, shape, posture, and hardness of the preform (press material) P, as well as external environmental factors such as temperature and humidity.

FIG. 2A shows an example of a lens L with good quality because the movement time and the movement position from the initial position to the fully press-cut position are within appropriate ranges. FIG. 2B shows an example of the lens L whose quality has deteriorated because the movement time and movement position from the initial position to the fully pressurized position are not in the proper ranges. The lens in FIG. 2A has uniform interference fringes throughout, but the lens in FIG. 2B has conspicuous radiation scratches and non-uniform interference fringes.

The present inventors performed experiments and simulations in advance to obtain lenses L by pressing a preform P with an upper mold 10 and a lower mold 20 (a pair of molding dies), and performed experiments and simulations in advance. The movement time and movement position of the mold) from the initial position to the press-cut position are monitored, and a graph of the movement time and movement position when the molding accuracy of the lens L is excellent is acquired as "optimal trajectory data". I came up with the idea to

This optimum trajectory data is such that, for example, the pair of molds must be at the position △ after ○ seconds from the start of press molding (start of mold movement), or conversely, the start of press molding (start of mold movement) , the pair of molds must reach the position of .DELTA. after .times. seconds. Hereinafter, the relationship between the travel time and the travel position indicated by the optimal trajectory data may be referred to as "planned travel time" and "planned travel position."

FIG. 3 shows an example of optimal trajectory data including planned travel time and planned travel position. The optimum trajectory data in FIG. 3 defines that the movement position (planned movement position) after the start of press molding is 10 mm when the movement time (planned movement time) after the start of press molding is 1 sec. It is defined that the movement position (planned movement position) after the start of press molding is 20 mm when the movement time (planned movement time) after the start of molding is 2 seconds. A similar definition is repeated to specify that the movement position (planned movement position) after the start of press molding is 110 mm when the movement time (planned movement time) after the start of press molding is 11 sec. Of course, what is shown in FIG. 3 is an example, and the optimum trajectory data when the movement time (scheduled movement time) after the start of press molding is 11 seconds or later and the movement position (scheduled movement position) after the start of press molding is 110 mm or later. may be included.

FIG. 4 is a functional block diagram showing constituent elements of the press forming apparatus 1. As shown in FIG. As shown in FIG. 4 , the press forming apparatus 1 has an optimum trajectory data holding section 40 and a control section 50 . The press-molding method and press-molding program according to the present embodiment are implemented by causing a computer (CPU) constituting the control unit 50 to execute various processing steps.

The optimum trajectory data holding unit 40 holds (stores) the optimum trajectory data (scheduled travel time and planned travel position) as described with reference to FIG.

Based on the optimum locus data (scheduled movement time and planned movement position) held (stored) by the optimum locus data holding unit 40, the control unit 50 sets press molding parameters for the upper mold 10 and the lower mold 20 (a pair of molds). to control. The control unit 50 controls at least one of press load (press pressure), press speed, and press acceleration as press forming parameters. In the present embodiment, since the press lower part 21 rises toward the press upper part 11 during press forming, the control unit 50 mainly controls the press forming parameters by the press lower part 21 (specifically, the position of the pedestal 23). .

The control unit 50 is connected to the servo motor unit 30 , the timer 60 , and the encoder 70 in addition to the optimum trajectory data holding unit 40 . The timer 60 measures the current movement time (measured movement time) of the upper mold 10 and the lower mold 20 (a pair of molds) after the start of press molding (after the start of movement of the mold). The encoder 70 detects, for example, the rotation angle (rotational position) and rotation speed (movement speed) of the servomotor of the servomotor unit 30, thereby determining the upper mold 10 and lower mold 20 (a pair of molding dies) after the start of press molding. ) is measured. The control unit 50 can refer to the current movement time (measured movement time) measured by the timer 60 and the current movement position (measured movement position) detected by the encoder 70 .

In this embodiment, since the press lower part 21 rises toward the press upper part 11 during press molding, the current movement time (actually measured movement time) and the current movement position (measured Movement position), and the planned movement time and the planned movement position indicated by the optimum trajectory data are intended for the movement time and movement position of the pedestal 23 of the press lower part 21 .

The control unit 50 is used based on the concept of multiple points (including both time and position) from the initial position (Fig. 1A) to the press-cutting position (Fig. 1B) of the upper mold 10 and the lower mold 20 (a pair of molding dies). ) so that the current travel time measured by the timer 60 and the current travel position detected by the encoder 70 follow the planned travel time and planned travel position of the optimum trajectory data held by the optimum trajectory data holding unit 40. 10 and the lower mold 20 (a pair of molds) are varied in press molding parameters.

5 and 6 are first and second diagrams showing an example of variation control of press-forming parameters by the control unit 50. FIG. In FIGS. 5 and 6, 11 points where the elapsed time after the start of press molding (after the start of mold movement) is 1 sec, 2 sec, .

As shown in FIGS. 5 and 6, the current movement position matches (follows) the planned movement position until the elapsed time from the start of press forming reaches 1 sec to 4 sec. However, at the point where the elapsed time after the start of press forming reaches 5 sec, the current movement position is 55 mm and the planned movement position is 50 mm, and the current movement position exceeds the planned movement position. . At this stage, the control unit 50 controls the press molding parameters of the upper mold 10 and the lower mold 20 (a pair of molds), for example, by lowering the rotation speed (moving speed) of the servomotor of the servomotor unit 30. (For example, the rising speed of the pedestal 23 is reduced). As a result, at the point where the elapsed time after the start of press forming reaches 6 sec, both the current movement position and the planned movement position coincide at 60 mm.

After that, the current movement position matches (follows) the planned movement position until the elapsed time reaches 6 sec to 9 sec after the start of press forming. However, at the point where the elapsed time after the start of press forming reaches 10 sec, the current movement position is 95 mm and the planned movement position is 100 mm, and the current movement position is short to the planned movement position. . At this stage, the control unit 50 controls press molding parameters by the upper mold 10 and the lower mold 20 (a pair of molds), for example, by increasing the rotation speed (moving speed) of the servomotor of the servomotor unit 30. (For example, the rising speed of the pedestal 23 is increased). As a result, at the point where the elapsed time after the start of press forming reaches 11 sec, both the current movement position and the planned movement position match at 110 mm.

The control of the press-forming parameters of the upper mold 10 and the lower mold 20 (a pair of molds) by the control unit 50, that is, the position control of the lower mold 20 is performed, for example, as follows. The rotation angle (rotation position) and rotation speed (moving speed) of the servomotor of the servomotor unit 30 are determined by the position command, and the control unit 50 operates according to the position command. For example, the difference between the position command signal and the detection result of the encoder 70 is calculated at predetermined time intervals, and feedback control based on the difference is executed (amplifies or attenuates the output signal to the servomotor). An electric brake (servo clamp) is applied to hold the current position of the pedestal 23 while the servomotor is stopped.

Further, instead of/in addition to the above-described position control, the control section 50 may perform torque control for controlling the generated torque by controlling the current flowing through the servo motors of the servo motor unit 30 . For example, a processing loop for calculating the difference between the torque command signal and the power-amplified signal of the torque command signal may be executed at predetermined time intervals, and the output of the processing loop may be fed back from the encoder 70 to a controller (not shown). good.

Further, instead of/in addition to the above-described position control and torque control, the control unit 50 may execute speed control that changes the speed steplessly according to the speed command voltage. For example, a processing loop for calculating the difference between the speed command signal and the power-amplified signal of the speed command signal may be executed at predetermined time intervals, and the output of the processing loop may be fed back from the encoder 70 to the controller (not shown). good.

In this way, the control unit 50 causes the current travel time measured by the timer 60 and the current travel position detected by the encoder 70 to follow the planned travel time and planned travel position of the optimum trajectory data held by the optimum trajectory data holding unit 40. The press molding parameters by the upper mold 10 and the lower mold 20 (a pair of molds) are varied so as to do so. This makes it possible to obtain a lens (press-molded product) L of high quality and stable quality.

By the way, according to the intensive research of the present inventors, the divergence between the current travel time and the planned travel time, and the divergence between the current travel position and the planned travel position are, in particular, the following two points in time and position, and their It was found to occur easily in the vicinity.
(1) When the preform (press material) P is started to be pressed by the upper mold 10 and the lower mold 20 (a pair of molds) or at the start position of the press (when the lower surface of the press head 13 contacts the upper surface of the upper mold 10 or the position ) is the first point (first inflection point). This is because the press lower part 21 (pedestal 23) can be raised without any obstacle before the preform P is pressed, so relatively high-precision control is possible. This is because, in addition to the size, shape, posture, and hardness of P, it slightly changes (and cannot help but change) depending on external environmental factors such as temperature and humidity. The deviation between the current travel time and the planned travel time at or near the first point (first inflection point), and the deviation between the current travel position and the planned travel position, lead to variations in the push-off time and, in turn, deterioration of the molding accuracy of the lens L. Directly connected.
(2) A second point (a second inflection point) at which the upper die 10 and the lower die 20 (a pair of molding dies) reach or reach the press-cut position. This is because the time and position when the preform P is pressed until it reaches the press-cutting position slightly changes depending on the size, shape, posture, and hardness of the preform P, as well as external environmental factors such as temperature and humidity. This is because they have no choice but to The deviation between the current movement time and the planned movement time at or near the second point (the second inflection point) and the deviation between the current movement position and the planned movement position lead to variations in the press-off time and, in turn, deterioration of the molding accuracy of the lens L. Directly connected.

The control unit 50 selects the above-described first point (first inflection point) and two points (second inflection point ) is preferably included. This makes it possible to obtain a lens (press-molded product) L of higher quality and more stable quality.

Based on the above point of view, the multiple points include relatively many temporal and positional points in the area including at least one of the first point (first inflection point) and two points (second inflection point). In addition, a relatively large number of temporal and positional points may be included in an area that does not include the first point (first inflection point) and the second point (second inflection point).

For example, in the region containing the first point (first inflection point) and the region containing the second point (second inflection point), the time interval for monitoring the deviation between the current movement position and the planned movement position is relatively small. (for example, 0.5 seconds), and monitor the divergence between the current movement position and the planned movement position in a region that does not include either the first point (first inflection point) or the second point (second inflection point). The time interval may be relatively large (eg, 2 seconds).

Alternatively, as a plurality of points, the area from the initial position to the first point (first inflection point) includes relatively few temporal and positional points, and from the first point (first inflection point) A relatively large number of temporal and positional points may be included in the area up to the push-off position (this area includes the second point (second inflection point)).

For example, in the area from the initial position to the first point (first inflection point), the time interval for monitoring the deviation between the current movement position and the planned movement position is relatively large (for example, 2 seconds), and the first point In the region from (the first inflection point) to the full push position, the time interval for monitoring the deviation between the current movement position and the planned movement position may be relatively small (for example, 0.5 seconds).

As described above, it is possible to obtain a lens (press-molded product) L of high quality and stable quality while reducing the computation amount and computation time of the computer of the control unit 50 .

FIG. 7 is a diagram showing an example of the relationship between movement time and movement position of four samples using the press molding apparatus 1 according to this embodiment. As is clear from FIG. 7, since the movement time and the movement position have little variation between samples, the variation in the press cutting time is suppressed to obtain a lens (press-molded product) L with high reproducibility, high quality, and stable quality. becomes possible.

FIG. 8 is a diagram showing an example of the relationship between movement time and movement position of five samples using a press molding apparatus according to a comparative example. As is clear from FIG. 8, the sample-to-sample variation in the movement time and movement position is large, which increases the variation in the push-off time and deteriorates the lens quality (radiation scratches, uneven interference fringes, lens foaming, surface unevenness). (cracking or chipping)).

In the above embodiment, the case where the lens L is obtained by pressing the preform P has been exemplified and explained.

1 press molding device 10 upper mold (a pair of molds)
11 Press upper part 12 Upper base part 13 Press head 15 Body mold 20 Lower mold (a pair of molds)
21 Press lower part 22 Lower base part 23 Pedestal 30 Servo motor unit 40 Optimum trajectory data holding part 50 Control part 60 Timer 70 Encoder P Preform (pressing material)
L lens (press molding)

Claims (4)

a pair of molds for pressing the preform to obtain a lens ;
A control unit that controls press molding parameters by the pair of molds based on the planned movement time and the planned movement position from the initial position where the pair of molds are separated from each other to the press-cut position where the pair of molds are approached. When,
has
The control unit varies the press forming parameters so that the current movement time and the current movement position follow the planned movement time and the planned movement position at a plurality of points from the initial position to the push-cut position. let
The plurality of points include a first point at which the pair of molding dies start pressing the preform or a position at which pressing is started, and a second point at which the pair of molding dies reach the press-cut position or reach the position. and
As the plurality of points, the area from the initial position to the first point includes a relatively small number of temporal and positional points, and the area from the first point to the second point includes relatively contain many temporal and positional points,
A press molding device characterized by: The press forming parameters include at least one of press load, press speed and press acceleration.
The press molding apparatus according to claim 1 , characterized in that: A press molding method for obtaining a lens by pressing a preform with a pair of molds,
a step of controlling press molding parameters by the pair of molds based on the planned movement time and the planned movement position from the initial position where the pair of molds are separated from each other to the press-cut position where the pair of molds are close to each other; have
In the controlling step, the press forming parameters are set so that the current movement time and the current movement position follow the planned movement time and the planned movement position at a plurality of points from the initial position to the push-cut position. fluctuate,
The plurality of points include a first point at which the pair of molding dies start pressing the preform or a position at which pressing is started, and a second point at which the pair of molding dies reach the press-cut position or reach the position. and
As the plurality of points, the area from the initial position to the first point includes a relatively small number of temporal and positional points, and the area from the first point to the second point includes relatively contain many temporal and positional points,
A press molding method characterized by: A press molding program for obtaining a lens by pressing a preform with a pair of molding dies,
a step of controlling press molding parameters by the pair of molds based on the planned movement time and the planned movement position from the initial position where the pair of molds are separated from each other to the press-cut position where the pair of molds are close to each other; let the computer run
In the controlling step, the press forming parameters are set so that the current movement time and the current movement position follow the planned movement time and the planned movement position at a plurality of points from the initial position to the push-cut position. fluctuate,
The plurality of points include a first point at which the pair of molding dies start pressing the preform or a position at which pressing is started, and a second point at which the pair of molding dies reach the press-cut position or reach the position. and
As the plurality of points, the area from the initial position to the first point includes a relatively small number of temporal and positional points, and the area from the first point to the second point includes relatively contain many temporal and positional points,
A press molding program characterized by:

Images