Powder compression molding machine

Abstract

This invention suppresses excessive mixing of internal lubricant during trial runs of rotary powder compression molding machines, thereby optimizing the quality of molded products produced during trial runs. [Solution] In a powder compression molding machine in which a die hole is provided that penetrates the table of a rotating disk, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotating disk is rotated horizontally and the die hole passes under the stirring feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and the powder filled into the die hole is compressed and molded by the punch to produce a molded product, during a trial run in which molded products are manufactured by reducing the rotation speed of the rotating disk compared to the normal operation in which molded products are mass-produced, the load torque of the motor that rotates the stirring blades of the feed shoe or the current flowing through the motor coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotation speed of the stirring blades of the feed shoe to a lower level than before.

Description

Technical Field

[0001] The present invention relates to a powder compression molding machine that compresses powder to form tablets for pharmaceuticals, foods, electronic components, and the like.

Background Art

[0002] A rotary powder compression molding machine is known in which a large number of mortar holes are provided on the outer periphery of a table of a rotating disk, and an upper pestle and a lower pestle are respectively held slidably above and below each mortar hole. The mortar hole and the pestle are both rotated horizontally. When the mortar hole passes directly below the powder filling device, the mortar hole is filled with powder. Then, when the pair of upper and lower pestles passes between the upper and lower rolls, the powder in the mortar hole is compression molded or tabletted.

[0003] The filling device mounted on a rotary powder compression molding machine mainly uses a stirring feed chute that incorporates rotating stirring blades and injects powder into the mortar holes while stirring the powder. Powder is supplied to the feed chute of the powder compression molding machine from a powder mixing and supplying device. The powder supplying device mixes a plurality of powders (when producing tablets for pharmaceuticals, the main drug (active ingredient), excipients, lubricants, etc.) and then sends them out toward the feed chute (for example, refer to the following patent documents).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A method of adding a lubricant to a powder obtained by mixing a main drug and an excipient, etc., and then supplying it to a powder compression molding machine, and compression molding the mixed powder in the molding machine to obtain a molded product is called the "internal lubrication method". This is a measure to prevent a part of the mixed powder from sticking to the inner peripheral surface of the mortar hole of the molding machine or the tip surface of the pestle and a part of the molded product from being missing.

[0006] Specific examples of lubricants include magnesium stearate and talc. These lubricants are spreadable. Therefore, it is not advisable to continue stirring after adding and mixing them with the powder raw materials for molded products. This is because it is as if the lubricant is being kneaded, causing it to spread and coat the powder particles of the main ingredient and excipients, which can impair the compressibility of the powder in the molding machine or reduce the elution of the main ingredient in the finished molded product, thus potentially adversely affecting the quality of the molded product.

[0007] During normal operation when mass-producing molded products using a powder compression molding machine, the machine's turntable rotates at high speed, quickly filling the die holes in the table from the feed shoe, resulting in high powder consumption. Accordingly, the flow rate of powder supplied from the powder mixing and supplying device to the machine's feed shoe also increases. Therefore, powder is less likely to accumulate in the feed shoe or powder mixing and supplying device, and the degree of agitation and mixing of the powder, including the internal lubricant, does not become excessively high.

[0008] Meanwhile, in the manufacturing of molded products, the powder compression molding machine is test-run before the start of normal operation, i.e., mass production of molded products. The test run is important for optimizing the tableting conditions for mass production of molded products (rotation speed of the molding machine's turntable, amount of powder to fill the die cavity (position of the lower punch inside the die cavity (height of the die cavity bottom)), pressure to compress the powder (position of the upper and lower rolls that press the punch), rotation speed of the stirring blades built into the feed shoe, etc.). The parameters of these conditions differ for each type of molded product being manufactured, and are also fine-tuned according to the properties of the powder, temperature, humidity, etc. Furthermore, a test run is performed again when parts such as molds like dies and punches, or rails that guide the punches are replaced.

[0009] During trial runs, the rotation speed of the powder compression molding machine's turntable is intentionally set lower than during normal operation. This is also intended to minimize powder consumption during trial runs. As a result, the amount of powder filled from the feed shoe into the die holes of the table per unit time decreases, causing powder to accumulate inside the feed shoe, and then in the powder mixing and supply device.

[0010] Nevertheless, the continuous rotation of the stirring blades in the stirring feed shoe or the stirring blades in the powder mixing and supply device increased the number of stirring cycles for the powder that remained in place for a long time, leading to excessive mixing and spreading of the added internal lubricant. This made it difficult to accurately assess the quality of the molded products produced during trial runs, and consequently, to set appropriate tablet compression conditions for mass production of the actual molded products.

[0011] This invention was made in response to the above-mentioned problems for the first time, and its intended purpose is to suppress excessive mixing of internal lubricant during trial operation of a rotary powder compression molding machine. [Means for solving the problem]

[0012] The present invention provides a rotary powder compression molding machine in which a die hole is provided that penetrates the table of a rotary disk, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotary disk is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, wherein the feed shoe has stirring blades that stir the powder inside, and in a trial run in which molded products are manufactured by reducing the rotation speed of the rotary disk compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the feed shoe or the current flowing through the coil of the motor is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotation speed of the stirring blades of the feed shoe to a lower level than before. This makes it possible to suppress excessive stirring and mixing of powder that remains in the stirring feed shoe during the trial run of the powder compression molding machine.

[0013] Furthermore, the present invention provides a rotary powder compression molding machine in which a die hole is provided that penetrates the table of a rotary disk, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotary disk is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, and a powder mixing and supplying device is attached which has stirring blades that supply the powder mixed with a lubricant towards the feed shoe while stirring, and in a trial run in which molded products are manufactured by reducing the rotation speed of the rotary disk compared to the normal operation in which molded products are mass-produced, the load torque of the motor that rotates the stirring blades of the powder mixing and supplying device or the current flowing through the coil of the motor is measured, and if the load torque or current exceeds a predetermined value, the rotation speed of the stirring blades of the powder mixing and supplying device is controlled to be slower than before. This makes it possible to suppress excessive stirring and mixing of powder that remains in the powder mixing and supply device during the trial run of the powder compression molding machine.

[0014] Furthermore, the present invention provides a rotary powder compression molding machine in which a die hole is provided that penetrates the table of a rotary disk, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotary disk is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, wherein a stirring blade supplies the powder mixed with the lubricant toward the feed shoe while stirring it. The powder compression molding machine is equipped with a powder mixing and supplying device, and the feed shoe has stirring blades that stir the powder inside. During a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the powder mixing and supplying device or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the feed shoe to a lower level than before. This makes it possible to suppress excessive stirring and mixing of the powder that remains in the stirring feed shoe during the trial run of the powder compression molding machine.

[0015] Furthermore, the present invention provides a rotary powder compression molding machine in which a die hole is provided that penetrates the table of a rotary disk, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotary disk is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, wherein a stirring blade supplies the powder mixed with the lubricant toward the feed shoe while stirring it. The powder compression molding machine is equipped with a powder mixing and supplying device, and the feed shoe has stirring blades that stir the powder inside. In a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the feed shoe or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the powder mixing and supplying device to a lower level than before. This makes it possible to suppress excessive stirring and mixing of powder that remains in the powder mixing and supplying device during the trial run of the powder compression molding machine.

[0016] Here, "powder" refers to an aggregate of minute particles, encompassing both aggregates of granular materials such as granules and aggregates of powders smaller than granules. A mixture of multiple types of powders is also considered a powder. When a molded product is a pharmaceutical tablet, the main ingredient, excipients, lubricants, etc., are all powders, and a mixture of the main ingredient with excipients, lubricants, etc., also falls under the category of a powder. [Effects of the Invention]

[0017] According to the present invention, excessive mixing of the internal lubricant during trial operation of a rotary powder compression molding machine is suppressed, and the quality of the molded products manufactured during trial operation can be optimized. [Brief explanation of the drawing]

[0018] [Figure 1] A side cross-sectional view of a rotary powder compression molding machine according to one embodiment of the present invention. [Figure 2]Top view showing the turntable of the powder compression molding machine of the same embodiment. [Figure 3] Developed view showing the flow of the molding process of the molded product by the powder compression molding machine of the same embodiment, and the vertical movement of the pestle following the rotation of the turntable. [Figure 4] Diagram showing the configuration of the pestle, compression roll, and load cell of the same powder compression molding machine. [Figure 5] Side sectional view of the feed chute mounted on the powder compression molding machine of the same embodiment. [Figure 6] Perspective view of the same feed chute seen from below. [Figure 7] Perspective view of a modified example of the feed chute mounted on the powder compression molding machine of the same embodiment, seen from below. [Figure 8] Side view of the powder mixing and feeding device attached to the powder compression molding machine of the same embodiment. [Figure 9] Perspective view of the screw (agitation shaft) and agitation blades of the horizontal mixing device, which is an element of the powder mixing and feeding device of the same embodiment. [Figure 10] Block diagram of the control system of the powder compression molding machine of the same embodiment. [Figure 11] Flow chart showing the processing executed by the control device of the powder compression molding machine of the same embodiment according to a program. [[ID=?]] [[ID=?]] [[ID=3?]]

Embodiments for Carrying Out the Invention

[0019] An embodiment of the present invention will be described with reference to the drawings. First, an overall overview of a rotary powder compression molding machine (hereinafter referred to as "molding machine") A used for manufacturing molded products in this embodiment will be described. As shown in FIG. 1, in the frame of this molding machine A, a vertical shaft 2 serving as a rotating shaft is established, and a turntable 3 is attached to the upper part of the vertical shaft 2.

[0020] It should be noted that there are some tags with "?" in the original text which seem to be incorrect or incomplete tags. I've translated them as they are while keeping the "?" in place for reference. If these are meant to be something specific, they might need to be corrected for a more accurate translation.The rotating disc 3 rotates horizontally, i.e., on its own axis, around the axis of the vertical shaft 2. The rotating disc 3 consists of a table (mortar disc) 31, an upper punch holder 32, and a lower punch holder 33. As shown in Figure 2, the table 31 is roughly disc-shaped, and multiple mortar holes 4 are provided on its outer circumference at predetermined intervals along the direction of rotation. The mortar holes 4 penetrate the table 31 in the vertical direction. The table 31 may be divided into multiple plates. Alternatively, instead of directly drilling and forming the mortar holes 4 in the table 31 itself, multiple mortar members that are separate from the table 31 and detachable from the table 31 may be attached to the table 31, and each of these mortar members may have mortar holes that penetrate in the vertical direction.

[0021] As shown in Figures 1 and 3, an upper pestle 5 and a lower pestle 6 are positioned above and below each die hole 4. The upper pestle 5 and the lower pestle 6 are held by the upper pestle holder 32 and the lower pestle holder 33 so that they can slide individually in the vertical direction relative to the die hole 4. The tip 53 of the upper pestle 5 moves in and out of the die hole 4. The tip 63 of the lower pestle 6 is always inserted into the die hole 4. The upper pestle 5 and the lower pestle 6 rotate horizontally, i.e., revolve around the axis of the vertical shaft 2 together with the turntable 3 and the die holes 4.

[0022] A worm wheel 7 is attached to the lower end of the vertical shaft 2. A worm gear 10 meshes with the worm wheel 7. The worm gear 10 is fixed to a gear shaft 9 driven by a motor 8. The driving force output by the motor 8 is transmitted to the gear shaft 9 by a belt 11, and rotates the turntable 3 and the pestles 5 and 6, which are connected to the vertical shaft 2 via the worm gear 10 and worm wheel 7.

[0023] The powder that will be used as material for compression molded products, such as pharmaceutical tablets, is supplied from a powder mixing and supply device Z (described later) to a hopper or buffer tank 19, and then supplied from the hopper or buffer tank 19 to a feed shoe X. The powder is then filled into each die hole 4 of the table 31 from the feed shoe X. The feed shoe X is located on the outer circumference of the rotating table 31, in particular, directly above the rotational trajectory of the die holes 4. As the table 31 rotates together with the turntable 3, the die holes 4 are displaced relative to the feed shoe X.

[0024] In this embodiment, a stirring feed shoe X is used, which rotates a built-in stirring blade X1 to stir the powder and drop it into the die hole 4. As shown in Figures 5 and 6, the feed shoe X mainly consists of a housing X2 that receives the powder supplied from the powder mixing and supplying device Z, one or more stirring blades X1 that rotate within the housing X2 and stir the powder while dropping it from the housing X2 into the die hole 4 of the table 31, at least one motor X4 that outputs driving force to rotate the stirring blades X1, and a transmission mechanism X3 that transmits the rotation of the output shaft of the motor X4 to the shaft of each stirring blade X1.

[0025] The housing X2 is a flat enclosure-shaped structure with an internal space, formed by fixing a bottom plate member X22 to the lower part of the housing body X21. A powder inlet is provided on the upper surface of the housing body X21 for introducing powder into the housing X2. This powder inlet is connected to the powder mixing and supplying device Z. More specifically, as shown in Figure 8, a powder supply pipe 191, which is connected to the discharge section M6 of the powder mixing degree measuring device M in the powder mixing and supplying device Z, is connected to the powder inlet of the housing X2, and powder is supplied from the powder mixing degree measuring device M to the feed shoe X through the powder supply pipe 191.

[0026] The bottom plate member X22 is a flat, dish-shaped member that closes off most of the internal space of the housing body X21 from below. The bottom plate member X22 has a groove X23 that is roughly arc-shaped in plan view and penetrates the bottom plate member X22. The groove X23 is an outlet through which the powder to be filled into the die hole 4 of the table 31 of the molding machine A falls from inside the housing X2 towards the die hole 4, and in plan view it overlaps with the path that the die hole 4 passes through when the feed shoe X is attached to a predetermined mounting position in the molding machine A.

[0027] The stirring blade X1 is a component in which multiple blades X12 extend radially in a plan view from a central hub X11, and is housed in the internal space of the housing X2, stirring the powder inside the housing X2 with its blades X12. The feed shoe X of this embodiment is equipped with a pair of stirring blades X1, and each stirring blade X1 rotates horizontally around a vertical axis with the hub X11 as the center of rotation.

[0028] The transmission mechanism X3 is a gearbox having multiple meshing gears. The output shaft of the motor X4 is fixed to one of the gears X31, and the hub X11, which is the shaft of one of the stirring blades X1, is fixed to one of the gears X31, and the hub X11, which is the shaft of the other stirring blade X1, is fixed to one of the other gears X32, thereby transmitting the driving force output by one motor X4 to both stirring blades X1. The gear train of the transmission mechanism X3 is located at a height directly above the stirring blades X1 within the housing X2. The motor X4 is located above the housing X2, and its output shaft, which extends downward, enters the housing X2 by passing through a shaft hole drilled in the upper surface of the housing X2 and connects to the gear X31.

[0029] Motor X4 is a servo motor or the like whose rotational speed can be arbitrarily controlled, and the magnitude of the load torque currently acting on motor X4 and the magnitude of the applied current can be known by the control device 0. The rotational speed of each stirring blade X1 is determined by the rotational speed of motor X4 and the gear ratio of the gear train of the transmission mechanism X3. The rotational speed of the stirring blade X1 is usually 100 rpm or more. However, by adjusting the number of teeth on each gear in the gear train in the transmission mechanism X3, the ratio of the rotational speed of one stirring blade X1 to the rotational speed of the other stirring blade X1 can be arbitrarily changed.

[0030] Furthermore, by adjusting the number of gears interposed between the motor X4 and each stirring blade X1, the rotation direction of each stirring blade X1 can be arbitrarily changed. That is, one stirring blade X1 can be rotated in the opposite direction to the other stirring blade X1, and both stirring blades X1 can be rotated in the same direction.

[0031] The number of motors X4 that rotate the stirring blades X1 is not necessarily less than the number of stirring blades X1. The number of motors X4 can be the same as the number of stirring blades X1. For example, as shown in Figure 7, the same number of motors X4 as there are stirring blades X1 can be used, and the output shaft of each motor X4 can be connected to a hub X11 that serves as the axis of each stirring blade X1, thereby allowing each stirring blade X1 to rotate individually. In this configuration, the rotation speed and direction of each stirring blade X1 can be individually changed by controlling the rotation speed and direction of each motor X4. Furthermore, the number of stirring blades X1 is not limited to two; there may be three or more.

[0032] As shown in Figures 2 and 3, on the orbital path of the pestles 5 and 6 around the axis of the vertical shaft 2 are the upper pre-press roll 12 and lower pre-press roll 13, and the upper main pressure roll 14 and lower main pressure roll 15, which are positioned above and below the pestles 5 and 6, flanking them. The upper pre-press roll 12 and lower pre-press roll 13, and the upper main pressure roll 14 and lower main pressure roll 15 bias the upper and lower pestles 5 and 6 toward each other in order to compress the powder filled in the die cavity 4 from above and below with the tip surfaces of the pestle tips 53 and 63.

[0033] The upper pestle 5 and lower pestle 6 each have heads 51 and 61 that are pressed by the rolls 12, 13, 14, and 15, and bodies 52 and 62 that are smaller in diameter than the heads 51 and 61. The upper pestle holder 32 of the rotating disc 3 holds the body 52 of the upper pestle 5 so that it can slide up and down, and the lower pestle holder 33 holds the body 62 of the lower pestle 6 so that it can slide up and down. The tip portions 53 and 63 of the bodies 52 and 62 are even thinner than the rest of the body and have a diameter approximately equal to the inner diameter of the die hole 4, so that they can be inserted into the die hole 4. As the pestles 5 and 6 revolve, the rolls 12, 13, 14, and 15 approach the heads 51 and 61 of the pestles 5 and 6 and make contact with them by riding on top of them. Furthermore, rolls 12, 13, 14, and 15 push the upper pestle 5 downwards and the lower pestle 6 upwards. While rolls 12, 13, 14, and 15 are in contact with the flat surfaces on the pestles 5 and 6, the pestles 5 and 6 continuously apply constant pressure to the powder inside the die cavity 4.

[0034] Downstream from the pressurizing position by the main upper roll 14 and main lower roll 15, along the rotational direction of the turntable 3 and punches 5 and 6, there is a collection point for the finished molded product. A damper (or scraper) 17 is installed at this collection point.

[0035] The vertical movement of the upper pestle 5 and lower pestle 6 is caused by cam rails R1, R2, R3, R4, R5, and R6. Rails R1, R2, R3, R4, R5, and R6 extend along the rotational direction of the turntable 3 and the pestles 5 and 6, engaging with the heads 51 and 61 of the pestles 5 and 6, and guiding the pestles 5 and 6 as they move up and down.

[0036] As shown in Figure 3, on the rotational trajectory of the head 51 of the upper punch 5, there is an upward rail (upward cam) R1 that lifts the upper punch 5 upstream of the damper 17 and pulls its punch tip 53 out of the die hole 4, and a downward rail (downward cam) R5 that pushes down the upper punch 5 upstream of the rolls 12 and 14 and inserts its punch tip 53 into the die hole 4 in preparation for subsequent powder compression.

[0037] On the rotational trajectory of the head 61 of the lower punch 6, there is a push-up rail R4 that lifts the lower punch 6 upstream of the damper 17 to bring its punch tip 63 to approximately the same height as the top surface of the table 31, a lowering device R2 that pulls down the lower punch 6 upstream of or near the feed shoe X to adjust the volume of the die cavity 4 above the punch tip 63 to a size corresponding to the amount of powder that will be the constituent material of the molded product, and a volume rail R3 that slightly lifts the lower punch 6 downstream of the feed shoe X to fine-tune the amount of powder that will be filled into the die cavity 4. In the latter half of the volume rail R3, the lower punch 6 is slightly pulled down to prevent the powder in the die cavity 4 from spilling out due to centripetal force or the like after the amount has been adjusted.

[0038] To outline an example of the manufacturing process for a molded product, as shown in Figure 3, first the lower punch 6 descends, and lubricant is sprayed from the spraying device Y onto the inner circumferential surface of the die cavity 4 into which the punch tip 63 of the lower punch 6 is inserted, the upper end surface of the punch tip 63 of the lower punch 6, and the lower end surface of the punch tip 53 of the upper punch 5. Next, powder is filled into the die cavity 4 into which the punch tip 63 of the lower punch 6 is inserted from the feed shoe X, and the lower punch 6 rises until the amount of powder in the die cavity 4 reaches the required level, scraping off any powder that overflows from the die cavity 4.

[0039] Subsequently, the upper punch 5 descends, and the pre-pressing upper roll 12 and pre-pressing lower roll 13 press against the head 51 of the upper punch 5 and the head 61 of the lower punch 6, performing pre-compression by compressing the powder in the die cavity 4 with the punch tips 53 and 63 of the punches 5 and 6. Next, the main pressing upper roll 14 and main pressing lower roll 15 press against the head 51 of the upper punch 5 and the head 61 of the lower punch 6, performing main compression by compressing the powder in the die cavity 4 with the punch tips 53 and 63 of the punches 5 and 6.

[0040] As shown in Figure 4, the upper rolls 12 and 14 of the molding machine A are equipped with load cells 20 to detect the pressure when rolls 12, 13, 14, and 15 compress the powder in the die cavity 4 via punches 5 and 6. The signal output by the load cells 20 takes the form of a pulse signal train that peaks when the pressure exerted by a pair of punches 5 and 6 compressing the powder in one die cavity 4 is at its maximum. By referring to the output signal of the load cells 20, the magnitude of the pressure exerted by the pre-pressure rolls 12 and 13 to compress the powder (pre-pressure) and the magnitude of the pressure exerted by the main pressure rolls 14 and 15 to compress the powder (main pressure) can be determined.

[0041] Finally, the lower punch 6 rises until the upper end surface of the punch tip 63 is at approximately the same height as the upper end of the die cavity 4, that is, the upper surface of the table 31, pushing the molded product inside the die cavity 4 out onto the table 31. The molded product that has left the die cavity 4 comes into contact with the damper 17 at the product discharge section 16 due to the rotation of the turntable 3 and is scraped off, and moves along the damper 17 towards the molded product chute 18.

[0042] Figure 8 shows the configuration of the powder mixing and supplying device Z in this embodiment. The powder mixing and supplying device Z can mix multiple types of powders and supply them to the feed shoe X of the molding machine A. In the illustrated example, three metering feeders Z1 (Z1a, Z1b, Z1c) are used, with different types of powders stored in the first metering feeder Z1a, the second metering feeder Z1b, and the third metering feeder Z1c, respectively. Each of these metering feeders Z1a, Z1b, and Z1c measures and discharges the powder at an arbitrary target flow rate. If the molded product to be manufactured is a pharmaceutical tablet, for example, the first metering feeder Z1a supplies the main ingredient, the second metering feeder Z1b supplies an excipient such as lactose, and the third metering feeder Z1c supplies a lubricant such as magnesium stearate or talc.

[0043] The number of weighing feeders Z1 installed in the powder mixing and supplying device Z varies depending on the number of types of powders to be mixed; therefore, there may be two or four or more units, and there is no particular limit on the number. Furthermore, there is no prerequisite for weighing and supplying the same type of powder from multiple weighing feeders Z1.

[0044] The powder mixing and supplying device Z comprises a vertical mixing device Z3 that mixes the powder supplied from the first metering feeder Z1a and the second metering feeder Z1b, respectively; a first connecting pipe Z2a that connects the metering feeders Z1a and Z1b to the vertical mixing device Z3; a second connecting pipe Z2b that connects the vertical mixing device Z3 to the horizontal mixing device Z4; a horizontal mixing device Z4 that mixes the powder flowing down from the vertical mixing device Z3 and the powder supplied from the third metering feeder Z1c; a third connecting pipe Z2c that connects the third metering feeder Z1c to the middle of the horizontal mixing device Z4; a vertical mixing device Z5 that further mixes the powder flowing down from the horizontal mixing device Z4; a fourth connecting pipe Z2d that connects the horizontal mixing device Z4 to the vertical mixing device Z5; and a fifth connecting pipe Z2e that connects the vertical mixing device Z5 to the buffer tank 19. The shape, dimensions, and arrangement of each weighing feeder Z1 (Z1a, Z1b, Z1c) are not limited to the configuration shown in Figure 8 and can be changed as needed.

[0045] The first metering feeder Z1a and the second metering feeder Z1b each supply the main ingredient and excipients, which are in powder form, to the first connecting pipe Z2a while weighing them. The third metering feeder Z1c supplies the lubricant, which is in powder form, to the third connecting pipe Z2c while weighing it. Each metering feeder Z1 is a known type, for example, a loss-in-weight method (cumulative weight reduction method), in which the weight of the powder discharged from feeder Z1 is constantly measured via a weight sensor, and the change in this weight is compared to whether it matches the set target discharge flow rate. Feedback control is performed in which the discharge speed of feeder Z1 is increased or decreased in the direction that reduces the deviation between the two. In this way, by supplying each powder to be supplied as material for molded products to the connecting pipes Z2a and Z2c while weighing them, the content of the main ingredient and other components in the molded product is stabilized.

[0046] The powders discharged from each measuring feeder Z1a, Z1b, and Z1c are mixed by mixing devices Z3, Z4, and Z5. Regarding the horizontal mixing device Z4, it is important to note that it adds a lubricant to the powder, which has already been mixed with the main ingredient and excipients in the vertical mixing device Z3, and then further mixes it. The horizontal mixing device Z4 consists of a cylindrical case Z41 that is horizontal, nearly horizontal, or inclined at an angle closer to horizontal than 45° with respect to the horizontal direction, a screw (stirring shaft) Z42 built into the case Z41, and a motor Z43 that rotates the screw Z42. As shown in Figure 9, stirring blades Z44 are integrally attached to the screw Z42. The case Z41 does not fundamentally rotate (spin on its own axis), but a mechanism for the case Z41 to rotate may be employed.

[0047] The case Z41 of the horizontal mixing device Z4 is equipped with multiple supply ports Z411 and Z412 at the top for supplying powder into the case Z41, and an outlet Z413 for discharging the mixed powder from the case Z41. In the example shown in Figure 8, two supply ports Z411 and Z412 are used. The second connecting pipe Z2b is connected to the upstream supply port Z411 in the case Z41. The powder, which is obtained by mixing the main ingredient and excipients, etc. in the vertical mixing device Z3, flows through the second connecting pipe Z2b and is introduced into the case Z41 through the supply port Z411. The mixed powder moves within the case Z41 towards the outlet Z413 due to the rotation of the screw Z42 and the stirring blades Z44.

[0048] The third connecting pipe Z2c is connected to the downstream supply port Z412 in case Z41. The lubricant metered and supplied by the third metering feeder Z1c flows through the third connecting pipe Z2c and is introduced into case Z41 through the supply port Z412. The lubricant moves through case Z41 towards the discharge port Z413 while being mixed with the mixed powder of the main ingredient and excipients by the rotation of the screw Z42 and stirring blades Z44. As shown in Figure 8, it is preferable to connect the third metering feeder Z1c as far downstream as possible from the horizontal mixing device Z4. This shortens the length of time the lubricant discharged from the third metering feeder Z1c is agitated. Alternatively, a μR feeder (manufactured by Nisshin Engineering Co., Ltd.) may be used to supply the lubricant to the horizontal mixing device Z4. In addition, a spray device (injection device) may be used to supply the lubricant to the horizontal mixing device Z4.

[0049] Unused supply ports in case Z41 are closed with lids.

[0050] The screw Z42 extends along the longitudinal direction of the case Z41 and is positioned approximately in the center when viewed in cross-section. The screw Z42 is driven by the motor Z43 and rotates (spins) around its central axis. The shape of the stirring blade Z44 can be anything, but it is necessary that it can agitate and mix the powder inside the case Z41 while transferring it downstream, i.e., to the discharge port Z413, along the extension direction of the case 41. In the example shown in Figure 9, the stirring blade Z44 has a shape that spreads out at both ends, and the angle of the stirring blade Z44 with respect to the stirring shaft Z42 can be freely adjusted.

[0051] The discharge port Z413 of case Z41 is located below the downstream end of case Z41. The fourth connecting pipe Z2d is connected to the discharge port Z413. The powder, which is agitated and mixed inside case Z41, is discharged from the discharge port Z413 and moves to the fourth connecting pipe Z2d.

[0052] The fourth connecting pipe Z2d is a pipe that connects the horizontal mixing device Z4 and the vertical mixing device Z5. The fourth connecting pipe Z2d is connected to the lower part of the horizontal mixing device Z4 and the upper part of the vertical mixing device Z5, respectively, and supplies the powder that has passed through the discharge port Z413 of the horizontal mixing device Z4 to the vertical mixing device Z5. The supplied powder is further agitated in the vertical mixing device Z5.

[0053] The powder, which has been mixed sufficiently, is then supplied to the buffer tank 19 through the fifth connecting pipe Z2e, which is connected to the discharge port of the vertical mixing device Z5.

[0054] A powder measuring device M is interposed between the buffer tank 19 and the feed shoe X inside the molding machine A. The powder measuring device M consists of a case M1, a rotating body M2 which is a moving member located inside the case M1 that captures and transports the mixed powder, a servo motor or stepping motor M3 which is a drive device that drives the rotating body M2, PAT (Process Analytical Technology) sensors S2 and S3 which measure the properties of the mixed powder, especially the degree of mixing, a powder removal section M4 for removing mixed powder with poor properties, an inlet M5 for introducing the mixed powder from the buffer tank 19 into the case M1, and a discharge section M6 for discharging the mixed powder toward the stirring feed shoe X which is a filling device inside the molding machine A.

[0055] The properties, particularly the degree of mixing, of the mixed powder to be supplied to the feed shoe X of molding machine A are measured in real time by PAT sensors S1, S2, S3, S4, and S5 installed at various points along the flow of the powder. Various methods can be used to measure the degree of mixing and other properties of the powder, such as Raman spectroscopy, infrared spectroscopy, X-ray diffraction, X-ray transmission measurement, and high-performance liquid chromatography (HPLC), but any method that can measure the degree of mixing of the mixed powder in real time is acceptable. In this embodiment, near-infrared spectroscopy (NIR, or near-infrared absorption spectroscopy) is mainly used. That is, in order to evaluate the amount or proportion (ratio) of the main ingredient in the mixed powder moving from the powder mixing supply device Z to the feed shoe X of molding machine A, in other words, the uniformity of the mixed powder (whether segregation has occurred), near-infrared light is irradiated onto the moving mixed powder, the absorption and / or reflection (scattering) of the light is measured, and qualitative and quantitative analysis of the concentration of the main ingredient and other properties is performed based on the spectrum, and this is repeated at predetermined intervals. The measurement wavelength used is the wavelength band that has no peaks from excipients or lubricants and only the specific absorption peak of the main ingredient. In addition, near-infrared spectroscopy can also be used to measure the particle size of the mixed powder.

[0056] In this embodiment, first, the properties of the mixed powder, such as the degree of mixing, are measured upstream of the buffer tank 19 by a first sensor S1, which is a near-infrared sensor. After the properties have been measured, the mixed powder is temporarily stored in the buffer tank 19. The powder stored in the buffer tank 19 is then measured again by a second sensor S2, which is a near-infrared sensor, and supplied to the powder measuring device M. The mixed powder may also be further stirred and mixed within the buffer tank 19. Furthermore, the properties of the powder are also measured within the powder measuring device M by a third sensor S3, which is a near-infrared sensor.

[0057] If the degree of mixing and other properties of the mixed powder measured via the sensors S1, S2, and S3 are outside the required range (for example, if the amount or proportion (ratio) of the main ingredient in the mixed powder deviates from a predetermined range), the defective mixed powder is removed by the removal unit M4 of the powder measuring device M. At this time, the mixed powder in the moving unit M21 may be removed only if all measured values ​​of the degree of mixing, etc., from the first sensor S1, the second sensor S2, and the third sensor S3 are outside the predetermined range, or the mixed powder in the moving unit M21 may be removed only if the measured value from any of the sensors S is outside the predetermined range. Incidentally, the powder removal unit M4 can be used not only to remove defective mixed powder but also to sample any mixed powder.

[0058] Mixed powder that is not removed by the removal section M4 of the powder measuring device M is transferred to the regular discharge section M6, passes through the discharge hole M13, flows down into the powder supply pipe 191, and is supplied to the feed shoe X, which is the filling device of the molding machine A.

[0059] Alternatively, the properties of the mixed powder may be measured using a fifth sensor S5, which is a near-infrared sensor, within the feed shoe X, or the properties of the mixed powder may be measured using a fourth sensor S4, which is a near-infrared sensor, immediately before the mixed powder is supplied to the feed shoe X.

[0060] The mixed powder supplied to the feed shoe X is filled into the die cavity 4 located on the table 31 of the rotating disc 3 of the molding machine A. The mixed powder filled into the die cavity 4 is compressed and molded by the upper punch 5 and the lower punch 6. The compressed and molded mixed powder is collected as a molded product by the damper 17 at the molded product collection position 18. However, the properties of the mixed powder supplied to the feed shoe X and filled into the die cavity 4 are repeatedly measured in real time via the fourth sensor S4 and / or the fifth sensor S5. If the measured properties of the powder are outside the required range, the defective molded product compressed and molded in the die cavity 4 filled with that powder can be removed by the molded product removal mechanism (not shown) provided in the molding machine A. Such defective molded products do not reach the molded product collection position 18.

[0061] However, the control device 0, which is responsible for controlling the operation of the system including the molding machine A and the powder mixing and supplying device Z, is a microcomputer system, personal computer, or workstation, or a programmable logic controller, having a processor, memory, auxiliary storage device (which may be non-volatile memory such as flash memory or SSD (Solid State Drive)), input / output interfaces, etc. The control device 0 reads a program that has been stored in advance in the auxiliary storage device into the processor via memory, decodes it in the processor, and then executes the control of the molding machine A and the powder mixing and supplying device Z.

[0062] As shown in Figure 10, the control device 0 of the molding machine A receives signals output by the rotary encoder 21, which detects the rotational speed of the turntable 3 and the punches 5 and 6 while the molding machine A is in operation, and signals output by the load cell 20, which detects the magnitude of the pressure exerted by the rolls 12, 13, 14, and 15 to compress the powder via the punches 5 and 6 while the molding machine A is in operation. The control device 0 also controls the rotational speed of the motor 8 of the molding machine A to adjust the rotational speed of the turntable 3 and the punches 5 and 6.

[0063] Furthermore, the control device 0 constantly monitors the magnitude of the load torque acting on the motor X4 that drives the stirring blade X1 for stirring powder in the stirring feed shoe X mounted on the molding machine A. The load torque acting on the motor X4 may be measured via a torque sensor (torque meter) attached to the motor X4, or it may be estimated from the magnitude of the current applied to the motor X4 in order to adjust the rotational speed of the motor X4 and the stirring blade X1 to a certain set target value or target range.

[0064] In addition, the control device 0 constantly monitors the magnitude of the load torque acting on the motor Z43 that drives the stirring blade Z44, which agitates the powder in the powder mixing and supplying device Z attached to the molding machine A, particularly the screw Z42 of the horizontal mixing device Z4. The load torque acting on the motor Z43 may be measured via a torque sensor (torque meter) attached to the motor Z43, or it may be estimated from the magnitude of the current applied to the motor Z43 in order to adjust the rotational speed of the motor Z43, the screw Z42, and its stirring blade Z44 to a certain set target value or target range.

[0065] Then, as shown in Figure 11, during a trial run (step S1) in which molded products are manufactured with a reduced rotational speed of the rotating disc 3 of the molding machine A compared to normal operation for mass production of molded products, the control device 0 temporarily reduces the rotational speed of the motor X4 and stirring blade X1 of the stirring feed shoe X, and / or reduces the rotational speed of the motor Z43 and stirring blade Z44 of the powder mixing supply device Z (horizontal mixing device Z4), on the condition that the load torque (or current applied) of the motor X4 that drives the stirring blade X1 of the stirring feed shoe X is excessively large, exceeding the upper limit of a predetermined range, and / or the load torque (or current applied) of the motor Z43 that drives the stirring blade Z44 of the powder mixing supply device Z (horizontal mixing device Z4), exceeding the upper limit of a predetermined range (step S2).

[0066] During trial operation, if the load torque (or current applied) of the motor X4 that drives the stirring blade X1 of the stirring feed shoe X exceeds a predetermined value, it means that the mixed powder containing the lubricant is accumulating inside the feed shoe X. Moreover, there is a possibility that the mixed powder is accumulating not only inside the feed shoe X but also inside the powder mixing supply device Z (and even further inside the horizontal mixing device Z4) connected upstream of the feed shoe X. The same applies if the load torque (or current applied) of the motor Z43 that drives the stirring blade Z44 of the horizontal mixing device Z4, which is an element of the powder mixing supply device Z, exceeds a predetermined value.

[0067] When the conditions in step S2 are met, the control device 0 of molding machine A considers that the amount of powder currently lingering in the feed shoe X or the powder mixing supply device Z (horizontal mixing device Z4) is excessive, and performs the control in step S3. This reduces the number of times the mixed powder lingering in the feed shoe X and / or the powder mixing supply device Z (horizontal mixing device Z4) is stirred. This prevents excessive stirring and kneading of the internal lubricant added to the mixed powder during the trial run of molding machine A, and optimizes the quality of the molded products manufactured during the trial run. Ultimately, this leads to appropriately setting the tablet compression conditions during normal operation for mass production of molded products.

[0068] It should be noted that the present invention is not limited to the embodiments described in detail above. The specific configuration of each part can be modified in various ways without departing from the spirit of the present invention. [Explanation of Symbols]

[0069] A... Rotary powder compression molding machine 0...Control device 3… Rotating disc 31... Table 32, 33...Pinch holding part 4…Mortar hole 5, 6...Pestle 8…Motor that drives the rotating disc 12, 14... Upper Roll 13, 15... Lower Roll X... Agitation feed shoe X1... Agitation blade X4…Motor that drives the stirring blades Z...Powder mixing supply device Z4…Horizontal mixing device Z42... Screw (agitation shaft) Z43...Motor that drives the stirring blades Z44... Agitation blade

Claims

1. A rotary powder compression molding machine is provided with die holes that penetrate the table of a rotating disc, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotating disc is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, The feed shoe has stirring blades inside for stirring the powder, In a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the feed shoe or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the feed shoe to a lower level than before.

2. A rotary powder compression molding machine is provided with die holes that penetrate the table of a rotating disc, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotating disc is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, The system includes a powder mixing and supply device having stirring blades that supply a powder mixed with a lubricant towards the feed shoe while stirring it. In a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the powder mixing and supplying device or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the powder mixing and supplying device to a lower level than before.

3. A rotary powder compression molding machine is provided with die holes that penetrate the table of a rotating disc, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotating disc is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, The system includes a powder mixing and supply device having stirring blades that supply a powder mixed with a lubricant towards the feed shoe while stirring it. The feed shoe has stirring blades inside for stirring the powder, In a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the powder mixing and supplying device or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the feed shoe to a lower level than before.

4. A rotary powder compression molding machine is provided with die holes that penetrate the table of a rotating disc, and an upper punch and a lower punch are slidably held above and below each die hole, and when the rotating disc is rotated horizontally and the die hole passes under the feed shoe, powder containing a lubricant is filled into the die hole from the feed shoe, and when the pair of upper and lower punches pass between the upper roll and the lower roll, the powder filled in the die hole is compressed and molded to produce a molded product, The system includes a powder mixing and supply device having stirring blades that supply a powder mixed with a lubricant towards the feed shoe while stirring it. The feed shoe has stirring blades inside for stirring the powder, In a trial run in which molded products are manufactured by reducing the rotational speed of the turntable compared to normal operation for mass production of molded products, the load torque of the motor that rotates the stirring blades of the feed shoe or the current flowing through the motor's coil is measured, and if the load torque or current exceeds a predetermined value, control is implemented to reduce the rotational speed of the stirring blades of the powder mixing and supplying device to a lower level than before.

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