JP6182746B2 - Mold for foam molding and molding method using the same - Google Patents

Description

  The present invention uses a foam molding die capable of preventing the occurrence of burrs in a parting line, or making the burrs as small as possible, and further minimizing errors in the thickness direction of the product, and the same. The present invention relates to a molding method.

  Conventionally, foamed resin products made of thermoplastic resins such as polystyrene, polypropylene, and polyurethane have been widely used as cushioning materials for various products such as electrical appliances and precision equipment, or as interior materials for vehicles. As a method of molding such a foamed resin product, a thermoplastic resin is pre-foamed to produce pre-foamed particles, the pre-foamed particles are filled into a cavity formed by a pair of concave and convex molds, and heated by steam or the like. A method is known in which a foam-fused product is formed into a molded product having a desired shape.

In the conventional molding method described above, a slight gap or a step may occur in the joint of the concave and convex mold (referred to as a parting line). As a result, the horizontal direction (X axis) and the vertical direction of the molded product Assuming that (Y-axis) and the thickness direction (Z-axis), there are cases where protrusions and steps called burrs are generated in the molded product due to deviations in the vertical and horizontal directions of the mold.
The functional member is required to be 0.1 mm or less even if there are no burrs or steps on the surface or even if it exists. However, in applications such as cushioning materials and interior materials, it is sufficient to exhibit the function as a packaging material, and small burrs and steps are not considered to be a problem at all. For example, even if there are burrs or steps of less than 0.5 mm, it is normal that there is no problem in the function as a packaging material and that it does not have a problem in appearance and is not handled as a defective product.
Recently, however, in the case of high-quality electrical appliances and the like, it has been thought that it is not desirable in design to have burrs and steps that are visible even though they are cushioning materials. There has been a demand to suppress it to the extent that it is almost smooth visually when it is not present at all or is 0.1 mm or less. Furthermore, it has been required to minimize errors in the thickness direction of products.

  On the other hand, as a method of preventing the generation of burrs, a long hole is provided in the inner plate to which the mold is attached, and the positional relationship between the mold and the frame is finely adjusted using this long hole to align the mold. It is common to make eyes coincide. However, in the case of a multi-cavity molding machine in which a plurality of molds are mounted on the frame, the thermal expansion and mounting conditions of each mold are different, so only fine adjustment of one mounting plate is required. It was impossible to adjust the position of all molds. For this reason, it has been difficult to prevent the occurrence of burrs and steps in all molds (or 0.1 mm or less) by the above-described burr generation preventing method.

As other methods for preventing the occurrence of burrs, various proposals have been made as shown in Patent Documents 1 to 3. Patent Document 1 discloses a structure that suppresses thermal expansion of a concave mold with an inner plate, and Patent Document 2 discloses a structure that prevents the formation of a gap by using an abutment surface of an uneven mold as an inclined surface. No. 3 discloses a structure in which a protrusion along the contour is provided on the end face of the convex shape to prevent the generation of a gap with the concave shape.
However, all of those described in Patent Documents 1 to 3 completely prevent the problem that the mold structure is complicated and the mold production cost is high, and the generation of burrs (or less than 0.1 mm). There was a problem that we couldn't. In addition, any of them shows a structure in which only one mold is attached to the frame, and it cannot be applied as it is to a molding machine having a plurality of molds.

  On the other hand, conventionally, attention has not been paid to minimizing the error in the thickness direction (Z-axis) of the product, and no mold that can be finely adjusted in the Z-axis direction has been proposed. However, according to the inventor's research, as a result of measuring the thickness of each part with respect to the moldable plane of the molding machine, the thickness is insufficient at the central portion of the plane, and the thickness is increased at the outer periphery of the plane. Investigated that there is a tendency to end. For example, in the case of a plate product having a thickness of 20 mm, it has been confirmed that the thickness increases by about 0.5 mm at the outer peripheral portion, and conversely, the thickness decreases by about 0.5 mm at the central portion. Did not go.

JP 2003-33938 A JP 2004-338252 A JP 2007-261190 A

  The present invention solves the above-described problems, prevents the occurrence of burrs and steps in the parting line, or minimizes burrs and steps, and further minimizes errors in the product thickness direction. The present invention has been completed for the purpose of providing a foam molding die that can be molded and a molding method using the same.

  In order to solve the above-mentioned problems, a foam molding die of the present invention includes a pair of frame-shaped frames that can be contacted and separated, a pair of inner plates whose outer periphery is fixed to the frames, and one of the inner plates. A plurality of concave mold members disposed on the other side of the inner plate, and a plurality of convex mold members disposed on the other of the inner plates, and the pair of opposed concave and convex mold members are closed to form a molding cavity. A mold for foam molding in which a plurality of foam-molded products are molded by one cycle of molding operation, and the mounting position of each of the concave mold member and the convex mold member with respect to the inner plate is adjusted. In order to prevent gaps and steps in the parting line from occurring or to prevent errors in the product thickness direction when forming a molding cavity, a position adjustment mechanism is provided. It is characterized in that which enables adjustment of the mounting position for each die member and convex mold member.

  The position adjusting mechanism includes a positioning bracket and positioning bolts, and preferably has two types for the vertical direction and the horizontal direction, and this is the invention according to claim 2.

  Further, it is preferable that the position adjusting mechanism is capable of adjusting in the product thickness direction by pulling out or pushing in the concave-convex mold member, and this is an invention according to claim 3.

  A cooling control device for controlling cooling of the concave mold member and the convex mold member so that a temperature difference between the upper end portion and the lower end portion of the concave mold member and the convex mold member does not exceed a predetermined value; It is preferable that it is attached, and this is the invention according to claim 4.

  Moreover, it is preferable that the concave mold member and the convex mold member are attached to the inner plate via a heat insulating material, and this is the invention according to claim 5.

  Furthermore, in the molding method using the foam molding die according to any one of claims 1 to 5, the corresponding concave mold member and convex mold member are closed to form a molding cavity. In the molding method in which foamed beads are filled into the mold cavity and then heated steam is introduced into the mold to foam and fuse the foamed beads to form a foamed resin molded product of a predetermined shape. It is determined whether or not is 0.1 mm or less, and if it exceeds 0.1 mm, the mounting position of the corresponding concave mold member and the convex mold member with respect to the inner plate is adjusted for each mold, which occurs. The invention according to claim 6 is characterized in that this position adjustment is repeated until the burr or step becomes 0.1 mm or less to form a foamed resin molded product having a smooth surface.

  Moreover, the temperature of the upper end part and the lower end part of the concave mold member and the convex mold member during molding is measured, and it is determined whether or not this temperature difference exceeds 30 ° C. It is preferable to increase / decrease the supply amount of the mold cooling water, and repeat the increase / decrease of the supply amount of the mold cooling water until the temperature difference becomes 30 ° C. or less.

  In the invention according to claim 1, a pair of frame-shaped frames that can be contacted and separated, a pair of inner plates whose outer periphery is fixed to the frame, and a plurality of concave mold members disposed on one of the inner plates, And a plurality of convex mold members disposed on the other of the inner plates, the pair of opposed concave and convex mold members are closed to form a molding cavity, and a plurality of foams are formed by one cycle molding operation. A foam mold for molding a molded product, wherein each of the concave mold member and the convex mold member is provided with a position adjusting mechanism for adjusting the mounting position with respect to the inner plate, and for molding In order to prevent gaps and steps in the parting line from occurring when the cavity is formed, or to prevent errors in the product thickness direction, remove it for each concave mold member and convex mold member. Since the position can be adjusted, each concave mold member and convex mold member can maintain their exact positions, unlike the conventional method of aligning the entire inner plate. It is possible to prevent a gap, a step, or an error in the product thickness direction from occurring in the line.

  In the invention according to claim 2, since the position adjustment mechanism is composed of the positioning bracket and the positioning bolt and has two types for the vertical direction and the horizontal direction, the position adjustment mechanism can be positioned only by the tightening amount of the positioning bolt. Adjustment can be performed easily, and it can be adjusted both vertically and horizontally so accurate adjustment is possible.

  In the invention according to claim 3, since the position adjusting mechanism can adjust the product thickness direction by pulling out or pushing in the concavo-convex mold member, an error in the product thickness direction occurs. Can be prevented.

  In the invention which concerns on Claim 4, cooling control of the said concave mold member and a convex mold member is carried out so that the temperature difference of the upper end part of a concave mold member and a convex mold member may not exceed predetermined value Since the cooling control device is installed, the mold temperature can be controlled to be as uniform and free of temperature unevenness as possible, and gaps and steps in the parting line can be prevented by performing uniform foam molding. be able to.

  In the invention according to claim 5, since the concave mold member and the convex mold member are attached to the inner plate via the heat insulating material, the heat transfer from the inner plate is prevented and the mold is locally heated. Can be prevented.

  The invention according to claim 6 is a molding method using the foam molding die according to any one of claims 1 to 5, wherein the corresponding concave mold member and convex mold member are closed and molded. In the molding method, after forming a cavity and filling the molding cavity with foamed beads, heat steam is introduced into the mold to foam and fuse the foamed beads to form a foamed resin molded product of a predetermined shape. Judgment is made on whether or not the burrs and steps generated in the product are 0.1 mm or less, and if it exceeds 0.1 mm, the adjustment of the mounting position of the corresponding concave mold member and convex mold member with respect to the inner plate is adjusted This position adjustment was repeated until the generated burrs and steps were 0.1 mm or less, and a foamed resin molded product having a smooth surface was molded. Therefore, each concave mold member and convex mold Exactly all mold parts Prevent the gap or step is formed on the parting line can be combined location, also it is possible to mold while preventing the error in the product thickness direction is generated.

  In the invention which concerns on Claim 7, the temperature of the upper end part and lower end part of the concave mold member in a shaping | molding and a convex mold member is measured, it is determined whether this temperature difference exceeds 30 degreeC, 30 degreeC Since the mold cooling water supply amount is increased or decreased and the mold cooling water supply amount is repeatedly increased or decreased until the temperature difference becomes 30 ° C. or less, the mold temperature is made as uniform and temperature as possible. It can be controlled so that there is no unevenness, and by performing uniform foam molding, molding can be performed while preventing gaps and steps from occurring in the parting line.

It is the schematic which shows the molding machine equipped with the metal mold | die of this invention. It is sectional explanatory drawing of the principal part which shows the metal mold | die of this invention. It is a front view which shows the example of arrangement | positioning of a some metal mold | die. It is a front view which shows a metal mold | die member. It is a flowchart which shows an example of the control process of a position adjustment mechanism. It is the schematic which shows the cooling control apparatus of a metal mold | die. It is a flowchart which shows an example of the control process of a cooling control apparatus. It is the schematic which shows the position adjustment direction of a mold member.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a foam molding machine, and FIG. 2 is a cross-sectional explanatory view of a main part showing a mold of the present invention. In the figure, reference numeral 1 denotes a molding apparatus for a foamed resin molded product, and reference numerals 2a and 2b denote a pair of frame-like frames that can be contacted and separated. Reference numeral 2a denotes a moving side frame, 2b denotes a fixed side frame, and 3a and 3b denote die plates that support the frames 2a and 2b, respectively. Reference numerals 4a and 4b denote back plates that block the back side of each frame.

  A pair of inner plates 5a and 5b is attached to the frame so that the outer periphery is fixed. A plurality of convex mold members 6 are arranged on the inner plate 5a on the moving side, while a plurality of concave mold members 7 are arranged on the inner plate 5b on the fixed side. The mold members 6 and 7 are closed to form a molding cavity 8. Further, the back surfaces of the concavo-convex mold members 6 and 7 are closed by back plates 4a and 4b to form a convex steam chamber 9a and a concave steam chamber 9b.

In the figure, 10 is a mold opening / closing cylinder for opening and closing the convex mold member 6 by moving the moving frame 2a back and forth, 11 is a foamed bead raw material hopper, 12 is a filler, and 13 is after molding is completed. The mold release pin for extruding the molded product out of the mold.
The convex steam chamber 9a and the concave steam chamber 9b are connected to various service nozzles (not shown) necessary for molding, and supply and discharge of various services are performed. Is the same as this conventional molding machine. The utility here refers to the supply of heated steam and cooling water for heating, fusing, cooling, dehydration, etc. during the process of forming the expanded beads, which are raw materials, as well as the decompression operation with a decompression pump, and the addition with pressurized air. It means operating elements such as pressure operation and drainage. The utility nozzle means a connecting pipe for supplying and discharging these operating elements.

  In the foam molding die of the present invention, among the pair of inner plates, a plurality of convex mold members 6 are arranged on the inner plate 5a on the moving side, while on the inner plate 6b on the fixed side. A plurality of concave mold members 7 are arranged, and the pair of opposed concave and convex mold members 6, 7 are closed to form a molding cavity 8, and a plurality of foam molded products are formed by one cycle molding operation. It is configured to be molded (called a multi-cavity mold).

In FIG. 3, four convex mold members 6 are arranged on the inner plate 5a on the moving side, and four concave mold members 7 are arranged on the inner plate 6b on the fixed side. In this configuration, four foamed molded articles can be obtained by one cycle of molding operation.
However, in FIGS. 1 and 2, in order to simplify the description, a set of mold members arranged on a set of inner plates is illustrated.

As shown in FIG. 3, each of the concave mold member 7 and the convex mold member 6 is provided with a position adjusting mechanism for adjusting a mounting position with respect to the inner plates 5a and 5b. Unlike the conventional adjustment mechanism, this position adjustment mechanism is provided on each mold member, unlike the adjustment of the mounting position of the entire inner plate with respect to the frame. The mounting position can be adjusted for each concave mold member 6 and convex mold member 7 so as not to cause a gap or a step in the contour.
FIG. 8 shows the position adjustment direction of the mold member. Fine adjustment of the mounting position for each concave mold member 6 and convex mold member 7 in the horizontal direction (X-axis direction), vertical direction (Y-axis direction), and thickness direction (Z-axis direction) of the molded product, respectively. It is configured to do so.

As shown in FIG. 4, the position adjustment mechanism includes an X-direction position adjustment mechanism 15 and a Y-direction position adjustment mechanism 16. The X-direction position adjusting mechanism 15 is a set of two arranged in the horizontal direction, and is provided at two locations on the upper and lower end portions of the convex mold member 6 in the figure. In addition, the Y-direction position adjusting mechanisms 16 are two vertically arranged as one set, and are provided at two positions on the left and right end portions of the convex mold member 6 in the illustrated example.
Further, the X-direction position adjusting mechanism 15 includes an adjusting bolt 15a and a fixing bracket 15b, and has a structure capable of adjusting a subtle position in the X direction by tightening the adjusting bolt 15a. Similarly, the Y-direction position adjustment mechanism 16 includes an adjustment bolt 16a and a fixing bracket 16b, and has a structure capable of adjusting a fine position in the Y direction by the tightening degree of the adjustment bolt 16a.
As described above, the position adjustment mechanism 15 in the X direction and the position adjustment mechanism 16 in the Y direction can finely adjust the mounting positions of the individual mold members 6 and 7, thereby generating gaps and steps in the parting line. Can be prevented.
FIG. 4 illustrates the convex mold member 6, but the concave mold member 7 is also provided with a similar position adjusting mechanism.

Furthermore, the position adjusting mechanism is configured so that the product thickness direction (Z-axis direction) can be adjusted by pulling out or pushing in the concavo-convex mold members 6 and 7.
For example, with respect to the moldable plane of the molding machine, the thickness of the product is increased from the outside of the concave mold member 7 or from the outside of the convex mold member 6 when the thickness of the central portion of the plane is insufficient. Make adjustments to pull out the mold with the adjustment mechanism. Further, when the thickness is increased at the outer peripheral portion of the plane, adjustment is performed so that the mold is pushed in by the position adjusting mechanism so as to reduce the thickness of the product from the outside of the concave mold member 7 or from the outside of the convex mold member 6. .
As the drawer or push-in structure, for example, a well-known technique such as a structure in which a rod (not shown) attached to the outside is pulled out by a screw type adjustment mechanism or fine adjustment of push-in can be applied. . The drawer or push-in mechanism can be attached to either or both of the concave and convex mold members.

As shown in FIG. 6, in the concave mold member 7 (NO.4) and the convex mold member 6 (NO.4), the temperature difference between the upper end portion and the lower end portion of the mold exceeds a predetermined value. A cooling control device 20 for controlling the cooling of the concave mold member is attached so as not to be present.
This is because the inventor has studied the prevention of the occurrence of gaps and steps in the joints of the concavo-convex mold (called parting line), and as a result, it is effective to eliminate the temperature unevenness of the mold forming the molding cavity. By investigating a certain thing. As a result of experiments, it has been found that the temperature difference is preferably within 30 ° C.
Specifically, the temperature of the concavo-convex mold members 6 and 7 is measured, it is determined whether or not the temperature difference is within 30 ° C., and the mold cooling water is supplied based on the control of the rejection control device 20. The amount is increased or decreased by the supply valves 21a and 21b and supplied from the cooling water showers 22a and 22b. Furthermore, the mold cooling water is supplied while controlling the increase / decrease in the amount of mold cooling water until the temperature difference becomes 30 ° C. or less, and the molding is continued in a state where there is little temperature unevenness of the mold.

In addition, as shown in FIG. 2, the concave mold member 6 and the convex mold member 7 are attached to the inner plates 5a and 5b via heat insulating materials 14, respectively. As the heat insulating material 14, a fluororesin such as polytetrafluoroethylene having excellent heat insulating properties, durability, and sealing properties can be used.
The heat insulating material 14 cuts off heat conduction from the inner plates 5a and 5b to prevent local temperature changes of the concave and convex mold members 6 and 7, thereby reducing temperature unevenness.

Below, the shaping | molding method using the metal mold | die for foam molding of this invention is demonstrated.
As shown in FIG. 1, each corresponding concave mold member 7 and convex mold member 6 are closed to form a molding cavity 8, and foam beads are filled into the molding cavity 8 from a filler 12. Next, heated steam is introduced into the mold to foam and fuse the foam beads to form a foamed resin molded product having a predetermined shape. The above steps are basically the same as the conventional method for forming a foamed molded product.

In the present invention, burrs and steps are inspected for all molded products of the mold, and it is determined whether the burrs and steps are 0.1 mm or less. If it is 0.1 mm or less, production is continued with no problem, but if it exceeds 0.1 mm, the corresponding concave mold member and the mounting of the convex mold member to the inner plate as shown in FIG. Position adjustment is performed for each mold, and this position adjustment is repeated until the generated burrs and steps are 0.1 mm or less, and adjustment is performed so as to mold a foamed resin molded product having a smooth surface.
Specifically, from the state of occurrence of burrs and steps, the adjustment bolt 15a of the X-direction position adjustment mechanism 15 and / or the adjustment bolt 16a of the Y-direction position adjustment mechanism 16 are tightened or loosened to form a mold member. Fine adjustment of the mounting position with respect to the inner plate is performed so that the concave mold member and the convex mold member completely coincide with each other at the joint. In this way, by adjusting the mounting positions of all the concave mold members and convex mold members, the burrs and steps of all molded products can be reduced to 0.1 mm or less, and molded products with excellent appearance quality can be obtained. Can be obtained. Moreover, since the mold member accurately aligned in this way continues to hold the correct position thereafter, it is possible to continue production of molded products having burrs and steps of 0.1 mm or less.

Furthermore, in the present invention, when the thickness of the center portion of the plane is insufficient with respect to the moldable plane of the molding machine, the thickness of the product is increased from the outside of the concave mold member or from the outside of the convex mold member. Pull out the central part of the mold with the adjusting mechanism. On the other hand, when the thickness of the outer peripheral portion of the plane is increased, adjustment is performed by pushing the outer peripheral portion of the mold with an adjusting mechanism so as to reduce the thickness of the product from the outside of the concave mold member or the outside of the convex mold member. For example, when the outer peripheral portion of the plate product has increased in thickness by 0.5 mm, the mold is pushed in from the outside by the increased amount. On the other hand, when the thickness of the central portion is reduced by 0.5 mm, it is possible to perform molding so as not to cause an error in the thickness direction by adjusting the die so that the thickness is reduced. .
Conventionally, there is no awareness of minimizing errors in the thickness direction (Z-axis) of products, and there is no foam molding mold that can adjust the position in the thickness direction (Z-axis direction). The invention is the first proposal.

Further, as shown in FIG. 6, the temperature of the upper end portion and the lower end portion of the concave mold member and the convex mold member during molding is measured to check whether temperature unevenness has occurred. If this temperature difference does not exceed 30 ° C, production is continued with no problem, but if it exceeds 30 ° C, the amount of mold cooling water supplied is increased or decreased until the temperature difference becomes 30 ° C or less. Repeat the increase and decrease of the mold cooling water supply.
Specifically, as shown in FIG. 7, when the temperature difference exceeds 30 ° C. and the mold temperature is high, the mold cooling time is increased, and when the mold temperature is low, the mold cooling time is decreased to adjust the mold temperature. The temperature is controlled so as to be 30 ° C. or less. Thereby, it is possible to effectively prevent a uniform foam molding from being performed and a gap or a step in the parting line.

  As is clear from the above description, the present invention is provided with a position adjustment mechanism for adjusting the mounting position with respect to the inner plate in each concave mold member and convex mold member in the multi-cavity mold, Since it is possible to adjust the mounting position for each concave mold member and convex mold member so that there is no gap or step in the parting line when forming the molding cavity, each concave mold member and Each of the convex mold members can maintain an accurate position and can prevent a gap or a step in the parting line, and even if there is no or no burr or step on the surface, it is 0. It is possible to obtain a foam-molded product having a design quality of about 1 mm or less and high appearance quality that looks almost smooth visually.

DESCRIPTION OF SYMBOLS 1 Molding apparatus 2a Moving side frame 2b Fixed side frame 3a Moving side die plate 3b Fixed side die plate 4a Moving side back plate 4b Fixed side back plate 5a Moving side inner plate 5b Fixed side inner plate 6 Convex mold member 7 Concave mold member 8 Molding cavity 9a Convex steam chamber 9b Concave steam chamber 10 Mold opening / closing cylinder 11 Raw material hopper
12 Filler 13 Mold Release Pin 14 Heat Insulating Material 15 Position Adjustment Mechanism in X Direction
15a Adjustment bolt
15b Fixed bracket 16 Y-direction position adjustment mechanism
16a Adjustment bolt
16b Fixed bracket 20 Cooling control device
21a Supply valve
21b Supply valve
22a Cooling water shower
22b Cooling water shower

Claims (7)

  A pair of frame-like frames that can be contacted and separated, a pair of inner plates whose outer periphery is fixed to the frame, a plurality of concave mold members disposed on one of the inner plates, and the other of the inner plates A plurality of convex mold members, and the pair of opposed concave and convex mold members are closed to form a molding cavity, and a plurality of foam molded products are molded by one cycle molding operation. A mold for foam molding, wherein each of the concave mold member and the convex mold member is provided with a position adjusting mechanism for adjusting the mounting position with respect to the inner plate, and when the molding cavity is formed, It is possible to adjust the mounting position for each concave mold member and convex mold member so that there are no gaps or steps in the mold line or errors in the product thickness direction. Foam molding mold characterized and.   2. The foam molding die according to claim 1, wherein the position adjustment mechanism includes a positioning bracket and a positioning bolt, and has two types for a vertical direction and a horizontal direction.   The mold for foam molding according to claim 2, wherein the position adjusting mechanism is capable of adjusting the thickness direction of the product by pulling out or pushing in the concavo-convex mold member.   A cooling control device for controlling the cooling of the concave mold member and the convex mold member is attached so that the temperature difference between the upper end portion and the lower end portion of the concave mold member and the convex mold member does not exceed a predetermined value. The mold for foam molding according to any one of claims 1 to 3.   The foam mold according to any one of claims 1 to 4, wherein the concave mold member and the convex mold member are attached to the inner plate via a heat insulating material.   A molding method using the foam molding die according to any one of claims 1 to 5, wherein the corresponding concave mold member and convex mold member are closed to form a molding cavity, and the molding cavity In a molding method in which a foamed bead is formed by filling heated foam into the mold by foaming and fusing the foamed bead and molding the foamed resin molded product of a predetermined shape. .1 mm or less is determined, and if it exceeds 0.1 mm, the mounting position of the corresponding concave mold member and the convex mold member with respect to the inner plate is adjusted for each mold, and the generated burrs and A molding method characterized in that this position adjustment is repeated until the step becomes 0.1 mm or less to mold a foamed resin molded product having a smooth surface.   Measure the temperatures of the upper and lower ends of the concave mold member and the convex mold member during molding, determine whether this temperature difference exceeds 30 ° C, and if it exceeds 30 ° C, mold cooling The molding method according to claim 6, wherein the supply amount of water is increased and decreased, and the increase and decrease of the supply amount of the mold cooling water is repeated until the temperature difference becomes 30 ° C. or less.