FR2945236A1 - Blowing/draw-blowing machine's mold for molding bottle, has centering reliefs formed by studs, where portion of centering reliefs or complementarily-shaped centering reliefs is made of anti-friction composite piece - Google Patents

Abstract

The mold (10) has mould parts comprising centering reliefs formed by studs (36, 38) and complementarily-shaped centering reliefs formed by housings (40, 42). The centering reliefs and complementarily-shaped centering reliefs are cooperated with one another. A portion of one of the centering reliefs and complementarily-shaped centering reliefs is made of an anti-friction composite piece (43) e.g. polyetherimide, PTFE or polyphenylene sulfide, so as to avoid lubrication of the portion, where the piece is covered with diamond like carbon (DLC). An independent claim is also included for a method for fabricating a mold.

Description

1

Mold, blowing apparatus and method of making a mold

The present invention relates to the field of molding containers, especially bottles, made of thermoplastic material, such as PET (polyethylene terephthalate) by blowing or stretch-blow molding heated preforms.

More specifically, the invention relates to a mold of a container blowing installation and to the manufacturing process of the mold, and to the blowing installation 10 comprising such a mold.

According to a configuration, a mold of such a blowing installation comprises two half-molds to form the shoulder and the body of the containers, and a mold bottom to form the bottom of the containers. The two half-molds are articulated with respect to each other about an axis. They are moved relative to each other between a mold closing and blowing position, and an opening position of the mold during which the shaped container is removed. The mold bottom is moved vertically between the closed position and opening of the mold.

Centering and locking pieces are fixed on the half-molds and on the bottom to ensure the centering and accurate formation of the molding cavity, and to avoid burrs due to the joint plane.

However, these centering and locking parts must be regularly lubricated. These maintenance operations require the shutdown of the blowing installation and, more generally, the shutdown of the entire production line of the containers.

These stops reduce production rates and increase the cost of manufacturing containers. In addition, these maintenance operations are performed under relatively difficult conditions for the operators because, in particular, of the ambient temperature which prevails around the installation.

In addition, these lubrication operations sometimes defile the molds. 2

The purpose of the invention is in particular to eliminate these maintenance operations.

For this purpose, the subject of the invention is a mold for installation for blowing containers made of thermoplastic material, the mold comprising two mold parts comprising one, a centering relief, and the other a centering relief of complementary shape. ; said centering relief and centering relief of complementary shape being capable of cooperating with each other, at least part of at least one of the centering relief and centering relief of complementary shape comprising an anti-composite material friction to avoid lubrication.

According to particular embodiments, the mold comprises one or more of the following features: at least one relief among the centering relief and the complementary shape centering relief is attached to a mold part; said fixed relief being made of anti-friction composite material; the anti-friction composite material comprises plastic, and wherein at least one relief of the centering relief and the complementary shape centering relief is attached to a mold part; said fixed relief being made by plastic injection molding; the anti-friction composite material comprises polyetherimide; the anti-friction composite material comprises lubricating compounds; the lubricating compounds comprise polytetrafluoroethylene; the anti-friction composite material (43) is a DLC coating; The subject of the invention is also a process for manufacturing a mold intended for an installation for blowing containers made of thermoplastic material; the mold comprising two mold parts comprising one, a centering relief, and the other a centering relief of complementary shape; said centering relief and centering relief of complementary shape being capable of cooperating with each other, said method comprising the following steps: machining of two mold parts, at least one mold part comprising at least one face of reception; injection molding of at least one relief among a centering relief and a centering relief of complementary shape in an anti-friction composite material; and - fixing the molded relief to the receiving face of the or each mold part.

Alternatively, the method of manufacturing a mold for an installation for blowing containers of thermoplastic material; the method comprising a step of machining two mold parts comprising one, a centering relief, and the other a centering relief of complementary shape; said centering relief and centering relief of complementary shape being capable of cooperating with each other, said method comprising a step of applying a composite anti-friction coating on at least a part of at least one of the reliefs centering and centering relief of complementary shape to prevent lubrication of the mold.

Finally, the subject of the invention is an apparatus for blowing containers, in particular bottles, made of thermoplastic material, characterized in that the installation comprises at least one mold as mentioned above.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings, in which:

- Figure 1 is a partially sectional view of the mold according to the invention; FIG. 2 is a perspective view of a half-mold and a bottom according to the invention; and - Figure 3 is a perspective view of a wear ring and a wear ring portion of the mold according to the invention.

In the remainder of the description, the terms upper and lower are defined with respect to the usual position of a mold in a blowing installation. These terms should not be interpreted as limiting the scope of the present invention to any orientation of the mold.

In known manner, a blowing installation comprises a frame carrying a carrousel adapted to be rotated about a central axis. 20 25

The carousel supports several molding units. Each molding unit comprises a console 8, a mold 10 and one or more actuators for manipulating the different parts of this mold. According to a possible configuration of the invention, not shown, the mold comprises only two half-molds each provided with an imprint capable of forming the entire shoulder, the body and the bottom of the containers.

According to another embodiment of the invention shown in Figures 1 and 2, the mold 10 comprises a first 14 and a second 16 mold half-faces, hereinafter called half-molds, in which is dug a footprint 14A, 16A to form the shoulder and the body of the containers, and a mold bottom 18 in which is dug a footprint 18A to form the bottom of the containers. In the illustrated example, the two half-molds 14, 16 are articulated with respect to one another about an axis not shown. This type of mold is usually called wallet mold. A first drive unit, not shown, and able to move the half-molds 14, 16 between a closed position of the mold in which the half-molds are contiguous, and a mold opening position in which the half molds are spaced from each other to allow removal of the shaped container.

The bottom 18 is carried by a support 19 which is vertically movable relative to the bracket 8. The bottom 18 and the support 19 are assembled together by screws 21.

A second drive unit, not shown, is able to move the support 19 between the closed position of the mold 10 in which the bottom 18 cooperates with the half-molds 14, 16, and an open position in which the bottom 18 is moved to a position remote from the half-molds 14, 16.

Alternatively, the mold 10 is formed of two half-molds movable linearly relative to each other. Each half-mold 14, 16 is equipped with two connectors 26 for thermoregulating the preforms which are in the mold 10.

Referring to Figures 1 and 2, each half-mold 14, 16 has a substantially semi-cylindrical shape. In particular, each half-mold 14, 16 comprises a support 20, a shell holder 22 nested and fixed on the support 20, and a shell 24 fitted and fixed in the shell holder 22. The cavities 14A and 16A are hollowed out in the inner face of the shells 24. They form with the cavity 18A of the bottom, a cavity 28 of molding, when the half-molds 14, 16 and said bottom 18 are contiguous.

The half-mold 14 has cooperating faces or bearing faces 29, 30 which, in the closed position of the mold, are in mutual abutment on the bearing faces 32, 34 of the half-mold 16.

The bearing faces 29, 30 of the half-mold 14 are provided with centering reliefs intended to cooperate with centering reliefs of complementary shape to the other half-mold 16.

In the example illustrated, the reliefs 36, 38 of centering are constituted by pins 36, 38 of centering and the centering reliefs of complementary shape are formed by housings 40, 42 of shape and depth corresponding to those of said pins of centering.

The pins 36, 38 and the housings 40, 42 are adapted to ensure a wedge and a correct positioning of a half-mold 14 relative to the other half-mold 16. The pins 36, 38 or the housings 40, 42 or pins 36, 38 and housings 40, 42 comprise an anti-friction composite material 43 to prevent lubrication thereof.

Thus, no lubrication is performed on the pins 36, 38 or the housings 40, 42 after more than 300,000 blowing cycles.

According to a first embodiment of the invention, the anti-friction composite material 43 comprises a plastic material.

In this case, the pins 36, 38 and / or the housings 40, 42 are made by injection molding of a pin-shaped or socket-shaped insert. Then, they are force-fitted in holes drilled in the half-mold 14 and / or the half-mold 16.

In a variant, the pins 36, 38 and the housings 40, 42 are screwed into tappings of the half-molds 14, 16. In particular, the anti-friction composite material 43 comprises polyetherimide and preferably polyetherimide loaded with lubricating compounds such as than polytetrafluoroethylene.

The polyetherimide is also loaded with glass fibers or carbon fibers to increase its rigidity.

For example, the friction composite material 43 marketed by Sabic Innovative Plastics as UFL 36 or UFL 4036 may be used.

According to a second embodiment of the invention, the anti-friction composite material 43 is a DLC (Diamond Like Carbon) coating.

The DLC coating is then applied to the inserts forming the pins 36, 38 and / or the inserts forming the housings 40, 42 which are, in this case, machined in aluminum.

As a variant, the DLC coating is directly deposited in the housing formed in the semi-mold 16.

This type of coating is described in particular in the following documents: US 6,303,226; US 5,250,322 and US 5,470,661. 10

As can be seen in FIGS. 1 and 3, a wear ring portion or segment 44 is fixed on the lower face 48 of each half-mold 14, 16 by screws 49. This wear ring portion 44 is intended to cooperate with a wear ring 50 arranged around the bottom 18 to center and lock the bottom 18 on the half-molds 14, 16 during the closing operation of the mold 10.

For this purpose, a groove 58 is formed on the periphery of the bottom 18. This groove 58 is able to receive the wear ring 50. The bottom 18 and the wear ring 50 are assembled together by screws 60.

The wear ring 50 and the wear ring portions 44 comprise the anti-friction composite material 43 to prevent their lubrication.

As described above, this anti-friction composite material 43 is, according to the first embodiment of the invention, a material comprising polyetherimide or according to the second embodiment of the invention, a DLC coating.

As a variant of the second embodiment of the invention, only part of the wear ring 50 and part of the wear ring portions 44 comprise the anti-friction composite material 43. These parts are then the parts of the wear ring and the wear ring portion in mutual contact with each other.

According to another embodiment of the invention, only the wear ring 50 and the wear ring portions 44 comprise the anti-friction composite material 43. The pins 36, 38 and the housings 40, 42 are then lubricated in a conventional manner. In this case, the half-mold 14 (or 16) and the bottom 18 form a first mold part within the meaning of the invention. The half-mold 16 (or 14) forms, by itself, the second mold part within the meaning of the invention. The wear ring 50 constitutes the centering relief of the first part 14, 18 of the mold. The wear ring portion 44 constitutes the centering relief complementary in shape to the second part 16 of the mold.

According to a last embodiment of the invention, only the pins 36, 38 and / or the housings 40, 42 comprise the anti-friction composite material 43. The wear ring 50 and the wear ring portions 44 are then lubricated in a conventional manner. In this case, the half-mold 14 forms the first mold part within the meaning of the invention. The half-mold 16 forms the second mold part within the meaning of the invention. The pins 36, 38 constitute the centering reliefs of the first mold part 14. The housings 40, 42 form the complementary centering reliefs of the second part 16 of the mold.

The invention also relates to a method of manufacturing the mold 10 as mentioned above. The method comprises the following steps: machining of two mold parts, at least one mold part comprising at least one receiving face; - Injection molding of at least one relief among a relief 36, 38, 50 of centering 15 and a relief 40, 42, 44 centering of complementary shape in a composite material 43 anti-friction; and - fixing the molded relief to the receiving face of the mold part.

In a variant, the method comprises the following steps: machining of the two half-molds 14, 16 and of the bottom 18; machining at least one of the pins 36, 38, the housings 40, 42, the wear ring 50 and the wear ring portions 44, the application of an anti-friction composite coating 43 at least a part of a relief among the pins 36, 38, the housings 40, 42, the wear ring 50 and the wear ring portions 44.

Claims (10)

REVENDICATIONS1. Mold (10) for blowing thermoplastic containers, the mold (10) having two mold parts including one, a centering relief (36, 38, 50), and the other a relief (40, 42, 44) of complementary shape centering; said centering relief (36, 38, 50) and centering relief (40, 42, 44) of complementary shape being able to cooperate with each other, characterized in that at least a part of the one at least centering relief and relief (36, 38, 50) of centering and relief (40, 42, 44) complementary shape centering comprises a composite material (43) anti-friction to prevent lubrication. 2. Mold (10) according to claim 1, wherein at least one relief from the relief (36, 38, 50) of centering and the relief (40, 42, 44) centering of complementary shape is attached to a portion of mold; said fixed relief being made of anti-friction composite material (43). 3. Mold (10) according to any one of claims 1 and 2, wherein the material (43) composite anti-friction comprises plastic, and wherein at least one relief among the relief (36, 38, 50) of centering and the complementary shape centering relief (40, 42, 44) is attached to a mold part; said fixed relief being made by plastic injection molding. The mold (10) according to any one of claims 1 to 3, wherein the anti-friction composite material (43) comprises polyetherimide. 5. Mold according to any one of claims 1 to 4, wherein the material (43) composite anti-friction comprises lubricating compounds. The mold (10) according to claim 5, wherein the lubricating compounds comprise polytetrafluoroethylene. The mold (10) of claim 1, wherein the antifriction composite material (43) is a DLC coating. 8. Apparatus for blowing or stretch-blow molding containers, especially bottles, of thermoplastic material, characterized in that the installation comprises at least one mold according to any one of Claims 1 to 7. 9. A method of manufacturing a mold (10) according to any one of claims 1 to 7, said mold (10) being intended for an installation for blowing containers of thermoplastic material; the mold (10) having two mold parts including one, a centering relief (36, 38, 50), and the other a complementary shaped centering relief (40, 42, 44); said relief (36, 38, 50) of centering and relief (40, 42, 44) centering of complementary shape being able to cooperate with each other; characterized in that the method comprises the following steps: - machining of two mold parts, at least one mold part comprising at least one receiving face; - Injection molding of at least one relief from a relief (36, 38, 50) of centering and a relief (40, 42, 44) centering of complementary shape in a material (43) anti-friction composite; and - fixing the molded relief to the receiving face of the or each mold part. 10. A method of manufacturing a mold (10) according to any one of claims 1 to 7, said mold (10) being intended for an installation for blowing containers of thermoplastic material; the method comprising a step of machining two mold parts including one, a centering relief (36, 38, 50), and the other a complementary shape centering relief (40, 42, 44); said relief (36, 38, 50) of centering and relief (40, 42, 44) centering of complementary shape being able to cooperate with each other; characterized in that the method comprises a step of applying a coating (43) anti-friction composite on at least a portion of at least one of the relief (36, 38, 50) of centering and relief (40, 42, 44) of complementary shape centering to prevent lubrication of the mold.