Patent Description:
<CIT> discloses an injection mould comprising mould platens with a mould cavity and a mould core, a parting surface and gas outlet ports in the parting surface for blowing gas after the mould core and the mould cavity have been separated. The US patent application <CIT> discloses a mould for injection moulding, the mould having an air cooling system for cooling injection moulded item after the mould halves/parts are separated from each other, following the injection moulding step. <CIT> teaches air passages configured for directing an air flow towards the moulded item, after the mould parts have been separated from each other. Air can be blown onto the moulded item via four air passages and an "air providing part" formed as linear conduits having apertures directed toward the item on the mould core, the linear conduits and the apertures formed in a structure raised from a an inner surface of the core mould part and surrounding the core. In order to target all sides, of the injection moulded item, four separate conduits are needed each formed in a raised sidewall surrounding the core. In order to provide sufficient cooling of the injection moulded item, <CIT> thus teaches a very complex structure of the core part and the cavity part of the mould. Further, the cooling air conduits take up a lot of space in the mould part, which prevents - or at least impedes - arrangement of other necessary or desired structures, such as vent channels, mould cooling channels, ejector pins, alignment posts, etc..

Therefore, there is at least a need for a mould or at least a mould insert for a mould box, which has a simpler structure.

It is one object of the invention to provide a mould or at least a mould insert for a mould box, which has a simpler structure, than the prior art.

In a first aspect, the objects of the invention are achieved by a mould insert part for injection moulding, the mould insert part comprising.

In an embodiment, at least two of the two or more gas outlet ports are arranged on opposite sides of the mould core.

In a further embodiment, at least one gas conduit of the gas conduit system has a bend of <NUM>° or more.

In a further embodiment, at least one gas conduit at least partially extends under the mould core of the mould insert part.

In a further embodiment, the two or more gas outlet ports are configured to direct gas towards a centreline of the mould core.

In a further embodiment, each of the two or more gas outlet ports are configured to direct the gas in an angle relative to a plane defined by the first surface, where the angle is larger than <NUM>° and smaller than <NUM>°.

All the gas outlet ports may have the same angle relative to the plane. In other embodiments, each gas outlet port may be formed at angles relative to the plane, which are different from the other gas outlet ports.

In some embodiment, the angle of each gas outlet port is configured to blow gas onto a desired area of the free outer surface of the injection moulded item, and predetermined dependent on the shape of the injection moulded item.

In any of the previously mentioned embodiment, or any other embodiment mentioned in this application, the mould insert part may be formed in an additive manufacturing process.

When mould plates/mould insert parts are formed in steal - as is conventional -it is very difficult to form anything other than linear channels. When the mould insert part according to the invention is formed in an additive manufacturing process, such as 3D printing, and in a polymer material, e.g. a plastic, it is relatively easy to produce a mould insert part with complexly shaped gas conduits.

Further, the objects of the invention may be achieved in a second aspect, by a combination of a mould box for an injection moulding machine and a mould insert part as defined in claim <NUM>.

Further, the objects of the invention may be achieved in a third aspect, by an injection moulding machine as defined in claim <NUM> comprising a combination according to claim <NUM>.

It should be emphasized that the term "comprises/comprising/comprised of" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

<FIG> illustrates schematically an injection moulding machine <NUM> as known in the art. The injection moulding machine <NUM> generally comprises an injection unit <NUM>, shown in the left side of the figure, and a clamping unit <NUM>, shown in the right side of the figure. The injection unit <NUM> handles injection of plastic material into a mould formed in the clamping unit <NUM> of the injection moulding machine <NUM>. The injection unit <NUM> and the clamping unit <NUM> of the injection moulding machine <NUM> are attachable to a mount <NUM>.

Injection moulding machines <NUM> generally works in the following way: Plastic granules <NUM> are fed into the barrel <NUM> of a reciprocating screw <NUM> of the injection unit <NUM> via a hopper <NUM>. The reciprocating screw <NUM> is driven by a drive mechanism <NUM>, such as an electrical motor. The plastic granules <NUM> fed through the hopper <NUM> are then transported towards the clamping unit <NUM> by the reciprocal screw, while being compacted and they are heated by heating devices <NUM> surrounding the reciprocating screw <NUM>, until they melt and reach a suitable viscosity at a nozzle <NUM> at the entrance to the clamping unit <NUM> with the mould. The mould is formed in a mould box <NUM>.

The fluid plastic material is fed from the nozzle <NUM> through sprue channels <NUM> in a base plate <NUM> of the mould box <NUM>, and reaches a mould cavity <NUM> formed in a first mould plate <NUM> of the mould box <NUM>. The first mould plate <NUM> of the mould box <NUM> is connected to the base plate <NUM>. The base plate <NUM> is connected to the mount <NUM>. A second mould plate <NUM> which may comprise a mould core and/or further portions of a mould cavity is arranged moveably relative to the first mould plate <NUM>, such that the mould box may be completely closed (clamped together) to allow injection of the melted plastic, and such that the mould box <NUM> may be opened to extract a moulded item <NUM> (see <FIG>).

In <FIG>, the second mould plate <NUM> is attached to a moveable platen <NUM>. The moveable platen <NUM> - and thereby the second mould plate <NUM> - is slideably arranged on a set of cylindrical main guide rail pillars <NUM>. Typically, the clamping unit <NUM> of injection moulding machines <NUM> comprises four cylindrical main guide rail pillars <NUM> for guiding the movement of the moveable platen <NUM> with the second mould plate <NUM>. The movement of the moveable platen <NUM> with the second mould plate <NUM> is performed by a linear drive mechanism <NUM>, typically a hydraulic mechanism.

Each of the main guide rail pillars <NUM> of the main guide rail system of the mould box <NUM> of the clamping unit <NUM> has an elongate body, which is cylindrical, and has a first end <NUM> and a second end <NUM>. The first end <NUM> is fixed to the base plate <NUM>, which is fixed to a frame (not shown) of the clamping unit <NUM>. The frame of the clamping unit <NUM> may form part of the frame <NUM> of the injection moulding machine <NUM>, or may be fixed thereto.

The opposite end, the second end <NUM>, of the elongate body of each main guide rail pillars <NUM> is fixedly connected to a second end structure <NUM> of the clamping unit <NUM>. The second end structure <NUM> of the clamping unit <NUM> is fixed to the mount <NUM> of the clamping unit <NUM>.

The second end structure <NUM> may also, as shown in <FIG>, form a mount for the linear drive mechanism <NUM>.

Now, returning to the moveable platen <NUM> with the second mould plate <NUM>, this moveable platen <NUM> comprises through-going bearings e.g. slide bearings or ball bearings, slidably receiving the cylindrical main guide rail pillars <NUM>.

In an injection process, the linear drive mechanism <NUM> clamps the first mould plate <NUM> and the second mould plate <NUM> together, whereupon plastic is injected by the reciprocal screw <NUM> through the nozzle <NUM> and into the mould cavity <NUM>. When the plastic has filled the mould cavity <NUM> completely, and has cooled sufficiently for the plastic to be in solid state, then the linear drive mechanism <NUM> moves the second mould plate <NUM> away from the first mould plate <NUM>, and the moulded item <NUM> is ejected from the mould. The ejection of the moulded item <NUM> is typically done by ejector pins (not shown) formed in/through the base plate <NUM>.

After the injection of plastic into the mould and when the mould plates <NUM>, <NUM> have been separated from each other it is often desirable to further cool the injection moulded item <NUM> further before removing the injected moulded item <NUM> from the mould.

It is known in the art to cool the injection moulded item <NUM> by blowing a gas such as air onto the injection moulded item <NUM> when it is still located on a mould core <NUM> of one of the mould plates <NUM>, <NUM> after the mould plates have been separated.

Often the mould including the mould core and the corresponding mould cavity are arranged on mould insert. Mould inserts a generally plate shaped structures which are attachable to the mould plates <NUM>, <NUM> by inserting them there into. Thereby, it is obtained that the often very heavy mould plates do not need to be replaced every time a new type of item is to be injection moulded. Instead only the mould inserts are exchanged.

In one aspect, the present invention relates to such a mould insert part <NUM>. The mould insert part <NUM> is described in connection with <FIG> below. It will be appreciated that the mould insert part <NUM> described may be used in a mould box <NUM> as outlined above, in connection with <FIG> above. It will further be appreciated that such a mould bow may be implemented in an injection moulding machine <NUM> as outlined above, in connection with <FIG> above.

It will also be appreciated, that although the features for cooling an injection moulded item <NUM> is described in connection with a mould insert part <NUM> in the embodiments show in <FIG>, the same features may in principle be implemented in mould plates as such, i.e. in mould boxes not havening replaceable mould inserts.

Now turning to <FIG>, <FIG> are see-through elevated perspective views, of an embodiment of the mould insert part <NUM> according to the invention. <FIG> shows the mould insert from one angle. <FIG> shows the mould insert from a different angle.

The mould insert part <NUM> comprises a main body <NUM>, which is a generally plate shaped structure having a first surface <NUM>, and, opposed thereto, a second surface <NUM>.

The first surface <NUM> defines a plane P, see <FIG> shows the mould insert part <NUM> of <FIG> in a side view, where also the first surface <NUM> and the opposite second surface <NUM> is visible. The first surface <NUM> faces a second mould insert part with a mould cavity, when both are inserted in/attached to mould plates of a mould box, e.g. as described above.

The mould insert part <NUM> comprises a mould core <NUM> extending outwardly from said first surface <NUM> of the main body <NUM>. This means that the mould core <NUM> extends above the plane P.

The mould insert part <NUM> is configured for cooperating with a second mould insert part (not shown) having a mould cavity, which is configured for - together with the mould insert part <NUM> with the mould core <NUM> - forming a mould for injection moulding an injection moulded item <NUM>.

The mould insert part <NUM> is insertable into a mould plate of a mould box, e.g. as exemplified above. The second mould insert part with the mould cavity likewise is insertable into another mould plate of a mould box, e.g. as exemplified above.

The main body <NUM> of the mould insert part <NUM> may - as shown - be rectangular or quadratic in shape.

The main body <NUM> of the mould insert part <NUM> - at least in the shown embodiment - further comprises side flanges <NUM>. The side flanges <NUM> are optional. The side flanges <NUM> extend above the first surface <NUM> of the main body <NUM> of the mould insert part <NUM>. This means that the side flanges <NUM> extend above the plane P. The side flanges <NUM> are configured for cooperating with recesses (not shown) on the cooperating second mould insert part (not shown). In the embodiment shown in the <FIG> there are two side flanges <NUM>.

The mould insert part <NUM> further comprises a gas inlet port <NUM>. The gas inlet port <NUM> is connectable to a supply of pressurized gas (not shown).

The pressurized gas may be air. The air may be pressurized by a pump (not shown). Alternatively, the supply of pressurized gas may be a replaceable pressurized container (not shown).

The supply of pressurized gas may form part of an injection moulding machine <NUM>, e.g. as described above.

The supply of pressurized gas may be connected to the gas inlet port <NUM> by suitable connection tubing configured for conducting pressurized gas and/or conduits formed in the mould plate(s) or other parts of the injection moulding machine <NUM>.

The gas inlet port <NUM> is connected to gas outlet ports <NUM> via a gas conduit system <NUM>.

It will be appreciated that a mould insert part <NUM> according to the invention may comprise more than the gas outlet ports <NUM>, <NUM> shown in <FIG>, such as <NUM>-<NUM> gas outlet ports <NUM>.

Each of the two or more gas outlet ports <NUM>, <NUM> are arranged at least partially through the first surface <NUM>.

In the <FIG> embodiment, a first gas outlet port <NUM> is arranged fully in and through first surface <NUM> of the main body <NUM>, and a second gas outlet port <NUM> is arranged in an intersection between the first surface <NUM> of the main body <NUM>, and one of the side flanges <NUM>. In the embodiment, shown in <FIG>, all of the total of seven outlet ports <NUM> are arranged fully in and through first surface <NUM> of the main body <NUM>. Thus, all of the gas outlet ports <NUM> in the <FIG>embodiment are of the type designated with the reference number <NUM> in the <FIG> embodiment.

In any case, the gas outlet ports <NUM>, <NUM>, <NUM> are arranged to direct a gas flow from the gas inlet port <NUM> (when the gas inlet port <NUM> is connected to the source of pressurized gas) and through the gas conduit system <NUM>, towards an uncovered surface of an injection moulded item <NUM> located on the mould core <NUM> in situations where the mould core <NUM> and the mould cavity have been separated from each other.

By uncovered surface in the context is meant that, when after the mould halves/plates have been moved away from each other, and the injection moulded item <NUM> rests on the mould core <NUM>, some of the surfaces of the injection moulded item <NUM> are not covered by the opposite mould part any more, and are accessible. Other surfaces of the injection moulded item <NUM> will be in contact with the mould core <NUM> or the first surface <NUM> of main body <NUM> of mould insert part <NUM>, and these are covered.

<FIG>, showing a section, section A-A, of <FIG>, illustrates a situation, where the mould insert parts have been spaced apart after an item <NUM> has been injection moulded in the mould formed by the mould insert part <NUM> with the mould core <NUM> and the other - not shown - mould insert part with the mould cavity. In <FIG> the injection moulded item <NUM> is located on the mould core <NUM>. The arrows <NUM> indicate a flow/stream of gas - for example atmospheric air being blown onto the free outer surfaces <NUM> of the injection moulded item <NUM>. By free surfaces is meant surfaces of the item <NUM> which are not facing the mould core <NUM> or the first surface <NUM> of the main body10 of the mould insert part <NUM>, i.e. the surfaces of the item <NUM>, which has been exposed after the other mould insert part with the mould cavity has been moved away from the insert mould part <NUM> (with the mould core <NUM>).

The gas conduit system <NUM> extends inside the main body <NUM> of the mould insert part <NUM>, and connects the two or more gas outlet ports <NUM> with the gas inlet port <NUM>.

Thus, the gas inlet port <NUM> is common to the two or more gas outlet ports.

In the embodiment, shown in <FIG>, the gas conduit system <NUM> comprises a first conduit <NUM> extending from the gas inlet port <NUM> to the first gas outlet port <NUM>. The gas conduit system <NUM> further comprises a second conduit <NUM> extending from the gas inlet port <NUM> to the second gas outlet port <NUM>. As shown, the first and second conduits <NUM>, <NUM> branches of from each other in close vicinity of the gas inlet port <NUM>. In other not shown embodiments, the gas conduit system <NUM> may comprise intermediate conduit sections and/or branching off of conduits at other locations.

As shown in <FIG>, in other embodiments, the gas conduit system <NUM> may comprises a common gas conduit <NUM>, extending from the gas inlet port <NUM>, and which branches into sub-conduits <NUM>, which sub-conduits <NUM> connect to the gas outlet ports <NUM>. In, the embodiment, shown in <FIG> there are seven such sub-conduits <NUM>.

In either case, as shown, the gas conduit system <NUM> is provided in below said first surface <NUM>. This means that the gas conduit system <NUM> is provided below the plane P.

As shown, the gas inlet port <NUM> may also be provided below said first surface <NUM>. This means that the gas inlet port <NUM> is provided below the plane P.

In the embodiments shown in <FIG> and in <FIG> respectively, the gas inlet port <NUM> is provided in and through a side wall of the main body <NUM> of the mould insertion part <NUM>. In other, not shown embodiments the gas inlet port <NUM> may be provided in/through the second surface <NUM>.

In the embodiment shown in <FIG>, the two gas outlet ports <NUM>, <NUM> are arranged on opposite sides of the mould core <NUM>. In the embodiment shown in <FIG>, the seven gas outlet ports <NUM> completely surrounds/encircles the mould core <NUM>. More generally, in embodiments where the mould insertion part <NUM> comprises more than two gas outlet ports <NUM>, at least two of the two or more gas outlet ports <NUM> are arranged on opposite sides of the mould core <NUM>.

As mentioned above, the mould insert part <NUM> may - in not shown embodiments comprise more than the two gas outlet ports <NUM>, <NUM> shown in <FIG>, such as <NUM>-<NUM> gas outlet ports <NUM>. Preferably, the plurality of gas outlet ports <NUM> surrounds the mould core <NUM>. In some embodiments the plurality of gas outlet ports <NUM> are equidistantly spaced apart. In further embodiments the plurality of gas outlet ports <NUM> are formed in a circle surrounding the mould core <NUM>, as exemplified in the <FIG> embodiment. Alternatively, the plurality of gas outlet ports <NUM> may be formed at positions in the first surface <NUM>, dependent on a shape of the item <NUM> to be injection moulded, such that surfaces of the item <NUM> that are in particular need of cooling may be reached by the cooling gas from the outlet ports <NUM>.

In embodiments, such as the <FIG> embodiment, where there are more than two gas outlet ports <NUM>, all of the gas outlet ports <NUM> may be of the type designated with the reference number <NUM> in the <FIG> embodiment, i.e. where a first gas outlet port <NUM> is arranged fully in and through first surface <NUM> of the main body <NUM>.

However, in other - not shown embodiments, where there are more than two gas outlet ports <NUM>, some or all of the gas outlet ports <NUM> may be of the type designated with the reference number <NUM> in connection with the <FIG> embodiment, i.e. where a second gas outlet ports <NUM> is arranged in an intersection between the first surface <NUM> of the main body <NUM>, and one of the side flanges <NUM>.

As the plurality of gas outlet ports <NUM> are connected to one common gas inlet <NUM>, preferably provided at a side wall of the main body <NUM> of the mould insert part <NUM>, and the since the plurality of gas outlet ports <NUM> are arranged to surround the mould core <NUM>, at least some of the conduits of the gas conduit system <NUM> needs to stretch first in one direction, and then in the opposite direction. In one embodiment, a gas conduit <NUM> of the gas conduit system <NUM> comprises a bend <NUM>, of <NUM>° or more. In further embodiments, a gas conduit <NUM> of the gas conduit system <NUM> comprises a bend <NUM>, of <NUM>° formed in the first conduit <NUM>. In the embodiment shown in <FIG>, a bend <NUM> of <NUM>° is visible in <FIG>. The bend <NUM> is formed at least in a plane parallel to the plane P defined by the first surface <NUM>. As also shown in <FIG>, a second bend <NUM> is also formed in the first conduit <NUM>, which is less than, but very close to <NUM>°.

As is also visible in <FIG> some gas conduits <NUM>, in <FIG> the first gas conduit <NUM> is formed such that it at least partially extends under the mould core <NUM> of the mould insert part <NUM>. As shown in the section A-A in <FIG>, the mould insert part <NUM> may further comprise an injection channel <NUM> for injecting molten plastic into the mould. The injection channel <NUM> is arranged centrally through the mould core <NUM>. In other - not shown embodiments - and depending also on the shape and size of the item <NUM> to be injection moulded, an injection channel <NUM> may be arranged at other positions relative to the mould core, and in some cases, there may be more than one injection channel <NUM> (not shown). The gas conduits of the gas conduit system <NUM> necessarily must avoid such structures such as the injection channel <NUM> and for example passageways for ejector pins and the like. However, it has been realized that some gas conduits <NUM> may extend very close to and even under the core to save space in the mould insert part <NUM>.

As illustrated in <FIG>, the mould core <NUM> may comprise a centreline C.

In some embodiments, two or more gas outlet ports <NUM>, <NUM>, <NUM> are further configured to direct gas towards the centreline C of the core <NUM>. As shown in <FIG> this is the case with the <FIG> embodiment. It is also the case in the <FIG> embodiment.

Now referring again to <FIG>, the two gas outlet ports <NUM>, <NUM> are configured to direct the gas in an angle relative to a plane P defined by the first surface <NUM>. As shown this angle may be an obtuse angle. In general, the angle is larger than <NUM>° and smaller than <NUM>°.

The angle of each gas outlet port <NUM> is preferably configured to blow gas onto a desired area of the free outer surface <NUM> of the injection moulded item, and predetermined dependent on the shape of the injection moulded item <NUM>.

All of the gas outlet ports <NUM> may have the same angle relative to the plane P. In other embodiments, each gas outlet port <NUM> may be formed at angles relative to the plane, which are different from the other gas outlet ports <NUM>.

As also mentioned above, the mould insert part <NUM> in the embodiment shown in <FIG> generally has the same features as the mould insert part <NUM> in the embodiment shown in <FIG>, the difference being the arrangement of the gas conduit system <NUM> and the gas outlet ports <NUM>. The same reference numbers are used for like parts.

In the embodiment shown in <FIG>, the gas inlet port <NUM> shown with a connection stud <NUM>. It will be appreciated that also the embodiment of <FIG> may be equipped with such a connection stud.

The connection stud may be a separate part assembled to the mould insert part or it may be formed integral therewith.

In the embodiment shown in <FIG> seven gas outlet ports <NUM> are arranged in and through the first surface <NUM> of the main body <NUM> of mould insert part <NUM>. The gas outlet ports <NUM> are arranged to encircle (surround) the mould core <NUM>. The gas outlet ports <NUM> are connected to the gas inlet <NUM> via a main gas conduit <NUM>, which branches of into sub-conduits <NUM>, each of which connect a gas outlet port <NUM> with the main gas conduit <NUM>. Where the sub-conduits <NUM> branches of from the main gas conduit <NUM> a bend <NUM> between the main gas conduit <NUM> and the sub-conduit <NUM> is provided, which is <NUM>° (seen perpendicular to the plane P).

In any of the above described embodiment, at least the mould insert part <NUM> may be formed in an additive manufacturing process. In further embodiments thereof, both the mould insert parts, or even the mould plates of a mould box may be formed in an additive manufacturing process.

In mould plates/mould inserts formed in steal - as is conventional - it is very difficult to form anything other than linear channels. When instead the mould insert part <NUM> according to the invention is formed in an additive manufacturing process, such as 3D printing, and in a polymer material, e.g. a plastic, it is easier to shape complexly shaped gas conduits.

Turning now to <FIG>, these figures illustrates a mould insert part <NUM> having means for venting the mould during the injection moulding process. As also described above, the mould insert parts or even the mould plates of mould boxes may be formed in a in an additive manufacturing process, such as 3D printing, and in a polymer material, e.g. a plastic.

In such cases, when the mould plates/mould insert parts are clamped together for injecting the molten plastic into the mould, it has shown that the polymer material makes the mould plates/mould insert parts more air tight, than is the case with mould plates/mould insert parts formed in e.g. steel. This increases the need for venting the mould. Before injecting the molten plastic into the mould (mould cavity), the mould is filled with atmospheric air. When the molten plastic enters the mold cavity, this air must efficiently be vented from the mould cavity in order to make space for the molten plastic, and to ensure even distribution of molten plastic and to prevent air bubbles in the finished injection molten item <NUM>.

A mould insert part according to a fourth aspect of the invention alleviates or eliminates these problems.

<FIG> shows a mould insertion part <NUM> according to the fourth aspect.

The mould insertion part <NUM> in <FIG> is illustrated as a mould insertion part <NUM> with a mould cavity <NUM>. The mould cavity <NUM> shown is as such unrelated to the mould core <NUM> shown in connection with <FIG>. However, the mould insert part <NUM> is configured for cooperating with a mould insertion part with a mould core (not shown), where the mould core is configured to cooperate with the mould cavity to form an injection moulded item (not shown). In <FIG>, the mould cavity <NUM> has an elongate cylindrical shape configured to form an elongate cylindrical item.

The first surface <NUM> defines a plane P2. The first surface <NUM> is configured for facing a second mould insert part with a mould core (not shown), when both are inserted in/attached to mould plates of a mould box, e.g. as described above.

The mould insert part <NUM> comprises a mould core cavity <NUM> extending inwardly from said first surface <NUM> of the main body <NUM>. This means that the mould core <NUM> extends below the plane P2.

The mould insert part <NUM> is configured for cooperating with a second mould insert part (not shown) having a mould core, which is configured for - together with the mould insert part <NUM> with the mould cavity <NUM> - forming a mould for injection moulding an injection moulded item (not shown).

The mould insert part <NUM> is insertable into a mould plate of a mould box, e.g. as exemplified above. The second mould insert part with the mould core likewise is insertable into another mould plate of a mould box, e.g. as exemplified above.

The mould insert part <NUM> may be configured to cooperate with a mould insert part <NUM> (having a mould core <NUM>) as described above, but where the mould core and the mold cavity of the respective mould insert parts are adapted to cooperate. In other embodiment the mould insert part <NUM> may be configured for cooperating with a more conventional type of mould insert part with a core.

<FIG> shows a section A-A through the mould insert part <NUM> as indicated in <FIG>. The side sectional view in <FIG> reveals that the mould insert part <NUM> comprises an injection channel <NUM> for injecting molten plastic into the mould. The injection channel <NUM> is arranged centrally through the mould insert part <NUM> and may interface with further channels/runners of cavity portions in the cooperating mould insert part to fill the mould cavity <NUM>.

<FIG> shows the detail B indicated by circle in <FIG>. In <FIG> it is shown that a venting conduit <NUM> is formed extending from an extreme end of the mould cavity <NUM>.

The venting conduit <NUM> forms an air vents configured for allowing air to escape from the mould cavity <NUM> as the mould cavity <NUM> is filled with melted material.

In steel mould plates/mould insert parts, it is very difficult to form other than linear channels. The mould insert part <NUM> according to the invention is 3D printed in plastic. Thereby, it is easier to shape complexly formed air vents <NUM>.

In the shown example, the venting conduit <NUM> has a generally cylindrical main portion <NUM>. Where the venting conduit main portion <NUM> approaches the mould cavity <NUM>, a conical potion <NUM> of the venting conduit <NUM> is provided such that a restriction hole <NUM> is provided between the mould cavity <NUM> and the venting conduit <NUM>.

The restriction hole is so small that it prevents molten plastic to exit the mould cavity <NUM>, while still allowing the air otherwise trapped in the mould cavity <NUM> to escape.

Claim 1:
A mould insert part (<NUM>) for injection moulding, comprising
- a main body (<NUM>) having a first surface (<NUM>) and an opposed second surface (<NUM>), the first surface defining a plane (P)
- a mould core (<NUM>) extending from the first surface (<NUM>) of the main body (<NUM>) of the mould insert part (<NUM>);
- a gas inlet port (<NUM>) connectable to a supply of pressurized gas;
- two or more gas outlet ports (<NUM>) arranged to direct a gas flow towards an uncovered surface (<NUM>) of an injection moulded item (<NUM>) located on the mould core (<NUM>), after the mould core (<NUM>) and the mould cavity have been separated from each other; and
- a gas conduit system (<NUM>) extending inside the main body (<NUM>) of the mould insert part (<NUM>), and connecting the two or more gas outlet ports (<NUM>) with the gas inlet port (<NUM>), common to the two or more gas outlet ports (<NUM>),
wherein each of the two or more gas outlet ports (<NUM>) are arranged at least partially through the first surface (<NUM>), and
wherein the gas conduit system (<NUM>) is provided in the main body (<NUM>) below said first surface (<NUM>).