TECHNICAL FIELD
The present disclosure relates to an injection moulding machine. More particularly, the present invention relates to an inert gas feeding system provided on the injection moulding machine.
BACKGROUND
Injection moulding machines are commonly known to manufacture plastic moulded products made of various polymer materials. The injection moulding machine commonly includes a material feeding system, a barrel heating system, and a clamping arrangement. The material feeding system generates vacuum and pulls solid granules of plastic material (raw material) from material bags / material bins, and then feeds to the barrel which has got the heating system. The barrel heating system melts the solid granules of plastic material (raw material) and injects the molten plastic material to the mould which is clamped under tonnage in the injection moulding machine. The clamping arrangement employs the mould that receives the molten plastic material, shapes the molten plastic material, and then cools the molten plastic material with the help of cooling fluid which is circulated through the holes in the mould, to obtain the plastic moulded product of desired shape.
In conventional injection moulding machines, the material feeding system intakes air along with the solid granules of plastic material (raw material), and thus a mixture of air and solid granules of plastic material (raw material) is transferred to the barrel heating system. Therefore, while the barrel heating system melts the solid granules of plastic material (raw material), a portion of the solid granules of plastic material (raw material) burns by reacting with oxygen available in the air so received therein. Such burning of the portion of the solid granules of plastic material (raw material) causes a defect in the final plastic moulded product, called black dots. In particular, the injection moulding machine may be used to manufacture the moulded products made of Poly Methyl Methyl

Acrylate (PMMA) material, such as but not limited to, a glass cover for automotive speedometer, a window panel, a headlight panel, and the like. Such moulded products are usually transparent in nature. Due to transparent nature of such moulded products, the defect of black dots is relatively more visible. Thus, the moulded products are more likely to rejection, increasing the overall cost of the moulded products.
Various solutions have been suggested to solve the problem of black dots defect in manufacturing of the plastic moulded products, with use of the injection moulding machine. One of such solutions provides an inert gas feed that feeds in pressurized inert gas in a hopper of the material feeding system of the injection moulding machine. Such feed of the inert gas to the hopper causes removal of oxygen from the hopper, and a mixture of the granules of raw material and the inert gas is supplied to the barrel heating system. However, in such solution, the hopper undergoes heavy operational load of receiving the material, receiving the inert gas, and exiting the dust and moisture. Accordingly, the hopper is required to be provided with a material receiving port, an inert gas receiving port, and a dust and gas exiting port. This makes a structure and arrangement of the hopper relatively more complex, and thus increases chances of inert gas leakage from any of the aforementioned port. Also, in such solution of the injection moulding machine, the inert gas causes obstruction in the flow of material to the barrel heating arrangement, due to a pressure of the inert gas.
Accordingly, in light of the aforementioned drawbacks and several other inherent in the existing arts, there is a well felt need to provide an injection moulding machine, employing an inert gas feeding system capable of supplying the inert gas with less complex and leak-proof structure, and concurrently avoid obstruction to the flow of the granules of raw material.

SUMMARY
An object of the present invention relates to an injection moulding machine employing an inert gas feeding system. The inert gas feeding system includes a gas supply and a gas adapter. The gas adapter is positioned between a material feeding system and a barrel heating system in a material flow direction, such that the gas adapter replaces air in the raw material, passing therethrough, with the inert gas.
Another object of the present invention relates to an injection moulding machine employing an inert gas feeding system. The inert gas feeding system includes a gas supply and a gas adapter. The gas adapter is a separate unit positioned between a material feeding system and a barrel heating system in a material flow direction, adding to a relatively less complex and leakage-proof design of a hopper of the material feeding system of the injection moulding machine. Also, such design of the injection moulding machine facilitates relatively easy assembly of the injection moulding machine.
Yet another object of the present invention relates to an injection moulding machine employing an inert gas feeding system. The inert gas feeding system includes a gas supply and a gas adapter. The gas adapter is positioned between a material feeding system and a barrel heating system in a material flow direction, such that the gas adapter replaces air in the raw material, passing therethrough, with inert gas. Particularly, the gas adapter allows a supply of the inert gas at a pressure lesser than 1 bar or equal to 1 bar, to the raw material flowing therethrough. Such low pressure supply of the inert gas in the gas adapter allows easy and unrestricted flow of the raw material, while performing the function of replacement of the air with the inert gas in the raw material. Thereby, an unobstructed flow of the raw material is facilitated.
The present disclosure relates to an injection mounding machine comprising, a material feeding system, a barrel heating system, and an inert gas feeding

system. The material feeding system is adapted to receive raw material, provided in form of granules of raw material surrounded by air. The barrel heating system is disposed downstream to the material feeding system in a material flow direction. The inert gas feeding system includes a gas supply and a gas adapter. The gas supply is adapted to supply inert gas. The gas adapter is disposed between the material feeding system and the barrel heating system, such that the granules of raw material flows from the material feeding system to the barrel heating system through the gas adapter. Further, the gas adapter is a separator unit configured to receive the inert gas from the gas supply, and to replace air in the raw material passing therethrough with the inert gas.
BRIEF DESCRIPTION OF DRAWINGS
The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings. These and other details of the present invention will be described in connection with the accompanying drawings, which are furnished only by way of illustration and not in limitation of the invention, and in which drawings:
Figure 1 illustrates a schematic of an injection moulding machine, in accordance with the concepts of the present disclosure.
Figure 2 illustrates a sectional view of a gas adapter of an inert gas feeding system deployed on the injection moulding machine of Figure 1, in accordance with the concepts of the present disclosure.
DETAILED DESCRIPTION
In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, that

embodiments of the present invention may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only one of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Example embodiments of the present invention are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.
Figure 1 shows a schematic of an injection moulding machine [100], in accordance with the concepts of the present disclosure. The injection moulding machine [100] is employed to manufacture one or more injection moulded products made of raw material. Preferrably, the raw material is Poly Methyl Methyl Acrylate (PMMA) material. Although, concepts of the present disclosure will be described for the manufacture of moulded products, made of Poly Methyl Methyl Acrylate (PMMA) material as the raw material, by the injection moulding machine [100], manufacturing of moulded products, made of other type of polymer materials, as the raw material by the injection moulding machine [100], may also be considered within the scope of the present disclosure. The injection moulding machine [100] comprises of a material feeding system [102], a barrel heating system [104], a clamping unit [106], and an inert gas feeding system [108], each of which work in conjunction to facilitate manufacture of one or more injection moulded product made of raw material. A structure and arrangement of various components of the injection moulding machine [100] will be described hereinafter.
The material feeding system [102] is adapted to intake raw material from material bags, perform initial processing on the raw material, and supply the raw material to the barrel heating system [104] via the inert gas feeding system [108]. The material feeding system [102] includes a hopper [110] and a cyclone

separator [112]. Although, the hopper [110] and the cyclone separator [112] are defined as separate components of the material feeding system [102], it may be noted that the hopper [110] and the cyclone separator [112] may also be provided as a single integrated unit of the material feeding system [102] and is within the scope of the present disclosure. Although, the hopper [110] and the cyclone separator [112] are only disclosed as component of the material feeding system [102], various other components of the material feeding system [102] for transferring and supply of the raw material may be contemplated.
The hopper [110] is a suction unit that transfers the raw material from material bags. The hopper [110] includes a suction port [114] connected to a vacuum generator, and a material intake port [116] connected to the material bags. The vacuum generator generates negative pressure at the suction port [114], such that the raw material is transferred at the material intake port [116] of the hopper [110] of the material feeding system [102]. Particularly, the hopper [110] pulls in the raw material in the form of granules of raw material. In doing so, air and dust is also taken along with the granules of raw material. Therefore, the hopper [110] transfers the granules of raw material surrounded by air and dust, as the raw material.
The cyclone separator [112] is adapted to separate dust particles transferred in by the hopper [110] of the material feeding system [102]. The cyclone separator [112] is positioned downstream to and fluidly connected to the hopper [110] in a material flow direction [118]. The hopper [110] and the cyclone separator [112] are arranged, such that dust and a portion of air is removed from the suction port [114] of the hopper [110], while the granules of raw material surrounded by remaining portion of air is supplied to the inert gas feeding system [108], in the material flow direction [118]. The inert gas feeding system [108] replaces the air in the raw material with the inert gas, and supplies the raw material surrounded by the inert gas to the barrel heating system [104]. The material flow direction [118] is a direction of flow of the raw material between various components of

the injection moulding machine [100]. In the present invention, the cyclone separator [112] is provided with an air vent [120].
The barrel heating system [104] is a heating unit disposed downstream to the cyclone separator [112] via a portion of the inert gas feeding system [108], in the material flow direction [118]. Particularly, the barrel heating system [104] is positioned downstream to a gas adapter [122] of the inert gas feeding system [108], which in turn is positioned downstream to the cyclone separator [112], in the material flow direction [118]. The barrel heating system [104] is adapted to receive the granules of raw material surrounded by an inert gas (free from air), melt the granules of raw material, and inject the molten raw material in the clamping unit [106]. Particularly, the gas adapter [122] replaces the air with the inert gas, while the raw material flows therethough, and thus the barrel heating system [104] receives the granules of raw material surrounded by the inert gas. Replacement of the air with the inert gas in the gas adapter [122] of the inert gas feeding system [108], will be described later in details. The barrel heating system [104] includes a screw [124] positioned within a barrel [126]. The barrel [126] employs heavy-duty heaters. The screw [124] receives the granules of raw material (surrounded by the inert gas) from the gas adapter [122] of the inert gas feeding system [108], and thus linearly transport to an injection portion. While the granules of raw materials are transported in the screw [124], the heavy-duty heaters of the barrel [126] melts the granules of raw material. Thus, the molten raw material is supplied to the injection portion of the barrel heating system [104], through which the molten raw material is injected to the mould which is in the machine clamping unit [106].
The clamping unit [106] includes the mould with a core half [128] and a cavity half [130], and a toggle unit (not shown). The toggle unit facilitates mating together and separating away of the core half [128] of the mould and the cavity half [130] of the mould [130], relative to each other. As the core half [128] and the cavity half [130] mates together, a cavity is formed between the core half

[128] and the cavity half [130] of the mould. In such conditions, the molten raw material is injected in the cavity at defined pressure, to fill the cavity with the molten raw material. The cavity is suitably shaped to take a defined shape of desired moulded product. Furthermore, as the molten raw material is filled in the cavity of the clamping unit [106], a cooling unit cools the molten raw material in the cavity of the clamping unit [106]. Thus, the moulded product of the raw material is manufactured in the desired shape. Moreover, the toggle unit then separates the core half [128] from the cavity half [130] of the mould, to facilitate removal of the moulded product therefrom.
Furthermore, as mentioned in the aforementioned disclosure, the inert gas feeding system [108] is provided to replace air with the inert gas in the raw material, as the raw material flows from the material feeding system [102] to the barrel heating system [104] through the inert gas feeding system [108]. The inert gas feeding system [108] includes a gas supply [132], the gas adapter [122], and a control unit [134]. The gas supply [132] is fluidly connected to the gas adapter [122], via the control unit [134]. Particularly, the control unit [134] is disposed between the gas adapter [122] and the gas supply [132] that controls a supply of the inert gas therethrough. Particularly, the control unit [134] is control valve that allows the supply of the inert gas form the gas supply [132] to the gas adapter [122], at a pressure lower than or equal to 1 bar pressure. Furthermore, the control unit may be provided with an interface that may be manipulated to control a pressure of supply of the inert gas from the gas supply [132] to the gas adapter [122].
The gas supply [132] is a cylinder that stores compressed inert gas, which may be supplied to the raw material flowing through the gas adapter [122]. Preferably, nitrogen gas is supplied as the inert gas to the raw material flowing through the gas adapter [122]. Although, usage of nitrogen gas as the inert gas is disclosed in the present disclosure, any other conventionally known inert gas may also be

used as the inert gas that may be supplied to the raw material flowing through the gas adapter [122].
The gas adapter [122] is fluidly connected to the gas supply [132], to receive the inert gas therein. Moreover, the gas adapter [122] is disposed between the cyclone separator [112] of the material feeding system [102] and the barrel heating system [104], such that the raw material passes through the gas adapter [122] while flowing from the cyclone separator [112] of the material feeding system [102] to the barrel heating system [104]. Particularly, the gas adapter [122] receives the granules of raw material surrounded by air from the cyclone separator [112] of the material feeding system [102], replaces the air with the inert gas, and allows a supply of the granules of raw material surrounded by the inert gas to the barrel heating system [104]. A structure and arrangement of the gas adapter [122], will now be described in details hereinafter.
Figure 2 shows a sectional view of the gas adapter [122]. The gas adapter [122] includes a material inlet [136], a material outlet [138], two gas inlets [140], and a separation chamber [142] defined between the material inlet [136], the material outlet [138], and the two gas inlets [140]. The material inlet [136] is fluidly connected to the cyclone separator [112] of the material feeding system [102]. The material outlet [138] is fluidly connected to the barrel heating system [104]. The two gas inlets [140] are defined on opposite sides of an external periphery [144] of the gas adapter [122], and are fluidly connected to the gas supply [132]. Further, the separation chamber [142] is defined within the gas adapter [122], such that the separation chamber [142] is in fluid communication with each of the material inlet [136], the material outlet [138], and the two gas inlets [140]. The separation chamber [142] replaces air in the raw material with the inert gas. Particularly, with such arrangement, the gas adapter [122] receives the granules of raw material surrounded by air from the cyclone separator [112] of the material feeding system [102] through the material inlet [136], receives the inert gas at a pressure lower than 1 bar from the gas supply [132] through the two gas

inlets [140], replaces the air in the raw material with the inert gas in the separation chamber [142], and exits the raw material surrounded by the inert gas to the barrel heating system [104] through the material outlet [138]. Therefore, the granules of raw material surrounded by the inert gas is transported to the barrel heating system [104], and air is returned back to the cyclone separator [112] of the material feeding system [102] through the material inlet [136]. The cyclone separator [112] further vents out air through the air vent [120].
In operation, the injection moulding machine [100] is employed to manufacture moulded products, made of Poly Methyl Methyl Acrylate (PMMA) material (interchangeably referred to as the raw material hereinafter). In particular, the hopper [110] of the material feeding system [102] transfers granules of raw material from the material bags. The hopper [110] of the material feeding system [102] takes in air and dust along with the raw material. The hopper [110] thereafter supplies the raw material surrounded by dust and air to the cyclone separator [112]. The cyclone separator [112] vents dust and a portion of the air, and supplies the raw material surrounded by remaining portion of air to the gas adapter [122] of the inert gas feeding system [108]. The gas adapter receives the raw material surrounded by air from the hopper [110], receives the inert gas from the gas supply [132], and replaces the air with the inert gas. An operation of the gas adapter [122], for replacement of the air with the inert gas will be described hereinafter.
The gas adapter [122] receives the raw material surrounded by air from the hopper [110] through the material inlet in the separation chamber [142], and receives the nitrogen gas (interchangeably referred to as the inert gas hereinafter) from the gas supply [132] from the two gas inlets [140] in the separation chamber [142]. As the control unit of the inert gas feeding system [108] allows the supply of the inert gas to the gas adapter [122] at a pressure below 1 bar or equal to 1 bar, the supply of the raw material to the separation

chamber [142] is not obstructed. Thereafter, the gas adapter [122] separates the air form the raw material, and replaces the air with the inert gas, in the separation chamber [142]. As the inert gas is received form two opposite positioned inlets [140] in the separation chamber, a relatively uniform mixture of the inert gas with the raw material is facilitated. Therefore, complete removal of the air from the raw material is facilitated. Furthermore, the gas adapter [122] supplies the air (removed from the raw material) back to the cyclone separator [112] through the material inlet [136], which in turn vents the air to the external environment through the air vent [120]. Moreover, the gas adapter [122] supplies the raw material surrounded by the inert gas to the barrel heating system [104] through the material outlet [138].
The barrel heating system [104], upon receiving the raw material surrounded by the inert gas, transports the raw material through the screw [124] of the barrel heating system [104]. The raw material is heated to melt in the screw [124] of the barrel heating system [104]. As the raw material is surrounded by the inert gas, and is free from air, burning of the raw material does not take place and thus the defect of black dots is not observed. The molten raw material is transported to the cavity (between the core half [128] of the mould and the cavity half [130] of the mould) of the clamping unit [106]. The molten raw material is then cooled in the mould which is in the clamping unit [106], to be shaped to form the plastic moulded product.
In accordance with the aforementioned points, the injection moulding machine [100] disclosed in the present invention may facilitate manufacture of the plastic moulded product made of Poly Methyl Methyl Acrylate (PMMA) material, without the defect of black dots. Therefore, manufacturing of the plastic moulded product is relatively more defect-free, less costlier, and more reliable in operation.

While the preferred embodiments of the present invention have been described hereinabove, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims. It will be obvious to a person skilled in the art that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.
List of Components:
100 - Injection Moulding Machine
102 - Material Feeding System
104 -Barrel Heating System
106- Clamping Unit
108 - Inert Gas Feeding System
110-Hopper
112 - Cyclone Separator
114-Suction Port
116- Material Intake Port
118 - Material Flow Direction
120-Air Vent
122-Gas Adapter
124 - Screw
126-Barrel
128-First Mould

130-Second Mould 132- Gas Supply 134-Control Unit 136-Material Inlet 138-Material Outlet 140-Gas Inlets 142 - Separation Chamber 142 - External Periphery

We Claim:
1. An injection moulding machine [100], comprising:
a material feeding system [102] adapted to receive raw material, the raw material being provided in form of granules of raw material surrounded by air;
a barrel heating system [104] disposed downstream to the material feeding system [102] in a material flow direction; and
an inert gas feeding system [108], including:
a gas supply [132] adapted to supply inert gas; and
a gas adapter [122] disposed between the material feeding system [102] and the barrel heating system [104], such that the granules of raw material flows from the material feeding system [102] to the barrel heating system [104] through the gas adapter [122], wherein
the gas adapter [122] is a separator unit configured to receive the inert gas from the gas supply [132], and to replace air in the raw material passing therethrough with the inert gas.
2. The injection moulding machine [100] as claimed in claim 1, wherein the inert gas feeding system [108] includes a control unit [134] disposed between the gas supply [132] and the gas adapter [122], to control a supply of the inert gas flowing therethrough.
3. The injection moulding machine [100] as claimed in claim 2, wherein the control unit [134] allows the gas supply [132] to supply the inert gas to the gas adapter [122] at one of a pressure lower than 1 bar and equal to 1 bar.

4. The injection moulding machine [100] as claimed in claim 1, wherein the gas adapter [122] includes a material inlet [136] for receiving the raw material from the material feeding system [102].
5. The injection moulding machine [100] as claimed in claim 1, wherein the gas adapter [122] includes two or more gas inlets [140] disposed on opposite sides of an external periphery [144] of the gas adapter [122], for receiving the inert gas therein.
6. The injection moulding machine [100] as claimed in claim 4 and claim 5, wherein the gas adapter [122] includes a separation chamber [142] in connection with the material inlet [136] and the two or more gas inlets [140], the separation chamber [142] facilitates replacement of the air with the inert gas in the raw material.
7. The injection moulding machine [100] as claimed in claim 1, wherein the material feeding system [102] includes a cyclone separator [112] disposed upstream to the gas adapter [122] in the material flow direction [118], the cyclone separator vents out air separated by the gas adapter [122].
8. The injection moulding machine [100] as claimed in claim 1, wherein the inert gas is nitrogen.
9. The injection moulding machine [100] as claimed in claim 1, wherein the raw material is Poly Methyl Methyl Acrylate (PMMA).