DESC:Form 2

The Patents Act,
(39 of 1970)

Complete Specification
(See Section 10 Rule 13)

“An Improved Injection frame for Injection molding machine”

Milacron India Pvt. Ltd.
An Indian Company
93/2 & 94/1, Phase-1, GIDC Vatva,
Ahmedabad–382445, Gujarat, India.

The following specification particularly describes the nature of the invention and the manner in which it is to be performed:

Field of Invention:

The present invention relates to an improved injection frame for injection molding machine. In particular it provides an improved injection frame for electric injection molding machine. It provides the injection frame for the reciprocating screw type electrically operated injection unit.

Background of Invention:

Plastic injection molding is the process of heating plastic raw material to its melting point, forcing the viscous material into a mold, and allowing it to cool into a hardened shape. Melted plastic under pressure take shape as per mold cavity so various shape of plastic article can be produced with this process. The equipment for process of plastic injection molding process is called Injection molding machine. Injection molding machine consists of mainly two parts, an Injection unit and a clamping unit. The injection unit melts polymer and pushes polymer under high pressure into mold cavity. The clamping unit performs mainly two functions. First, it holds the mold together and in place as the molten polymer is pushed under pressure into the mold. Second, it controls the opening and closing of the mold.

Injection unit has mainly two functions. First is to melt the plastic raw material known as plasticizing function. Second is to inject the metered quantity of melted plastic in to mold cavity from an opening at front thru nozzle tip, known as injection function.

Clamping unit and Injection unit involves movable parts for performing above functions. In prior art most of actuator for such movements were hydraulically operated. If such actuators as operated by electric motors then machine is called electric injection molding machine. Recently electric Injection molding machine are more popular due to their more precision, repeatability, speed and energy efficiency.

Prior Art and Its Disadvantages:

Referring to Figure 1, shows the Conventional electric injection unit. Here front and rear platen (7) are connected by four guide rod (8) to make a connected structure. Middle platen (6) is placed over four guide rod thru guide bush which allow middle platen (6) sliding relative to rear platen (7) and Front platen (5) or barrel (1). Rotation of feed screw (2) and axial movement of middle platen (6) is done by separate electric actuators. One Electric motor (10) imparts rotational movement to feed screw (2) via belt (12) and pulley (11) which is mounted on middle platen (6). Second electric motor (10) is placed on middle plate or rear platen (7), moves middle platen (6) forwards and reverse with use of ball screw (13) mechanism, which convert rotary motion of motor to linear motion of middle platen (6). When feed screw (2) moves forward very high force called injection force is imparted to middle platen (6) from rear platen (7) via ball screw (13) mechanism, which generate high pressure in plastic melt at front of feed screw (2). Patent application US5955117A discloses similar arrangement and targets to reduce the effect of friction in ball screw mechanism.
However said application fails to disclose friction force due to bending of guide rod. Due to high injection force front and rear platen (7) deflects which in turn also deflects the guide rod towards center. This creates an extra friction force between bushing and guide rod as middle platen (6) is guided in guide rod. The injection force imparted by motor is wasted in overcoming said friction force reducing the effective pressure on melt. This creates processing related issues in plastic product as actual pressure is less than required pressure. In addition to above, as bushings being the sliding members, it will worn-out over time. Bushing wear can shift one end of feed screw (2) connected to middle platen (6) downwards. As other end of feed screw (2) is inside barrel it creates misalignment of feed screw (2) relative to barrel (1) and related problem occurs. The invention disclosed herein the prior art also does not mention downward deflection due to weight of middle platen (6) causing misalignment of feed screw (2). Sometimes such misalignment of middle platen (2) cause failure in actuator elements like ball screw which are costly item.
Another invention is disclosed in patent application JP2001269974 (A). It discloses an improvement by adding sliding support members below middle platen to eliminate deflection due to weight.
However this requires bushing and guide rod structure for guidance. So it doesn’t eliminates friction force generated due to guide rod bending during injection.

An improvement is mentioned in US patent application US2003049351A1 for an injection unit of a three-plate structure. Front plate and rear plate are connected to each other through a plurality of tie bars. An intermediate plate is arranged between the front plate and the rear plate and guided by the tie bars such that it can be moved in forward/backward direction. The front plate is fixed to a slide table. The rear plate and intermediate plate are supported by a linear slide guide on the slide table. A rear end portion of a barrel is fixed to a central area of the front plate. A rear end portion of a screw is supported by the intermediate plate with a bearing in between. A ball screw is incorporated in the rear plate and a forward end of a threaded rod of the ball screw is fixed to a central area of a back surface of the intermediate plate through a load cell. Object of that invention was to provide an injection unit of an injection molding machine which can enhance the detection accuracy of a forward thrust force of a screw and obtain small sized unit.
However this prior art does not disclose that slide table over which linear guide member is placed should be very rigid. Unless it is designed with good rigidity, middle platen can still deflect vertically with reference to front and rear platen and it can create alignment issue of barrel with reference to feeds crew. Increasing rigidity requires heavier section so height of slide table needs to be high. Also this arrangement does not eliminate tie bar so there is chance of twisting while tightening nut during assembly. Also it needs due care that guiding member are assembled parallel to the barrel axis as slide table is a separate part from frame.

Referring to FIG. 2 shows Conventional high speed electric injection unit with single piece frame. For simplicity of construction, some conventional injection unit structure can have linear guide element placed directly over side wall (16) as shown in fig. Linear guide element consists of linear guide block (17a) and linear guide rail (17b). linear guide block (17a) slides over linear guide rail (17b) without friction. In such construction the side wall (16) of frame itself acts as support member for guiding elements that is linear motion guide. This single piece frame (15) replaces front platen, rear platen and connecting tie bars by single piece member. For supporting middle or traverse platen (6) linear motion guide block and rail (17a & 17b) are mounted over both side wall (16). Side wall (16) also withstand injection force so guide rod (8) are not needed. Such single piece frame (15) is shown in FIG 4 in detail. With this arrangement problem of vertical deflection of middle platen and feed screw can be solved as side members are rigid compared to tie bar. Also, sliding motion is replaced by rolling motion via linear motion guide resulting in less friction. Due to less friction, injection force and hence pressure lost is minimum, so all the pressure applied to platen transfer to melt via feed screw (2). Also rolling element of linear motion guide is having almost nil wear during its lifetime, so consistency and smoothness of motion preserved for longer lifetime. So this kind of structure is also suitable for high speed injection.
However, this conventional single piece injection frame (15) is also having limitation due to deflection of side wall or undesirable side load over linear guide element. As shown in FIG 5, in such single piece frame, Injection force (19) acts in center portion of front and rear area of frame, as indicated by two large arrows. This force is transmitted by two side wall (16), each carries half of load (20). Due to difference in line of action, a bending moment (21) acts on front and rear end as shown. This bending moment (21) will deflect front and rear portion of Frame. As sides walls are directly connected to front and rear portion both side wall (16) will also deflected in bow shape. FIG 6 shows deflection (23) of frame under Injection Force (19). Its deflection is shown in exaggeratedly for ease of understanding, which is evaluated with use of Finite Element Analysis software. The side wall (16) of frame also contains linear guide blocks for support of middle platen (6). So, this deflection creates deflection in rail (17b) or heavy side load on linear guide block (17a). This side deflection or side reaction force if ignored can lead to premature failure of linear guide member (17a and 17b). Failure of linear guide member can also lead to failure of other precision parts like feed screw (2), barrel (1), ball screw (13) actuator, bearings etc. Hence it’s desired to reduce this side deflection in case of single piece box type frame.
Another Japanese patent application JP2010111020A discloses an injection apparatus, in which the guiding member is provided on the frame of an injection unit through a guiding supporting structure. A screw rotating mechanism is assembled to the guiding member. This prevents the guide member from being affected by deformation of the frame. This allows the movement of the screw rotation mechanism to be smoother. Thus a screw rotatable coupled to the screw rotation mechanism can be smoothly moved.
However in this prior art the guiding supporting structure is having an extra support member over both sidewalls. This support is fixed on top of side walls only at its both ends by set screw to provide flexure in middle portion having relief below it. So during assembly it needs to take care for play (or clearance) in the fixing area and keep support member precisely parallel to barrel and screw. Also such play may increase over a time after running continuously. Once there is play it may not be able to guide the middle platen hence feed screw precisely.
In another invention as per JP, 2017-138311A side deflection of side walls can be reduced by building a cross rectangular bridge to connect two side walls. A rectangular shaped cross bridge is provided to reduce the flexure or deflection of side members.
However, the middle platen contains driving member like electric motor on top as shown in FIG 2, which are not shown in the reference document. So to avoid collosion of electric motor with this connecting bridge, structure can be placed near rear end. With this arrangement deflection can be reduced only upto some extent, but as flexure from front plate cannot be neglected, it can still deflect side walls and reduce life of linear guide element
Another way to reduce side wall deflection is to make the Frame very rigid with very higher thickness of Front, Rear and side walls. But this leads to very high weight of frame casting, so the cost of machine also increases. One limitation to all single piece frame is that, single piece casting is not suitable for larger size injection unit as its casting and machining becomes very costly as the size increases. Because this single piece machining needs to be carried out on large size and accurate milling machines, larger size machine tools needs high investment and cost are also higher.
Disadvantages of prior art:
The prior art suffers from all or at least one of the following disadvantages:
• Most of the prior art fails to provide an improved injection frame for injection molding machine.
• Most of them do not provide an improved injection frame for electric injection molding machine.
• Many of them fails to provide the injection frame for the reciprocating screw type electrically operated injection unit.
• Most of the prior art imparts higher injection force. Due to this injection force, front and rear platen deflects, which also deflects guide rod. As middle platen is guided in guide rod, due to guide rod deflection friction force in bushing will increase, thus some of injection force imparted by motor is wasted in overcoming friction.
• Many of them provides substantially less injection force, which creates processing related issues as actual pressure is than required pressure.
• Many of them fail to provide high injection speed.

• Most of the prior art discloses, an injection unit with three-plates and guide rod structure. Due to these guide rods structure, number of parts increases which in turn increases the maintenance during assembly to avoid twisting during applying torque to nut.
• None of the prior art provides mechanism for smooth rotation of feed screw inside the barrel.
• Most of them fails to describe the technicalities to provide less deflection in sidewall during injection.

Thus, there is an unmet urge to provide the invention that obviates the disadvantages of prior art and provides a solution to the problems yet unaddressed.
Objects of Invention:
The primary object of the present invention is to provide an improved injection frame of electric injection unit of injection molding machine.
Another object of the present invention is to provide the improved injection frame for injection molding machine, which supports linear guide elements and improves the life of them due to reduced side load and deflection.

Yet another object of the present invention is to provide the improved injection frame for injection molding machine, which provides smooth movement of feed screw inside the barrel and prevents premature motion of reciprocating feed screw transferring metal particles to melt.

Another object of the present invention is to provide the improved injection frame for injection molding machine, which increases the speed of injection unit to increase the productivity.

Yet another object of the present invention is to provide the improved injection frame for injection molding machine, which supports the production of thin wall plastic parts as well as complex articles.
Another object of the present invention is to provide the improved injection frame for injection molding machine, which provides ease of assembly operation by reducing number of parts.
Yet another object of the present invention is to provide the improved injection frame for injection molding machine, which is cost-effective.
Yet another object of the present invention is to provide the improved injection frame for injection molding machine, that obviates the problem of prior art.
Brief Description of Drawings:
Fig:1 : Shows Conventional electric injection unit
Fig:2 : Shows Conventional high speed electric injection unit with single piece frame
Fig:3 : Shows an embodiment of present Injection frame for Injection molding machine
Fig:4 : Shows Conventional injection frame
Fig:5 : Shows the Forces and moments of the conventional frame
Fig:6 : Shows the Deflection of conventional frame as per prior art during injection
Fig:7 : Shows the isometric view of the present Injection frame for Injection molding machine
Fig:8 : Shows the geometry and connection of side wall to front and rear plate in frame as per present invention
Fig:9 : Shows the forces and moments of the present invention
Fig:10a : Shows the deflection of frame as per present invention
Fig:10b : Shows the deflection of frame with very less amount undercut in present invention
Fig:10c : Shows the deflection of frame with high amount undercut in present invention
Fig:11 : Shows an alternative embodiment of present Injection frame for Injection molding machine
Fig:12 : Shows the top view of an alternative embodiment of present Injection frame for Injection molding machine
Fig:13 : Shows the detailed sidewall of an alternative embodiment of present Injection frame for Injection molding machine
Meaning of reference numerals for the present Injection frame for Injection molding machine:
P : Present Injection frame for Injection molding machine
1 : Barrel
2 : Feed screw
3 : Heater
4 : Nozzle tip
5 : Front platen
6 : Middle platen or pusher platen
7 : Rear platen
7.1 : Rear platen’
8 : Guide rod
9 : Feed throat
10 : Electric motor
10.1 : Electric Motor’
11 : Pulley
12 : Belt
13 : Ball screw
14 : Nut
15 : Single piece injection frame
15.1 : Single piece injection frame’
16 : Side wall of single piece injection frame
16.1 : Side wall’
17a : Linear guide block
17a’ : Linear guide block’
17b : Linear guide rail
17b’ : Linear guide rail’
18 : Housing portion for ball screw
19 : Injection Force
19.1 : Injection Force’
20 : Half of injection force thru each sidewall
20.1 : Half of injection force thru each sidewall’
21 : Moment due to bending of plate
21.1 : Moment due to bending of plate’
22 : Centerline of Injection unit
23 : Deflection of side wall
23.1 : Deflection of side wall’
24.1 : Connection of side wall to platens’
25.1 : Undercut geometry’
26.1 : Amount of undercut’
27 : Thickness of side wall
28.1 : Radius’
29.1 : Additional projection of side wall’
30.1 : Slant angle’
31.1 : Moment due to undercut’
32.1 : Separate side wall for assembled injection frame’
33.1 : Bolts for assembled side wall’
34.1 : Offset’
35.1 : Key’
36.1 : Bolt holes’
37.1 : Mounting area of sidewall to platen’
38.1 : Mounting area for linear guide on sidewall’
Summary of Invention:

The embodiment of the present invention provides an improved injection frame for electric injection molding machine. The improved injection frame acts as support member for linear guidance elements which supports and precisely guides middle platen during linear movement ensuring smooth and aligned motion of feed screw inside barrel as feed screw is supported in middle platen at one end and inside barrel at other end.

Detailed Description and Working of Invention:
Embodiments of the present disclosure present technological improvements as solution to one or more of the above-mentioned technical problems recognized by the inventor in conventional practices and existing state of the art.
The accompanying drawings constitute a part of this specification and illustrate one or more embodiments of the invention. Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale

In order to provide foregoing objects, an embodiment of the present invention provides an improved injection frame for electric injection molding machine. The improved injection frame acts as support member for linear guidance elements which supports and precisely guides middle platen during linear movement ensuring smooth and aligned motion of feed screw inside barrel as feed screw is supported in middle platen at one end and inside barrel at other end. In particular the invention substantially increases speed of injection unit during forward stroke due to which productivity increases and more complex parts with less wall thickness can be produced.

The following detailed description illustrates embodiments of the present disclosure and ways in which the disclosed embodiments can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

Referring to Figure 3, 7 to 13 present Injection frame for Injection molding machine is provided. Said Injection frame for Injection molding machine (P) comprises:

Front platen (5),
Middle platen’ or pusher platen (6),
Rear platen’ (7.1),
Electric motor (10),
Electric motor’ (10.1),
Pulley (11),
Belt (12),
Ball screw (13),
Single piece injection frame’ (15.1),
Side wall’ (16.1),
Linear guide block’ (17a’),
Linear guide rail’ (17b’),
Housing portion for ball screw (18),
Injection Force’ (19.1),
Half of injection force thru each sidewall’ (20.1),
Moment due to bending of plate’ (21.1),
Centerline of injection unit (22),
Deflection of side wall’ (23.1),
Connection of side wall to platens’ (24.1),
Undercut geometry’ (25.1),
Amount of undercut’ (26.1),
Thickness of side wall (27),
Radius’ (28.1),
Additional projection of side wall’ (29.1),
Slant angle’ (30.1),
Moment due to undercut’ (31.1),
Separate side wall for assembled injection frame’ (32.1),
Bolts for assembled side wall’ (33.1),
Offset’ (34.1),
Key’ (35.1),
Bolt holes’ (36.1),
Mounting area of sidewall to platen’ (37.1),
Mounting area for linear guide on sidewall’ (38.1);
Said Middle platen’ or pusher platen’ (6) is placed over Linear guide block’ (17a’) and Linear guide rail’ (17b’). It is provided for smooth linear movement of middle platen (6). Said linear guide block’ (17a’) and Linear guide rail’ (17b’) are placed on the side wall’ (16.1) of single piece injection frame’ (15.1). Said linear guide block’ (17a’) and Linear guide rail’ (17b’) can be smaller in size or of same size compared to conventional art. Said invention comprises of pair of electric motor (10); One of which is placed on middle platen (6) imparts rotational movement to feed screw (2) similar to conventional machines. Another electric motor’ (10.1) is placed on said rear platen’ (7.1) and is connected to ball screw (13) by pulley (11) and belt (12). It converts rotary motion of middle platen (6) to linear motion. The Linear movement of said middle platen (6) results in movement of said feed screw (2) inside the barrel (1).

Referring to figure.7, an isometric view of the present Injection frame for Injection molding machine (P) is shown. Said Front plate (5) and Rear plate’ (7.1) are connected by two side wall’ (16.1) One end of rear plate’ (7.1) is extended in Housing portion for ball screw (18) which is hollow cylindrical shaped to accommodate the ball screw (13). At end of the Housing portion for ball screw (18) there is provision to mount pulley (11) and its bearing. Now referring to Figure 8, said undercut geometry’ (25.1) is provided between side wall’ (16.1) to front platen (5) and rear platen’ (7.1). Instead of straight connection, Amount of undercut’ (26.1) is provided at inside corner as shown in enlarged view in FIG 8 by dotted lines. This Amount of undercut’ (26.1) is kept in the ratio of atleast 0.15 to 0.5 times thick of Thickness of side wall (27). A large radius’ (28.1) is provided at this undercut geometry’ (25.1) to avoid stress concentration at corner. The Radius’ (28.1) value may vary in the ratio 0.5 to 1.5 times thick than thickness of sidewall (27). This connecting structure is similar at four places where side wall’ (16.1) is connected to Front platen (5) and rear platen’ (7.1). Further to avoid high stresses in the corner region due to reduction in thickness of thickness of sidewall (27), present invention (P) provides Additional projection of side wall’ (29.1) on the side wall’ (16.1) in the connection area. This projection is merged to side wall’ (16.1) in an angular manner with a slant angle’ (30.1). Preferably said slant angle’ (30.1) is in range of 30 to 45 degree to avoid weight addition.

Now, referring to Figure 9 which shows the forces and moments generated by said undercut geometry’ (25.1) of the present invention. Due to said Moment due to bending of plate’ (21.1) an additional outward moment is generated due to said Moment due to undercut’ (31.1). This moment is in reverse direction to the moment due to bending plate’ (21.1). The moment due to bending plate’ (21.1) is undesirable moment which deflects Side wall (16.1) inside in bow shape and bending moment due to undercut’ (31.1) deflects the Side wall (16.1) towards outside. Thus, due to opposite direction of bending moments the net effect of bending moment is reduced to a greater extent. The above technicalities in selecting undercut geometry’ (25.1) balances these two moments and the same is validated using Finite element analysis (FEA).

The deflection of side wall (23) for conventional injection frame under injection force (19) is shown in FIG 6 in exaggerate manner. Here the value for deflection of side wall (23) is 0.086 mm for conventional frame. Whereas with the technicalities of undercut geometry’ (25.1) of the present invention (P), Deflection of side wall’ (23.1) is as shown in Fig.10a. The shape of the frame before Deflection of side wall’ (23.1) is also shown in same image by line diagram for better visualization. It’s clear by comparing FIG 6 and FIG 10a that, although Front platen (5) Deflects almost similarly, but said side wall’ (16.1) are deflecting very less in FIG 10a as compared to side wall of single piece injection frame (16) in Fig 6. Also, instead of bow shape its deflection is almost in straight manner, which is good for uniform straight motion of Middle platen (6). This type of uniform and less deflection is desirable for linear guidance of high speed injection unit. As the Deflection of side wall’ (23.1) is less, reaction force on Linear guide block is also very less which allows smaller size of linear guide to be selected without compromising its shelf life. Fig. 10b and Fig 10c shows Deflection of side wall’ (23.1) of said side wall’ (16.1) with Amount of undercut’ (26.1) very less and very high respectively. It is observed that although Deflection of side wall’ (23.1) is less compared to conventional frame but it’s not as good as per FIG 10a. The shape of side wall’ (16.1) after deflection is also not straight. Comparison of side wall’ (16.1) deflection in relation to amount of undercut’ (26.1) is shown in below table 01 for thickness of side wall’ (27.1) as 50mm and radius’ (28.1) as 30mm.
Case Thickness of side wall in mm Amount of undercut in mm Radius in mm Amount of Undercut/ Thickness of side wall (27) Deflection of side wall in mm
Conventional Frame 50 0 30 0.00 0.086
Frame as per invention 50 12.8 30 0.26 0.033
Frame with very Small Undercut 50 5 30 0.10 0.05
Frame with very Larger Undercut 50 29.4 30 0.59 0.07

Table 01: Comparison between prior art and present invention for deflection of side wall
For larger size Injection unit such single piece frame may be complex and costly to manufacture. In order to provide the solution to such problem, as an alternative embodiment present invention (P) provides an assembled Injection Frame as shown in figure 11 and 12 and a Separate side wall for assembled injection frame’ (32.1) as shown in Fig.13. Said Front Platen (5), rear plate’ (7.1) and plurality of Separate side wall for assembled injection frame’ (32.1) preferably two are manufactured individually, and assembled together to make an Injection Frame. Said side wall for assembled injection frame’ (32.1) have different geometry to reduce deflection of side walls as shown in Fig 13. The thickness of said side wall (27) is kept same along its length. Further an amount of offset’ (34.1) is generated in Mounting area of sidewall to platen’ (37.1). Said offset’ (34.1) is kept as 0.15 to 0.5mm times the thickness of side wall’ (27.1) which is similar to amount of undercut’ (26.1) of single piece frame (15.1) and provides similar benefits. Said Separate side wall for assembled injection frame’ (32.1) further comprises Bolt holes’ (36.1) and Keys’ (35.1 ) at Mounting area of sidewall to platen’ (37.1), for fixing the sidewall’ (16.1) to front platen (5) and rear platen’ (7.1). Alternatively locating pin or step machining may be used for ease of assembly.

Advantages of Present invention:
• It provides an improved injection frame for injection molding machine for electric injection molding machine.
• It provides the injection frame for the reciprocating screw type electrically operated injection unit.
• It provides lesser deflection in sidewall during injection. Reduced side deflection reduces effective side load on linear guide member and improve its life.
• It provides substantially higher injection force, which eliminates processing related issues as actual pressure is than required pressure.
• It provides high injection speed.
• Due to less deflection of side wall, linear guide members provides better linear guidance to middle plate and hence to the feedscrew so feedscrew moves smoothly inside barrel. This avoids premature wear of feedscrew and also supports high speed injection.
• Performance of injection unit is improved without extra weight/cost.
• Larger size Injection unit frame with advantages similar to single piece frame member can be made at much less manufacturing cost due to possibility to do machining on smaller machine tool.
• Provides technicalities for less deflection in sidewall during injection.
• Less number of parts required for assembly due to elimination of guide rod and less skills required during assembly of injection unit.

,CLAIMS:We Claim:

1. An Improved Injection frame for Injection molding machine, wherein said Injection frame(P) comprises:
• A Front platen (5),
• A Middle platen’ or pusher platen (6),
• A Rear platen’ (7.1),
• An Electric motor (10),
• An Electric motor’ (10.1),
• A Pulley (11),
• A Belt (12),
• A Ball screw (13),
• A Single piece injection frame’ (15.1),
• A Side wall’ (16.1),
• A Linear guide block’ (17a’),
• A Linear guide rail’ (17b’),
• A Housing portion for ball screw (18),
• An Injection Force’ (19.1),
• A Half of injection force thru each sidewall’ (20.1),
• A Moment due to bending of plate’ (21.1),
• A Centerline of injection unit (22),
• A Deflection of side wall’ (23.1),
• A Connection of side wall to platens’ (24.1),
• An Undercut geometry’ (25.1),
• An Amount of undercut’ (26.1),
• A Thickness of side wall (27),
• A Radius’ (28.1),
• An Additional projection of side wall’ (29.1),
• A Slant angle’ (30.1),
• A Moment due to undercut’ (31.1),
• A Bolts for assembled side wall’ (33.1),
Wherein
Said Middle platen’ or pusher platen’ (6) is configured over Linear guide block’ (17a’) and Linear guide rail’ (17b’) for smooth linear movement of middle platen (6); Said linear guide block’ (17a’) and Linear guide rail’ (17b’) are placed on the side wall’ (16.1) of single piece injection frame’ (15.1); a pair of electric motor where one is configured on the middle platen (6) to impart rotational movement to feed screw (2) and Another electric motor’ (10.1) is configured on said rear platen’ (7.1) and is connected to ball screw (13) by pulley (11) and belt (12) to convert rotary motion of middle platen (6) to linear motion; Said Front plate (5) and Rear plate’ (7.1) are connected by two side wall’ (16.1), where One end of rear plate’ (7.1) is extended in Housing portion for ball screw (18) which is hollow cylindrical shaped configured to accommodate the ball screw (13); said pulley (11) is connected at end of Housing portion for ball screw (18); said undercut geometry’ (25.1) is configured between side wall’ (16.1) to front platen (5) and rear platen’ (7.1) along with a radius’ (28.1) configured to void stress concentration at corner; said Amount of undercut’ (26.1) is configured at inside corner; said Additional projection of side wall’ (29.1) on the side wall’ (16.1) is configured to avoid high stresses in the corner region; said projection of side wall’ (29.1) is merged to side wall’ (16.1) in an angular manner with a slant angle’ (30.1); said Moment due to bending of plate’ (21.1) is configured to generate an additional outward moment in reverse direction due to said Moment due to undercut’ (31.1);
Wherein the present improved injection frame (P) utilizes existing
• A Front platen (5),
• A Middle platen’ or pusher platen (6),
• An Electric motor (10),
• A Pulley (11),
• A Belt (12),
• A Ball screw (13),
• A Housing portion for ball screw (18),
• A Centerline of injection unit (22),
• A Thickness of side wall (27).
2. The Injection frame for Injection molding machine (P) as claimed in claim 1, wherein said Amount of undercut’ (26.1) is kept in the ratio of at least 0.15 to 0.5 times thick of Thickness of side wall (27).
3. The Injection frame for Injection molding machine (P) as claimed in claim 1, wherein value of said Radius’ (28.1) is in ratio 0.5 to 1.5 times thick than thickness of sidewall (27).
4. The Injection frame for Injection molding machine (P) as claimed in claim 1, wherein said slant angle’ (30.1) is in range of 30 to 45 degree.
5. The Injection frame for Injection molding machine (P) as claimed in claim 1, wherein said injection frame (P) for larger size Injection unit comprises:
• A Separate side wall for assembled injection frame’ (32.1),
• An Offset’ (34.1),
• A Key’ (35.1),
• A Bolt holes’ (36.1),
• A Mounting area of sidewall to platen’ (37.1),
• A Mounting area for linear guide on sidewall’ (38.1);
Wherein
Said pair of Separate side wall for assembled injection frame’ (32.1) with geometry are configured to provide an injection frame (P) to reduce deflection of side walls; said offset’ (34.1) is generated in Mounting area of sidewall to platen’ (37.1); Said Separate side wall for assembled injection frame’ (32.1) comprises Bolt holes’ (36.1) and Keys’ (35.1 ) at Mounting area of sidewall to platen’ (37.1), for fixing the sidewall’ (16.1) to front platen (5) and rear platen’ (7.1).
6. The Injection frame for Injection molding machine (P) as claimed in claim 1, wherein said offset’ (34.1) is kept at 0.15 to 0.5mm times the thickness of side wall’ (27.1).

Dated this 3rd Day of February, 2022

Gopi Trivedi (Ms)
IN/PA 993
Authorized Agent of Applicant
To,
The Controller of Patents
The Patent Office
At Mumbai