Description:FORM 2
The Patent Act 1970
(39 of 1970)
and
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“HIGH PRESSURE DIE CASTING FEED SYSTEM FOR AUTOMOTIVE COMPONENTS”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

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

Field of Invention

[001] The present invention relates to a high pressure die casting feed system for automotive components. More particularly, the invention is related to a uniquely profiled casting feed runner to be used in high pressure die casting system for manufacturing thin-walled automotive components.

Background of the Invention

[002] Casting is a manufacturing process to make complex shape of metal components during mass production. The casting is generally categorized a low pressure die casting (LPDC) and high pressure die casting (HPDC) wherein the molten metal flows in the mold with the help of a feed system. The feed system includes a biscuit, a main runner, sub runners and in gates designed in a manner to guide molten metal during filling and solidification which takes place after intensification. The feed system plays a very important role in improving quality and reducing the losses of the final casted product.

[003] The conventional high pressure die-casting (HPDC) mold structure has a runner structure that includes a plurality of main runners, end runners, and in-gates. In the conventional die-casting mold structure, the in-gates are connected with the main runners with the help of end runners. The HPDC process requires a huge amount of energy to feed the molten metal through the runner structure to produce a good quality of casting. The cross-sectional area of the runner structure plays an important role in the filling and solidification of the casting as the feed velocity depends on the area of the cross section of the feed runner structure. Reducing the cross-sectional area at different portions of the runner structure can lead to an increased flow velocity and hence reduced solidification time but at the same time it can also lead to have cold shuts and gas entrapment leading to reduced product yield, high amount of rejections and increased cost of manufacturing.

[004] Hence, there is a long pending need to have a uniquely profiled feed runner structure optimised in a manner to have an optimum cross-sectional area at its desired portions so as to have an improved filling and solidification of casting, reduced porosity volume, reduced scrap rate, improved productivity, shorter cycle time and reduced energy consumption.

Objectives of the Present Invention

[005] The main object of the present invention is to provide a uniquely profiled casting feed runner for manufacturing thin walled automotive casting components by high pressure die casting system.

[006] Another main object of the present invention is to provide a casting feed runner which is configured to have an optimum ratio of runner to gate area so as to optimize the energy consumption.

[007] Another objective of the present invention is to provide a casting feed runner having a uniquely profiled main gate and sub-runners employed therein to impart an improved filling and solidification of casting.

[008] Yet, another objective of the present invention is to provide a casting feed runner configured to produce thin walled engine casting devoid of any internal defects, visual defects and improved mechanical properties in the casted components.

[009] Further, the objective of the present invention is to provide a uniquely profiled casting feed runner to be used in high pressure die casting system which imparts improved filling and solidification of casting, reduced porosity volume, reduced scrap rate, improved productivity, shorter cycle time and reduced energy consumption as well.

Brief Description of Drawings

[0010] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein

[0011] Figure 1 discloses the isometric view of the uniquely profiled casting feed runner as per the present invention.

[0012] Figure 2 describes the exploded view of the casting feed runner of the present invention.

[0013] Figures 3a and 3b disclose the top view of the casting feed runner in accordance with the present invention.

[0014] Figure 4 discloses the isometric view of the casting feed runner along with the automotive component (engine casting) being casted in accordance with the present invention.

[0015] Figure 5a presents simulation report plots showing the air entrapment and shrinkage porosity of the casted component by the present invention.

[0016] Figure 5b presents radiography report plots showing the air entrapment and shrinkage porosity of the casted component by the present invention.

[0017] Figure 6a presents microstructure in the casted component produced by traditional feed runner, whereas the Fig. 6b presents the microstructure in the casted component produced by the casting feed runner (100) of the present invention.

Detailed Description of the Present Invention

[0018] The invention will now be described in detail with reference to the accompanying drawings which must not be viewed as restricting the scope and ambit of the invention.

[0019] Referring to Figs. 1 to 3b, the high pressure die casting feed runner (100) of the present invention is configured to have a biscuit (10), a plurality of main runners (20), a plurality of main gates (25), a plurality of sub-runners (30) and a plurality of in-gates (35). The main runners (20) are configured to have at least two main runners (20A and 20B) connecting with the sub-runners (30). The sub-runners (30) are configured to have at least four sub-runners (30A, 30B, 30C and 30D) connected with the main runners (20A and 20B) with the help of the main gates (25) wherein the said main gates have four gates (25A, 25B, 25C and 25D). The sub-runners (30A, 30B, 30C and 30D) further are connected with the in-gates (35) wherein the said in-gates (35) have four in-gates viz. (35A, 35B, 35C and 35D).

[0020] The biscuit (10) is configured to have a cylindrical profile connecting to the main runners (20). The main runners (20) have at least two runners (20A and 20B) extending laterally away from the biscuit (10) in a manner such that the runner (20A) maintains an angle θ1 with the vertical in anticlockwise direction and the runner (20B) maintains an angle θ2 with the vertical in clockwise direction. The angle θ1 is preferably set to be in a range of 10-50° and the angle θ2 is preferably set to be in a range of 10-40°. The main runners (20A and 20B) are configured to have a trapezoidal channeled (TC) cross sectional profile. The main runner (20A) is configured to have a proximal end (20AP) and a distal end (20AD) wherein the cross sectional area of the distal end (20AD) is less than the cross-sectional area of the proximal end (20AP). Similarly, the main runner (20B) is configured to have a proximal end (20BP) and a distal end (20BD) wherein the cross sectional area of the distal end (20BD) is less than the cross-sectional area of the proximal end (20BP). The molten metal flows from the respective proximal ends (20AP, 20BP) to the respective distal ends (20AD, 20BD) of the main runners (20) and the gradually reduced cross sectional area towards the respective distal ends (20AD, 20BD) is intelligently configured to increase the velocity of the molten metal. The sub-runners (30A and 30B) are configured to branch out in a transverse direction from the main runner (20A) whereas the sub-runners (30C and 30D) are configured to branch out in a transverse direction from the main runner (20B). The each of the said sub-runners (30A, 30B, 30C and 30D) is configured to have a V-shaped profiled (V) channel.

[0021] The sub-runners (30A and 30B) branch out from the main runner (20A) wherein the main gate (25A) connects the sub-runner (30A) with the main runner (20A) and the main gate (25B) connects the sub-runner (30B) with the main runner (20A). Similarly, the sub-runners (30C and 30D) branch out from the main runner (20B) wherein the main gate (25C) connects the sub-runner (30C) with the main runner (20B) and the main gate (25D) connects the sub-runner (30D) with the main runner (20B). The main gates (25A to 25D) are constriction passages having a rectangular profiled (R) channel which connects with the V-shaped profiled (V) channel of the sub-runners (30A to 30D), respectively. The rectangular profiled (R) constriction passage of the main gates (25A to 25D) are configured to increase the velocity of the molten metal so as to require a reduced energy consumption, have a high mold filling rate which consequently produce automotive engine castings, particularly the thin-walled castings, with high dimensional accuracy and extremely good surface properties. Further, the sub-runners (30A to 30D) having the V-shaped profiled (V) channel helps in establishing a laminar flow of molten metal which consequently removes gases leading to produce a thin-walled automotive casting devoid of porosity and surface irregularities.

[0022] The sub-runners (30A to 30D) are further connected with the in-gates (35A to 35D) wherein the sub-runner (30A) is connected with the in-gate (35A) and the sub-runner (30B) is connected with the in-gate (35B). Similarly, the sub-runner (30C) is connected with the in-gate (35C) and the sub-runner (30D) is connected with the in-gate (35D). The each of the in-gates (35A to 35D) is configured to have an arcuate slit profiled channel (AS) opening into the mold cavity of the casting to be formed.

[0023] Referring to the Fig. 3b, the high pressure die casting feed runner (100) of the present invention is configured to produce a thin walled aluminum alloy die casting (50) having excellent surface properties along with a reduced energy consumption. The feed runner (100) is optimized to have a unique profiled cross-sectional area distribution of the main runners (20A and 20B), sub-runners (30A to 30D), the main gates (25A to 25D) and the in-gates (35A to 35D). During the tooling design of the feed runner (100) of the present invention, the cross-sectional areas of various sections of the feed runner (100) are configured to maintain the relations of quadratic nature as given below:
A2 * A10 = C1*A62;
A1 * A9 = C2*A52;
A3 * A11 = C3*A72;
A4 * A12 = C4*A82; and
A1 + A2 ~ A3 + A4
Where,
A1 is the cross-sectional area of the distal arm of the main runner (20A);
A2 is the cross-sectional area of the proximal arm of the main runner (20A);
A3 is the cross-sectional area of the proximal arm of the main runner (20B);
A4 is the cross-sectional area of the distal arm of the main runner (20B);
A5 is the cross-sectional area of the main gate (25A);
A6 is the cross-sectional area of the main gate (25B);
A7 is the cross-sectional area of the main gate (25C);
A8 is the cross-sectional area of the main gate (25D);
A9 is the area of the in-gate (35A);
A10 is the area of the in-gate (35B);
A11 is the area of the in-gate (35C);
A12 is the area of the in-gate (35D); and
C1 to C4 are the flow constants, wherein the C1 = 10.5 to 11.0; C2 = 6.0 to 6.5; C3 =9.0 to 9.5; and C4 = 5.0 to 5.5.

[0024] The feed runner (100) having the optimized cross-sectional areas is injected with a molten aluminum alloy at the biscuit (10) with an average velocity of 3.5-4.5 m/s in a high pressure die casting system. The feed pressure is set to be in the range of 800-900 bar and the temperature of the molten alloy is in the range of 600-800 °C resulting in improved filling and solidification of the casted product. A detailed virtual and physical validation was carried out to observe the various parameters of the thin-walled casting manufactured by the feed runner (100) of the present invention the results of which are at par or even superior as shown in Figs. 5a to 6b.

[0025] The feed runner (100) of the present invention has the reduced porosity volumes as compared to the conventional feed system as can be seen in the virtual validation study as shown in Fig. 5a. The radiography study as depicted in Fig. 5b confirms the results of the virtual validation study. The 6 shows that casting (50) produced from the feed runner (100) has the better microstructure eutectic Si fine fibers (refer Fig. 6a) in comparison to the conventional feed system (refer Fig. 6b). The microstructure of the thin walled automotive casting produced by the feed runner (100) of the present invention do have secondary dendrite arm spacing (SDAS) 8.00 µm which much lower than the SDAS derived in the casting produced by the conventional feed runners. The lower SDAS imparted by the feed runner of the present invention in the thin walled automotive castings leads to improved molecular bond in the casting, imparts micro-finished structure and imparts enhanced tensile strength and elongation. Also, the thin walled casting (50) produced from the feed runner (100) of the present invention has more hardness than the casting produced from conventional feed system.

[0026] The feed runner (100) of the present invention provides the following technical advantages that contributes to the advancement of technology:
- It provides an improved casted product having reduced porosity and fine microstructure for automotive applications, e.g. engine casting.
- It provides an improved filling and solidification of thin walled casting.
- It provides reduced scrap rate and improved productivity.
- It provides shorter cycle time and reduced energy consumption.
- It provides thin walled automotive castings with improved molecular bond in the casting, imparts micro-finished structure and imparts enhanced tensile strength and elongation.

[0027] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the invention herein has been described in terms of a generalized form, those skilled in the art will recognize that the invention herein can be practiced with modification within the spirit and scope of the invention as described herein.
, Claims:We Claim

1. A high pressure die casting feed runner (100) for automotive components comprising of a biscuit (10), at least two main runners (20A and 20B), a plurality of main gates (25A, 25B, 25C and 25D), a plurality of sub-runners (30A, 30B, 30C and 30D) and a plurality of in-gates (35A, 35B, 35C and 35D)
wherein,
- the biscuit (10) is configured to have a cylindrical profile and is in communication with the main runners (20A and 20B);
- the said main runners (20A and 20B) are configured to extend laterally away from the biscuit (10) in a manner such that the main runner (20A) makes an angle θ1 with the vertical in anticlockwise direction and the main runner (20B) makes an angle θ2 with the vertical in clockwise direction;
- the sub-runners (30A and 30B) are configured to branch out in a transverse direction from the main runner (20A) through the main gates (25A and 25B), and the sub-runners (30C and 30D) are configured to branch out in a transverse direction from the main runner (20B) through the main gates (25C and 25D); and
- each of the said sub-runners (30A, 30B, 30C and 30D) is configured to get connected with the respective in-gates (35A, 35B, 35C and 35D).

2. The high pressure die casting feed runner (100) as claimed in claim 1, wherein
- the main runner (20A) is configured to have a proximal end (20AP) and a distal end (20AD) wherein the cross sectional area of the distal end (20AD) is less than the cross-sectional area of the proximal end (20AP); and
- the main runner (20B) is configured to have a proximal end (20BP) and a distal end (20BD) wherein the cross sectional area of the distal end (20BD) is less than the cross-sectional area of the proximal end (20BP).

3. The high pressure die casting feed runner (100) as claimed in claim 2, wherein
- the main runners (20A and 20B) are configured to have a trapezoidal channeled (TC) cross sectional profile;
- the proximal ends (20AP, 20BP) of said main runners (20A and 20B) are configured to flow molten metal to the respective distal ends (20AD, 20BD); and
- the gradually reduced cross sectional area towards the distal ends (20AD, 20BD) of said main runners (20A, 20B) is configured to increase the velocity of the molten metal.

4. The high pressure die casting feed runner (100) as claimed in claim 3, wherein the angle θ1 made by the main runner (20A) with the vertical is in a range of 10 to 50°, and the angle θ2 made by the main runner (20B) with the vertical is in a range of 10 to 40°.

5. The high pressure die casting feed runner (100) as claimed in claim 1, wherein
- each of the sub-runners (30A, 30B, 30C and 30D) is configured to have a V-shaped profiled (V) channel;
- the sub-runners (30A and 30B) branch out from the main runner (20A) wherein the main gate (25A) connects the sub-runner (30A) with the main runner (20A) and the main gate (25B) connects the sub-runner (30B) with the main runner (20A); and
- the sub-runners (30C and 30D) branch out from the main runner (20B) wherein the main gate (25C) connects the sub-runner (30C) with the main runner (20B) and the main gate (25D) connects the sub-runner (30D) with the main runner (20B).

6. The high pressure die casting feed runner (100) as claimed in claim 5, wherein
- each of the main gates (25A, 25B, 25C, 25D) is configured to have a constriction passage having a rectangular profiled (R) channel which connects with the V-shaped profiled (V) channel of the respective sub-runner (30A, 30B, 30C, 30D);
- said rectangular profiled (R) constriction passage of the main gates (25A to 25D) are configured to increase the velocity of the molten metal so as to have a high mold filling rate which consequently produce thin-walled automotive casting with high dimensional accuracy; and
- said sub-runners (30A to 30D) having the V-shaped profiled (V) channel are configured to establish a laminar flow of molten metal which removes gases leading to produce a thin-walled automotive casting devoid of porosity and surface irregularities.

7. The high pressure die casting feed runner (100) as claimed in claim 6, wherein
- each of the sub-runners (30A, 30B, 30C, 30D) is connected with the respective in-gates (35A, 35B, 35C, 35D) wherein the sub-runner (30A) is connected with the in-gate (35A), the sub-runner (30B) is connected with the in-gate (35B), the sub-runner (30C) is connected with the in-gate (35C) and the sub-runner (30D) is connected with the in-gate (35D); and
- each of the in-gates (35A to 35D) is configured to have an arcuate slit profiled channel (AS) opening into the mold cavity of the casting to be formed.

8. The high pressure die casting feed runner (100) as claimed in any of the claims 4 and 7, wherein
- the quadratic relation between the cross-sectional area of the proximal arm of the main runner (20A), the area of the in-gate (35B) and the cross-sectional area of the main gate (25A) of the feed runner (100) is A2 * A10 = C1*A62 wherein C1 is the flow constant ranging from 10.5 to 11.0; and
- the quadratic relation between the cross-sectional area of the distal arm of the main runner (20A), the area of the in-gate (35A) and the cross-sectional area of the main gate (25A) of the feed runner (100) is A1 * A9 = C2*A52 wherein C2 is the flow constant ranging from 6.0 to 6.5.

9. The high pressure die casting feed runner (100) as claimed in claim 8, wherein
- the quadratic relation between the cross-sectional area of the proximal arm of the main runner (20B), the area of the in-gate (35C) and t the cross-sectional area of the main gate (25C) of the feed runner (100) is A3 * A11 = C3*A72 wherein C3 is the flow constant ranging from 9.0 to 9.5; and
- the quadratic relation between the cross-sectional area of the distal arm of the main runner (20B), the area of the in-gate (35D) and the cross-sectional area of the main gate (25D) of the feed runner (100) is A4 * A12 = C4*A82 wherein C4 is the flow constant ranging from 5.0 to 5.5.

10. The high pressure die casting feed runner (100) as claimed in claim 9, wherein said feed runner (100) is configured to impart microstructure having secondary dendrite arm spacing (SDAS) of 8.00 µm in the thin walled automotive casting produced by said feed runner (100) which leads to improved molecular bond in the casting, imparts micro-finished structure and imparts enhanced tensile strength and elongation.

Dated this 24th day of Sept. 2024

Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai