DESIGN AND MANUFACTURING OF 6V 120Ah BATTERY …

International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected]

Volume 10, Issue 1, January 2021 ISSN 2319 - 4847

Volume 10, Issue 1, January 2021 Page 20

ABSTRACT The Objective of work involves design and manufacture of injection mould for Lead Acid Battery Container for its application in trains. The battery is subject to various factors like temperature and pressure. Thus, we have made considerable improvements to the battery container design which includes: In essence, we have designed the container of the battery, made an exhaustive analysis through different software on the design and finally manufactured the injection mould for the battery container. With respect to the design of the container, the honeycomb structure has been implemented with changes to the rib thickness. The results obtained have been promising with increase in strength and life of component, reduced maintenance and less space used. A Moulding Simulation of the battery container has been done to optimize the part quality like fill balance, injection pressure, clamping force & deflection pattern. Keywords: 16V 120AH Lead Acid Battery, battery container, injection pressure, clamping force & deflection pattern.

1. INTRODUCTION A mould is a hollowed-out block that is filled with a liquid or pliable material such as plastic, glass, metal, or

ceramic raw material. The liquid hardens or sets inside the mould, adopting its shape. A mould is the counterpart to a cast. The very common bi-valve moulding process uses two moulds, one for each half of the object. Articulated moulds have multiple pieces that come together to form the complete mould, and then disassemble to release the finished casting; they are expensive, but necessary when the casting shape has complex overhangs. Piece moulding uses a number of different moulds, each creating a section of a complicated object. This is generally only used for larger and more valuable objects. A manufacturer who makes moulds is called a mould maker. A release agent is typically used to make removal of the hardened/set substance from the mould easily. Typical uses for moulded plastics include moulded furniture, moulded household goods, moulded cases, and structural materials.

1.1 OVERVIEW The housing or the container of any battery requires a comprehensive design and thorough study to be applicable for

said battery. We have chosen a 6V 120AH Lead Acid Battery for our study. This battery is used in train coaches for lighting purposes in general; but only for speeds less than 30 kmph. This work involves design and manufacture of injection mould for lead acid battery container for its application in trains. The battery is first designed using “SOLIDWORKS” and “AUTODESK AUTO-CAD (Drafting)” and then static analysis has been conducted. “HYPERMESH” software has been used to conduct static analysis. In this, battery is subjected to various factors like temperature and pressure. By analyzing the results, we have made considerable improvements to the battery container design. A moulding simulation of the battery using “AUTODESK MOULDFLOW INSIGHT” has been done to optimize the part quality like fill balance, injection pressure, clamping force & deflection pattern. With respect to the design of the container, the honeycomb structure has been implemented with changes to the rib thickness which has led to reduced weight and improved strength. In essence, we have designed the container of the battery, made an exhaustive analysis through different software on the design and finally manufactured the injection mould for the battery container. The results obtained have been promising with increase in strength and life of component, reduced maintenance and less space used.

DESIGN AND MANUFACTURING OF 6V 120Ah BATTERY CONTAINER MOULD FOR TRAIN

LIGHTING APPLICATION K SANTOSH KUMAR1, S AJAY KUMAR2, B. GOVINDA REDDY3 , P. SHASHIDAR REDDY4

1,2,3,4Assistant Professor in Dept. of Mechanical Engineering, Mahatma Gandhi Institute of Technology, Hyderabad.




1.2.1 COMPONENT DETAILS

COMPONENT : Lead Acid Battery Container

MATERIAL : Polypropylene – Flame retardant

SHRINKAGE : 1.35%

MOULD TEMP : 90-100

MATERIAL MELTING TEMP : 200-225 C

COMPONENT WEIGHT : 1500 ± 50 grams

MACHINE : Windsor 450T

TYPE OF INJECTION : Stripper

COLOUR : Greyish White

Fig. 1.1 Injection Moulding

2. PREPARATION AND PROCESS PLANNING FOR MOULD: 2.1 MOULD

Mould is a hollow form or cavity into which molten plastic material is forced into to give the shape of the required component.

The term generally refers to the whole assembly of parts which go to make up the section of the injection moulding equipment in which plastic components are moulded.

2.2 INJECTION MOULD FEATURES The following factors were considered while designing this mould: 1) Injection System 2) Parting Line 3)

Cooling System 4) Ejection System 5) Core and cavity layout 2.3 MANUFACTURING PROCESS

This mould for screw cap was well planned and processed in a manner that the tool cost was minimum and completed within estimated time as per the design and planning. After the procurement of the raw materials according to design specification the mould was divided into two parts: 1) The mould base 2) Core & Cavity. The work on core and cavity was performed on Non-conventional machines like CNC lathe or CNC milling if the profiles are complex; whereas simple form was made on conventional machining. The mould base works were performed on conventional machining. 2.4 OPERATIONS TO BE PERFORMED ON MOULD

1. Heat Treatment 2. Hardening 3. Polishing




2.5 SELECTION OF RAW MATERIALS FOR PREPARING MOULD Injection mould die material must be resistant to thermal shock, softening and corrosion at high temperature. The

performance of die material is directly related to the injection temperature of the molten material. To guarantee the successful operation of an injection mould, the die steel should have the following characteristics: 1) High compressive strength combined with sufficient toughness. 2) Sufficient strength & hardness to resist deformation. 3) Low-Coefficient of thermal expansion. 4) Good wear resisting property. 5) Corrosion resistance 6) Good machinability 7) Low or no distortion during heat treatment 8) Structural soundness & uniformity 9) Good polish ability 2.6 ASSEMBLY Assembly is the final and for most important stage in the manufacturing of the mould. In this process even a slight inaccuracy may cause distortion or incorrect functioning of the tool. To overcome this problem may cause distortion or incorrect functioning of the tool. 1) Preparation and checking the alignment of mould box 2) Assembly of cavity half 3) Assembly of core half 2.7 BILL OF MATERIALS

Table 2.1 Bill of Materials




Fig. 2.1 Mould Assembly

3. PREPARING 3D CAD MODELS (SOLID WORKS): 3.1 PREVIOUS BATTERY PROBLEMS 1. Insufficient Strength of the Ribs Provided. 2. Frequent Bulging of the Battery. 3. Leaking of the Acid. 3.2 UPGRADED DESIGN Through various corrections and modifications, the final 3-D Models have been finalized as given below. Some of the major changes made to the upgraded designs were:

Correction of Rib thickness. Changing of Handle design. Adding Draft to the Honeycomb Ribs. Adding Draft to the Handle thread provisions.

Fig.3.1 Isometric View




3.3 2-D DRAFTING (AUTO-CAD):

Fig.3.2 Top, Side and Front views of the model

Fig.3.3 2-D Sectional views

FIG.3.4 2-D HIGHLIGHTS

4. CALCULATIONS AND MODIFICATIONS

4.1 RIB CALCULATIONS




Rib thickness for non-reinforced crystalline thermoplastics (Polypropylene) is given by Wmax = 0.5 x thickness of the container

From the 2D DRAFT model, we can see that the thickness of the container is designed as: Outer width = 82±0.2 mm Inner width = 75±0.2 mm

Therefore, Thickness = (Outer width-Inner width) / 2

= (82 – 75) / 2 = 3.5mm

FIG.4.1 RIB CALCULATIONS

4.2 MODIFICATIONS TO EXISISTING MODEL

Some of the modifications made were: Initially the rib thickness was estimated to be 3 mm and the top thickness has been estimated as 2.8 mm. The thickness has been changed to 3.5 mm on bottom and 3.3 mm on top of the rib. Proper parting line has been created by matching it with parting face as shown in Fig. Drafting has been added to the handle as shown in below figures. Fillets have been added to the edges of honeycomb structure. Container Handle has been modified as shown in the Hyper mesh report. Draft angle has been added to Honeycomb ribs as well.

Fig.4.2 Modification by matching and drafting & Modification by Drafting




FIG.4.3 MODIFICATION BY DRAFTING OF HANDLE & MODIFICATION BY FILLETING

FIG.4.4 MODIFICATION BY DRAFTING AT BOTTOM

5. STATIC AND MOULD FLOW ANALYSIS:

5.1 STATIC ANALYSIS: A static analysis helps us to determine the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed; that is, the loads and the structure's response are assumed to vary slowly with respect to time. A static structural load can be performed using the ANSYS, Hyper works, Samcef, or ABAQUS solver.

The types of loading that can be applied in a Static analysis include: a) Externally applied forces and pressures b) Steady-state inertial forces (such as gravity or rotational velocity) c) Imposed (nonzero) displacements d) Temperatures (for thermal strain)

Various inputs to this software include:

a) Material Properties b) 3-D CAD Model c) Fixtures and DOF d) Force or Pressure or Thermal inputs e) Result Type

5.2 MOULD FLOW ANALYSIS (AUTODESK MOULD FLOW INSIGHT) Mould flow Analysis helps us to understand the filling of the mould, and different pressures required and the temperatures attained during filling. It also helps us to plot various graphs on the filling time, temperature and pressure plots etc. Mould flow, simulation software owned by Autodesk, Inc. that produces high-end plastic injection moulding computer-aided engineering software.

Mould flow has two core products: Mould flow Adviser providing manufacturability guidance and directional feedback for standard part and mould design and Mould flow Insight which provides definitive results for flow, cooling, and warpage along with support for specialized moulding processes.




The various inputs for Mould flow Insight are: Positioning of Gates Material properties 3-D Container Model

5.3 HYPERMESH ANALYSIS OF THE BATTERY CONTAINER To find out the deflection in the battery under the fluid pressure of 5 psi, the battery is meshed with higher order tetra elements. Linear Static Analysis has been carried out on the battery and the deflections in the structure obtained. DETAILS: Tools: Hyper Mesh & Optistruct Material Properties: PP M3530 Young's Modulus: 1300 MPa Poisson's Ratio: 0.43 The internal pressure of 5 psi applied inside the battery surfaces.

Fig.5.1 Component Final Weight

5.3.1 DEFLECTIONS OBSERVED IN VARIOUS ITERATIONS:

Table 5.1 Old vs New model Deflections

Fig.5.2 Old design deflection plot & New design deflection plot

Fig.5.3 Final Deflection Plot of the container




5.4 MOULD FLOW REPORT: 5.4.1 OBJECTIVE To Perform Moulding Simulation of ‘6V 120Ah BATTERY BOX’ to optimize the Part Quality like Fill balance, Injection pressure, Clamping Force & deflection pattern. Material: PP-MI3530 - Reliance Grade: Equivalent Material used for simulation. Processing Conditions: Melt temperature = 220 Mould temperature = 30 Fill time = 2.3 secs Packing time = 8 sec Cooling Time = 35 sec

Fig.5.4 Pressure vs Time Plot

5.4.2 INPUTS FOR MOULD FLOW ANALYSIS

Fig. 5.5 Materials Properties

5.4.3 VARIOUS PLOTS:

Fig 5.6 Time Plot for mould filling & Pressure plot during mould filling




Fig 5.7 Temperature plot during mould filling & Shear rate observed during fill

5.4.4 CLAMP FORCE Clamping force refers to the force applied to a mould by the clamping unit of an injection moulding machine. In

order to keep the mould closed; this force must oppose the separating force, caused by the injection of molten plastic into the mould. The required clamping force can be calculated from the cavity pressure inside the mould and the shot projected area, on which this pressure is acting. The calculated tonnage can be used to select a capable machine that will prevent part defects, such as excessive flash. Plastic injection moulding presses are classified or rated based on tonnage, or more specifically the clamping pressure or force. Presses can run in size from less than 5 tons of clamping pressure to over 4000. Higher the press-ton rating, larger the machine.

Fig.5.8 Clamp force (max) variation plot

1. As for mould flow total required of 240 ton (after packing), so considering 25 % extra for safety. 2. As per tool design this part may go on a higher tonnage machine which is 350 ton machine. 5.4.5 DEFECTS OBSERVED AFTER FILLING

Fig.5.9 Weld lines Observed & Air Traps observed




Fig.5.10 Sink marks detected & Warpage in all directions

Fig.5.11 Warpage in X, Y and Z-directions

5.5 GATE POSITIONING: To ensure proper filling of the mould, the gates have to be placed at equal distance from the sprue, the optimal gate diameter was calculated as 2.5mm so as to ensure proper filling under required pressure.

Fig.5.12 Gate positioning at equal distance




6. RESULTS: Injection mould design for parts is done using Pro-E, auto cad, Uni graphics Creo, and simple software. The

different processing parameters and machine selection is according to the design calculations done. The mould base and inserts are being manufactured at the manufacturing facilities available with M/s HBL. Production of components is to be done at the in-house customer's end. Hence the mould is supplied to the customer after acceptance of the sample by them.

6.1 HYPERMESH REPORT: Wall deflection reduced from 1.39mm to 1.3mm. Rib thickness increased to 3 to 3.5mm in bottom & top 2.8 to 3.3mm in the honey comb structure. Updated weight is 1538g. Handle changed.

6.2 MOULD FLOW REPORT: After conduction simulation analysis, the following observations have been made:

Air trap observed, need air venting at the end filling & provide insert. Injection time optimized at 2.2 sec. Max. Injection Pressure observed 57.9 MPa. Shear rate, within the raw material limit. Weld lines observed on part. Sink Marks will visible. Clamp force observed during filling is 240 tones, at 80% of filling pressure, suggested Clamping force 350T

m/c.

FIG. 6.1 FINAL CONTAINER & FINAL MOULD

7. Conclusions:

Plastics are increasingly used in today's world. Injection moulding is one of the most common methods used to process plastics. We have to consider various factors to produce a defect free and economical plastic component during the design stage itself. Through this project various improvements in battery performance have been observed. With observation, there has been reduction in maintenance and failure of the battery. Along with performance, the backup capacity as well as the life of the battery has increased compared to the previous model. In overall context, through rigorous testing and improvements, the battery obtained was found to be of better standards.

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[3] Musa Rasim Kamal, Avraam I. Isayev, Shih- Jung Liu, “Injection Molding: Technology and Fundamentals”, (Hanser, 2009: 978-1569904343)

[4] Dominick V. Rosato, Donald V Rosato, Marlene G. Rosato, “Injection Molding Handbook”, (Kulver Academic Publishers, 2000: 978-0792386193)

[5] Freindrich Johannaber, “Injection Molding Machines: A User’s Guide”, (Hanser, 2007: 978-1569904183) [6] Alam, MR, Lee, KS and Rahman, M. 2003. Process planning optimization for the manufacture of injection

moulds using a genetic algorithm. Int. J. Comput. Integr. Manuf., 16: 181–191. [7] Hui, KC. 1997. Geometric aspects of the mouldability of parts. Comput. Aid. Des., 29: 197–208. [8] Li, CL, Yu, KM and Li, CG. 2005. A new approach to parting surface design for plastic injection moulds using

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Prod. Res., 41: 2301–2324. AUTHOR

K. Santosh Kumar, Assistant Professor, MED, MGIT. HYD.

Ajay Kumar S, Assistant Professor, MED, MGIT HYD B.Govinda Reddy, Assistant Professor, MED, MGIT HYD

P. Shashidar, Assistant Professor, MED, MGIT

DESIGN AND MANUFACTURING OF 6V 120Ah BATTERY …

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