Water Pump Report

8/2/2019 Water Pump Report

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B.ENG(Hons) MECHANICAL ENGINEERINGIn collaboration with

University of Sunderland

ASSIGNMENT

DESIGN FOR MANUFACTURE

SUBJECT CODE: EAT 206

Level 2

LECTURER :MR. FONG WH

STUDENT :CHEEN WENG HOONG (SCSJ0003047 / UOS - 109079253)

: CHANG SAU SEN (

: MATTHEW CHEW ZHI MING (: TAN WEI KHIN (SCSJ0004704 / UOS089104758)

: CHONG GHEENG FOO (SCSJ 0009407 / UOS 109079301)

: TAN YEN XIANG (SCSJ 0009428 / UOS109098151)

TITLE :Car Water Pump Cost Reduction Exercise
http://www.sunderland.ac.uk/newsevents/news/news/index.php?nid=6http://www.sunderland.ac.uk/newsevents/news/news/index.php?nid=6


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Introduction

Water pumps are impeller pump, they are attach to the front of the engine and also

driven by a belt from the crankshaft pulley. The pump circulates 28,000 litre of coolant an

hour. As the impeller rotates the curved blades draw coolant from the bottom of the radiatorand force the coolant through the pump outlet to the water jackets.

The impeller shaft is supported on sealed bearings which never past the bearings. The

water pump is driven by the fan belt. The water pump may also be driven by a single belt that

also drives other components. In some engines the water pumps are gear-driven from the

engine crankshaft.

The purpose of the water pumps are to pump the coolant to parts of the engines, it is

to cool down the engines and also to maintain the temperature at a safe limit. Over heating

will lead unwanted accidents.


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Objective

The objective of this assignment is to find a better design for the water pump.

Improvise the current design. Besides just designing, we must also state what are the benefits

of it? In terms of cost, labour, method of manufacturing and so on.

The performance of the water pump must be compared between the improved design

and the existing design in order to know that the changes are needed.

Besides that the purpose of this assignment is also to practices our skill to use the

software Autodesk Inventor Professional.


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Chapter 3: Existing product design

Chapter 3.1: Table

Component Quantity Materials Manufacturers technology

Water pump casing 1 Cast iron Sand cast

Pulley hub 1 Cast iron Sand cast

Bearing 1 Carbon steel By supplier

Gasket 1 1 Rubber Stamping

Gasket 2 1 Rubber Stamping

Impeller lock 1 Carbon steel By supplier


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Impeller 1 Steel (anti rust

paint)

Forging and cutting

Oil seal 1 1 Carbon steel By supplier

Oil seal 2 1 Carbon steel By supplier

Shaft 1 Carbon steel Casting

Water seal 1 Carbon steel By supplier

Water pump cover 1 Carbon steel By supplier

Bolt 5 Steel By supplier

Chapter 3.2: Method of Manufacture

For water pump casing and pulley hub

a molten metal is poured into a mold or cavity that approximates the shape of the finish part (figure

1). Heat is extracted through the mold, and the molten metal solidifies into the final solid shape. The

functions for the mold are:

- To provide an entry for the molten metal into the mold that creates laminar flow through thesprue and runner.

- To provide a source of molten metal, suitably located in the mold so that it stays molten until allof the casting has been filled.

- And the cores are suitably placed to provide hollow features for the part.

Figure 1: parts of a conventional sand casting process.


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For gasket

The cold stamping of a sheet of rubber with dies can be classified as either a cutting .cutting operation

are to punch holes in sheets or to separate entire parts from sheets by blanking. A blanked shape may

be either a finished part or the first stage in a forming operation in which the final shape is created by

plastic deformation.

The sheared edge that is produced when sheet metal is punched or blanked is neither perfectly smooth

nor perpendicular to the sheet surface. Simple blank contours should be used whenever possible since

the die cost depends upon the length and the intricacy of the contour of the blank. It may be less

expensive to construct a component from several simple parts than to make an intricate blanked part.

Blanks with sharp corners are expensive to produce, the layout of the blanks on the sheet should be

such as to minimize scrap loss.

Notch a blank along one edge results in an unbalanced force that makes it difficult to control

dimensions as accurately as with blanking around the entire contour. The usual tolerances on blanked

parts are 0.003in.

Impeller

Using the forging process which is typical of a group of bulk deformation processes in which a solidbillet is forced under high pressure by the use of a press to undergo extensive plastic deformation into

a final near-to-finished shape. After this operation is the cutting which in the machining process. The

machining process is required for the drilled holes and finishing.

Assembly for the impeller, impeller lock, oil seals and pulley hub onto a shaft

Use the shaft which is manufactured by sand cast as the first step of the assembly process. Then, use

the impeller lock fit for assemble the ball bearing onto the shaft. After that, place bushing in oil seal.

Into the fourth step, assemble the shaft into the oil seal by knocking and champing. After this, installthe oil seal together with the spring onto the shaft by knocking and clamping under a high pressure

machine. Install the pulley hub onto the shaft by impeller lock fit as the sixth step. At last step, install

the impeller and knocking with the water pump cover into the shaft.


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Chapter 3.3: Method of Assemble and Comment

Generally, the main assembly is assembled within water pump casing by applying the bearing parts

upon one end of the shaft, inserting the shaft and bearing into one end of the housing, and then

applying the oil seal and the impeller, upon the opposite portions of the shaft and into the opposite end

of the water pump casing.

The assembly is relatively time-consuming to accomplish and consequently, expensive. Thus, the

water pump casing, bearing and the system used for sealing the bearing to the water pump casing are

relatively expensive parts which require considerable labor to produce. By apply a considerable

amount of machining to finish the surfaces in order to obtain the accuracy necessary in the finished

pump.

In addition, improving the bearing construction and wherein the bearing and bearing seal arrangement

are considerably simplified to eliminate a considerable portion of the previously required machining

and assembly operations. Thus, the improving of assembly can be lesser weight than the previously

used.

Besides that, objectives of the invention is to substantially reduce the cost of manufacturing,

assembling and handling the main component of the coolant pump used with an automotive-type

engine, while simultaneously decreasing the weight but maintaining the dimensional accuracy of the

water pump.


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Chapter 3.4: Design for Manufacture rules (DFM)

The rule of DFM is protecting public safety and assisting the designer in performing high-quality

work. Reducing the variety of parts that achieve the same function can have many benefits to theproduct development enterprise. Firm numbers on the cost of part proliferation are difficult to obtain,

but estimates are that about half of manufacturing overhead costs are related to managing too many

part numbers.

The benefits of the DFM rules are cost reduction, quality improvement, production flexibility, and

manufacturing responsiveness. The specifics of benefits in each area are outlined here.

Cost reduction

- Purchasing costs Standardization of parts and the subsequent reduction in part numbers. This allow for

flexible delivery schedules, quantity discounts, and less work for the purchasing

department.

- Reduce costs through raw materials standardization Cost for in-house production of parts can be reduced if raw materials can be standardized

to a single size of bar stock, tubing, and sheet metal.

Metal casting and plastic molding operations can each be limited to a single material.- Feature standardization

Standardized the specification of radii in lathe turning or milling will reduced themaintenance a large inventory of cutting tools.- Reduction of inventory and floor space requirements

Reduction of inventory and floor space, tooling costs, and purchasing and otheradministrative costs will be decreased in overhead costs.

Quality improvement

- Product quality Reduces using wrong part in an assembly.

- Prequalification of parts The standard parts can be prequalified for use in new product without the requirement

for extensive testing.

- Supplier reduction means improved quality Giving more business to fewer suppliers will be an incentive for developing stronger

supplier relationships.

Production flexibility

- Materials logistics The flow of parts must within the plant.

- Reliable delivery of standard low-cost parts Restocked directly to points of use in the plant by parts suppliers using long-term

purchase agreement.


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- Flexible manufacturing Eliminating setup operations allows products to be made in any batch size.

Manufacturing responsiveness

- Parts availability Fewer part types used in greater volume.

- Quicker supplier delivers By standardization of parts and materials.

- Financially stronger suppliers With larger volume orders and fewer part types to make.

As an engineer to design water pump not only to standardization from DFM rule but is needed to

achieve a minimum-cost design is to create a minimum-weight design. The most economicalapproach is to select the next larger standard size of motor and pump to achieve adequate

functionality.

In addition, Group Technology which is parts grouped into part families in terms of commonality of

design features as well as manufacturing processes and processing steps is required. Thus, the benefits

of Group Technology can be developed using previous similar designs with a great saving in cost and

time. Another advantage of group technology addresses the trend among customers for greater variety

in products.


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4.1 IMPROVED PRODUCT DESIGN

Part/Component Material Manufacturing Method

Casing 1 Cast Iron Sand Cast

Gasket Iron By Supplier

Pulley Hub Grey Cast Iron Sand Cast

Ball Bearing Steel By Supplier

Shaft Carbon Steel Casting

Cap seal with Spring Plastic By Supplier

Impeller Mild Steel, paint By Supplier

Retaining Ring Carbon Spring Steel By Supplier

Bolt Cast Iron Forging

Bushing Bronze By Supplier


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4.2 How to Manufacture?

Each part of the water pump is manufactured using different method and it is formed by

different materials. For Casing 1 the components are made by Sand Casting method and the

material to manufacture it is cast iron. Sand Casting is a method used to build largecomponents which is pouring molten metal into a cavity casted by sands. When the molten

metal is cool it will formed as the same shape with the cavity and therefore the parts are

build. This manufacturing method is using lower cost and even can be used in for refractory

sufficiently therefore a lot of metal foundries are forming the parts using it. Other than casing

the pulley hub in the water pump are formed using sand cast as well. Forging is another

manufacturing method other than sand cast in for the components in water pump. It is one of

the eldest well known manufacturing methods using in metal working process. Forging can

be define explain as shaping of metal using localized compressive forces.

4.3 How to Assemble?

Water pump in a car engine consist of a lot components so normally the manufacturers are

combining it into a part using hydraulic jet. It is needed to use this machine as we need a high

pressure to push the entire component together to form the water pump. The attachment of all

the parts is very important as it is needed to let a high pressure water to flow on the inlet to

outlet. Therefore if it is not combined intelligently or the screw and the nut are loose, it will

cause the engine to burst or even harm the drivers. Water pump will be needed to screw

tightly on the bottom of the engine.


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4.4 DFM Rules

DFM (Design for manufacture) is one of the most used and abused buzzword today. This

started when foundries where ramping up 0.13um production, many designs where hit with

low yield problems. To improve yields, some design rules were modified. These design rulesare sometimes referred to as DFM rules.

At the same time, CAD tool vendors started to write software that would help improve yield,

or check for potential problems. They also market these tools under DFM.

There are also some design techniques that can help yield, such as memory redundancy and

logic reconfiguration, which again may be thrown under the DFM world. Focusing on this

rules can bring out safety issues and it is causing lower cost for the manufacture therefore it is

encourage to apply the rule.


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4.1 Comparison Between Existing Design and New Design

The figure above is the improved design of the Casing for the water pump. We have redesigned the

casing by changing the left side of the component into holes. The reason we are designing it to

become hollow is to reduce the material used to manufacture this component. Reducing the material

will make the cost of manufacturing this part lower comparing to the existing one.

Figure 2 is to show that the water inlet had been redesign from 2 holes into direct water inlet

at the right side. We modify it because we found out that the existing design is using more

effort to manufacture it and it is unnessacery to put another flat hole on the right side. Weredesign it into a direct water inlet hole so that it is easier to be manufactured and so the

manufacturing process can be easily done.

Figure

Figure


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For the bottom part of this casing we have change the complicated design in to a simple one

.The purpose of redesigning it is to made it easier to design comparing to the existing one.

The top figure is the hub on the water pump. In the existing design it is separated into two

parts and we are combining it into one piece. The new design of the shaft is as shown in the

figure. The purpose of combine it is to make it easier to replace if it is spoil or rusted.

Therefore the end user doesnt need to find the parts 1 by 1 and reduce parts will make therepairing job easier compare to the old design.

Figure

Figure


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On top is the new water impeller which has been redesign by us. It is more focus on the blade

part as we found that the new impeller is more endure comparing to the existing one. The

existing can be say that it i easier to get rust and exhaust. Other than that, the new design willbe easier to be manufacture as it can be formed using sand cast or moulding method. The cost

can be reduced and therefore the parts would not be too expensive when we need to replace

it.

Figure

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