SlideShare ist ein Scribd-Unternehmen logo
1 von 6
Downloaden Sie, um offline zu lesen
Casting of Tap and Faucet
				
											 Page
	 1.) 	 Introduction								 2	
	 2.)	 Product Brief								 2
	 3.)	 Executive Summary							 2
			 3.1) Final Selection						 2
			 3.2) Advantages and Disadvantages				 2
	 4.)	 Design Process								 2
			 4.1) Selecting a material						 3
				 Option 1: Stainless steel					 3
				 Option 2: Copper					 3
				 Option 3: Brass						 3
				 Option 4: Aluminium alloy				 4
			 4.2) Selecting a Casting Process					 4
				 Option 1: Sand casting					 5
				 Option 2: Shell mould					 5
				 Option 3: Die casting					 5
				 Option 4: Permanent mould casting/ gravity die casting	 5
				 Option 5: Investment casting				 5
	 5.)	 Bibliography								 5
1.) Introduction
This report aims to explore and select an economical manufacturing method for a hypothetical tap and
faucet design. Many considerations come into play when designing a tap and faucet for manufacture.
Well before any final drawings are produced for the manufacture of the tapware, the materials and their
treatments, the methods of manufacture, and associated costs, availabilities, time and business issues
must be addressed. In order to commence the assessment of casting method, assumptions have been
made in the following Product Brief.
2.) Product Brief
•	 The tap and faucet are destined for general use in mains- supplied homes, schools, offices etc. 	
•	 The brand is mid-market in placement. Affordability, along with reasonable product quality and
lifespan, are as critical as appearance.
•	 An initial production run of 35,000 units is planned; per unit cost is an essential consideration
as investments in dies must be covered by returns from this production run.
•	 The selected casting method should be capable of withstanding a further 6 production runs, at
minimum.
•	 An 18 week period is the maximum time frame, from final design to completed production run.
Tooling, availability of materials, and finishing requirements must be achievable within this period.
•	 A common sense approach must be applied to issues of product safety such as toxicity.
•	 Where possible sustainability issues such as manufacturing wastes and recyclability must be
considered. Manufacturing wastes are becoming increasingly expensive to dispose of, and a considera-
tion of ‘green’ issues demonstrates responsibility worthy of marketing.
3.) Executive Summary
3.1) Final selection
The material selected for casting the taps and faucets is DCB3 Die Casting Brass (CuZn39Pb1Al-C
CC754S). Chrome plating will impart an appealing and resilient finish.
The casting process will be Permanent Mould Casting, also known as Gravity Die Casting.
3.2) Advantages and disadvantages
DCB3 Die Casting Brass has excellent corrosion resistance- the most important functional aspect when
considering the constant contact with water. It is readily plated for an attractive, long wearing finish.
Although chrome plated brass lacks the visual finesse of stainless steel, it is a very cost effective choice
for our chosen market.
The initial cost of the Permanent Mould Casting dies is high, but the proposed production volumes
mean the process is inexpensive. Thousands of castings can be made without replacing the die.
Although the finish is not quite as precise as die casting, it is superior to sand casting, and economical
for taps and faucets.
4.) Design Process
Ideally the design process is not linear. In selecting materials and casting methods, the functions, costs,
appearance, availability and time frames, environmental factors and product lifespan were considered
simultaneously.
4.1) Selecting a material
Taps need to perform certain functions in a particular environment.
	 •	 Continual contact with water dictates that the material must be resistant to corrosion.
	 •	 Moving parts imply wear will be an issue.
	 •	 The material must be suited to casting.
	 •	 Finishing will need to be attractive and easily cleaned/ hygienic.
	
	 Option 1: Stainless steel
Stainless steel does not stain, corrode, or rust as easily as ordinary steel. Cast high alloy steels are widely used
for their corrosion resistance in aqueous media at or near room temperature. (www.steel.keytometals.com)
Stainless steel is defined as a ferrous alloy with a minimum of 11% chromium content. Most cast stainless
steels are more complex compositionally than this, typically containing one or more alloying elements in ad-
dition to chromium (for example, nickel, molybdenum, copper, niobium, and nitrogen) to produce a specific
microstructure, corrosion resistance, or mechanical properties for particular service requirements. (www.
steel.keytometals.com)
Service temperature provides the basis for selection of cast grades. Stainless material suited to tap casting does
not need additional alloys specifically for excessively high temperature, strength, hardness, or chemically cor-
rosive environments.
The most commonly used identification system for cast stainless steels is the system of the Alloy Casting Insti-
tute (ACI). (Engineering Materials, p 552- 555). The Cast-Alloy Designation ASTM A 743 would be specified
on any final drawings, along with the Grade. The C series of grades designates the corrosion-resistant steels
(www.steelforge.com). CA15 is a suitable selection, as it contains the minimum amount of chromium to be
considered rust proof. This Cast Alloy is equivalent to the Wrought Alloy Type 410; a more familiar identifier.
Widely used grades of stainless steel (such as Wrought Alloy Type 304) are only marginally more expensive
than copper alloys (brasses). However the 410 grade selected for tap casting is approximately double this cost
(Engineering Materials, p768-769). Machining costs are significantly higher (x4) for stainless steel than for
brass (Engineering Materials, p771).
A modern and beautiful finish can be achieved with stainless steel without any further coating or plating.
Electropolishing uses special chemicals and an electric current to uniformly corrode the surface, leaving a
smooth, polished finish. This would also remove any carbon pick-up from casting moulds, which potentially
reduce the corrosion resistance of the surface.
Stainless steel is 100% recyclable.
	 Option 2: Copper
Pure copper is extremely difficult to cast as well as being prone to surface cracking, porosity problems, and to
the formation of internal cavities.
The casting characteristics of copper can be improved by the addition of small amounts of elements including
zinc, chromium, beryllium, silicon, nickel, tin and silver. (www.nonferrous.keytometals.com). Important and
useful copper alloys include the brasses.
	 Option 3: Brass
Brasses are ideal for a very wide range of applications, and are frequently the cheapest material to select (www.
brass.org). The generic term ‘brass’ covers a wide range of copper-zinc alloys with differing combinations of
properties, including:
•	 Corrosion resistance
	 •	 Machinability
	 •	 Wear resistance
	 •	 Cost effective material
	 •	 Colour
	 •	 Readily finished/plated
Brasses can easily be cast to shape, and machine finishing is straight forward and quick. In fact, the
machinability of brass sets the standard by which other materials are judged.
Brass is easily finished to the attractive self-colour. In either a polished or lacquered state it is clean,
hygienic and durable with a natural beauty. This would suit elegant, old-fashioned tap styles suited to
period renovation retro fitting. Our main market, however, is fittings in new constructions. A more
modern look is sought, which could be achieved by plating. Brass readily accepts chrome or gold plat-
ing and its inherent corrosion resistance means no rust blisters or cracks commonly seen on inferior,
steel-substrated products. Chrome plating in particular is relatively inexpensive, and best suited to our
mid-range market.
There are over sixty Standard compositions for brass, with copper contents ranging from 58% to 95%.
Apart from the major alloying element, zinc, small additions (less than 5%) of other alloying elements
are made to modify the properties.
For diecasting the 60/40 type alloys are normally used (http://www.brass.org). This has good fluidity
while pouring, and hot strength to avoid hot tearing while solidifying. The higher zinc content lowers the
casting temperature and gives essential hot ductility. Small additions of silicon or tin improve fluidity; tin
also improves corrosion resistance. An addition of lead improves machinability. Aluminium is added to
form a protective oxide film to keep the molten metal clean and reduce the attack on the die materials.
CuZn39Pb1Al-C CC754S (DCB3 Die casting brass) is used extensively for plumbing fittings (www.
brass.org). This extensive use suggests the material would be readily available.
The initial die cost is high compared to aluminium alloy. (www.diecasting.org). This loses some signifi-
cance when the large quantity of units is considered.
The high value of any process scrap can be used to reduce production costs significantly. Further, the
material can be recycled without loss of properties, at the site of production.
	 Option 4: Aluminium alloy
On its own, pure aluminium is prone to high shrinkage, and susceptibility to hot cracking. It is alloyed
with silicon (9%), copper (3.5%) and several other alloy materials in relatively small proportions to im-
prove the properties.
Aluminium as a base material is inexpensive. Alloy ‘A380’ is the most common and cost effective of all
die casting alloys (www.kenwalt.com) Machining costs are low- less even than for brass (Engineering
Materials, p771), and the initial cost for dies is also less than for brass.
Aluminum die casting alloys are lightweight, easy to cast, with good mechanical properties. Both the
resistance to corrosion and dimensional stability is good, but less than that of brass.
4.2) Selecting a Casting Process
The casting process is ideal for the production of complex shapes. In the case of taps, detailed internal
shapes cannot be machined; casting is the only method to repeat the form economically.
The choice of process is determined by the materials to be shaped, the shape itself and the economics of
the process ( Materials and Design, p 89).
Option 1: Sand casting
Many castings are made by pouring metal into sand moulds. Depending on the casting required, the sand
may be bonded with clay or silicates or various organic mixes.
The cavity in the sand is formed by using a pattern, typically made out of wood, sometimes metal. The cavity
is contained in a box, called the flask. For hollow castings, cores are used. The core is a sand shape inserted
into the mold to produce the internal features of the part. Core print is the region added to the pattern, core,
or mold that is used to locate and support the core within the mold. A riser is an extra void created in the
mold to contain excessive molten material. The purpose of this is feed the molten metal to the mold cavity as
the molten metal solidifies and shrinks, and thereby prevents voids in the main casting. (www.efunda.com)
Sand casting does not impart a smooth finish, and a lot of finishing is required. It is economical for low pro-
duction quantities.
	 Option 2: Shell mould
Shell moulding involves the use of a thermosetting resin bond in the sand. This process offers better surface
finish and better dimensional tolerances than sand casting, and higher throughput due to reduced cycle times.
A heated (200 ºC) metal pattern is covered with a mixture of the sand and thermoset plastic. This causes a skin
of about 3.5 mm of the mixture to adhere to the pattern. This skin is removed from the pattern to form the
shell mold. The two halves of the shell mold are secured together and the metal is poured in the shell to form
the part. Once the metal solidifies, the shell is broken.
A fairly high capital investment is required, but high production rates can be achieved. The process overall is
quite cost effective due to reduced machining and cleanup costs.
The materials that can be used with this process are cast irons, aluminum, brass, bronze and copper alloys.
	 Option 3: Die casting
Die casting is accomplished by forcing molten metal under high pressure into reusable metal dies.
Die casting is very fast, This is in contrast to sand casting, which requires a new sand mold for each casting.
Compared with sand casting, the process of die casting produces parts with thinner walls, smoother surfaces
and even closer dimensional limits- as good as 0.2 % of casting dimension. Also there are no risers to machine
off. Finishing costs are less and labour costs per casting are lower. (www.diecasting.org).
These factors are also true when die casting is compared with permanent mold castings. However operational
costs, utilising equipment more complex and expensive than for permanent mould castings, will be higher
per unit. (www.efuna.com).
	 Option 4: Permanent mould casting/ gravity die casting
Permanent mould castings are also made in metal moulds, this time under a gravity head rather than high
pressure injection.
Tool steel moulds or dies are necessary for between 100 and 100, 000 pieces. Beyond this quantity, Stellite (an
alloy based on cobalt, tungsten and chromium) is necessary. Although the die is expensive initially, thousands
of castings can be made without die replacement.
Tooling may take between 4 and 12 weeks, with samples typically available the week the die is available (www.
efuna.com).
The metal flow under gravity is slower than for pressure injected die casting, but less complex machines are
required, keeping prices lower. Because of solidification shrinkage and other considerations, not all brasses
can be cast this way. Suitable alloys do, however, include our selected 60/40 brass.
Cooling too quickly is the biggest problem faced by this casting method. A spiral mould test would allow flow
rates to be tested prior to a large production run. There are advantages to quicker cooling; better grain size is
achieved, therefore the part is stronger.
Correct taper, risers for shrinkage and webbing to moderate high stress points are other factors to con-
sider in the final designs.
The finish of permanent mould castings is not as quite precise as die casting, but is far superior to sand
casting. There is a trade off between quality of finish, and cost.
	 Option 5: Investment casting
Investment casting by the ‘lost wax’ method has been used for centuries to make useful and decorative,
high precision components in all sizes and weights. It can produce complicated shapes that would be
difficult or impossible with die casting.
It is generally more expensive per unit than die casting or sand casting but with lower equipment cost.
This method is best suited to extremely high precision, low volume applications (www.wikipedia.org)
5.) Bibliography
Books:
Budinski, Kenneth G. Budinski, Michael K. ‘Engineering Materials.’ Pearson Education Ltd. New Jersey,
U.S.A. 1979
Beylerian, George M. Dent, Andrew. Moryadas, Anita (Ed). ‘Material Connexion.’ John Wiley & Sons
Inc. U.S.A. 2005
Manzini, Ezio. ‘The Material of Invention.’ The Design Council, London. 1986
Ashby, Mike. Johnson, Kara. ‘Materials and Design.’ Butterworth- Heineman. Oxford, England. 2003
Aspin, B. Terry. ‘Foundrywork for the amateur.’ Argus Books Limited, London. 1985
Clegg, A.J. ‘Precision Casting Processes.’ Pergamon Press, Oxford, England.1991
Benham, Paul. ‘Foundrywork design and practice.’ Jarrold & Sons Ltd, Norwich, Great Britain. 1966
Beadle, John D.(Ed). ‘Castings.’ Macmillan Engineering Evaluations. The Macmillan Press Limited,
Hampshire, U.K. 1971
Web sites:
www.brass.org
www.wikipedia.org
www.steelforge.com
www.steel.keytometals.com
www.kineticdiecasting.com
www.kenwalt.com
www.diecasting.org

Weitere ähnliche Inhalte

Was ist angesagt?

Carburization & Decarburization in Fasteners
Carburization & Decarburization in FastenersCarburization & Decarburization in Fasteners
Carburization & Decarburization in FastenersAbdullah Ansari
 
IF Steel & BH Steel
IF Steel & BH SteelIF Steel & BH Steel
IF Steel & BH SteelMahmoud Farg
 
Steel presentation
Steel presentationSteel presentation
Steel presentationAqeeb Rehman
 
copper and copper alloys
copper and copper alloyscopper and copper alloys
copper and copper alloysAbdul Rahman
 
Surface or case hardening
Surface or case hardeningSurface or case hardening
Surface or case hardeningAnuj Jha
 
Duplex Stainless Steel - Presentation Oct.16, 2013 Conference
Duplex Stainless Steel - Presentation Oct.16, 2013 ConferenceDuplex Stainless Steel - Presentation Oct.16, 2013 Conference
Duplex Stainless Steel - Presentation Oct.16, 2013 ConferenceRamesh Bapat CMfgE PE
 
17767705 heat-treatment-oct08
17767705 heat-treatment-oct0817767705 heat-treatment-oct08
17767705 heat-treatment-oct08moh481989
 
Hot Rolling And cold rolling process
Hot Rolling And cold rolling processHot Rolling And cold rolling process
Hot Rolling And cold rolling processDhyey Shukla
 
Alloy-Effect of Alloying Elements in Iron and Steel.pdf
Alloy-Effect of Alloying Elements in Iron and Steel.pdfAlloy-Effect of Alloying Elements in Iron and Steel.pdf
Alloy-Effect of Alloying Elements in Iron and Steel.pdfAnnamalai Ram
 
hot and cold rolled sections -bms
hot and cold rolled sections -bmshot and cold rolled sections -bms
hot and cold rolled sections -bmsShrutiGarg261479
 
Advanced High Strength Steels and their Heat Treatment processes
Advanced High Strength Steels and their Heat Treatment processesAdvanced High Strength Steels and their Heat Treatment processes
Advanced High Strength Steels and their Heat Treatment processesSudarshan Sundar
 
Electron beam welding and friction welding
Electron beam welding and friction weldingElectron beam welding and friction welding
Electron beam welding and friction weldingPravinkumar
 
Scale formation and its removal in hot rolling process
Scale formation and its removal in hot rolling processScale formation and its removal in hot rolling process
Scale formation and its removal in hot rolling processRadi Nasr
 
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...Matteo Sporchia
 

Was ist angesagt? (20)

Carburization & Decarburization in Fasteners
Carburization & Decarburization in FastenersCarburization & Decarburization in Fasteners
Carburization & Decarburization in Fasteners
 
IF Steel & BH Steel
IF Steel & BH SteelIF Steel & BH Steel
IF Steel & BH Steel
 
Steel presentation
Steel presentationSteel presentation
Steel presentation
 
copper and copper alloys
copper and copper alloyscopper and copper alloys
copper and copper alloys
 
Surface or case hardening
Surface or case hardeningSurface or case hardening
Surface or case hardening
 
Steel Naming Conventions
Steel Naming ConventionsSteel Naming Conventions
Steel Naming Conventions
 
Cast iron
Cast ironCast iron
Cast iron
 
Duplex Stainless Steel - Presentation Oct.16, 2013 Conference
Duplex Stainless Steel - Presentation Oct.16, 2013 ConferenceDuplex Stainless Steel - Presentation Oct.16, 2013 Conference
Duplex Stainless Steel - Presentation Oct.16, 2013 Conference
 
Steel
SteelSteel
Steel
 
17767705 heat-treatment-oct08
17767705 heat-treatment-oct0817767705 heat-treatment-oct08
17767705 heat-treatment-oct08
 
Aluminum Recycling
Aluminum Recycling  Aluminum Recycling
Aluminum Recycling
 
Types of steels in use
Types of steels in useTypes of steels in use
Types of steels in use
 
Hot Rolling And cold rolling process
Hot Rolling And cold rolling processHot Rolling And cold rolling process
Hot Rolling And cold rolling process
 
Aluminium production-process
Aluminium production-processAluminium production-process
Aluminium production-process
 
Alloy-Effect of Alloying Elements in Iron and Steel.pdf
Alloy-Effect of Alloying Elements in Iron and Steel.pdfAlloy-Effect of Alloying Elements in Iron and Steel.pdf
Alloy-Effect of Alloying Elements in Iron and Steel.pdf
 
hot and cold rolled sections -bms
hot and cold rolled sections -bmshot and cold rolled sections -bms
hot and cold rolled sections -bms
 
Advanced High Strength Steels and their Heat Treatment processes
Advanced High Strength Steels and their Heat Treatment processesAdvanced High Strength Steels and their Heat Treatment processes
Advanced High Strength Steels and their Heat Treatment processes
 
Electron beam welding and friction welding
Electron beam welding and friction weldingElectron beam welding and friction welding
Electron beam welding and friction welding
 
Scale formation and its removal in hot rolling process
Scale formation and its removal in hot rolling processScale formation and its removal in hot rolling process
Scale formation and its removal in hot rolling process
 
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...
ELECTRIC ARC FURNACE AC (PART 3) - The Charging Phase (steel, steelmaking, ir...
 

Ähnlich wie Tap and Faucet Casting

Educational Presentation High Performance Metals
Educational Presentation High Performance MetalsEducational Presentation High Performance Metals
Educational Presentation High Performance MetalsJimHalliday
 
Material technology
Material technologyMaterial technology
Material technologyPrem Baboo
 
Ch 27.10 cutting tool materials
Ch 27.10 cutting tool materialsCh 27.10 cutting tool materials
Ch 27.10 cutting tool materialsNandan Choudhary
 
Using Steel In Solar Racking and Mounting
Using Steel In Solar Racking and MountingUsing Steel In Solar Racking and Mounting
Using Steel In Solar Racking and MountingJMCSteelGroup
 
Ch 27.10 cutting tool materials (1)
Ch 27.10 cutting tool materials (1)Ch 27.10 cutting tool materials (1)
Ch 27.10 cutting tool materials (1)Nandan Choudhary
 
Case study for material selection (Automobile Silencer)
Case study for material selection (Automobile Silencer)Case study for material selection (Automobile Silencer)
Case study for material selection (Automobile Silencer)Nishit Karkar
 
Assignment on casting
Assignment on castingAssignment on casting
Assignment on castingtareq hasan
 
Casting of metals and alloys
Casting of metals and alloysCasting of metals and alloys
Casting of metals and alloysBhavanish Singh
 
Field welding and cutting ductile iron pipe
Field welding and cutting ductile iron pipeField welding and cutting ductile iron pipe
Field welding and cutting ductile iron pipeLudi Lunar
 
Waste Minimization and Cost Reduction in Process Industries
Waste Minimization and Cost Reduction in Process IndustriesWaste Minimization and Cost Reduction in Process Industries
Waste Minimization and Cost Reduction in Process Industriesijsrd.com
 
Design of castings and selection of the parting line
Design of castings and selection of the parting lineDesign of castings and selection of the parting line
Design of castings and selection of the parting lineAnand Prithviraj
 
4 Machine design material selection
4 Machine design material selection4 Machine design material selection
4 Machine design material selectionDr.R. SELVAM
 
International Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentInternational Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentIJERD Editor
 
Cutting tools chap_1_7225
Cutting tools chap_1_7225Cutting tools chap_1_7225
Cutting tools chap_1_7225rossnewman50
 
Cr alloy steel shot & bearing steel grit ( duoleng)
Cr alloy steel shot & bearing steel grit ( duoleng)Cr alloy steel shot & bearing steel grit ( duoleng)
Cr alloy steel shot & bearing steel grit ( duoleng)belen zhang
 
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptx
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptxCHARACTERISATION OF HONEYCOMB STRUCTURE.pptx
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptxLaxmiManu
 

Ähnlich wie Tap and Faucet Casting (20)

Educational Presentation High Performance Metals
Educational Presentation High Performance MetalsEducational Presentation High Performance Metals
Educational Presentation High Performance Metals
 
Material technology
Material technologyMaterial technology
Material technology
 
Ch 27.10 cutting tool materials
Ch 27.10 cutting tool materialsCh 27.10 cutting tool materials
Ch 27.10 cutting tool materials
 
Using Steel In Solar Racking and Mounting
Using Steel In Solar Racking and MountingUsing Steel In Solar Racking and Mounting
Using Steel In Solar Racking and Mounting
 
Ch 27.10 cutting tool materials (1)
Ch 27.10 cutting tool materials (1)Ch 27.10 cutting tool materials (1)
Ch 27.10 cutting tool materials (1)
 
Case study for material selection (Automobile Silencer)
Case study for material selection (Automobile Silencer)Case study for material selection (Automobile Silencer)
Case study for material selection (Automobile Silencer)
 
Assignment on casting
Assignment on castingAssignment on casting
Assignment on casting
 
Investment Casting FAQ
Investment Casting FAQInvestment Casting FAQ
Investment Casting FAQ
 
Casting of metals and alloys
Casting of metals and alloysCasting of metals and alloys
Casting of metals and alloys
 
Field welding and cutting ductile iron pipe
Field welding and cutting ductile iron pipeField welding and cutting ductile iron pipe
Field welding and cutting ductile iron pipe
 
Waste Minimization and Cost Reduction in Process Industries
Waste Minimization and Cost Reduction in Process IndustriesWaste Minimization and Cost Reduction in Process Industries
Waste Minimization and Cost Reduction in Process Industries
 
Tribology
TribologyTribology
Tribology
 
Design of castings and selection of the parting line
Design of castings and selection of the parting lineDesign of castings and selection of the parting line
Design of castings and selection of the parting line
 
4 Machine design material selection
4 Machine design material selection4 Machine design material selection
4 Machine design material selection
 
International Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentInternational Journal of Engineering Research and Development
International Journal of Engineering Research and Development
 
MP-II- UNIT 2-HP (1).pptx
MP-II- UNIT 2-HP (1).pptxMP-II- UNIT 2-HP (1).pptx
MP-II- UNIT 2-HP (1).pptx
 
Cutting tools chap_1_7225
Cutting tools chap_1_7225Cutting tools chap_1_7225
Cutting tools chap_1_7225
 
Cr alloy steel shot & bearing steel grit ( duoleng)
Cr alloy steel shot & bearing steel grit ( duoleng)Cr alloy steel shot & bearing steel grit ( duoleng)
Cr alloy steel shot & bearing steel grit ( duoleng)
 
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptx
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptxCHARACTERISATION OF HONEYCOMB STRUCTURE.pptx
CHARACTERISATION OF HONEYCOMB STRUCTURE.pptx
 
Cutting-Tool-Applications.pdf
Cutting-Tool-Applications.pdfCutting-Tool-Applications.pdf
Cutting-Tool-Applications.pdf
 

Mehr von Felicity Topp

Packaging process drawings WS
Packaging process drawings WSPackaging process drawings WS
Packaging process drawings WSFelicity Topp
 
Solidworks Certificate
Solidworks CertificateSolidworks Certificate
Solidworks CertificateFelicity Topp
 
MA Thesis Results Notice
MA Thesis Results NoticeMA Thesis Results Notice
MA Thesis Results NoticeFelicity Topp
 
MFCO Student Society poster
MFCO Student Society posterMFCO Student Society poster
MFCO Student Society posterFelicity Topp
 
Reflexive Governance 72dpi
Reflexive Governance 72dpiReflexive Governance 72dpi
Reflexive Governance 72dpiFelicity Topp
 
Consider all factors
Consider all factorsConsider all factors
Consider all factorsFelicity Topp
 
403 Intervention Logic Final
403 Intervention Logic Final403 Intervention Logic Final
403 Intervention Logic FinalFelicity Topp
 
402 six hats kids food
402 six hats kids food402 six hats kids food
402 six hats kids foodFelicity Topp
 
403 design languages final
403 design languages final403 design languages final
403 design languages finalFelicity Topp
 

Mehr von Felicity Topp (14)

Brand Mood Board
Brand Mood BoardBrand Mood Board
Brand Mood Board
 
Gallery single page
Gallery single pageGallery single page
Gallery single page
 
Packaging process drawings WS
Packaging process drawings WSPackaging process drawings WS
Packaging process drawings WS
 
Solidworks Certificate
Solidworks CertificateSolidworks Certificate
Solidworks Certificate
 
MA Thesis Results Notice
MA Thesis Results NoticeMA Thesis Results Notice
MA Thesis Results Notice
 
MFCO Student Society poster
MFCO Student Society posterMFCO Student Society poster
MFCO Student Society poster
 
Reflexive Governance 72dpi
Reflexive Governance 72dpiReflexive Governance 72dpi
Reflexive Governance 72dpi
 
401 30 x A3
401 30 x A3401 30 x A3
401 30 x A3
 
Consider all factors
Consider all factorsConsider all factors
Consider all factors
 
403 Intervention Logic Final
403 Intervention Logic Final403 Intervention Logic Final
403 Intervention Logic Final
 
Natural Capitalism
Natural CapitalismNatural Capitalism
Natural Capitalism
 
402 six hats kids food
402 six hats kids food402 six hats kids food
402 six hats kids food
 
Strategic Design A4
Strategic Design A4Strategic Design A4
Strategic Design A4
 
403 design languages final
403 design languages final403 design languages final
403 design languages final
 

Tap and Faucet Casting

  • 1. Casting of Tap and Faucet Page 1.) Introduction 2 2.) Product Brief 2 3.) Executive Summary 2 3.1) Final Selection 2 3.2) Advantages and Disadvantages 2 4.) Design Process 2 4.1) Selecting a material 3 Option 1: Stainless steel 3 Option 2: Copper 3 Option 3: Brass 3 Option 4: Aluminium alloy 4 4.2) Selecting a Casting Process 4 Option 1: Sand casting 5 Option 2: Shell mould 5 Option 3: Die casting 5 Option 4: Permanent mould casting/ gravity die casting 5 Option 5: Investment casting 5 5.) Bibliography 5
  • 2. 1.) Introduction This report aims to explore and select an economical manufacturing method for a hypothetical tap and faucet design. Many considerations come into play when designing a tap and faucet for manufacture. Well before any final drawings are produced for the manufacture of the tapware, the materials and their treatments, the methods of manufacture, and associated costs, availabilities, time and business issues must be addressed. In order to commence the assessment of casting method, assumptions have been made in the following Product Brief. 2.) Product Brief • The tap and faucet are destined for general use in mains- supplied homes, schools, offices etc. • The brand is mid-market in placement. Affordability, along with reasonable product quality and lifespan, are as critical as appearance. • An initial production run of 35,000 units is planned; per unit cost is an essential consideration as investments in dies must be covered by returns from this production run. • The selected casting method should be capable of withstanding a further 6 production runs, at minimum. • An 18 week period is the maximum time frame, from final design to completed production run. Tooling, availability of materials, and finishing requirements must be achievable within this period. • A common sense approach must be applied to issues of product safety such as toxicity. • Where possible sustainability issues such as manufacturing wastes and recyclability must be considered. Manufacturing wastes are becoming increasingly expensive to dispose of, and a considera- tion of ‘green’ issues demonstrates responsibility worthy of marketing. 3.) Executive Summary 3.1) Final selection The material selected for casting the taps and faucets is DCB3 Die Casting Brass (CuZn39Pb1Al-C CC754S). Chrome plating will impart an appealing and resilient finish. The casting process will be Permanent Mould Casting, also known as Gravity Die Casting. 3.2) Advantages and disadvantages DCB3 Die Casting Brass has excellent corrosion resistance- the most important functional aspect when considering the constant contact with water. It is readily plated for an attractive, long wearing finish. Although chrome plated brass lacks the visual finesse of stainless steel, it is a very cost effective choice for our chosen market. The initial cost of the Permanent Mould Casting dies is high, but the proposed production volumes mean the process is inexpensive. Thousands of castings can be made without replacing the die. Although the finish is not quite as precise as die casting, it is superior to sand casting, and economical for taps and faucets. 4.) Design Process Ideally the design process is not linear. In selecting materials and casting methods, the functions, costs, appearance, availability and time frames, environmental factors and product lifespan were considered simultaneously.
  • 3. 4.1) Selecting a material Taps need to perform certain functions in a particular environment. • Continual contact with water dictates that the material must be resistant to corrosion. • Moving parts imply wear will be an issue. • The material must be suited to casting. • Finishing will need to be attractive and easily cleaned/ hygienic. Option 1: Stainless steel Stainless steel does not stain, corrode, or rust as easily as ordinary steel. Cast high alloy steels are widely used for their corrosion resistance in aqueous media at or near room temperature. (www.steel.keytometals.com) Stainless steel is defined as a ferrous alloy with a minimum of 11% chromium content. Most cast stainless steels are more complex compositionally than this, typically containing one or more alloying elements in ad- dition to chromium (for example, nickel, molybdenum, copper, niobium, and nitrogen) to produce a specific microstructure, corrosion resistance, or mechanical properties for particular service requirements. (www. steel.keytometals.com) Service temperature provides the basis for selection of cast grades. Stainless material suited to tap casting does not need additional alloys specifically for excessively high temperature, strength, hardness, or chemically cor- rosive environments. The most commonly used identification system for cast stainless steels is the system of the Alloy Casting Insti- tute (ACI). (Engineering Materials, p 552- 555). The Cast-Alloy Designation ASTM A 743 would be specified on any final drawings, along with the Grade. The C series of grades designates the corrosion-resistant steels (www.steelforge.com). CA15 is a suitable selection, as it contains the minimum amount of chromium to be considered rust proof. This Cast Alloy is equivalent to the Wrought Alloy Type 410; a more familiar identifier. Widely used grades of stainless steel (such as Wrought Alloy Type 304) are only marginally more expensive than copper alloys (brasses). However the 410 grade selected for tap casting is approximately double this cost (Engineering Materials, p768-769). Machining costs are significantly higher (x4) for stainless steel than for brass (Engineering Materials, p771). A modern and beautiful finish can be achieved with stainless steel without any further coating or plating. Electropolishing uses special chemicals and an electric current to uniformly corrode the surface, leaving a smooth, polished finish. This would also remove any carbon pick-up from casting moulds, which potentially reduce the corrosion resistance of the surface. Stainless steel is 100% recyclable. Option 2: Copper Pure copper is extremely difficult to cast as well as being prone to surface cracking, porosity problems, and to the formation of internal cavities. The casting characteristics of copper can be improved by the addition of small amounts of elements including zinc, chromium, beryllium, silicon, nickel, tin and silver. (www.nonferrous.keytometals.com). Important and useful copper alloys include the brasses. Option 3: Brass Brasses are ideal for a very wide range of applications, and are frequently the cheapest material to select (www. brass.org). The generic term ‘brass’ covers a wide range of copper-zinc alloys with differing combinations of properties, including:
  • 4. • Corrosion resistance • Machinability • Wear resistance • Cost effective material • Colour • Readily finished/plated Brasses can easily be cast to shape, and machine finishing is straight forward and quick. In fact, the machinability of brass sets the standard by which other materials are judged. Brass is easily finished to the attractive self-colour. In either a polished or lacquered state it is clean, hygienic and durable with a natural beauty. This would suit elegant, old-fashioned tap styles suited to period renovation retro fitting. Our main market, however, is fittings in new constructions. A more modern look is sought, which could be achieved by plating. Brass readily accepts chrome or gold plat- ing and its inherent corrosion resistance means no rust blisters or cracks commonly seen on inferior, steel-substrated products. Chrome plating in particular is relatively inexpensive, and best suited to our mid-range market. There are over sixty Standard compositions for brass, with copper contents ranging from 58% to 95%. Apart from the major alloying element, zinc, small additions (less than 5%) of other alloying elements are made to modify the properties. For diecasting the 60/40 type alloys are normally used (http://www.brass.org). This has good fluidity while pouring, and hot strength to avoid hot tearing while solidifying. The higher zinc content lowers the casting temperature and gives essential hot ductility. Small additions of silicon or tin improve fluidity; tin also improves corrosion resistance. An addition of lead improves machinability. Aluminium is added to form a protective oxide film to keep the molten metal clean and reduce the attack on the die materials. CuZn39Pb1Al-C CC754S (DCB3 Die casting brass) is used extensively for plumbing fittings (www. brass.org). This extensive use suggests the material would be readily available. The initial die cost is high compared to aluminium alloy. (www.diecasting.org). This loses some signifi- cance when the large quantity of units is considered. The high value of any process scrap can be used to reduce production costs significantly. Further, the material can be recycled without loss of properties, at the site of production. Option 4: Aluminium alloy On its own, pure aluminium is prone to high shrinkage, and susceptibility to hot cracking. It is alloyed with silicon (9%), copper (3.5%) and several other alloy materials in relatively small proportions to im- prove the properties. Aluminium as a base material is inexpensive. Alloy ‘A380’ is the most common and cost effective of all die casting alloys (www.kenwalt.com) Machining costs are low- less even than for brass (Engineering Materials, p771), and the initial cost for dies is also less than for brass. Aluminum die casting alloys are lightweight, easy to cast, with good mechanical properties. Both the resistance to corrosion and dimensional stability is good, but less than that of brass. 4.2) Selecting a Casting Process The casting process is ideal for the production of complex shapes. In the case of taps, detailed internal shapes cannot be machined; casting is the only method to repeat the form economically. The choice of process is determined by the materials to be shaped, the shape itself and the economics of the process ( Materials and Design, p 89).
  • 5. Option 1: Sand casting Many castings are made by pouring metal into sand moulds. Depending on the casting required, the sand may be bonded with clay or silicates or various organic mixes. The cavity in the sand is formed by using a pattern, typically made out of wood, sometimes metal. The cavity is contained in a box, called the flask. For hollow castings, cores are used. The core is a sand shape inserted into the mold to produce the internal features of the part. Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold. A riser is an extra void created in the mold to contain excessive molten material. The purpose of this is feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting. (www.efunda.com) Sand casting does not impart a smooth finish, and a lot of finishing is required. It is economical for low pro- duction quantities. Option 2: Shell mould Shell moulding involves the use of a thermosetting resin bond in the sand. This process offers better surface finish and better dimensional tolerances than sand casting, and higher throughput due to reduced cycle times. A heated (200 ºC) metal pattern is covered with a mixture of the sand and thermoset plastic. This causes a skin of about 3.5 mm of the mixture to adhere to the pattern. This skin is removed from the pattern to form the shell mold. The two halves of the shell mold are secured together and the metal is poured in the shell to form the part. Once the metal solidifies, the shell is broken. A fairly high capital investment is required, but high production rates can be achieved. The process overall is quite cost effective due to reduced machining and cleanup costs. The materials that can be used with this process are cast irons, aluminum, brass, bronze and copper alloys. Option 3: Die casting Die casting is accomplished by forcing molten metal under high pressure into reusable metal dies. Die casting is very fast, This is in contrast to sand casting, which requires a new sand mold for each casting. Compared with sand casting, the process of die casting produces parts with thinner walls, smoother surfaces and even closer dimensional limits- as good as 0.2 % of casting dimension. Also there are no risers to machine off. Finishing costs are less and labour costs per casting are lower. (www.diecasting.org). These factors are also true when die casting is compared with permanent mold castings. However operational costs, utilising equipment more complex and expensive than for permanent mould castings, will be higher per unit. (www.efuna.com). Option 4: Permanent mould casting/ gravity die casting Permanent mould castings are also made in metal moulds, this time under a gravity head rather than high pressure injection. Tool steel moulds or dies are necessary for between 100 and 100, 000 pieces. Beyond this quantity, Stellite (an alloy based on cobalt, tungsten and chromium) is necessary. Although the die is expensive initially, thousands of castings can be made without die replacement. Tooling may take between 4 and 12 weeks, with samples typically available the week the die is available (www. efuna.com). The metal flow under gravity is slower than for pressure injected die casting, but less complex machines are required, keeping prices lower. Because of solidification shrinkage and other considerations, not all brasses can be cast this way. Suitable alloys do, however, include our selected 60/40 brass. Cooling too quickly is the biggest problem faced by this casting method. A spiral mould test would allow flow rates to be tested prior to a large production run. There are advantages to quicker cooling; better grain size is achieved, therefore the part is stronger.
  • 6. Correct taper, risers for shrinkage and webbing to moderate high stress points are other factors to con- sider in the final designs. The finish of permanent mould castings is not as quite precise as die casting, but is far superior to sand casting. There is a trade off between quality of finish, and cost. Option 5: Investment casting Investment casting by the ‘lost wax’ method has been used for centuries to make useful and decorative, high precision components in all sizes and weights. It can produce complicated shapes that would be difficult or impossible with die casting. It is generally more expensive per unit than die casting or sand casting but with lower equipment cost. This method is best suited to extremely high precision, low volume applications (www.wikipedia.org) 5.) Bibliography Books: Budinski, Kenneth G. Budinski, Michael K. ‘Engineering Materials.’ Pearson Education Ltd. New Jersey, U.S.A. 1979 Beylerian, George M. Dent, Andrew. Moryadas, Anita (Ed). ‘Material Connexion.’ John Wiley & Sons Inc. U.S.A. 2005 Manzini, Ezio. ‘The Material of Invention.’ The Design Council, London. 1986 Ashby, Mike. Johnson, Kara. ‘Materials and Design.’ Butterworth- Heineman. Oxford, England. 2003 Aspin, B. Terry. ‘Foundrywork for the amateur.’ Argus Books Limited, London. 1985 Clegg, A.J. ‘Precision Casting Processes.’ Pergamon Press, Oxford, England.1991 Benham, Paul. ‘Foundrywork design and practice.’ Jarrold & Sons Ltd, Norwich, Great Britain. 1966 Beadle, John D.(Ed). ‘Castings.’ Macmillan Engineering Evaluations. The Macmillan Press Limited, Hampshire, U.K. 1971 Web sites: www.brass.org www.wikipedia.org www.steelforge.com www.steel.keytometals.com www.kineticdiecasting.com www.kenwalt.com www.diecasting.org