Clever knife sharpener (PDM Project)

1
PRODUCT DESIGN AND MANUFACTURING
BMFR 3513
SEMESTER 5 (2016/17)
PROJECT
PREPARED BY:
1. MOHAMAD FARID BIN CHE AWANG B051410202
2. SISUBALAN A/L SELVAN B051410128
3. SHAIK MUHAMMAD FAKHRULL BIN SHAIK ALAUDIN B051410178
4. NURUL AMANINA AMANDA BINTI ISMAIL RIDHA B051410256
5. NOORHANIM BINTI ALI B051410234
6. SITI KHADIJAH BINTI ABU SAMAH B051410190
PREPARED FOR:
DR. MOHAMAD KAMIL BIN SUED

2
TABLE OF CONTENTS
Title Page
1 Introduction 3
2 Name of Product 4
3 Technical Critical Specification of the
Product
5
4 Drawings
I. Product Drawing
II. Assembly and Detail Drawing
7
5 Manufacturing Processes of the Parts 23
6 Design for Manufacturing and Assembly
(DFMA)
27
7 Design for Environment (DFE) 32
8 Bill of Materials 35
9 Conclusion 40

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INTRODUCTION
This report is a product portfolio of the manufacturing design that was assigned to us
in embracing new technologies. We as a team of engineers have decided to do some of the
household creative product by ourselves. Some innovation and improvements were
implemented and the clever knife sharpener was chosen as our product to ease these groups
of customers such as cooks and housewives in catering their basic culinary function and
outdoor enthusiasts (campers, hikers and etc.). Clever knife sharpener is a process of making
a knife and tool sharpener by grinding against hard, rough surface and a soft surface with
hard particles using injection moulding, powder metallurgy and welding. This product is
designed for sharpening serrations as it is compact, lightweight and durable. Clever knife
sharpener offers innovative features that is never seen on a manual knife sharpener sold in the
retail consumer marketplace and functional performance unmatched by standard edge
maintenance products. Clever knife sharpener is consumable at home due to its small size,
portable, easy to use and energy saving.
Our analysis of Clever knife sharpener innovation links to the technical specification
and quality improvements made to it or the inclusion of new components, materials or
desirable functions into an existing knife sharpener. All of the drawings must be applied to
Design for Manufacture (DFM) and Design for Assembly (DFA) to achieve the same
functionality of the product, but make mass production more efficient. Concepts of Design
for environmental processing and manufacturing (DFE) were carried out using
environmentally preferable materials and processes which are not dangerous to the
environment or the employees working on said a process which includes the minimization of
waste and hazardous by-products, air pollution, energy expenditure and other factors. Our
designed of engineers were assigned to find all the possible drawings which can improve our
product. Lastly, the bill of material and the cost of our proposed product must be considered
and estimated in order to get the profit margin each year.

4
NAME OF PRODUCT
MULTIPURPOSE KNIFE
SHARPENER

5
TECHNICAL CRITICAL
SPECIFICATION OF THE PRODUCT
In this product design, we decided to do some of the household creative product by
ourselves. Some innovation and improvements were implemented and the multipurpose knife
sharpener was chosen as our product. Multipurpose knife sharpener is a process of making a
knife and tool sharpener by grinding against hard, rough surface and a soft surface with hard
particles. This product is designed for sharpening serrations as it is compact, lightweight and
durable. Multipurpose knife sharpener offers innovative features that is never seen on a
manual knife sharpener sold in the retail consumer marketplace and functional performance
unmatched by standard edge maintenance products.
Multipurpose knife sharpener is consumable at home due to its small size, portable,
easy to use and energy saving. To make this product flexible in the near future, we conducted
a survey in order to know exactly what customer needs from the products that we offered.
Below are the specifications required by our customers from our product.
Specifications of Multipurpose knife sharpener:
i. The knife sharpener has multiple functions such as a cutting knife with knife
adjustable, knife sharpener and carrot cutter.
- It also caters to basic culinary functions like cutting, dicing, and coating with
precision. Knife sharpener can be used to sharpen dull and nicked knives quickly
and efficiently, realign the edges and maintain fine sharpness as all knives do get
worn out with time. Knife adjustable can be used to adjust the length of the knife
as it is a super-efficient knife sharpener, ideal for regular use.
ii. The product design should be small and light weight, non-slip rubber grip handle and
portable.
- Multipurpose knife sharpener is portable and user can bring it to anywhere. This
product is small and light weight to make the user feel easy to use to cater basic
culinary functions like cutting and dicing. It is also travel friendly and the compact
size makes for convenient storage in any drawer. For smooth grip and firm control
over the action, the multipurpose knife sharpener comes with an ergonomic

6
comfort non-slip rubber grip handle and lightweight components for easy handle
which maximizes the safety of the consumers.
iii. The product is eco-friendly.
- Multipurpose knife sharpener is an eco-friendly and economy because this product
does not pollute the environment as it function manually in catering basic culinary
function besides providing a knife sharpener to ensure that their knives are
steadily and uniformly sharpened. No power supply is used.
iv. The product has long durability, longevity and warranty
- Multipurpose knife sharpener provide user with durability and plenty of longevity
for a long lasting product which is not easily rust. A lengthy warranty will ensure
that consumer’s investment is well worth it and will prove to be fruitful.
v. This product is affordable
- The product provides unmatched quality at an affordable price for its
ergonomically designed soft-grip handle, aesthetics and functionality of the
multipurpose knife sharpener.

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DRAWINGS
I. PRODUCTDRAWING
Diagram 1: Left side knife sharpener

8
Diagram 2: Right side knife sharpener

15
Diagram 9: Carrot cutter blade

16
Diagram 10: Carrot cutter hole

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II. ASSEMBLY AND DETAIL DRAWING
Diagram 11: Multipurpose Knife Sharpener assembly
Diagram 12: Multipurpose Knife Sharpener assembly
(2)

18
Diagram 13: Extracted assembly
Diagram 14: Right view knife sharpener

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Diagram 15: Left view knife sharpener
Diagram 16: Carrot cutter (1)

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Diagram 17: Carrot cutter (2)
Diagram 18: Carrot cutter sharpener

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Diagram 19: Holder rubber
Diagram 20: Knife sharpener

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Diagram 21: Knife
Diagram 22: Knife adjuster

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MANUFACTURING PROCESSES
OF THE PARTS
1) Identification of parts (Assembly)
1.0 Outer casting or body
Knife Sharpener Body (Left View)
Process : Injection Molding
Material : Acrylonitrilebutadiene styrene (ABS)
Knife Sharpener Body (Right View)

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2.0 Carrot Cutter
3.0 Carrot Cutter’s Blade (Shredder)
Carrot Cutter
Process : Injection Molding or Extrusion
Material : Polypropylene (PP)
Blade
Process : Powder Metallurgy
Material : Stainless Steel

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4.0 Knife
5.0 Knife Length Adjuster
Sharp Knife with a bridge connecting the Adjuster.
Process : Powder Metallurgy & Welding
Material : Stainless Steel
Knife Length Adjuster (Connected to tip of the bridge)

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6.0 Sharpening Steel
7.0 Soft Grip Handle Rubber
Soft grip Elastomers
Material : Silicone Rubber
Sharpening steel / stones
Process : Powder Metallurgy of abrasive materials
Material : Hard Carbide Ceramics

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DESIGN FOR MANUFACTURING
AND ASSEMBLY (DFMA)
 It is the combination of two methodologies; Design for Manufacture (DFM), which
means the design for ease of manufacture of the parts that will form a product, and
Design for Assembly (DFA), which means the design of the product for ease of
assembly.
 The purpose of applying this method was to achieve the same functionality of the
product, but make mass production more efficient. However, the majority of the
design remained unchanged, since the manufacturing engineers could never be sure
whether a change would affect some functional requirement.
Part Number Part Name
1 Outer casting / Body
2 Carrot Cutter
3 Carrot Cutter’s blade
4 Knife
5 Sharpening Steel
6 Soft Grip Handle Rubber
7 Knife Length Adjuster
Table 1: Identification of parts

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Assembly sequence
1. The knife is adjusted and secured into its corresponding slots.
2. Both sides of the bodies are connected by snap-fit mechanism, enclosing the knife
inside the body.
3. Knife level adjuster connected to the tip that welded to the knife.
4. The soft grip handle is inserted into its respective slot and secured by snap-fit
mechanism.
5. The carrot cutter’s blade is inserted into its respective position in the carrot cutter’s
body.
6. Then fit the carrot cutter into the knife sharpener’s body and sealed it off by snap-fit
mechanism.
Component Manufacturing Process Material
Outer casting / Body Injection Molding Acrylonitrile butadiene styrene
(ABS)
Carrot Cutter Injection Molding /
Extrusion
Polypropylene (PP)
Carrot Cutter’s blade Powder Metallurgy Stainless Steel
Knife Powder Metallurgy and
Welding
Stainless Steel
Sharpening Steel Powder Metallurgy of
abrasive materials
Hard carbide ceramic
Soft Grip Handle Rubber Injection Molding Silicone Rubber
Knife Length Adjuster Injection Molding Acrylonitrile butadiene styrene
(ABS)
Table 2: Component’s manufacturing and assembly processes and the materials used

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Part 1: Outer Casting or Body
 This part is made of Acrylonitrile butadiene styrene (ABS).
 ABS is a lightweight material that is much easier to machine compared to other
plastics.
 A variety of machining processes can be applied to it like turning, drilling, milling,
sawing, die-cutting and shearing.
 It is also cheap and easy to obtain.
 It has higher impact resistance and tough. It is also has higher heat resistance.
 It is more preferable to use injection molding technology for ABS, because this
process is much easier to carry out and reduce the processing time and production
cost.
 This part is made to be snap-fitted in order to reduce number of components like
screws, hence reduce the cost of production.
Part 2: Knife
 This part is made of stainless steel through powder metallurgy.
 Stainless steel is used compared to other material because of it superiority in
withstanding the corrosion rates. In short, it has higher resistance to corrosion.
 Stainless steel also produced a product with shiny surfaces.
 Ceramics are fragile and other metal like steel corrodes easily and have higher
densities.
 Powder metallurgy is used to manufacture the knife because it takes less
manufacturing times compared to forging and need less finishing. Hence, higher
volume of products can be produced and thus may increase the profits of the
company.
 Knife of powder metallurgy are really hard and sharp.
 The finishing can be done by buffing it with chrome oxide to get a polish shine
appearances or by hand rubbing with dry or wet abrasive papers and Japanese water
stones.
 The knife is made to be inserted to the corresponding slots in the body of the knife
sharpener. So, the exact size and the tolerances of the knife should be not too tight or
not too loose. Because tight tolerances will require more care to be taken during
machining which will leads to larger processing time, higher reject rates, more
expensive measurement/inspection systems and restricted set of machine tools.

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Part 3&4: Carrot cutter and its blade (Shredder)
 The blade is made of stainless steel through powder metallurgy.
 The blade also can be made via forging but ever since the size of the blade is too
small, powder metallurgy are far more preferable.
 This blade also should be made to be fitted into the corresponding slots in the carrot
cutter.
 Meanwhile, the carrot cutter is made of polypropylene, a thermoplastic polymer that
resistant to many chemical solvents, bases and acids.
 Polypropylene is cheap and it is the world's second-most widely produced synthetic
plastic, after polyethylene.
 The carrot cutter is manufactured through injection molding and extrusion. But it is
more preferable to use extrusion.
Part 5: Sharpening stone
 The part is made of hard carbide ceramics like Silicon Carbide.
 This stone can made through by powder metallurgy method at where a mixture of
silica sand and carbon are sintered at a high temperature, between 1,600 °C (2,910 °F)
and 2,500 °C (4,530 °F), inside an Acheson graphite electric resistance furnace.
 Silicon carbide (SiC) is used due to its durability and low cost of the material. It is
also used for its hardness in abrasive machining processes such as grinding, honing,
water-jet cutting and sandblasting.
Part 6: Knife length adjuster
 The knife length adjuster is used to adjust the length and move the knife in and out of
the knife sharpener.
 This part is connected to the tip of the bridge that welded on the knife.
 This part is made of Acrylonitrile butadiene styrene (ABS) via injection molding
because of its smaller size.
Part 7: Soft grip handle rubber
 This rubber or elastomers is made of Silicone.
 Silicone rubbers are cheap and safe to use.
 It is also can be manufactured and form into the desired shape easily by injection
molding.
 Silicone rubber offers good resistance to extreme temperatures.
 Silicone rubber is highly inert and does not react with most chemicals.
 Silicone has a long life term which this will eventually eliminate or reduce the need
for adjustments and replacements. By doing so, we can prevent the malfunction of the
product after some usage by customers.

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Redesign motivations and improvements
1) The needs for screws are eliminated and replaced with snap-fit mechanism. Thus
decrease the weight and the production cost and time.
2) Soft silicone-d rubber handle designed for better grip surface. (Ergonomically well-
designed).
3) Number of components is reduced to ensure that these parts are easy to assemble.
4) Fewer parts usually mean smaller stacked tolerances, and therefore lead to better
functioning of the assemblies, and fewer rejects.
5) Designing parts with widest possible tolerances to minimize the reject rates.
6) All the selected materials are cheap, easy to manufacture or processed and safe to use.

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DESIGN FOR ENVIRONMENT
(DFE)
Designfor Environment (DFE)
 It is a design approach used to reduce the overall human health and environmental
impact of a product, process or service, where impacts are considered across its life
cycle.
 The wastage of material also should be eliminated.
Concepts of DFE
Designfor environmental processing and manufacturing:
1. The manufacturing of these parts are done using environmentally preferable
materials and processes which are not dangerous to the environment or the
employees working on said processes. This includes the minimization of waste
and hazardous by-products, air pollution, energy expenditure and other factors.
2. Acrylonitrile butadiene styrene (ABS)
a) Stable to decompose under normal use. (Only hazardous when
exposed to 400oC)
b) Since pure ABS contains no halogens, its combustion does not
typically produce any persistent organic pollutants, and the most toxic
products of its combustion or pyrolysis are carbon monoxide and
hydrogen cyanide.
3. Polypropylene (PP)
a) At room temperature, it is resistant to fats and almost all organic
solvents, apart from strong oxidants.
b) It has a good rate of degradability.
c) The production of PP is not dangerous and it does not produce
hazardous by-products.
Designfor environmental packaging:
1. The materials used in the packaging are environmentally friendly, which can
be achieved through the reuse of shipping products, elimination of
unnecessary paper and packaging products, efficient use of materials and
space, use of recycled and/or recyclable materials.

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Designfor disposal or reuse:
1. At the end-of-life of this does not emit dangerous chemicals into the air,
ground and water after they disposed of in a landfill.
2. After used or at the end of the life, this product can be reused and
disassembled for the future used. Thus, may reduce the material consumption
and the production cost.
3. Glues and adhesives can create processing challenges for recyclers, so snap-
fits mechanism is being used on this product.
4. Acrylonitrile butadiene styrene (ABS), Polypropylene (PP) and Silicone
rubber can be recycled.
Designfor energy efficiency:
1. The design of this product can reduce overall energy consumption throughout
the product's life.
a) The product can be easily manufactured since the shape of the product
is not too complex and the size is not too big.
b) The use of snap-fit mechanism also may reduce the processing time
and energy consumption.

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Design criteria Description / Planning
Function  This knife sharpener comes with multiple functions like sharpening
knife and cutting carrots or vegetables.
 The carrot cutter is made so that it can be removed from the knife
sharpener for cleaning purposes.
Hazardous  This product does not use or made of the material that listed as the
prohibited and restricted substances.
 This product is made of eco-friendly materials like ABS, PP and
Silicone. All these products do not cause or brings any harm to both
users and the environment.
Weight and size  This product has been reduced to smaller quantity of materials. (11
materials).
 The need for screws to tighten up the parts is eliminated, replaced with
snap-fit mechanism.
 Most part of the products is made of light materials, for example like
ABS and PP which have lower densities. Those materials can be
recycled except the hard carbide ceramic which wears out slowly as in
use.
 This product is made into smaller size to save some space. Hence, even
when it disposed, it won’t take large space.
Energy  This product does not need electricity or fuel to function. Hence, the
energy and resource consumption in the use phase is minimized.
 This product is much easier to operate and safe to use.
Upgrade  Since the product involves the snap fit mechanism, it is made to
increase the repeatability and sustainability.
 All those materials are also easily obtainable in the market.
Lifetime and
Protection
 The knife sharpener is made of materials that have longer lifetime and
higher reliability.
 Both ABS and PP are mechanically strong and they even withstand
high temperature. These materials are also have higher resistant to
corrosion and it has higher impact resistance.
 This product is design for easy refurbishing and has higher flexibility.
 The design is made to increase the durability for long-life parts and
components.
Table 3: Design for Environment (DFE)

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BILL OF MATERIALS
Group of customers: Cooks, housewives and outdoor enthusiasts (campers, hikers and etc.).
Production per year: 400 000 units
Selling Price per product: RM39.79 (USD 8.99)
Part No. Part Name No. of Parts Estimated Cost (RM)
1 Outer casting / Body 2 (Right and Left) 2x0.50
2 Carrot Cutter 1 0.86
3 Carrot Cutter’s blade 1 0.67
4 Knife 1 2.66
5 Sharpening Steel 4 4x0.99
6 Soft Grip Handle Rubber 1 0.30
7 Knife Length Adjuster 1 0.50
Table 4: Cost estimation of each component
Total estimated cost per product = RM9.95 (USD 2.25)

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Break-Even Analysis
Fixed costs:
 Worker’s Salary (per month): RM 2500 per person (350 workers)
 Electric resource’s bill per month: RM 25000
 Water resource’s bill per month: RM10000
Total = RM 10 920 000 (USD 2 467 239.04)
Variable costs:
 Knife Sharpener: RM9.95 (USD 2.25) per product
Selling Price:
 Knife Sharpener: RM39.79 (USD 8.99) per product
Total cost:
 Fixed costs + Variable costs = RM 10 920 000 + RM9.95
 Total cost = RM 10 920 009.95 (USD )
Contribution Margin
 Selling Price – Variable cost = RM39.79 - RM9.95
 CM = RM29.84 (USD 6.74)
 For every knife sharpener sold, RM29.84 can go towards covering fixed costs.

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Break Even Point
 Fixed Costs / Unit Contribution = RM 10 920 000 / RM29.84
 BEP = 365 952 units
 Therefore 365 952 units of knife sharpener must be sold to Break Even, at this the
point the business is not making a Profit nor incurring a Loss, it is merely covering its
Total Costs.
 In order to get profit, about more than 365 952 units should be produced.
Profit-Volume Chart
Sales (400 000 units X RM39.79) RM15 916 000
Variable costs (400 000 units x RM 9.95) RM 3 980 000
Contribution margin (400 000 units x RM 29.84) RM11 936 000
Fixed costs RM10 920 000
Operating Profit RM 1 016 000
Table 5: Calculation of profit of the company
Graph of break-even analysis of profit volume charts
Fixed Cost RM10920000
Variable cost (per
unit) RM9.95
Sales price (per unit) RM39.79
unit increments (x-
axis) 50000
Break Even (units) 365952
Break Even (RM) 14203120

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Units Fixed Cost
(RM)
Variable
cost
total cost sales CM Operating
point.
0 10920000 0 10920000 0 0 -10920000
50000 10920000 497500 11417500 1989500 1492000 -9428000
100000 10920000 995000 11915000 3979000 2984000 -7936000
150000 10920000 1492500 12412500 5968500 4476000 -6444000
200000 10920000 1990000 12910000 7958000 5968000 -4952000
250000 10920000 2487500 13407500 9947500 7460000 -3460000
300000 10920000 2985000 13905000 11937000 8952000 -1968000
350000 10920000 3482500 14402500 13926500 10444000 -476000
400000 10920000 3980000 14900000 15916000 11936000 1016000
Tap 6: Data collection for break-even analysis

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Graph 1 Profit-Volume Chart
 At 365 952 units sold, the operation profit obtained would be zero (no profit), hence
reaching the break-even point.
 Meanwhile, when more than 365 952 units sold, our company will start to gain profit.
 The region between unit of sales and operating profit line after the break-even point
known as the Operating Point.
 Meanwhile, the region between the unit of sales and the operating point line before
reaching the break-even point known as the Operating Loss, which means that our
company will started to gain loss when less than 365 952 units sold.
-12000000
-10000000
-8000000
-6000000
-4000000
-2000000
0
2000000
0 50000 100000 150000 200000 250000 300000 350000 400000
Operatingprofit(RM)
Unit of sales
Break-Even Analysis
Operating profits
Break-even point

40
CONCLUSION
In this report, the design of our proposed product which is the clever knife sharpener,
which was manufactured using powder metallurgy, extrusion and injection molding offers an
innovative features and functional performance. DMFA and DFE was applied in our product.
Among the quality improvements required in redesigning our product for a better technical
specifications are the needs for screws which are eliminated and replaced with snap-fit
mechanism. In addition to it, fewer parts usually mean smaller stacked tolerances, which lead
to better functioning of the assemblies, and fewer rejects. Number of components of the parts
were also reduced to ensure the parts of product are easy to assemble and lastly, designing
parts of the product with widest possible tolerances to minimizes the reject rates.
For DFE, the design is to reduce the overall human health and environmental impact
of the product and process that are considered in life cycle. This can minimize of waste and
hazardous by air pollution, energy expenditure and others. The product consists of design for
environmental processing, environmental packaging, disposal or reuse and energy efficiency.
Besides, the product is easy to operate and safe to use. The design is made to increase the
durability for long-life parts components and higher reliability.
The bill of material and the cost of our proposed product have been considered and
estimated in order to get the profit margin each year. Therefore, with an estimation of more
than 356952 units sold, there would be a profit gain in our proposed product. With this result,
this estimation in the BOM is crucial for the beneficial of our product business in determining
the loss and profit of it. We, as a team of engineers hope that our chosen product will help to
ease these group of customers such as cooks and housewives in catering their basic culinary
function and outdoor enthusiasts (campers, hikers and etc.) which suit their preference, as our
main objective in inventing this product is to simplify daily life chores for the consumers
besides fulfilling their requirements.

Clever knife sharpener (PDM Project)

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