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Published by joel.p.thomson, 2019-06-20 08:48:29

Demo

PRODUCT
DECONSTRUCTION
REPORT
DNB304 2016.1
DYLAN ANDREWS / JACK DRAPIER / JOEL THOMSON / GERARD KALASHNIKOFF


CONTENTS
3 INTRODUCTION
5-6 DECONSTRUCTION 7-13 ASSEMBLY ANALYSIS
8 BILL OF MATERIALS 15-26 COMPONENT ANALYSIS 27-30 REDESIGN
31-32 REFERENCES
33-34 APPENDICES
01


02


INTRODUCTION
The Predator drill (figure 1) is a 14.4v lithium ion battery drill produced by Predator.
This report is focusing on the deconstruction and analysis of the Predator drill.
This product retails for roughly $50, and is on the low end of the cost spectrum (when it comes to lithium-ion battery drills). It can be seen from the bill of materials that the drill is comprised of five major sub-assemblies, these are:
the body
the electronics the gearbox
the torque setting the chuck
the driveshaft
These sub-assemblies will be analysed later in this report.
Figure 1 — Predator (Jack Drapier, 2016)
03


04


DECONSTRUCTION
1 7
13
14 15 8
11 9 10
32
4 5
05
6
12


16 17 18 19
20
21 22 23
24
25
25
26
LEGEND
27
28
29
30 31 32 33
06
1 — Main body casing 2 — Body screws
3 — Rear rubber grip 4 — Bottom clip ring 5 — Bottom casing
12 — Battery terminal clips 13 — Electric motor
14 — Motor housing screws 15 — Gearbox cover plate 16 — Plastic gears
17 — Planetary gear hub 18 — Steel gears
19 — Internal gear
20 — Gearbox cover
21 — Bearing balls 22 — Torque spring
23 — Torque spring housing 24 — Torque setting
25 — Chuck housing
26 — Drive shaft
27 — Cover insert
28 — Chuck body
29 — Clamping jaws
30 — Thrust bearing
31 — Flat washer
32 — Threaded chuck ring 33 — Internal chuck cover
6 — Bottom plastic cover 7 — Heat sink
8 — Electronic wires
9 — Switch housing
10 — Trigger
11 — Direction switch


ASSEMBLY ANALYSIS
INTRODUCTION
The drill is a mix of custom made and off the shelf bought parts; these choices have been made to be as economical as possible while not putting too much emphasis on a high level of quality.
As can be seen in the bill of materials (refer to page 8) the overall cost estimation was $22.81 per unit. This is believed to be accurate to a reasonable degree, judging by the selling price of the unit.
The main assembly of the product was put together with the chuck at the front; this was the screwed to the torque setting via the main body of the chuck. The torque setting modulated with the gearbox to act as a clutch. The gearbox then connected to the electric motor via three screws, the motor formed the integral part of the electrical system. The electrical system and gearbox was then covered by the body of the drill which clamped the internals together with a series of eight screws.
COST ANALYSIS
As seen in this report each part has been priced. This has been done through a cost analysis; to conduct this cost analysis first it was determined whether the part was custom made or purchased off the shelf . This was mostly obvious, however on a few occasions some help from tutors or experts was needed.
For the custom made parts, all injection moulded parts were estimated using the estimator on “custompartnet.com.”
The steel parts were priced by contacting an industry expert, who then gave a rough estimate on pricing. For the off the shelf parts, their closest equivalents were found on “alibaba.com.”
This method of cost analysis is not a perfect representation of the cost involved, however it is what could be described as reasonably accurate. It provides a reasonable price to base decisions on and would be the most accurate method of pricing without encountering considerable price and effort. All in all it should be considered an effective method of pricing. The sub-assemblies will now be discussed in more depth on the follow pages.
07


BILL OF MATERIALS
08
Item
Sub Assembly
Name
Material
Manufacturing Proccess
Dimensions(mm)
Qty Unit Price
1 2 3 4 5 6 7 8 9
Body
Rear Rubber Grip Bottom Plastic Cover Main body Casing left Main body Casing right Bottom casing Bottom Clip Ring Body Screws Battery Terminal Clips Metal Drill Bit Holder
silcon rubber Polyurethane Polyurethane Polyurethane Polyurethane Nylon
Injection Moulded Injection Moulded Injection Moulded Injection Moulded Injection Moulded
90*35*40 65*65*2 200*150*70 200*150*70 85*85*60
30 dia 15 length 3 dia 8 length
1 $0.62 1 $0.45 1 $4.02 1 $4.02 1 $0.98 1 $0.23 8 $0.01 2 $0.01 1 $0.05
9 10 11 12 13 14 15 16 17
Electronics
Heat Sink Heat Sink Washer Heat Sink Screw Electronics Wires Switch Housing Trigger Directrion Switch Electric Motor Motor Housing Screws
Aluminium Extrusion
25*25*10
3 dia
3 dia 3000*2.5 dia
1 $1.00 1 $0.01 1 $0.01 1 $0.03 1 $0.24 1 $0.18 1 $0.18 1 $2.00 3 $0.01
$1.00 $0.01 $0.01 $0.03 $0.24 $0.18 $0.18 $2.00 $0.03
18 19 20 21 22 23
Gearbox Cover Plate Plastic Gears Planetary Gear Hub Steel Gears Gearbox Cover Internal Gear
Low Carbon Steel Nylon w/ Glass Fibre Low Carbon Steel Low Carbon Steel Nylon w/ Glass Fibre Low Carbon Steel
Sheet Metal Stamping Injection Moulded Die Cast/Milled Milling and Hobbing Injection Moulded Milling and Hobbing
40 dia 50 length
1 $0.05 3 $0.01 1 $0.15 1 $0.02 1 $0.62 1 $0.15
$0.05 $0.03 $0.15 $0.02 $0.62 $0.15
24 25 26 27 28 29
Torque Setting
Torque Setting Housing Torque Spring Housing Torque Spring Torque Spring Holding Tab Torque Spring Holding Ring Torque Setting Cover Plate
Polyurethane
Nylon w/ Glass Fibe
Steel Alloy
Steel Alloy
Polyurethane Powdercoated Steel Alloy
Injection Moulded Injection Moulded Coiling/ Milling Sheet Metal Stamping/ Bending Injection Moulding Sheet Metal Stamping
50 dia 40 length 45 dia 10 length 40 dia 30 length 30*20*5
1 $0.57 1 $0.32 1 $0.05 1 $0.02 1 $0.18 1 $0.05
$0.57 $0.00 $0.05 $0.02 $0.18 $0.05
30 31 32 33 34 35 36 37 38 39 40 41 42
Chuck Housing Internal Chuck Cover Threaded Chuck Ring Thrust Bearing Flat Washer Clamping Jaws Chuck Body Drive Shaft Circlip Bearing Cover Gearbox to Chuck Clip Ball Bearings
Polyurethane
Steel Alloy
Low Carbon Steel
Nylon w/ Glass Fibre/ Chrome Steel Low Carbon Steel
Injection Moulded Sheet Metal Stamping/ Bending Die Cast/Milled Injection Moulded/ Cold headed and smoothed Sheet Metal Stamping Die Cast/Milled Die Cast/Milled Sheet Metal Stamping Sheet Metal Stamping Sheet Metal Stamping/ Bending Cold Headed and Smoothed Die Cast/Milled Milled
40 dia 40 length 35 dia 10 length 35 dia 5 length 35 dia 2 length 35 dia 2 length 40*5*5
1 $0.53 1 $0.05 1 $0.15 1 $0.10 1 $0.01 3 $0.50 1 $2.50 1 $0.01 1 $0.01 1 $0.05 26 $0.01 1 $1.50 1 $0.10
$0.53 $0.05 $0.15 $0.10 $0.01 $1.50 $2.50 $0.01 $0.01 $0.05 $0.26 $1.50 $0.10
Gearbox
Low Carbon Steel
Continuous casting
3 dia 12 length
Chuck/ Drive Shaft
30 dia 4 length 45 dia 10 length
Product Name: Product Amount:
Predator Drill 100,000
Grand Total:
$22.81 Total price $0.62
Drive Shaft Cover Insert
Low Carbon Steel
Low Carbon Steel
Low Carbon Steel
Steel Alloy
Powdercoated Steel Alloy Chrome Steel
30 dia 55 length 20 dia
40 dia
40 dia 20 length 2 dia
Extrusion Continuous casting Sheet Metal Stamping/ Bending Aluminium Extrusion
$0.45 $4.02 $4.02 $0.98 $0.23 $0.08 $0.02 $0.05
Low Carbon Steel Steel Alloy
10*15*10
Sheet Metal Stamping Continuous casting Wire Drawing/ Heat Treatment Injection Moulded Injection Moulded Injection Moulded Multiple Multiple
Steel Alloy
Zinc Alloy
polyethelyne coated copper Plastic Housed electrical switch Polyurethane
Polyurethane
Low Carbon Steel Low Carbon Steel
25 dia/ 10 dia 60 length 20 dia 30 length


THE BODY
The body of the drill consists of the following parts:
The two main body casings, bottom casing, rear rubber grip, bottom plastic cover, body screws, battery terminal clips, and an aluminium drill bit holder
MAIN BODY CASING
The main body casing (figure 2) consists of two custom-made Injection moulded polyurethane pieces, which are clamped together around the internals via eight standard off the shelf screws.
Figure 2 — Main Body Casing (Jack Drapier, 2016)
This casing was custom made because it was necessary — the drill had a unique shape. It also formed the majority of the cost, costing approximately $4.02 a side [1].
This is mostly due to the custom made nature of the part; additionally the cost was driven up by the size of the part and the relative complexity of the part.
BOTTOM CASING
The bottom casing and bottom plastic cover (figure 3) are both parts that attach the main body of the drill to the detachable battery. They are also custom made parts made from polyurethane.
Figure 3 — Bottom Casing (Jack Drapier, 2016)
These were custom made because of the unique shape of the drill. However they were nowhere near as expensive costing approximately $0.45 and $0.98 respectively [1]. This is due to their relative simplicity compared to the main body of the drill.
REAR RUBBER GRIP
The rear rubber casing (figure 4) is the rear hand grip of the drill and as such, it is made from a different material, silicon rubber.
Figure 4 — Rubber handle (Jack Drapier, 2016)
Silicon rubber is a much softer material than polyurethane and is much more suited for use as a hand grip. This was also a custom made part for the same reason as it had to fit the unique shape of the body. The price of this part came to around $0.62 [1]. This was due to the relative simplicity of the part. The Rubber grip attached to the body via a number of tabs that slotted into pre-cut holes in the body. It was then also glued to the body with a permanent adhesive.
09


ELECTRICAL SYSTEM
The Electrical system consists of the following parts
Electric motor, heat sink, electronic wires, switch housing, trigger, direction switch, and motor housing screws
ELECTRIC MOTOR
The electric motor (figure 5) is an off the shelf component providing the source of power for the drill.
Figure 5 — Motor (Jack Drapier, 2016)
This was determined to be an off the shelf component for two reasons. Firstly, it is comprised of many different elements, to develop an electric motor from scratch that would be fit for use would be an incredibly expensive exercise. Secondly, there are many companies who currently make completely applicable electric motors in vast quantities (allowing them to sell them for extremely cheap). This motor could be purchased for around $2.00. This means it is of little cost compared to a custom made part [2]. It affixes to the gearbox by 3 off the shelf screws, and sits in the body of the drill by using the inbuilt housing provided by the casing
HEAT SINK
The Heat Sink (figure 6) is a custom made extruded aluminium part. Its main purpose is to draw the heat from the electronics system into a place where it can be extracted from the body through the use of vents in the main casing.
Figure 6 — Heatsink (Jack Drapier, 2016)
It was custom made due to its unique shape, which was designed to maximise surface area to be the most efficient at drawing heat. Due to the custom made nature of the product and the relative price of the material this part costs approximately $1.00 [3].
SWITCH + HOUSING
The switch housing (figure 7) is a hybrid of custom made and off the shelf with the internal switch being off the shelf, and the housing around it being custom made (injection moulded polyurethane). The housing makes up the vast majority of the pricing, with the switch price being negligible in comparison (costing approximately $0.24) [1].
Figure 7 — Trigger (Jack Drapier, 2016)
This is due to the small size of the part. It was custom made due to the unique layout and size of the trigger mechanism. The trigger (figure 7) is a custom made injection moulded part (due to the product’s unique layout and size). However due to the small part size and small wall thickness it cost only approximately $0.18 [1]. The direction switch was a custom made injection moulded part, with the price being also approximately $0.18 [1]. This is because while it is smaller than the trigger, it is slightly more complex with indents needed to show drive direction.
10


THE GEARBOX
The gearbox of the drill consists of the following parts:
Gearbox cover plate, plastic gears, planetary gear hub, steel gears, gearbox cover, and internal gear.
PLASTIC GEARS
These gears (figure 8) were situated at the motor end of the gearbox and are used to slow down the incredibly high rpm from the electric motor. They are made from nylon with glass fibre content for added strength. They are also an off the shelf product as they are readily available in large quantities from many suppliers. As such they only cost around $0.01 each [2].
Figure 8 — Planetary Gears (Jack Drapier, 2016)
PLANETARY HUB + STEEL GEARS
The Planetary gear hub (figure 9) is used to centralise the rotation of the previous three nylon gears. It is made from low carbon steel and is mostly custom made.
The insert pins would be off the shelf components. These pins are then inserted into the custom made plate via a process of heat treatment where the plate was heated up to expand it, and the pin was cooled down to contract. This allowed the pin to enter the hole and as the metals cured they clamped into each other.
The costing for this part in total would be around $0.15 — due to the small size and high simplicity of the part (estimated by an industry expert).
11
The steel gears (figure 9) are also made from low carbon steel and are a standard off the shelf component. They are used to slow the speed of rotation to a manageable rate. The pricing for these gears are approximately $0.02 each [2].
Figure 9 — Planetary Gears (Jack Drapier, 2016)
INTERNAL GEAR
The internal gear (figure 10) is used to house the repeated use of three gears to slow down the rotation of the motor. It also facilitates the rotation of the sets of three gears.
It is made from low carbon steel and is a standard off the shelf component. Due to the larger size of the part and the higher complexity compared to the standard spur gears, this part cost approximately $0.15 [2].
Figure 10 — Internal Gear (Jack Drapier, 2016)


TORQUE SETTING
The torque setting consists of the following parts
Torque setting housing, spring housing, spring, spring holding tab, holding ring, and cover plate
TORQUE SETTING HOUSING
The Torque Setting Housing (figure 11) is the outside body of the torque setting and facilitates the user changing the torque level of the drill. It is a custom made part of injection moulded Polyurethane. It costs approximately $0.57 [1]. It is custom made because it must fit the unique size and shape of the drill body. It is a relatively high price because it is quite big and is surprisingly complex..
Figure 11 — Torque setting (Jack Drapier, 2016)
TORQUE SPRING + HOUSING
The torque spring (figure 12) is the clutch mechanism that engages and disengages the drive depending on the torque level selected by the user. It is a standard off the shelf spring available from many suppliers and as such only costs $0.05 [2]. However the housing piece (figure 12) that holds it in place is a custom made part. It is made from nylon with glass fibre to give it high strength. It is approximately $0.57 [1]. This is due to the high quality material and relative complexity.
Figure 12 — Spring (Jack Drapier, 2016)
12


CHUCK + DRIVE SHAFT
The chuck and drive shaft consists of the following parts:
Chuck housing, internal chuck cover, threaded chuck ring, thrust bearing, flat washer, clamping jaws, chuck body, drive shaft circlip, bearing cover, gearbox to chuck clip, bearing balls, drive shaft, and cover insert.
CHUCK BODY
The chuck body (figure 13) is the main piece of steel in the front of the drill. It holds the clamping jaws in, and facilitates their movement. It also attaches to the drive shaft to provide the turning motion to the front of the drill. It is made from low carbon steel and could be either custom made or off the shelf.
DRIVE SHAFT
The drive shaft (figure 15) is the piece that connects the gearbox to the chuck body. It has a planetary gear hub on the rear side to attach the steel gears to, and a thread on the other to screw to the chuck body. This would most likely be a custom part, except for the pins which would be off the shelf and installed in the same way as the planetary gear hub. The main body of the drive shaft however would be custom made. This piece would be milled and cost around $1.50, (estimated by an industry expert). This is because while it is rather big, it is a considerably simpler piece than something like the chuck body.
As stated with the chuck body, these pieces could be an off the shelf component as part of a full chuck assembly. However, assuming they are custom made for the drill, they are made from low carbon steel. They would be milled and cost around $0.50 each (estimated by an industry expert). While they are quite small, the geometry is quite complex and that drives up the price.
Figure 14 — Clamping jaws (Jack Drapier, 2016)
However if it was purchased off the shelf the entire chuck would have been the unit purchased. Therefore for the purpose of this assignment, it was judged that this was custom made. In which case it would have been milled, which would have cost around $2.50 to produce due to the complexity and size of the part (estimated by an industry expert).
Figure 13 — Chuck body (Jack Drapier, 2016)
CLAMPING JAWS
These clamping jaws (figure 14) are situated triangularly in the chuck body — and are pushed inwards and forwards by rotating the chuck. These are the pieces that grip the drill bit and facilitate the drilling.
13
Figure 15 — Drive shaft (Jack Drapier, 2016)


14


COMPONENT ANALYSIS
INTRODUCTION
Four components of the drill were chosen for analysis, the outer casing, the trigger, shaft and planetary gears. These components use a number of different manufacturing processes, which will be covered in depth in this section. The research into the components will reveal the quality of materials used in the drill and the intended target market.
METHODOLOGY
A flow chart was used to correctly identify the type of plastic used for the outer casing and the trigger. Correct identification of the plastics used would give us a key insight into quality and help with redesign strategies. The flow chart (figure 16) [3] starts with touching the plastic with a heated metal tip. Depending on results, you would then test buoyancy of a thermoplastic or burn a small piece of the thermosetting plastic. Varying results of flame size, colour and burning speed helped us to correctly identify the plastic used. After testing the outer casing, the flow chart indicted the plastic as polyurethane (TPUR, PUR or PU)
Looking at the interior of the casing it appeared grainy. Upon further research we found a scratch test would reveal the presence of reinforcement materials in the plastic. Following the scratch test results presented the presence of glass fibre reinforcement. To gain confirmation of our results, research was conducted to track down “Predator”, the company that produced the drill. With extensive research performed it was revealed that the company had folded and have abandoned website prior to registration (see appendices).
MANUFACTURING
Two of the analysed components utilised the manufacturing process of injection moulding. These include the outer casing and the trigger button.
The planetary gears identified as low end carbon steel and the shaft, milled steel. These processes will now be discussed in detail, with any custom features also thoroughly examined.
15


16
Figure 16 – Plastics Identification Flow Chart [3]


INJECTION MOULDING
Injection moulding is commonly utilised for manufacturing a vast array of plastic parts with a wide range of shapes and sizes. During the deconstruction process a large number of parts in the assembly were found to be produced by the injection moulding method. Materials that are suitable for injection moulding range from metals, where the procedure is called die casting, to the most common application of plastics. Thermoplastics such as polystyrene, nylon, polypropylene and polythene are best suited for the process as when heated to a specific temperature they become malleable and are easily pushed through the injection unit. A typical injection moulding machine is illustrated in figure 17 below [13].
Figure 17 — Internal Moulding overview [4]
The whole process is very quick, normally between 2 seconds and 2 minutes.
The procedure (refer to figure 15) can be broken down into four stages:
1. The process begins with granules of plastic powder poured or fed into a hopper.
2. The plastic is heated in the injection unit tube and once a predetermined temperature is reached the screw thread starts turning. The thread is powered by a motor situated at the end of the unit.
17
3. As the motor turns it pushes the plastic (still in granules / powder form) along the heater section, where it changes to molten plastic.
4. Now in liquid form, the plastic is forced into the mould where it is allowed to cool and solidify. When hardened the mould opens and the finished product is removed.
Figure 18 — Injection Moulding process [5]
Depending on the product to be manufactured, a mould may be single or multiple cavity. A multiple cavity mould can consist of identical cavities, producing numerous matching parts, or they can be unique and form numerous different geometries during a solitary process.
The product to be produced will determine the material of the mould. Tool steel, which is a variety of carbon, and alloy steel, are most common, but aluminium and stainless steel also have their place. The problem with aluminium moulds is that they do not consistently produce quality parts in high volume production.


Aluminium’s low-grade mechanical properties are vulnerable to abrasion, damage and distortion during the injection process. Although they do have the advantage cost effective output in low-volume production. On the other end of the spectrum, steel moulds are very expensive. But with high price comes high quality, these moulds are able to generate over a million parts in their life cycle [5].
Figure 19 illustrates a multiple cavity mould. For the plastic to flow into the mould cavities, numerous channels are incorporated in the mould design. The liquid plastic injects into the mould by way of the sprue. This leads to the runners, these are channels that transport the plastic to all the cavities that will be filled. The runners connect to the gate, which guides the flow to the part. The blue dots in figure 19 illustrate the cooling channels. These allow water to pass over the mould walls and cool the liquid plastic.
Figure 19 — Mould channels [4]
After the part is cooled and ejected from the mould, the post processing procedure will occur. The runner, sprue and gate which form in the process are all by products of the desired part. These as well as any flash that has occurred during the process, will need to be trimmed.
Figure 20 — Injection moulded part [4]
Figure 20 shows a moulded part before and after the trimming process. The excess plastic that is trimmed off can be recycled in most cases. It is placed in a grinder and ground into granules that can be placed back into the hopper to repeat the injection process.
It is hard to completely remove the marks that are left from the gate in the injection process. It can be achieved, but the process is very expensive. Instead, the imperfections are usually hidden on the inside of parts, and once the product is fully assembled the defects are concealed. The plastic injection parts from the drill are displayed on the next page (figure 21) with circles around injection points. All these injection points are concealed once the drill is assembled [4].
18


I
19
Figure 21 — Injection mould gate marks
This method is utilised to manufacture thin- walled plastic parts used in a range of different functions. The thin walls reduce cooling time allow for faster cycle times and in turn a significantly cheaper product. The thin walls can be seen in the housing of the drill in figure 22. You can see ribs and bosses throughout the part to provide support and structure.
A material is selected for a number of reasons. The most important is the required characteristics of the final product. But consideration must also be given to how the material will react during the manufacturing process. The table on the following page (figure 23) illustrates the advantages and disadvantages of the polyurethane (drill casing) and some of the other most common plastics used for injection moulding and their applications.
Figure 22 — Injection mould walls
Plastics can also be integrally moulded together to create desired properties, which would otherwise be impossible to fabricate using a sole plastic. The table (figure 24) on the following page illustrates a variety of combined plastics and their properties.


Type of Plastic
Polyurethane
Polystyrene
Nylon
Code
TPUR, PUR, PU
PS
N/A
Advantages
Wide Range of Hardness, high Load Bearing Capacity, Abrasion & Impact Resistance
Light, hard, stiff, transparent, with good water resistance
outstanding mechanical and electrical properties, particularly toughness and wear resistance.
Disadvantages
Some types of TPUR have a short shelf life. Not as cost effective as other alternatives.
Brittle, low impact polystyrene breaks very easily, not strong
High shrinkage in moulded sections, pollution problems, lack of stability
Applications
Building insulation. Refrigerators and freezers. Furniture and bedding. Footwear. Automotive.
packaging applications and household appliances
From aircraft components to components for the electric utility industry.
20
Figure 24 – Plastics [7]
Figure 23 – Common Injection Moulding Plastics [6]
Acrylonitrile Butadiene ABS Styrene
Uniform shrinkage in both the flow and transverse-to-flow directions. Minimal warpage, strong and flexible.
Not weather resistant and opacity (opaque)
office machines, electronics and consumer related products. Casings for kitchen equipment (e.g. food processors), toys, telephones, car components, tool handles
Cheap, Decent chemical resistance Polypropylene PP and clarity. Good electrical
insulating properties
Not great for UV exposure. Moderate heat resistance.
Protective caps for electrical contacts; battery housings; and small containers.
Polybutylene PBT sections due to its low melt Teraphthalate viscosity.
Excellent for molding thin cross
High mould shrinkage. Poor resistance to hydrolysis. Prone to warping due to high differential shrinkage.
From under the hood automotive parts to plastic housing in electrical industry.


OUTER CASING
1. Softens
2. Sinks
3. Continues to burn
4. No drips
5. Yellow / Orange flame
6. Fast burn
7. Small amount of black smoke
This information was gathered by following figure 16 (Plastics Identification Flow Chart).
The plastic identified as Polyurethane (TPUR, PUR or PU)
MATERIAL
Polyurethane (TPUR, PUR or PU)
Polyurethane is a polymer created by the linking of urethane (carbamate) to form a structure. Polyurethane can be either a thermoplastic or a thermosetting polymer, in this case the casing is a thermoplastic. Polyurethane is created by mixing two or more liquid streams. There are two parts that make up polyurethane. The first part is the polyols, which may also include other additives such as chain extenders, cross linkers, surfactants, flame retardants, blowing agents, pigments and fillers. The second part is the isocyanate or B-side. Polyurethane has a wide range of applications because of its ability to adopt so many different characteristics by changing the isocyanate, polyol or additive percentages.
PART DESCRIPTION
The drill casing as mentioned houses and protects all the components of the drill. It was held together by 7 threaded phillips head screws. The outer skin of the casing (side which the user handles) has a glossy finish, which has a smooth feel to it. The inside is unfinished with ribs and bosses for mounting of components in a fixed position, while also directing heat away from the motor and out the slotted fins. The layer provides protection against human
21
interaction and the outside influences, making the mechanical properties of polyurethane an excellent choice for this protective layer. It has a matt surface with gate marks left from the injection moulding. If we were unable to identify the manufacturing process from the gate marks on the casing, there are other signs, which also guided to same conclusion. The draft angle on both sides of the outer case suggests injection moulding was used. Draft is a common feature of injection moulding, as it permits an easy removal of the part from the mould.
POLYURETHANE APPLICATIONS
Polyurethane has a wide range of applications. This can be attributed to the many characteristics that can be achieved in the production process. The most popular application for polyurethane is in the form of foam. Polyurethane packaging is so popular because of its low cost and particularly effective cushioning. As well as dominating the packaging industry polyurethane is prevalent in the automotive industry with a large selection of parts containing PU. Other notable applications include, apparel, appliances, building and construction, electronics, flooring, furnishings, marine and medical [14].
COST
As referenced in the Bill of Materials (page 8), the left and right sides of the body came to $4.02 each, making an $8.04 total for this part.


TRIGGER
1. Softens
2. Sinks
3. Continues to burn
4. No drips
5. Yellow / Orange flame
6. Fast burn
7. Small amount of black smoke
This information was gathered by following figure 16 (Plastics Identification Flow Chart).
The plastic identified as Polyurethane (TPUR, PUR or PU)
MATERIAL
Polyurethane (TPUR, PUR or PU)
Refer to outer casing material section.
PART DESCRIPTION
The trigger of the drill is a small injection moulded part (red component figure 25). It is connected to a switch, which also contains a circuit board. This junction connects power from the battery (red and black wires with clamps soldered) to the switch. When the trigger is depressed, dc voltage is sent to the motor through the red and black wires with the yellow heat braid over them. The trigger is hollow on the inside, with a similar wall
thickness to the outer casing. The wall thickness as well as the draft angle identifies the part as injection moulded. There are two gate marks inside the trigger at the very top but they are very hard to see. The surface is smooth with a matt texture. The inside is not as refined and adopts a slightly rougher surface.
Figure 25 — Trigger and switch
COLOUR
The trigger assumes a red colour. This could be to make it easily identifiable or maybe the colour scheme of the brand. It is hard to resolve these questions as the company has folded and it has been hard to source other drills or tools in the Predator line. What we do know though is that the colour has been added to the resin.
Dyes and pigments are added to the resin during manufacturing to achieve desired colours. Care must be taken in choosing the right dye as additions to the formula can change the chemical composition of the thermoplastic. Aliphatic and cycloaliphatic isocyanates are added in small amounts, often in coatings or products where colour or transparency is critical since polyurethanes produced with aromatic isocyanates darken with exposure to light [15].
COST
As referenced in the Bill of Materials (page 8), the trigger came to $0.18.
22


SHAFT
The first step taken in correct identification of the shaft was to refer to the metal identification table illustrated below (figure 26). The shaft was a finished surface or as the table reports a “filed surfaced”. The shaft presented as a bright silvery grey colour, which narrowed the selection down to low-carbon steel, high-carbon steel and stainless steel.
Figure 26 — Metal table [8]
MATERIAL
It would be safe to say the shaft is not stainless, because of the price tag attached to it and the home DIY quality this drill exhibits. Never the less a spark test was carried out to gain a result.
Figure 27 illustrates the different spread of sparks produces when held against a grinding wheel. The top two images would be the main focus during the testing. Low-carbon steel producing fewer sparks and an expansive range. While high-carbon produced a much denser cluster of sparks, which travelled a shorter distance. To gain a reference material to compare spark spread the table in figure 28 was used. Three objects were examined in testing. A bolt (low- carbon), chisel (high-carbon) and the drill shaft. The spark spread of the drill shaft and the chisel were very similar compared to the bolt, which as assumed produced a spark spread comparable to figure 27. The shaft identified as a high-carbon, tool steel.
Figure 27 — Spark identification [8]
23
Figure 28 — Carbon steel identification [9]


Tool steels are carbon and alloy steels (that as the name suggests are appropriate for tools). Their high quality hardness, resistance to abrasion and deformation properties make them well-suited in a wide range of tooling applications. Their carbon content sits between 0.5% - 1.5%, which is how they differ from a low carbon steel.
Tool steels are fabricated under precise conditions to acquire the desired properties. This includes an appropriate heat treatment from one of the six processes. The Predator drill shaft identified as undertaking a water-hardening treatment. This treatment includes rapidly quenching the steel, which is accomplished with the use of water. Water-hardening tool steel is the most common treatment because of the low cost compared to other processes. Water-hardening is suited for small parts where extreme temperatures are not faced. Toughness of the treated steel can be improved by alloying with manganese, silicon and molybdenum. With 1.11% - 1.30% carbon composition, typical applications include files, small drills, lathe tools and other light duty applications.
After the shaft has been heat treated a thread must be cut into the surface. This is done by means of a lathe (figure 29).
Figure 29 — Lathe identification [10]
The shaft is clamped in the chuck component and it rotates by force of the motor behind it. In the toolpost, a threading tool (figure 30) is fixed in position. The chuck moves back and forth until the thread is cut to the desired depth.
Figure 30 — Threading tool [11]
Figure 31 illustrates a lathe and threading tool in motion. There is usually a coolant hose running over the threading tool during operation. This is to cool the tip and prevent overheating and strains that could blunt or break the tip.
Figure 31 — Lathe in motion [12]
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PART DESCRIPTION
The shaft picture in figure 32 fits into the gear box by way of the three locating pins at the base. They fit into the planetary gears and spin the shaft. The threaded section at the top of the shaft connects to the chunk, where numerous tools and be clamped in place.
Figure 32 — Shaft
As referenced in the Bill of Materials (page 8), the price of the shaft came to $1.50.
PLANETARY GEARS
The planetary gear assembly (figure 33) is a component made of several smaller gears, attached together with shafts connecting to a base plate. This assembly included three small steel gears, three plastic gears, a housing, back- plate and ball-bearings. It has a low-shine finish, and are somewhat worn out. These are the gears responsible for the main functions of the drill, and allows for the user to change speeds and directions of the drill.
Figure 33 — Planetary gears
MATERIAL
The first step taken in the process of identifying the material that makes the gear assembly was first eliminating metals based on colour (refer to figure 26). Then using the same table again, and observing the piece, we can discern that the metal is either cast steel, high-carbon steel, or stainless steel.
As before, it was found that the price tag of stainless in comparison to the complexity of the drill did not meet, so stainless could be removed as a possibility. After the other metals had been eliminated due to having colours inconsistent with the component, a spark test was carried out (refer to figure 27).
The spark tests were carried out once again, on a variety of the gears, and they all exhibited the properties of a low-carbon or cast steel.
COST
25


Small parts of irregular metal near the base of the main gear suggests that this piece was cast, and formerly had flash cut or ground off, and is in line with the spark test’s discovery of cast steel.
Cast steel are steels that are poured into a mold instead of being routed or forged. This metal provides a fast manufacturing time, and allows for a relatively accurate construction of a piece in a small amount of time. These metals usually have a carbon content of around 0.1-0.3%. This carbon is not distributed evenly through the piece though, and results in small hardness/ carbon anomalies within the part
CASTING
Casting is the process of pouring a liquid material into a mold which has a hollow cavity which is in the shape of the desired object. Many materials are cast, including metals, resins and composites such as concrete. This process is over 6000 years old, and is still a common manufacturing process today.
The process used for this particular piece would be something called “Die Casting”. Die casting is a “non-expendable mold casting” technique which uses a mixture of extreme temperatures and pressure to inject material into a separating two part mold. For dies casting ferrous components, like low carbon steel, the type of die system used is a cold-chamber die casting.
Figure 34 shows a schematic of a cold-chamber die casting machine.
Firstly, the material is melted in a different furnace, and placed into a holding furnace, the material is then transferred in the shot chamber, and forced into the die via hydraulic press. This creates the desired shape.
This process unfortunately has a slower manufacturing rate than other casting methods, due to the fact that steel needs to be melted in another furnace, and then brought to the cold- chamber die, where metals with lower melting points use something called a hot-chamber die casting system instead.
Figure 34 — Die casting [13]
As referenced in the Bill of Materials (page 8), the price of the planetary gears came to $0.02, the gear hub was $0.15, and the internal gear was $0.15.
26
COST


REDESIGN
The current design for a cordless drill is suited well to the context of home renovation and casual handy-work. The current design employs relatively low end materials, and would most likely break under more professional/ harsh conditions. This drill was marketed as an entry- level home DIY product, and was inexpensive, and thus, accessible. Allowing for a range of activities to be completed, with a manufacturing process that really only covered the essentials of the item, this product was somewhat of a cheap and easy fix.
The conclusions of this products target market were based off the assembly analysis carried out earlier in this report, which stated that the drill was on the low end of the power tool spectrum in regards to selling cost, and manufacturing make.
The body of the drill is made of polyurethane, and manufactured through injection mould methods. The inside components are standard copper wires and various steels making the gear and shaft assembly/ chuck assembly and drill bits.
The chosen context to transport this product to is use in space. The self-given context is for exterior use in the vacuum of space. Due to the extreme nature of this environment, some changes to materials needed to be made.
Polyurethane is a thermal plastic used in a wide array of applications. In the vacuum of space, there is no Ozone layer, so the flow of UV and infrared radiation from the sun hits any object in full. This creates massive temperature differences, and would make use of any conventional thermoplastics extremely unwise, as it would melt on one side, whilst being snap frozen on the other.
27
Copper wires are not a bad choice for use in the vacuum, but copper has to go through a process of de-oxygenation before it can see proper use without rust scale formation (which would eventually lead to wire failure). Steel can be used if properly cared for and coated, but the inability to use it in high magnetic fields limits its use in the space repair/ exploration context.
As such, the materials that have been replaced are the thermoplastic polyurethane, regular copper wires and all steel screws and steel components.
After researching materials typically used in vacuums/ space, replacement materials were found and implemented into a new design.
The polyurethane was swapped out for a scandium-aluminium alloy, which is used because of its ability to not expand/ warp under continual heating of small areas, which would over time warp other metals. Scandium- aluminium is a mix of 0.1% to 0.5% scandium to aluminium [18]. Its most well-known applications was on the Russian Mig-21 and Mig-29 fighter jets, in which certain parts were made of the alloy. Scandium-Aluminium is not as strong as a metal like titanium, but it is much lighter, and allows for a sturdy, heat/ cold resistant product.
Oxygen-free copper was chosen as the substitute to normal copper, as it very rarely rusts and is an extremely pure, non-reactive metal.
Oxygen free copper boasts higher conductivity, and greater reliability in constant-use environments[19].Theuseoflow-oxygenornear oxygen-free materials also provides control over oxygen leaking from that material and causing damage to surrounding components.


The steel for the internals will be replaced with Grade 5 Titanium alloy, an extremely strong and corrosive resistant material [20]. Grade 5 titanium, also known as Ti-64 consists of 6% aluminum, 0.2% oxygen, 4% vanadium, 0.25% iron, and the remainder titanium. Typical applications of this alloy are high end machining parts and extreme condition machinery.
These changes allowed for a much stronger, higher-performing and longer lasting drill to be designed, with considerations made with the specific goal of creating a cordless drill to be used in the repair, construction and deconstruction of structures in space.
Concept images and rough orthographics are provided on the following page for reference.
28


SPACE PREDATOR
29

30


REFERENCES
[1] Custompart.net, “Manufacturing Cost Estimation”, Custompartnet.com, 2012. [Online]. Available: http://www.custompartnet.com/. [Accessed: 28- May- 2016].
[2] Alibaba, “Find quality Manufacturers, Suppliers, Exporters, Importers, Buyers, Wholesalers, Products and Trade Leads from our award-winning International Trade Site. Import & Export on alibaba.com”, Alibaba, 2016. [Online]. Available: http://www.alibaba.com/. [Accessed: 28- May- 2016].
[3] Partec, How do I identify Plastic Types? 2016 [Internet]. [cited 2016 May 21]. Available from:http://www.partec.qld.edu.au/plastics- identification-chart.
[4] Custompart.net. Injection Molding. 2009 [Internet]. [cited 2016 May 21]. Available from:http://www.custompartnet.com/wu/ InjectionMolding.
[5] Ryan. V. Injection Moulding of Plastics. 2009 [Internet]. [cited 2016 May 21]. Available from: http://www.technologystudent.com/ equip1/inject1.htm
[6] Rebling Plastics. Custom Molding. 2016 [Internet]. [cited 2016 May 21]. Available from: http://www.reblingplastics.com/nylon-pa.htm
[7] Verdigets, Christopher, Richard Sofranec. Molded sprocket. 2006 [Internet]. [cited 2016 May 21]. Available from: http://www.google.com/ patents/EP1623144A2?cl=en
[8] WCWelding.com. How To Identify Metal For Welding! 2016 [Internet]. [cited 2016 May 21]. Available from: http://www.wcwelding.com/ metal-identification.html
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[9] Slideshare. Important Engineering Materials. 2016 [Internet]. [cited 2016 May 21]. Available from: http://www.slideshare.net/ tparikh25/important-of-engg-materials
[10] Custompart.net. The Centre Lathe. 2009 [Internet]. [cited 2016 May 21]. Available from: http://www.technologystudent.com/equip1/ mlathe1.htm
[11] Concept Tooling LTD. Internal Threading Tool Holders. 2016 [Internet]. [cited 2016 May 21]. Available from: http://www.concept- tooling.co.uk/index.php?main_page=product_ info&cPath=21&products_id=69
[12] Glenn View. Hardinge lathes. 2016 [Internet]. [cited 2016 May 21]. Available from: http://www.glennview.com/hardingeholygrail. htm
[13] Xcentric mold and engineering. About injection molding. 2016 [Internet]. [cited 2016 May 21]. Available from: https://www.xcentricmold. com/about-injection-molding.php
[14] American Chemistry Council. Polyurethane Applications. . 2016 [Internet]. [cited 2016 May 21]. Available from: https:// polyurethane.americanchemistry.com/ Introduction-to-Polyurethanes/Applications
[15] ceresana. Market Study: Polyurethanes (PUR) and Isocyanates (MDI & TDI). 2016 [Internet]. [cited 2016 May 21]. Available from: http://www. ceresana.com/en/market-studies/plastics/pur- isocyanates/
[16] 278
Black and Kohser. 2003. Degarmo. 277-


[17] Parashar, Nagendra. 2004. Elements of Manufacturing Processes. 234-235
ISBN 978-81-203-1958-5
[17] Ahmad, Zaki (2003). “The properties and application of scandium-reinforced aluminum”. JOM 55 (2). 35.
doi: 10.1007 s11837-003-0224-6.
[18] Horace Pops (1997). The Metallurgy of Copper Wire. Accessed 27-05-2016 http://www.copper.org/publications/ newsletters/innovations/1997/12/ wiremetallurgy.html
[19] “Titanium-6-4”. Accessed 27-05-2016. http://asm.matweb.com/search/ SpecificMaterial.asp?bassnum=MTP641
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APPENDICES
33
Appendix 1 — Predator collapse
Appendix 2 — Predator Trademark


34
Appendix 3 — PP


DYLAN ANDREWS / JACK DRAPIER / JOEL THOMSON / GERARD KALASHNIKOFF


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