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MME 4492a – Production Management for Engineers

Automobile brake production

system design

Date Submitted: 1st December 2014

Group 7

Rafael Gomes Pereira

Aashish Gupta

Manpuneet Singh

Roman Astrachan

Peter Byers

Executive Summary

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Contents1. Market analysis.................................................................................................................................3

1.1 Product Classification........................................................................................................................3

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1.2 Market Growth Rate and Growth Trends....................................................................................4

2 Product Dissection and Reverse Engineering............................................................................11

2.1 Disassembly and Assembly Procedure................................................................................11

2.2 Major components and subassemblies.....................................................................................12

2.3 Component Manufacturing Process.....................................................................................15

2.4 Purchased and In-House Components................................................................................16

2.5 Bill of Materials........................................................................................................................17

2.6 Product Variants......................................................................................................................19

2.7 Modularity.................................................................................................................................21

2.8 Modular Bill of Materials.........................................................................................................21

2.9 Manufacturability Features....................................................................................................22

8 Supply chain....................................................................................................................................47

Table of Figures

Figure 1: Products and services segmentation (2014).................................................................................6Figure 2: Industry revenue trend.................................................................................................................7

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Figure 3: Revenue vs. employment growth trend.......................................................................................8Figure 4: TRW Automobile financial performance....................................................................................10Figure 5: Akebono Corporation financial performance.............................................................................11Figure 6: Continental AG financial performance.......................................................................................12Figure 7: Market share of major players...................................................................................................12Figure 8: Detailed view of caliper. Internal rusting prevented further disassembly..................................16Figure 9: Detailed view of both sides of vehicle disk brake caliper when brand new and un-rusted. Obtained from bmwe32.masscom.net on 20/11/14.................................................................................17Figure 10: Detailed view of the rotor disk. Surface rust normally develops but typically does not hinder braking ability............................................................................................................................................17Figure 11: Top view of brake pads and support brackets..........................................................................18Figure 12:Exploded view schematic of typical vehicle caliper and pad. Obtained from mjbobbitt.home.comcast.net on 20/11/14...............................................................................................21Figure 13: Coloured Disk Brake 1...............................................................................................................23Figure 14: caliper bodies, pistons, pressure seals, dust boots and abutments plates...............................31Figure 15: Caliper halves assembly............................................................................................................32Figure 16: Rotor and hat assembly............................................................................................................32Figure 17: Caliper bracket installed...........................................................................................................33Figure 18: Press machine...........................................................................................................................33Figure 19: Ready brake kit.........................................................................................................................34Figure 20: Brake kit boxed and labelled....................................................................................................34Figure 21: Rotor disc being machined.......................................................................................................40Figure 22: Disc being drilled......................................................................................................................41

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1. Market analysis

1.1 Product Classification

Disc brakes and drum brakes are the two main types of automobile brakes. While

drum braking systems use round brake pads to apply pressure to the inner surface of a

circular drum to cause friction and reduce the movement of the rotor, disc brakes use a

caliper to pinch the pads against the rotor.

This report will focus on the disc brakes and its market, as well as the production

system and application of lean production methods in automobile brake manufacturers.

Seventeen per cent of industry manufacturing revenue are due to disc brake

manufacturing, 2% less than the revenue generated by drum brake manufacturing.

Over the past five years, pads, valves and calipers represent 0.5% of industry

revenue. Brake pads require replacement every 32,000 to 96,000 kilometers due to the

fiction that warn down the pads over time. The valves and calipers make the transferring

of pressurized brake fluid from the pedal to the brake pad.

Brake discs (also known as rotor-discs or brake rotors) are the rotating metal

plates in which the brake pads clamp down to slow the rotation speed of the attached

tire. They represent 9.5% of industry revenue, and unless the rotor becomes distorted

by heavy stress, they normally do not need to be replaced. The industry revenue of

linings have largely declining, representing currently 3% of revenue.

To sum up, the pie chart below shows the products and services segmentation of

automobile brake manufacturing for 2014:

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Figure 1: Products and services segmentation (2014)

1.2 Market Growth Rate and Growth Trends

In 2010 brake manufacturers experienced for the first time recovery from the

recession of 2007-08, growing at an average annual rate of 5.8% over the past five

years, as consumer income and confidence gradually recovery from the recession.

Industry revenue is expected to grow 3.7% until the end of 2014, reaching $11 billion in

total and an average annual growth of 0.8% to $11.5 billion in total revenue is expected

from 2014 to 2019.

It is also expected that OEM and aftermarket companies to change brake

purchases from domestic to foreign manufacturers due to the relatively cheap cost of

labor in foreign nations, such as China and Japan. Industry exports have grown at an

average annual rate of 12.5% to a revenue of $2.9 billion, while foreign brake

manufacturers have increasingly penetrated the domestic market, growing at an

annualized rate of 10.5% to a revenue of $6 billion. It is estimated the total imports of

braking systems to increase at an annualized rate of 12% to $10.5 billion over the five

years to 2019, while exports will increase at a comparatively small rate of 5.5% to $3.8

billion revenue over the same period.

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The change rate in industry is plotted over the time in the graph below:

Figure 2: Industry revenue trend

1.3 Market Size, Size Reduction Trends and Profitability

It is estimated the number of brake manufacturing industries to decline at an

annualized rate of 0.8% to 153 due to the increasing competition from foreign

companies that will restrict the profit and cause industry contraction from 2014 to

2019, resulting in a declination of industry employment by an average annual rate of

0.4% to 20,845 as can be seen in the following graph:

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Figure 3: Revenue vs. employment growth trend

Technology innovation has already improved brake performance and lifespan, a

trend that hurts the replacement aftermarket companies.

By 2019 is it estimated for the industry profit to be 5.2%, which can be higher if

new braking technologies, such as brake-by-wire and regenerative braking, are

adopted. These technologies require heavy capital investments in machinery and new

materials, like new composites, resins and alloys.

A summary of the current market revenue, profit, exports and number of

businesses, as well as the expected annual growth trend is shown in the figure below:

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1.4 Major Companies and Market Leaders

TRW Automotive is the market leader in the brake manufacturing; from 2009 until

the end of 2014 the revenue in the segment is expected to increase at an average

annual rate of 5.4% to $1 billion. OEM market is the main buyer of industry brake

products from TRW, which make components for several automakers worldwide,

such as Volkswagen (24.7%), Ford (18.5%), General Motors (10.1%) and Chrysler

(9.9%), generating, in 2013, $17.4 billion in worldwide revenue.

After the recession of 2007-08 when the economy began to recover, vehicle

production increased rapidly and demand for brakes and brake systems have

increased gradually, generating in 2011 and 2012 a revenue growth of 15.4% and

11% respectively. Until the end of 2014 the brake manufacturing division is expected

to decline 6.2%.

Financial performance of TRW Automotive from 2009 to 2014 is shown in the table

below:

Figure 4: TRW Automobile financial performance

Following TRW Automotive in the worldwide revenue for automobile brakes

manufacturers is the Japanese Akebono Brake Corporation. Akebono produces

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original brake systems and brake components (including disc brake calipers, pads,

parking brakes and drum brakes) for automakers and for the automotive aftermarket.

An $82 million expansion project is expected to be finished in 2014 to include an

on-site warehouse with new furnaces and manufacturing equipment to perform

caliper machining, plating and assembly.

Akebono customers include major OEM such as General Motors, Nissan,

Toyota, Honda, Isuzu, Mitsubishi, Chrysler, Ford and Subaru. Besides producing

and selling brakes systems and components in 10 countries, the company has also

an engineering center, where researches and developments efforts are made to

reduce noise, vibration and harshness (NVH reduction initiatives). Furthermore,

Akebono have innovated the use of new material for brake pads, leading the use of

ceramic instead of semimetals.

Holding 40% share of the automobile OEM market in Japan, Akebono’s revenue

has grown annually at a rate of 12.2% after acquiring, in 2009, Bosch’s US facilities.

Nonetheless, after the earthquake and subsequent tsunami in 2011, Japan

hampered company’s part supply and restricted production for some of its largest

customers, as Toyota and Nissan. Despite this, it is estimated that Akebono’s brakes

manufacturing division will generate $995 million in revenue over 2014.

The following table shows the financial performance in US of Akebono Brake

Corporation from 2009 to 2014:

Figure 5: Akebono Corporation financial performance

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The third major company in the automobile brakes manufacturing, Continental

AG, has an automotive segment that includes the development of brake systems

and intelligent braking systems. The company generated a global revenue of $46

billion in 2013.

A revenue grow at an average annual rate of 8% to $573.3 million is expected

from Continental’s brake manufacturing segment over the five years to 2014.

After the recession, Continental experienced a 19.1% revenue growth in 2010,

followed by a growth of 10.6% in 2011, which has stabilized as the economy slowly

recovers. Driver assistance systems, ABS units and other technological brakes

systems as well as the higher restriction of safety legislation have increasing the

manufacturing opportunities, as Continental believes.

Financial performance of Continental AG from 2009 to 2014 is shown below:

Figure 6: Continental AG financial performance

Other minor players in the brake manufacturing market are Affinia Group and

ArvinMeritor, with estimated market share of 4.9% and 1% respectively.

Affinia Groups supplies automotive components to aftermarket distributors and

retailers, such as NAPA Auto Parts, CarQuest and Federated Auto Parts. Raybestos

brand brakes is one of Affinia’s products sold in 19 countries, as well as filtration and

chassis components. It is expected a total revenue of $550 million over 2014 from

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the Affinia’s Raybestos brand of brakes, but the long-term survival of the company is

unknown.

ArvinMeritor supplies integrated systems, modules and components for

commercial vehicles and, most recently, for aftermarket light-vehicle components.

The bar graph below sum up the market share of the major players discussed:

Figure 7: Market share of major players

1.5 New Technologies and Product Lifespan

In the past 50 years, brake systems have not changed much mechanically, but

technological innovations continue to improve vehicle safety, brake function and

lifespan, that is likely to hurt the replacement aftermarket.

Anti-lock braking systems (ABS), for example, is a technology used in almost all

modern vehicles to improve stopping characteristics on hard surfaces. Through a

sensor, brake force is optimized for each wheel in ABS systems to avoid skid and

improving safety.

Regenerative braking is another new technology that stores the energy

dispensed when braking in a battery of an electric or hybrid electric cars for future use.

Due to the fuel prices and new emissions regulations, hybrid and electric vehicles

production will grow, and so, brake manufacturers will need to produce regenerative

brake systems and other fuel-efficient brake technologies to meet the demands of

automobile manufacturers.

These systems are still part of a traditional braking system, since they still require

friction and components of traditional braking system, such as the disc and drum

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brakes; and so, they are not considered separately in the product segment breakdown.

The Toyota Prius, for example, recharge its batteries by using regenerative braking

system.

Along with the electric motors to replace internal combustion engines, the rise of

regenerative braking system is expected to share space with the traditional one in the

assembly line, assembly which is expected to be facilitated by the introduction of

Electronic integration that will allow substantial reductions in weight and mechanical

complexity, enhancing automobiles performance.

However, Electronic parking brake (EPB) systems will eventually eliminate

traditional parking brake systems, since they do not require drum brakes or cables.

Nowadays, they are only installed in most luxury cars and have been gaining more

importance since their first run in 2001.

2 Product Dissection and Reverse Engineering

2.1Disassembly and Assembly Procedure

Prior to disassembling the brake system into its constituent components, the entire

assembly had to be removed from the vehicle that housed it. The assembly

detachment process appears simple at first glance, however, upon further analysis and

several failed attempts, the engineering team failed to detach a functioning brake

assembly. This was due to a combination of factors including but not limited to rust

(inhibiting removal of components), and lack of necessary tools, and etc. Eventually, a

brake system was obtained and the reverse engineering process commenced.

The disassembly process was a difficult procedure in and of itself once again due

to the copious amounts of rust (since a brand new brake system was monetarily beyond

the scope of this project). The braking system consists of three main subassemblies:

the rotor, caliper and pad. The rotor itself is a complete unit, and has no parts that

could be disassembled. Similarly, while the pad consists of 2 main components (metal

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backing and brake pad material strip), the two appeared to be snapped together and

subsequently rusted.

Disassembling the caliper proved to be the most difficult component of the reverse

engineering process. As with the other components, the caliper assembly consists of

several parts including the supporting brackets, and locating pins. However, this

assembly is put together by a press-fit which prevented the engineering team from

disassembling it entirely. The University Machine Service was consulted on this matter.

The consultation results suggested that in order to disassemble the press-fit caliper

assembly, a very complicated and costly process was required (even by trained

machinists and mechanics).

The University Machine Services representative eventually suggested that the part

may become warped and potentially damaged by the process. It was then agreed that

the caliper assembly was to remain in its assembled state in order to preserve the

integrity of the part and prevent damage. Due to this, photographs of the original parts

will be shown, however, photographs showing the internal components of the brake

caliper will be acquired from schematics and resources from the internet (showing a

very similar set of components and configuration).

2.2 Major components and subassemblies

The brake system consists of three subassemblies as mentioned above: The rotor

(consisting of no internal parts), the brake pad assembly, and brake caliper. Please

refer to the figure below for details. The brake pad assembly consists of the brake pad

strip, the housing bracket, and squeal shim. The brake caliper assembly has the largest

number of internal components. Only 6 of the brake caliper components will be

analyzed in order to limit the total number of components and subassemblies to 10 (as

indicated by project requirements). The 6 internal brake caliper parts include: Support

bracket, piston dust boot, piston, locating pin, piston seal, and pin retainer.

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Figure 8: Detailed view of caliper. Internal rusting prevented further disassembly.

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Figure 9: Detailed view of both sides of vehicle disk brake caliper when brand new and un-rusted. Obtained from bmwe32.masscom.net on 20/11/14.

Figure 10: Detailed view of the rotor disk. Surface rust normally develops but typically does not hinder braking ability.

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Figure 11: Top view of brake pads and support brackets.

2.3Component Manufacturing Process

The processes used to manufacture the brake components are listed in the table

below:

Table 1: Components and Subassemblies Manufacturing Processes

Subassembly Component Manufacturing Process

Rotor Rotor Disk Cast & Machined

Brake Pad Braking Strip Plastic Mixing/Curing

Housing Bracket Stamping

Squeal Shim Stamping

Caliper Support Bracket Cast

Piston Machined

Piston Dust Boot Molded

Locating Pin Pressed & Rolled

Piston Seal Molded

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Pin Retainer Pressed & Rolled

Please note that some of the components listed are rubber components which

are not manufactured by the same factory which manufactures brake parts (they are

acquired). Similarly, the pin retainer and locating pins are also acquired.

2.4 Purchased and In-House Components

Most of the above listed components are manufactured in house, however a few

are acquired elsewhere. The details are listed in the table below:

Table 2: In-House Manufacturing and Outsourcing Details

Component Manufactured In House Outsourced

Rotor Disk X

Braking Strip X

Housing Bracket X

Squeal Shim X

Support Bracket X

Piston X

Piston Dust Boot X

Locating Pin X

Piston Seal X

Pin Retainer X

The decision whether to manufacture components in-house instead of

outsourcing largely depends on the cost associated with each method of acquisition. In

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this situation, the factory that manufactures the brake system components usually has

fabrication facilities in place to manipulate and process metal components. The

processing machines (stamping, machining, casting and etc) are already in place,

staffed by experienced personnel who are able to work metallic components with ease.

On the other hand, this factory may not have the facilities or personnel to

fabricate rubber components (such as rubber washer and seals). Therefore in this

particular case, the factory may choose to purchase these minor components from

vendors, while fabricating the rest of the metal-based components in-house. Some

potential part vendors include MacMaster-Carr and Misumi Corp. This mixed

manufacturing process should ensure a better overall quality of product.

2.5Bill of Materials

The components and the materials needed in order to fabricate them are

summarized in the table below:

Table 3: Bill of Materials

Part Number Subassembly Component Material

1 Rotor Rotor Disk Grey Cast Iron

2 Brake Pad Braking Strip Plastic

3 Housing Bracket Steel

4 Squeal Shim Steel

5 Caliper Support Bracket Cast Iron

6 Piston Steel

7 Piston Dust Boot Rubber/Plastic

8 Locating Pin Metal

9 Piston Seal Rubber

10 Pin Retainer Metal

Although information is available on many brake system manufacturers, it is

difficult to ascertain exactly what materials are used in this specific braking system.

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While it is not certain what kind of steels or plastics are utilized in the manufacturing

process, an assumption was made that most steel types used in the manufacturing of

common braking systems are similar enough to one another. This simplification allowed

the engineering team to assume that the fabrication processes used in this brake

system will be similar to the fabrication processes found in other brake system

manufacturing facilities. Due to a catastrophic amount of corrosion in the internal

sections of the caliper, the engineering team was unable to completely disassemble it,

however, a schematic is shown below to demonstrate the internal components of the

caliper and pads.

Figure 12:Exploded view schematic of typical vehicle caliper and pad. Obtained from mjbobbitt.home.comcast.net on 20/11/14.

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2.6Product Variants

Modern automobile brakes have several viable variants. While disk brakes were

invented in the late 1800’s by a British engineer named F.W. Lanchester, they were

used in conjunction with drum brakes in cars well into the 20th century. Today, disk

brakes are used in many vehicles, employing several variants. All of the variants

posses many qualities that benefit certain situations. The rotors could be consist of

solid cast iron (most common configuration), or it could have holes and channels drilled

or milled into the surface of the rotor. Holes drilled into the disk rotor promote better

cooling of the disk – a quality that high performance vehicles benefit greatly from.

Channels are milled into the rotor in order to promote water removal while braking

(increasing the performance of the brakes). Disk brakes are employed not only in motor

vehicles, but also in some aircraft, motorcycles and bicycles.

The brake pad has several variants as well. While the housing bracket is

typically made of steel, the braking pad itself could be fabricated from a variety of

materials. The brake pads could be made of non-metallic, semi-metallic, fully-metallic

and ceramic materials. All of these materials are desirable in different applications.

These materials range in braking ability (with fully ceramic being the best), abrasion of

the rotor disk (non-metallic being the gentlest), longevity of the pads, and audible

braking sounds (ceramic brakes are typically the quietest). Typically high performance

vehicles opt to use fully-metallic brakes for their superior braking ability, while a

common material for regular non-performance vehicles is ceramic pads due to its

balance of braking ability and longevity.

The brake calipers also posses 2 main variants: fixed and floating. Fixed brake

calipers clamp the rotor disk by engaging the two brake pads onto the rotor by a set

amount. There is typically a piston on each side of the rotor disk, which engages a

certain amount in order to push the two pads closer together. A floating disk brake

caliper has typically a single cylinder and piston, which engages the first brake pad onto

the rotor. The braking motion forces the other side of the caliper (and second pad) to

be pulled toward the rotor as well, resulting in the braking action.

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In addition to the structural variants presented above, disk brakes are available in

uncoloured or coloured appearances. Most brakes are typically uncoloured. Some may

desire coloured brakes (which are more expensive usually) in order to showcase a

better look for the vehicle. The coloured part is typically the brake pad housing bracket.

While regular steel rims would cover up the brake system, more expensive allow or

aluminum rims with cut-out sections allow a person to see the colour scheme of the

brakes. The picture below illustrates coloured brakes.

Figure 13: Coloured Disk Brake 1

The size of the disk braking system has many options as well. From small

bicycle brakes to regular vehicle brakes to large truck brakes. Each application will

require a different amount of braking power, and therefore different brake rotor, pad,

and caliper sizes have been used.

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2.7Modularity

Disk brake systems are modular in several aspects. As mentioned previously

there are several interchangeable parts within the system. Each vehicle manufacturer

specifies its own parameters as to what the brake system should be. However, there is

a myriad of after market part suppliers that specialize in modular components. For

instance, one may purchase different rotors for the vehicle, while keeping the pads

intact. Conversely, many people choose to only replace the brake pads and keep the

rotors in place, because it is generally less expensive to buy the pads than rotors.

Although many different types of pads will fit the same rotor, they must possess similar

physical dimensions as the original pads. Lastly, one may choose to swap calipers for a

different kind to obtain a better braking ability, however this is rarely done, since there is

less modularity allowed by the original car manufacturer for calipers.

2.8Modular Bill of Materials

Due to the hundreds of vehicle models and manufacturers, as well as thousands

of combinations of varying rotors, pads and calipers, it is nearly impossible to create a

complete bill of materials that will encompass the modularity of car disk brakes. The

particular set of disk brakes that was analyzed for this project was obtained from a

Hyundai Tiburon at a car wreckers yard. This particular set is an after market product,

from an unknown manufacturer. This missing information prevents the engineering

team from creating a proper modular bill of materials. However, as an example, a

typical Chevrolet Impala disk brake rotors would range from 9mm thickness to 28mm

thickness (Justanwear.com, obtained Nov. 2014).

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2.9Manufacturability Features

By analyzing principles of Design for Assembly (DFA) and Design for

Manufacturing (DFM), the particular disk brake system was evaluated. Upon

inspection, this brake system had several notable features that promoted ease of

assembly, and therefore minimized costs. For example, part count minimization was

evident in the construction of the brake pads. The pad braking strips appeared to

have been glued to the backing plates, thus minimizing the need for fasteners.

Proper installation of brake pads was achieved by using directional supporting

brackets, which allowed for precise snap fit of the pad into the caliper. The rotor was

constructed from a single piece of cast iron, thus eliminating the need for

complicated assembly. The calipers appear to have been constructed using top-

down assembly routines. Each part is sequentially attached to the growing

assembly, from bottom-up to prevent improper parts to be attached prematurely. In

addition, it appears that standard fasteners were using in this assembly (although

this fact cannot be confirmed), which indicates that the assembly as a whole can be

assembled and disassembled more easily. Furthermore, the assembly has a

bilateral symmetry, which is makes the assembly easier to work with while putting it

together. Lastly, the calipers have a base part onto which the rest of the assembly is

attached – thus optimizing assembly of the entire system.

The disk braking system in question evidently was constructed by adhering to

several Design for Manufacturing practices. For instance, the disk brake rotors are

made from a very hard steel, which would be difficult to machine (mill or turn) into

the proper shape. Therefore, the disk rotors were cast, rather than milled, and the

CNC mill or lathe was only used to provide polish and proper finish and tolerance.

Notably, only the rotor contact faces were machined, while all other unnecessary

remained rough in order to optimize the manufacturing process, and save time. In

addition, all drilled holes are located on flat (not inclined) surfaces, which eases the

drilling operation greatly. The caliper design appears to have minimized the use of

fillets internally as well as externally in order to speed up the milling process. Also, it

appears that standard hole threads were drilled and tapped into the parts thus

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preventing the need for specialized drills and tools. Disk brakes have been in

production for decades, and this is evident in the streamlined fabrication processes

employed using both Design for Assembly, as well as Design for Manufacturing.

3 Lifecycle Analysis

Most disc brake rotors are made of grey cast iron – its most common form –

because, among other reasons, it’s cheap to manufacture, durable, has a high specific

heat capacity and high thermal conductivity. Rotors with higher performance

requirements tend to be made of ceramic composites. The caliper frame, which

comprises most of its volume, is also usually made of cast iron. Other parts within a

caliper vary in their material makeup and are small enough to have a negligible life cycle

impact compared to the cast iron parts. Cast iron is the dominant material in disc brake

assemblies and is the biggest factor in a lifecycle impact analysis.

We suggest that cast iron disk brakes have a medium to low lifecycle impact.

Looking at the lifecycle of a cast iron disc brake, we found that the lifecycle impact

during production is medium, during use is also medium and at the end of its life, the

impact is small.

Cast iron is one of the most recycled materials in the world. In fact, recycled scrap

iron typically comprises around 60% of newly produced parts, meaning less iron ore

needs to be extracted from environmentally hazardous mines [1]. The main problems

with cast iron production comes from the high power usage to run the furnaces, the

waste of the molding sand and harmful gases that are created from the process. But

there are methods - like using an induction furnace to produce cast iron - to minimize

gas production and casting sand can actually be recycled [2][3]. Concerning the power

usage, furnaces are becoming much more efficient, especially induction furnaces.

The environmental impact of using disc brakes is due to its added weight. Cast iron

is one of the heaviest of the possible rotor material options, which adds additional

weight to the vehicle, resulting in poorer fuel efficiency [4]. However, this effect is

mitigated by the fact that any additional weight added by the disc brakes is very small in

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comparison to the weight of the whole car. The effect on fuel economy will certainly be

apparent in the long run, but may be negligible in the short run.

Using the disc brakes also results in substantial wear on the rotor over time. Disc

brakes are a very important part of car safety so the rotor needs to be periodically

replaced to avoid safety issues. The frequency of replacement is not nearly as much as

is needed for brake pads, but an average car may need two rotor replacements in its

life. However, considering the high recycling rates of cast iron, this is a small lifecycle

issue. Calipers do not sustain wear like the rotor and do not need to be periodically

replaced.

Higher performance disc brakes with ceramic composite rotors would likely have a

higher lifecycle impact due to poorer recyclability.

3.1Recycling/Disassembly

As mentioned, the main material in common disc brakes, cast iron, recycles very

well. This is due to the abundance of scrap iron produced in today’s world and the

durability and slow oxidation rate of iron. Disassembling a disc brake for recycling is

also straightforward. Obviously, the rotor requires no disassembly and the caliper is not

difficult to take apart. The other smaller parts of the rotor may have more difficulty in

recycling, depending on their material. We do not think the parts were design with

disassembly for recycling in mind, but it’s a fairly straightforward process for disc brakes

and they likely didn’t need to. We would expect longevity to be a primary design

objective.

3.2Repair

Rotors need to be periodically replaced to ensure their effectiveness so they are

certainly designed to be scrapped and replaced. While it is possible to repair a rotor with

minor damage, like resurfacing to restore the friction surface, but anything more will

result in a replacement. Calipers do not sustain nearly as much wear as rotors and are

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not necessarily expected to be replaced over the life of a vehicle. Calipers are thus

more open to being repaired instead of replaced, but if they are deemed at all a liability

to the effectiveness of the braking system, they will certainly be scrapped and replaced.

Proper brakes are too important to be overlooked.

This is not to say that they are not designed to last as long as possible. Durable, long

lasting brakes means fewer required rotor replacements and less opportunity for over-

worn and dangerous brakes.

4 Demand

According to a Scotiabank global auto report, global sales of consumer automobiles

are expected to reach 17MM units sold for 2014, roughly 5% greater than 2013 sales. In

North America, the 2014 figure is expected to be 19.4MM units, of which 1.8MM are

attributed to Canadian sales [1]. However, since Canada is a net exporter of

automobiles, sales do not tell the whole picture. Auto production in Canada for 2014 is

expected to be 2.34MM automobiles, including light, medium and heavy trucks.

It would stand to reason that demand for disc brakes in Canada is closely tied to

auto production. Commercial automakers are the primary market for disc break

manufacturers. The secondary or aftermarket is the sale of disc brakes as standalone

parts, mostly as replacements for worn out brakes. In recent years, the disc break

aftermarket has experienced relatively high growth, but it still pales in comparison to the

size of the automaker market. Therefore an analysis of the automaker market on its own

will produce sufficient demand and takt time numbers.

A few things need to be understood about our demand calculations. Automakers

typically contract a single company to supply the disc brake rotors or calipers or both for

a specific car make, model and year for a specific region [2]. It can then be assumed

that the total production numbers of a single car year, make and model ( ie, 2013

Toyota Corolla) represent the amount of cars that a single company supplies disc brake

parts for. For example, about 160 000 Toyota Corolla’s were produced in the US in

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2013, which means that a disc brake company’s demand for 2013 was about 320 000

(most cars have two disc brakes, two drum brakes).

So, to find demand for a typical company in this industry, we gathered US vehicle

production data from Marklines automotive industry portal and found the average

annual production over the past three years for a single make and model [2]. As seen

below, the average quarterly vehicle production per model in the US over the last three

years is about 41 000 in Q1, 43 000 in Q2, 38 000 in Q3 and 38 000 in Q4, or 211 000

annually. More detail can be found in Exhibit 1 (See appendix for all Exhibits).

Table 4: Average quarterly vehicle production per model

To reach rotor and caliper demand, we multiplied average quarterly production

by 2 disc brakes per car. We then applied a factor of 0.6 to that number to account for

the fact that the car production numbers we gathered are for well-known, popular cars.

If we could have included data from less popular cars, the average quarterly demand

number would be less than shown in Table 2.

Table 5: Rotor/Caliper quarterly demand schedule

A level schedule based on this demand can be found in Exhibit 2. Based on this

demand and the available time in the year – assuming 8-hour workdays, 5 times a week

– we reach a takt time of:

124800/224685=0 .56 min

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This is obviously a very low takt time, but multiple production lines would be able

to handle this demand. Some modern disc brake rotor plants can produce more than 10

million units annually [3].

Disk brakes are certainly a high volume product. This level of production works

because of the low level of variability within a supplier contract. If a disc brake

manufacturer agrees to supply parts for a certain car, they will produce thousands of the

exact same products and ship it to the automaker.

4.1Manufacturing strategy

The most appropriate manufacturing strategy considering the levels of demand

and variability between different products is make-to-order for calipers and disks. Auto

manufacturers typically contract disc brake makers to supply for specific makes and

years. From contract to contract, different cars require different brake specs, requiring

modifications to a company’s caliper or rotor designs. Each order is unique so it is

unfeasible for manufacturers to stock much inventory for a product that will need to be

modified for future customers. This is certainly true for higher end vehicles that require

more specialized brakes.

However, once a contract is reached and a design is agreed upon, a make-to-

stock strategy can be adopted because each brake produced for the customer will be

the same design. The change in strategy will be advantageous at this point because it

will enable a level production schedule with a buffer of finished inventory to deal with

fluctuating customer demand.

4.2Mass customization

Collaborative mass customization is important for automaker customers. Only the

automaker knows the brake specs that are needed for their vehicle so a collaborative

process would be ideal. Before a supply contract is struck, the two parties would need

to negotiate and reach an agreed upon design for the brake manufacturer to supply. For

common commercial vehicles, disc brakes are fairly consistent, but physical

characteristics like size and weight would need to be modified to fit the car. Other

30

characteristics like materials, caliper pressure, number of caliper cylinders and others

can be modified.

5. Design of production system

5.1Assembly cell tasks and task times

5.1.1 Tasks descriptions

TASK 1

Get the finished parts from the workcell.

Figure 14: caliper bodies, pistons, pressure seals, dust boots and abutments plates.

TASK 2

31

Mate the two caliper halves.

Figure 15: Caliper halves assembly

TASK 3

Mate the rotors and hats.

Figure 16: Rotor and hat assembly

TASK 4

32

Install the caliper bracket.

Figure 17: Caliper bracket installed

TASK 5, 6 and 7

Setup the press machine. After that, mount the supporting brackets, and locating

pins on the press and mate them by press-fit; finally detach the assembly from machine.

Figure 18: Press machine

TASK 8

33

Caliper assembly of support bracket, piston dust boot, piston, locating pin, piston

seal, and pin retainer. And finally, final assembly.

Figure 19: Ready brake kit

TASK 9 and 10

Brake kit is boxed and labelled for shipping.

Figure 20: Brake kit boxed and labelled

34

The only automated assembly is made by the press machine to press-fit two

components from the brake pad assembly. The setup time required is estimated in the

following table, as well as an approximation of the required assembly tasks and task

times:

Table 6: Assembly tasks and tasks times

5.2Assembly Cell Design

5.2.1 Required Cycle Time (Takt Time)

Assuming an 8-hr workday and a required demand of 90 units we have:

CTr= Time availablerequired demand

=8×360090

=320 sec

Number of workers=∑ Task×+∑ Setuptime+¿∑Walk׿CTr

¿¿

Number of workers=( 75+80+85+110+100+70+60+105+75+50+51320 )

Number of workers=2.7=3workers

35

ActualCellCT=max (CT 1,CT 2 ,CT 3)

CT1= 280 sec + 20 sec = 300 sec (Tasks 1, 2, 9 and 10 + walk time)

CT2= 280 sec + 12 sec = 292 sec (Tasks 4 to 6 + walk time)

CT3 = 250 sec + 19 sec = 269 sec (Tasks 3, 7 and 8 + walk time)

Thus,

ActualCellCT=300 sec

5.3 Possible Assembly Errors and Poke Yoke Methods to avoid them

A problem was detected by the customers of disc brakes that after some use

of disc brakes in the difficult terrains the disc brake eventually loses its functionality.

The company was complained about the malfunctioning of the brakes and the

company had to replace the brakes free of cost to the customers. So efforts were

made to find out the root cause of the problem and after collective effort of the teams

they got to know where the problem was. The problem was misplaced Locating Pin,

in the brake assembly. There are 2 locating pins in the assembly but in some cases

one locating pin was missing.

Further investigations revealed that the worker who is assembling the locating

pins does his work very efficiently and effectively throughout the day but during

assembling when the tea break bell rings he leaves the process right away and

proceeds. So if he had just assembled one locating pin inside the assembly before

break and when he returns back after break he forgets putting in another locating pin

and assembles the brake components. As one locating pin is present in the

assembly, when the brake is tested in the plant it works fine. But after prolonged use

36

in uneven difficult terrains another single locating pin loses its strength and

eventually fails, resulting into break down of the disc brakes.

Hence, in order to curb out this problem poka-yoke was done at the

workstation. In the poka-yoke plan the workstation was provided with a Place holder,

in which first the worker takes out locking pins from the bin and place them on the

place holder and the place holder was made to hold 2 pins at a time. After placing

locking pins there he then picked the pins one by one and place them into the

assembly. And by doing this if the worker leaves the station for some work or for

some break, then after returning he would come to know that both the rings are

placed or not. So by following this lean process the problem was curbed

permanently and defect was eliminated.

5.4 Standard Operation Sheet (SOS)

Table 7: Standard Operation Sheet (SOS) sample.

Standard Operations Sheet for checking Chemical effectiveness in Bath tubs used for

dipping Disc rotors

Sequence Bath Tub Operation Act Time Std Time Ctu

1 Degreasing

Bath Tub

1. Take sample from the bath

tub.

2. Mix 5-7 drops of Methyl

Orange.

3. Do the titrations with

Sulphuric Acid until color

becomes yellow to pink.

4. Note down the readings.

5 minutes 4 minutes

2 Derusting

Bath Tub

1. Take 45 ml fresh water

2. Take 5 ml sample from

bath tub

3. Mix well both of them

5 minutes 4 minutes

37

4. Take 10 ml sample from

mixed solution

5. Mix Bromosol Green

Solution into the solution

6. Titrate against NaOH

solution until color

becomes yellow to green.

7. Note down the readings.

3 Phosphatin

g Bath Tub

1. Take 10 ml of sample from

Bath tub.

2. Add 5-7 drops of

Phenolphthalein

3. Titrate against NaOH until

color becomes White to

pink.

4. Note down the readings.

5 minutes 4 minutes

4 Surface

Activation

Bath Tub

1. Take 100 ml solution from

Bath tank.

2. Mix 5-7 drops of Bromosol

Green Solution

3. Titrate against NaOH till

color becomes light green

to light yellow.

4. Note down the readings

5 minutes 4 min

utes

38

6 Machining Cell:

6.1 Casting work cell:

In disc brake assembly, the rotor disc and support bracket for caliper are made

using basic casting process. The time required for casting of rotor disc is estimated to

be 796 sec and 20 units are produced every cycle. The time required for casting of

support bracket is estimated to be 180 sec minutes and 20 units are produced in a

cycle. Both casting process are same and accomplished by two workers, one working

on rotor disc casting other working on support bracket casting.

Casting process for rotor disc

Casting process for support bracket

After the casting process is complete the work piece are placed on conveyer

belts. Rotor disc are on separate conveyer which goes to the machining cell and

support bracket is placed on the conveyer where it goes to the inspection procedure to

check casting effects and then to the assembly line.

Machining is required mainly for rotor disc for which the following machining

processes is used for machining of this component.

Heat the metal to melt

(180 sec)

Add the molten metal to molds

(10 sec)

Casting time for create disc(600 sec)

Remove casted part from mold & place on conveyer

(6 Sec)

Heat the metal till it is in molten

state(180 sec)

Add the molten metal to molds

(10 sec)

Casting time for support bracket

(400 sec)

Remove casted part from mold & place on conveyer

(5 sec)

39

6.2Machining of Rotor Disc:

After the casting of rotor disc, it is set up on a vertical turning lathe machine for

machining operation. The work piece (rotor disc) is kept stationary and the tool

moves around the work piece. Both the side are machined with precision on the

lathe machine.

Figure 21: Rotor disc being machined.

Estimated setup time: The time required to setup the vertical turning lathe machine

is estimated to be 4 minutes. This setup time includes:

- Setup the machine components for required operation

- Add the machining tools in the clamp

Estimated machining task times: During this time, both the faces of disc are

machined. The time required to perform the drilling is estimated to be 3 minutes for

both sides.

40

6.3Drilling on rotor disc:

After the surface machining is completed, work piece is removed. Then a vertical

drilling machine is used to create holes on the rotor disc. The disc is connected to

the axle of the automobile with these holes during assembly.

Estimated Setup time: The time required to setup the drilling machine is estimated to

be 1 minutes. This setup time is sum of machine setup time, all tool attachment

times, etc. Once setup, it can be used again and again without changes in machine

for other work pieces.

- Setup the machine components for required operation

- Clamp the drilling tool

- Set the work piece on the fixture for drilling

Estimated machining task times: During this time, holes are drilled on the front face

of the disc. The time required to perform the drilling is estimated to be 0.5 minutes.

Figure 22: Disc being drilled.

41

Machining Cell Design

3 sec

3 sec

Assume the required demand is 92,000 units in a year. Working days are

310 in a year. So, machine should produce 297 rotor disc per day to meet the

annual demand.

Also assume, machine is available 18 hours/day.

Then required takt time is = time available / required demand

= 18*60*60 / 306

= 211.7 sec/unit

CT=SUM Machine times + SUM Walk times

= (180+30) + (3+3)

= 216 sec

Cell Capacity = time available / CT

= 18*60*60 / 216

= 300 units/day

So, the annual demand can be met with the machine producing 300 units

of rotor discs per day.

Vertical lathe

machine (180 sec)

Drilling machine(30 sec)

42

6.4 Possible Machining Errors and Poke Yoke Methods to avoid them

In the Machining process when the work piece i.e. disc rotor is kept into the

fixture for machining, misalignment of disc rotor is possible which may lead to undesired

part machining. So in order to prevent this disorder, poka yoke should be done.

The poka yoke for this process is that bolts should be welded on the fixture and the

disc should be inserted between the bolts and this may enable precise placement of

disc rotor on the fixture and the misalignment of machining process can be eliminated.

During drilling process, the drilling is done by workers. So during unavailability of

skilled worker if an unskilled worker is employed for drilling operation he may drill on

undesired positions and misaligned drilling may take place.

Hence in order to prevent misaligned drilling, the drilling machine should be

placed on a cut out pattern of exactly the work piece drilling positions so that drill can

only be inserted on exact positions to be drilled .Hence precise aligned drilling may be

restricted.

43

6.5PLANT LAYOUT

Yellow Boxes Main assembly

Blue Boxes Casting process

Add Caliper Halves

Add rotor disc

Install the bracket

Take out Caliper bodies, pistons, pressure seal,

dust boots, abutments from

storage

Setup Press machine

Add supporting bracket &

locating pin

Packaging & ready for boxing

Attach Caliper Assembly

Setup Press fit machine

Boxed and Labelled for

shipping

Vertical Lathe Machine

Drilling Machine

Casting of Rotor disc

Casting of Bracket

44

Grey Boxes Machine parts

6.6Pull Production Implementation

The type of Kanban system used in this plant is Dual Kanban System. The

storage parts come in Kanban as well as production parts are in production Kanbans.

As the parts are getting assembled, there will be empty Kanbans which will go back to

the storage.

Pull Production is taken into account as first the required order is located on the

end of line and inventory is check. Then, operator at end of line will push button on the

terminal to previous operator for amount of assembly required at last terminal. Then,

that operator will push button for production of parts needed and for assembly. This

process is kept in process until the first operator makes sure that the production of

required parts has been started and will be produced in the required time.

7 Product and Process Quality

7.1 Quality of design

The quality of design is a vital issue in manufacturing of Disc brakes. As the disc

brakes are the most important part of the automobile .If disc brake fail its functioning

then it becomes a matter of life and death for the occupants of the car. So for these

reasons the quality of the discs are the highest priority. For manufacturing proper

brakes the quality control departments gets into play from the very first step towards the

manufacturing of the disc brake. As when the disc rotor is manufactured every single

piece of the disc rotor is fed to a machine which takes micron level pictures of rotor disc

and analyses for any flaws or faults in it. After rotor disc is passed by the camera

machine then visual inspection of every disc is done to check the finish of rotor disc.

After the parts are assembled on the calipers and is ready for paint, then the viscosity of

paint is checked with the help of viscosity cup for the desired viscosity. After the calipers

are painted coated then the density of the coat is checked using dry film test meter of 5

45

samples taken randomly from the lot. Each caliper is pressure tested to over 20000

psi .Then comes the turn of Brake pads, the thickness of the brake pads is then

checked using Vernier Calipers by again taking 5 random samples every hour during

the manufacturing of the brake pads from the lot. After complete inspection of every

part, the individual parts are assembled then and final assembly of Disc Brake is

completed. After the final assembly is completed then every complete disc brake is

Dyno tested to check their characterstics under diffrent conditions.For confirming every

single piece is checked O.K Tested sticker is placed on the disc brake and is ready to

be supplied.

The data gathered during inspection is analyzed for faults if the data shows large

differences from the actual to the expected values then the process is stopped right

away and then root cause analysis is done to eliminate the defect. If the variations are

between the tolerances then the batch is forwarded after controlling the root cause and

if the variations are out of the tolerances then the whole lot is either scrapped or if

possible reworked.

Quality Control department assures that the processes are working fine and

quality goods are produced in the plant. Whenever there is deviation in the dimensions

the quality inspectors check them during their regular hourly inspections and after

finding out the problem they make sure that the cause of problem is corrected and make

certain decisions by which the problems does not persists in future and the process is

continuously improved.

7.2 Robust design

The disc brake has only one main function i.e to stop the automotive when

brakes are engaged. And the braking is the combined effort of two main parts the disc

rotor and the brake pad. The disc pads are provided with a corrosion resistant ceramic

coating which prevents the pads from getting peeled or get corroded or rusted or even

get damaged at high temperatures. The material of the rotor disc has very high strength

so even if the padding of brake pad gets away after long use then when you apply brake

the metal gets in touch with the rotor , the rotor does not gets damaged very soon. The

46

tolerances for fitment of disc brake into the automotive are not very precise, so it can be

used interchangeably to other vehicles as well. Hence the disc brake deign is very

robust and it can be used efficiently and effectively even in the harsh conditions.  

The design of the disc rotor can be made more robust if it is provided with holes

along the disc which would help in easy and fast heat dissipation which is generated

while application of brakes. Another advantage of holes is also that when the disc

brakes are subjected to water the water can be scattered through the holes and faster

recovery from wet brake pads could be achieved.

7.3SPC (Manpuneet Singh) - MISSING

7.4Eliminating defects

A number of defects can arise in a Disc Brake manufacturing and assembly plant

which could lead to loss of resources, loss of time, loss of brand image and eventually

lead to loss of potential customers. So quality control is an area in which the research

and development is a continuous process leading to zero defect. As the real

manufacturing is done by the workers which may or may not be skilled to perform their

functions, also the workers are not permanently working on same machines and same

assembly workstations as if there is need of a worker in some other workstation then

workers are called from within the plant and so it is very difficult to make every worker

skilled in every job. So for overcoming this the processes should be designed like that

for even a unskilled worker there is no scope of mistake, hence the processes should

be made error proof. In other words we can say that even by mistake- mistake does not

happens. This is defined by as POKA YOKE in the terms of Lean thinking.

To remove an error the approach should not be like to detect the defect and

correct it but the approach should be like to find the root cause of the problem and

eliminating the root cause. If root cause of a problem is eliminated then the problem

cannot happen again and the resources which were to be spend on detecting the

problem again and then correcting it would now be used somewhere else for continuous

improvement. Sometimes the problems are relating to the visual appearance of the

47

product but sometimes relating to the basic functionality of the product. So likewise is

the criticality of the defect that the defect which harms the functionality of the product

should be on higher priority than the visual effect relating to the look and feel of the

product. This also depends on the type of product as if the product is a mechanical

component which will not be disclosed outside then minor visual defects can be

tolerated , but if the product is visible and is affecting the look of the parent product then

it should not be accepted.

7.5 Incoming Inspection: Eliminating Defects

The first step towards eliminating defects is detect an error as early as possible.

The later the defect is detected more resources are to be spend for correcting it. So it a

valuable to detect errors early. As some of the subparts in the assembly are outsourced

so checking the quality of those products is also duty of quality control department. As if

defected parts are introduced into the line then more parts would be attached to it or

that product might be introduced to some machining process and after these processes

and assemblies a lot of capital is used up already by the product and then the problem

gets detected, then correcting the problem might cost more. Hence the defect should be

checked from the first step. For our product as the piston seals are outsourced, so the

piston seals should be checked as soon as the shipment arrives so that if the lot is not

good then it should be returned right away and new lot can be ordered early.

Table 8: Inspection procedure sample.

Task Inspection Procedure Standard

time

Actual

time

Completion

time / unit

1 Pick sample parts from the shipping

incoming crate

15 sec. 20 sec 4 sec

48

2 Carry the samples to the quality control

room

120 sec 180

sec

3 Place the samples on inspection bench

4 Open the Engineering Drawing of the

pistons seals.

30 sec 60 sec

5 Take out the inspection tools such as

Vernier Caliper, Height Gauge.

30 sec 40 sec

6 Open up the inspection data record booklet

to write the dimensions

5 sec 10 sec

7 Visually check the seals for any flaws and

note them into booklet.

20 sec 50 sec 10 sec

8 With help of vernier caliper check the inner

diameter of the seal for every sample and

note it down into the booklet.

50 sec 60 sec 12 sec

9 With help of vernier caliper check the outer

diameter of the seal for every sample and

note it down into the booklet.

50 sec 60 sec 12 sec

10 With help of Height Gauge check the height

of the seal for every sample and note it

down into the booklet.

50 sec 55 sec 11 sec

11 If the dimensions are between the accepted

tolerances then take the samples back and

put them into their respective shipping

crates and stick ‘Quality check O.K’ sticker

on the crate and forward the crates to the

Assembly line.

125 sec 185

sec

49

12 If the dimensions are not between the

accepted tolerances then take the samples

back and put them into their respective

shipping crates and stick ‘Quality not

Approved’ sticker on the crate and forward

the lot to the Failed parts bin .

125 sec 185

sec

13 For failing parts call the supplier to replace

the lot.

8 Supply chain

Original equipment manufacturing (OEM) industries and aftermarket industries

are the two primary markets supplied by brake manufacturers. The OEM purchase

braking systems that are installed into new automobiles during the assembly line

manufacturing, while aftermarket industries retail braking components to individual

consumers.

In summary, Brake manufacturers supply automobile brakes into the assembly

process of automobile, truck and bus manufacturers as well as distribute them to auto

parts wholesaling.

Brake manufacturing industry is supplied by plastic products miscellaneous

manufacturers, ferrous metal foundry products (which supplies iron and steel casting

materials), and, as a minor supplier, wire & spring manufacturers.

50

Appendix I - Demand calculations

Select 2014 US Auto Production

Source: MarkLines Automotive Industry Portal. http://www.marklines.com/en/

51

Select 2013 US Auto Production

Source: MarkLines Automotive Industry Portal. http://www.marklines.com/en/

Select 2012 US Auto Production

52

Source: MarkLines Automotive Industry Portal. http://www.marklines.com/en/

Cumulative Average Quarterly Auto Production

Rotor/Caliper Quarterly Demand*

* Rotor/Caliper demand = average auto production * 2 disc brakes per car * 0.6

53

Appendix II - Level Production Scheduling

Quarterly Production Schedule*

* Rotor/Caliper demand + small buffer

Weekly Level Schedule*

* Weekly production = Quarterly production / 12

54

References

Petrillo, Nick. A. (2014, May). Automobile Brakes Manufacturing in the US. IBISWorld, 33634.

MJ Bobbitt.  Accessed at http://mjbobbitt.home.comcast.net/ on November 20, 2014.

Brake System: Rebuilding the brake calipers.  Accessed at http://bmwe32.masscom.net/sean750/caliper/RebuildBrakeCaliper.htm on November 20, 2014.

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http://www.epa.gov/compliance/resources/publications/assistance/sectors/notebooks/metcstsna.pdf

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http://www.wbwhitefoundry.co.uk/environment.php

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http://books.google.ca/books?id=f1C33ylS-8cC&pg=PA342&lpg=PA342&dq=cast+iron+impact+on+environment&source=bl&ots=KFgkG-2xkI&sig=LmeIlSrREJWjF9lB0ZgqsonJ3Wk&hl=en&sa=X&ei=4Nl4VJOOPKqIsQTBqIGoCw&ved=0CE0Q6AEwCDgK#v=onepage&q=cast%20iron%20impact%20on%20environment&f=false

http://www.gbm.scotiabank.com/English/bns_econ/bns_auto.pdf

2

http://www.marklines.com/en/

3

http://www.autoblog.com/2014/05/26/brembo-115m-michigan-plant-expansion/