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Table of Contents

[title] [page number]

Acknowledgement 2

Project Summary 3

Introduction 4

Methodology 5

Sketches & Dissection of Parts 6

Engineering Drawing 7 - 11Side assembly drawingCircular discBracketCylinderRendering

Material Selection 12 - 14Selected material (general)

Process Selection 15 - 22GeneralProcess flowCylinderBracket Welding/joiningHeat treatmentSurface treatmentProcess Flow Chart

Quality Control 23

References & Appendix A 24

Appendix B 25

Acknowledgement

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With much effort and time spent, we thank God for being able to complete the manufacturing process report about the shock absorber’s reserved tube designed for Proton Waja 1.8.

We wish to take this space and opportunity to express our thanks to En. Zulkepli bin Haji Muhammad as our Process and Manufacturing lecturer for his dedication and his incessant guidance to all of us in order to complete this report alongside with our syllabus. Our gratitude goes to all fellow coursemates and friends for providing us with helpful information and exchanging thoughts, family members for their financial support and Seng Kin Motors Sdn. Bhd. for supporting us in doing our prior research.

Lastly, we would certainly hope that this report will be a useful guide for future researches regarding vehicle shock absorbers.

Thank you.

Sincerely,

MEMBERS of GROUP 7

Project Summary

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As industrial designers in one of the most recent successfully set up companies, Technique and Co., we were formed into a group of five coded Group 7. The very first task was given to us, which is to come up with a new design of shock absorber for a European car manufacturer company, Audi’s latest creation, the Audi TT 406 2.8 ℓ. To simplify and to speed up the development process of the shock absorber, the company has decided to go for the reverse engineering approach.

In order to deliver the things on time, our group has looked on the similarity of the product which is the Kayaba 508 shock absorber designed specifically for Proton Waja 1.8 ℓ. We started by taking down every details of the product from dimension up to its process. Dimensions of the available product are measured using appropriate apparatus. Hidden inner parts were unveiled by dissecting it at the strategic place. This method is fast, accurate and is reliable.

Next is by knowing the material used on the available product. This task is challenging as there are many probabilities of the material can be. Part of our team went on to search at Perpustakaan Sultanah Zanariah while the rest searched online. We came to website which provides us with the list of the material used for the available shock absorber. Then, the process of the shock absorber making was discovered with the help of En.Zulkepli after a few hours of consultation with him.

Later in the stage, selection of material based on the properties of the current available product is initiated. There were a few criteria which made the proper material selection possible. These criterions were made based on the properties, cost analysis, manufacturing considerations and environmental issues. The material must satisfy all these considerations in order to be selected.

The next step is process selection which involves manufacturing process by part, joining process, heat treatment and surface treatment. This selection of process, of course is another vital step that keeps in track with the working condition of the end product as shock absorber. Therefore, we put the property and characteristic of material as the exceptionally first priority which is then followed by final properties required by the component, size, shape and thickness of components produced and finally the manufacturing cost.

All these were under four main objectives which are:

1. To visualize and analyze the product details of data/information through sketching/drawing and research done.

2. To revise and apply the knowledge of production into the design.3. To suggest the appropriate material to be used for the main product.4. To recommend the production activities by suggesting the tentative

manufacturing process that is arranged in the production flow.

Introduction

Manufacturing is defined as the process of converting raw materials into products. Started as early as 5000 - 4000 B.C. till present, the development of

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materials and manufacturing processes are so significant that various types of machines were introduced, capable of doing things that human are limited to. Imagine doing it all with machines which contrast to the origin of the word “manufacturing” or manu factus, meaning made by hand.

We may never understand how important the role of manufacturing process is until we realized that every product that exists around us doesn’t come for free. This is because of the involvement of manufacturing processes that takes place in the sequence of producing it. Altering ideas to products will just be mixing oil with water without manufacturing process.

In this project, we are going to reproduce a shock absorber based on the existing product; the Kayaba 508 shock absorber (only). Shock absorber as its name suggested is a device that absorbs the vertical impact which is known as the dampening process of a vehicle when it hits something uneven on the road. In general, shock absorbers are used widely in every car worldwide. Its service is always needed to prevent any form of damages to the car and to give comfort ride to the passenger inside. There are only two operations takes place in a shock absorber, the compression cycle and the extension cycle. Questions like “why we need a shock absorber since we have springs?” are sometimes asked, but the answer is as simple as the time factor (that is consumed for dampening process).

Each car has different needs. The bigger the car means the mass is bigger and therefore a more heavy duty shock absorber is required. In this project, we focused on designing a shock absorber which is customized for Audi TT 406 2.8 ℓ. Since similarity is found in the available product, the Kayaba 508 shock absorber, then this is where the reverse engineering part came in where we learn the way to disassemble, analyze and to figure out the next best thing to come up with another new product. Therefore, looking into a shock absorber; made up of 32 parts with each of the parts have its respective way of production, our team with full effort, has figured out the proper material and process to be chosen for the new product.

The next leaf of this project will bring you more into the steps of the “remaking of the shock absorber”.

Methodology

Group meeting: we had a few group meetings for discussion [refer appendix B]

Brainstorming of things to find out: things to find out were listed out [refer below]

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Task Division: each team members were given specific task to ease the work and for faster work rate/better work force [refer appendix B]

Dimensions of actual product taken:- Interview with Proton specialist (mechanic) [refer appendix B]- Meeting with technician/visitation to lab [refer appendix B]- Dissection of product [refer page 6]

Information gathering via book and web sites:- PSZ for information search [refer appendix B]- Browsing of material for actual product [refer appendix A]

Material & Process Selection:- Key to Steel Power Demo Plus software [refer appendix A]- Reference on few books [refer page 24]- Consultation with En.Zulkepli [refer appendix B]

Brainstorming of Things to Find Out

Sketches

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Existing product

Specific Part

Details

Production

dimension

material selectionprocess

selection

heat treatment

RE process

surface finishing

dimension

material

process

heat treatment

finishing

cylinder tube

bracket

circular disc

Dissection of Parts

Engineering Drawing: side assembly drawing

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Engineering Drawing: circular disc

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Engineering Drawing: bracket

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Engineering Drawing: cylinder

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Rendering10

Top:Rendering of product

Below left:Rendering of product section

Below right:Close up of product section

Material Selection

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Every aspects is taken into consider when choosing the right material. These aspects include the properties, cost analysis, manufacturing considerations and environmental issues. Base on these considerations, the best material will be chosen. Since the part that we are planning to produce is already existed in the market, the material selection will therefore focus on the reduction of the material cost, the reduction of the production cost, accommodation of some changes in function, solution to some material processing problems, taking the advantages of new materials or processing methods and also to incorporate failure analysis recommendations. The material for our product was chosen based on the material of the existing product which is Sandvik 20C shock absorber strip steel. Consideration during selection was according to the specifications below:

The characteristics of Sandvik 20C shock absorber steel are: High strength and wear resistance High fatigue strength under bending and impact stress Excellent surface finish Low level of non-metallic inclusions Good dimensional tolerances Good flatness

The properties of Sandvik 20C:Density (lb/cu. in.) 0.284Specific Gravity 7.86Specific Heat (Btu/lb/Deg F - [32-212 Deg F]) 0.107Melting Point (Deg F) 2760Tensile Strength 1750MPa

We have listed down several materials which have similar properties with the current Sandvik 20C shock absorber strip steel. The materials chosen are:1. carbon steel 1045(ASTM A682)2. carbon steel 1095 (ASTM A7113)3. alloy steel 4340 (ASTM A322)4. alloy steel 8620 (ASTM 519)5. tool steel H-11 (SAE J438)

The Strength-Cost Relation GraphTo ensure the best material is chosen for the benefits of both parties (the manufacturer and the consumer), the cost of the materials are considered, not forgetting the necessary strength however. Therefore, referring to the strength-cost graph in the previous page, fewer materials were taken into consideration. Comparisons were also made as shown in the chart in the next page.

Carbon steel 1095

Carbon steel 1045

Alloy steel 4340

Alloy steel 8620

Steel toolH-11

Density (lb/cu. in.) 0.284 0.284 0.28 0.283 0.281

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Strength & hardness High Moderate

HighModerate

High High Very high

Heat treatable

Cost Low Lowest Moderate Moderate Highest

Availability Good Good 1.30 Good Good

CARBON STEEL ALLOY STEEL STEEL TOOL

Carbon steel 1045(ASTM A682)● Extreme size accuracy,

straightness and concentricity

● greater strength and hardness

● machine ability better than 1095 alloy

● not recommended for carburizing or cyaniding

Carbon steel 1095(ASTM A7113)● high hardness and

strength● high fatigue strength● wear resistance

tends to be brittle

Alloy steel 4340(ASTM A322)● heat treatable● good fatigue strength● good ductility

Alloy steel 8620(ASTM 519)● good wear

characteristics● good forming

characteristics● typically used for

carburized parts

Tool steel H-11(SAE J438)● high harden ability● good toughness● machine ability is

reasonably good● fail in galling and

coating wear

Through these, the few materials were short listed.The current material used in the existing shock absorber (Sandvik 20C shock absorber strip steel) is also identified as carbon steel 1095. This material has good characteristics but it tends to be brittle. We know very well that shock absorber is a mechanism that controls unwanted spring motion through a process known as dampening. It has to support external force therefore it must be robust and hard enough. When it comes to hardness, steel tool H-11 has good toughness but it is too hard to machine.On other hand, carbon steel 1045 has similar characteristics with carbon steel 1095. However, its machinability is better than carbon steel 1095 and it has extreme dimension accuracy, straightness and concentricity combined to minimize wear in high speed applications. The hardness of carbon steel 1095 is higher than carbon steel 1045, but this can be overcame by heat treatment process. Comparison between both materials was made in a chart shown below.

Carbon steel 1095 (A 7113)

Carbon steel 1045(A 682)

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Properties: Density (lb/cu.in.) 0.284 0.284Specific Gravity 7.86 7.85Specific Heat (Btu/lb/Deg F - [32-212 Deg F])

0.107 0.116 

Tensile Strength, Ultimate

958 MPa 625 MPa

Tensile Strength, Yield

579 MPa 530 MPa

Pros: High hardness and strengthHigh fatigue strength under bending and impact stress Wear resistance

Extreme size accuracy, straightness and concentricityGreater strength and hardnessMachinability better than carbon steel 1095

Cons: Tends to be brittleMachinability is relatively poor

Not recommended for carburizing or cyaniding

After much consideration, carbon steel 1045 is chosen for our product.

Selected Material● Carbon steel 1045● Medium to high carbon steel● Extreme size accuracy, straightness and concentricity ● Turned, ground and polished bars can be machined unsymmetrically with

minimum distortion.● Can be hammer forged ● Can be heat treated, flame or induction hardened

Process Selection

Four factors were considered when it comes to choosing the best process selection. These factors are:1. The property and characteristics of materials2. The final properties required by the components3. Size, shape and thickness of components produced and4. Manufacturing cost

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General characteristics of manufacturing process for steels

Carbon steels

Alloy steels

Stainless steel

Tool and die steel

Casting:Sand A A A BCeramic A A A Ainvestment A A A ---Forging: Hot A A A AExtrusion: Hot A A A BCold A B A ---Rolling A A A ---Sheet-metal forming A A A ---Machining A A A ---Grinding A A A AWelding A A A ---

Note:A - Generally process by this method; B - Can be processed by this method; --- Usually not process by this method.

Process Flow

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*Note: please refer to the file process selection.pdf attached with this CD for better viewing

Process Selection: Cylinder16

Bending of Sheet Steel (in four-slide machine)The process of bending of sheet steel was chosen as the process for the cylinder tube for shock absorber. This process is simply perfect in making seamed tubing which makes less waste of material. The lateral movements of the dies are controlled and synchronized with the vertical die movement to form the part into desired shapes, bending relatively short pieces.

Advantages:1. Impacts stiffness to the part by increasing its moment of inertia.2. Suitable for making seamed tubing and conduits, bushings, fasteners, and

machinery components.

High Frequency Resistance Welding (following process)This process is paired with the bending of sheet steel process to produce seamed tube. Joining takes place without fusion at interface of the 2 parts to be welded. Is similar to seam welding, but high-frequency current (up to 450k Hz) is employed. Structural sections can be fabricated by high-frequency resistance welding by welding the webs and flanges made from long, flat pieces.

Advantages:1. Structural sections can be fabricated by high-frequency resistance welding by

welding the webs and flanges made from long, flat pieces.2. The surface finishing is good.

Steps:1. The current conducted through 2 sliding contacts to the edges of roll-formed

tubes.2. The heated edges then are passed together by passing the tube through a pair

of squeeze rolls.3. Any flash formed then is trimmed off.

Alternative Process (for Cylinder): Direct ExtrusionThere is an alternative process that can produce the rod part in shock absorber which is the direct extrusion process. The extrusion process is where the die moves toward the unextruded billet. Drawing through dies with different profiles can produce various solid cross-sections.

Alternative Process (for Cylinder): Rotary Tube PiercingThe process of reducing the thickness or changing the cross-section of a long work piece by compressive for applied through a set of rolls. The surface is smoothen and has better dimensional tolerances and mechanical properties by cold rolling.

Advantages:1. Hot rolling converts the cast structure to a wrought structure with finer grains

and enhanced ductility.Steps:1. Hot rolling (bloom and slab) are starting material for rod and wire-drawing

operation.17

2. Pickling and oiling to remove the scale developed during hot rolling.3. Cold rolling to produce better surface finish, dimensional tolerances, and

mechanical properties.4. Roller leveling to flatten and straighten rolled sheets.

Process Selection: Bracket

Factors for choosing casting process1. Least expensive casting process, that is low equipment and pattern/die cost and

mid labor cost.2. No limit to part size, shape, or weight3. Suitable for all typical material cast(Reference: MANUFACTURING ENGINEERING AND TECHNOLOGY fifth edition in SI units, pg 288 Table 11.2)

Sand ShellEvaporativ

epattern

Investment Permanent mold

Weight (kg) 0.01 -unlimited 0.01 - 100+ 0.01 - 100+ 0.001 - 100+ 0.1 - 300

Shape complexity best good best best good

Dimension accuracy normal good normal best best

TypicalDimension Tolerance

(mm)

1.6 - 4(0.25mm)For small

parts+/-0.003 ---- +/-0.005 +/-0.015

Cost Mid-low High-mid High-low High-low High-low

Investment Casting Process (for bracket)This process is chosen for the production of bracket since its shape is small, complicated and need to be mass produced with high accuracy dimension and surface finishing. Using the Lost Wax process to produce intricate and metallurgical accurate castings with tight tolerances, this method is used to mass produce parts with near net dimensions and a high quality "as cast finish" thereby producing a visually attractive finish and reducing machining cost.

Advantages:1. Complex shapes possible2. Thin wall section possible3. High production rates4. High dimensional accuracy

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5. Can be used with most pourable metals and Alloys6. Minimum Surface Treatment Prior to Plating7. Parts can be used as “cast”

Disadvantages:1. Castings Generally Limited to 10 Lbs or Less2. Expensive Dies for Wax Pattern3. Expensive Unit Cost, Labor Intensive

Alternative Process (for Bracket): Sand CastingThe common process which involves pattern making followed by forming of the mold. Widely used in many applications with complex design.

Advantages:1. Sand is inexpensive and is suitable as mold material because its high melting

point.2. Its composition can be controlled more accurately.3. Mold sand can be cleaned.4. Sand have fine, round grains can be packed closely and forms a smooth mold

surface.

Steps:1. A mechanical drawing of the part is used to generate a design for the pattern.2. Pattern has been mounted on plates equipped with pins for alignment.3. A core boxes produce core halves, which are pasted together. 4. The cope half of the mold is assembled by securing the cope pattern plate to

the flask with aligning pins and attaching insert to form the sprue and risers.5. The flask is rammed with sand and the plate and insert are removed.6. The drag half is produced in a similar manner with the pattern inserted. A

bottom board is placed below the drag and aligned with pins.7. The pattern, flask, and bottom board are inverted; and the pattern is

withdrawn, leaving the appropriate imprint.8. The core is set in place within the drag cavity.9. The mold is closed by placing the cope on top of the drag and securing the

assembly with pins.10. After the metal solidifies, the casting is removed from mold.11. The sprue and riser are cut off and recycled, and the casting is cleaned,

inspected.

Welding/Joining Process

Gas tungsten-arc welding (GTAW)Used in a variety of metals and applicationsAdvantages:1. Can be done without filler metals2. High quality and surface finish

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3. Equipment is portable4. Able to be used for variety of thicknesses and shapes5. The cost is average

Steps:1. To strike the welding arc, a high frequency generator provides a path for the

welding current through the shielding gas.2. The torch is moved in a small circle to create a welding pool, the size of which

depends on the size of the electrode and the current. 3. While maintaining a constant separation between the electrode and the

workpiece, the operator then moves the torch back slightly and tilts it backward about 10-15 degrees from vertical.

4. Filler metal is added manually and filler rod is withdrawn from the weld pool each time the electrode advances, but never being removed from the gas shield to prevent oxidation of its surface and contamination of the weld.

5. Filler rods composed of metals with low melting temperature, such as aluminum, require that the operator maintain some distance from the arc while staying inside the gas shield.

6. As the weld nears completion, the arc current is gradually reduced to prevent the formation of a crater at the end of the weld.

Alternative Process: Gas metal-arc welding (GMAW)1. Three methods to transfer metal in GMAW process:

o Spray transfero Globular transfero Short circuiting

2. Temperatures generated in GMAW are low3. Suitable only for thin sheets (>6mm)4. Easy to handle and used commonly for thin ferrous metals5. Suitable for most ferrous and non-ferrous metals6. Versatile, rapid and economical7. Productivity doubles SMAWAlternative Process: Shielded metal-arc welding (SMAW)1. Simple, versatile, requires smaller variety of electrodes2. Used in variety of metals and applications3. Plenty of equipments needed (portability)4. Best for workpiece of thickness 3 - 19mm5. Left out solidified slag can cause severe corrosion to workpiece6. Labor costs and material costs are high

Heat treatment

Shock Absorber: Heat Treatment (Quenching)Heat-treatment of steel involves the change of austenite, a face-centred cubic iron lattice containing carbon atoms in the interstices, into a body-centred cubic ferrite with a low solubility for carbon. The carbon atoms segregate into areas to form cementite. This involves mobility or diffusion of the carbon atoms and both time and temperature are important. Atomic movements are rapid at high temperatures

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but increasingly sluggish as the temperature decreases. As the rate of cooling of austenitised steel increases the time allowed for the changes is shortened and the reactions are incomplete at 600°C - 700°C. Residual austenite, therefore transforms at lower temperatures, with shorter movements of atoms and finer structures. At temperatures below about 250°C diffusion is so slow that another transition structure is formed.

Steps:1. Ferrite process: steels are heated until a range of temperature (between 400°C

– 727°C); steel will become ferrite and has a maximum 0.022% of carbon. 2. Austenite process: steels are heated to a certain temperature (around 800°C),

so iron undergoes a polymorphic transformation and become austenite. They consist of 1 % of carbon.

3. Steels are then cooled slowly for the austenite structure to maintain.

Surface Treatment

Thermal spraying (combustion spraying)

Advantages:The coating is hard and wear resistance with a layer structure of deposited material.

Steps:1. The surfaces are cleaned of oil and dirt

and roughened to improve bond strength. At a range of particles velocities about 150 to 1000 m/s and temperature about 3000 to 8000·C, the metal powder are sprayed on the product surface.

Process Flow Chart

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CylinderBracket

Investment casting Flat rolling

Bending of sheet steel

Frequency Resistance Welding

Production of Steels

Gas- Tungsten Arc Welding

Thermal spraying

Heat Treatment

Surface Treatment

Quality Control

Quality control is important to make sure each and every product passes a certain level of test. Each product must satisfy the needs and expectations of customer and cost, compatible with the customer’s working environment and functions reliably and safely over its intended life. Therefore, there are a few tests that our product must undergo. Below are a few testers to be considered:

Shock Durability TesterTo test shock absorber’s lifetime

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Hardness Testerto inspect the hardness of the whole shock absorber

Surface Roughness TesterTo inspect the roughness of the surface of the cylinder

Leakage TesterLeakage test for cylinder tube assembly

Universal Tester for MaterialsTo test the strength for welds

Shock Performance TesterTo inspect the shock performance of the absorber

High (Low) Temperature TesterShock absorber high (low) temperature performance test

Salt Spray TesterTo test the corrosion of the shock absorber

References

DeGarmo, E.P. (2002) Material and Process in Manufacturing 8th Edition. London: Maxwell Macmillan.

Kalpakjian, S. & Schmid, S.R. (2006) Manufacturing Engineering and Technology 5th Editon in SI units. Singapore: Pearson.

Zainal, A.A. (1999) Proses Pembuatan (Jilid I). Skudai, Johor: Universiti Teknologi Malaysia.

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Appendix A

Appendix B1st meetingDate: 21/7/2006Venue: Studio (E06)Attendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng5. Woo Kin HeeAgenda:

- leader selection

- discussion of parts to be considered (chosen by En. Zulkepli on 28/7)

2nd meetingDate: 29/7/2006Venue: Library (Perpustakaan Sultanah Zanariah)Attendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng

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Left:the Key To Steel Software

Left:the material data found at matweb.com

5. Woo Kin HeeAgenda:

- brainstorming of details to consider- task division among group

members- research task is distributed to one

another

3rd meetingDate: 9/8/2006Venue: P23 & Metrology LabAttendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng5. Woo Kin HeeAgenda:

- shock absorber dissected- dimensions taken down with

respected instruments- further discussion on research

methodology

4th meetingDate: 8/9/2006Venue: Studio (E06)Attendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng5. Woo Kin HeeAgenda:

- information gathered- data analyzed- presentation slides were made in

conjunction with the end report

5th meetingDate: 29/9/2006Venue: Musaha CafeteriaAttendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng5. Woo Kin HeeAgenda:

- slides were sort out- each one is assigned with their

presentation part

6th meetingDate: 5/10/2006Venue: Musaha CafeteriaAttendance:1. Chong Yin Bin2. Sufi Rafiq3. Mohd. Ilham4. Lee Chee Meng5. Woo Kin HeeAgenda:

- slides were amended following the weaknesses found in presentation

- report compiled, final touch

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