The Hong Kong Polytechnic University

Faculty of Engineering

 

 


IC349

Integrated Manufacturing Project

 

 

 

 


Water dispenser bottle changer Final report

Semester 3: 2011/12

                                                                       

                                                                       

Chung Wing Fai
11541589D

 

FUNG Sin Yu

10178099D

Hung Ming
10100688D

Lam Ka Leong
10273069D

Lam Hiu Man
10307638D

Lee KaKui
10306684D

Yam Hiu Man
10123795D

                                                                       

                                                                       

 

 

 

IC_logo

 

 

                                                                       

BRIEF CONTENTS

 

SECTION ONE Project Brief   3

1.1  Project Scope   3

1.2  Customer Requirements  3

1.3   Analysis

1.4  Project statements

1.5  Design Specification

1.6  Project workflow

 

SECTION TWO Design stage   5

2.1  Brain storming -  possible mechanism

2.2  The alternative designs   6

2.3  The final design and its component   9

2.4   Bill of material and estimated cost

 

SECTION THREE Manufacturing stage

3.1 Manufacturing workflow

3.2 Financial aspect

3.3 Team work and communication

 

SECTION FOUR Manufacturing process

4.1  Manufacturing Techniques   13

4.2 Problem encounter in manufacturing stage

4.2  Results

4.4 Critical self-assessment

 

SECTION FIVE Project Management   14

5.1 Time Management

5.2 Materials Management

 

SECTION SIX Conclusion

6.1 Conclusion and improvement

6.2 Group Reflection

 

 

 

 

 

 

 

 

 

SECTION ONE Project Brief

 

1.1  Project Scope

Traditional water dispenser is still widely use in the public despite the fact that uplifting Water Dispenser was invented, in this transition period, people are reluctant to purchase a new one before the existing one breaks. However, there is a hidden risk associated with the traditional water dispenser, the one who change the water bottle may hurt their back due to lifting of the heavy water bottle.

 

The existing guidelines to guarantee users’ safety is listed as following:
-     Post poster showing team lifting of distilled water bottle near the water dispenser

-          Arrange 2 staffs to change the distilled water bottles

-          Arrange manual handling training for staff handling distilled water bottles

-          Keep the attached risk assessment record at the workplace

 

Fig 1.1 Poster showing team lifting of distilled water bottle

 

However, these guidelines are unrealistic and hardly anyone will follow them, to solve the problem in this transition period, our group designed a water dispenser changer to help users changing the water bottle without using excessive force.

 

1.2  Customer Requirements

We had identified and prioritized the following 9 requirements that had to consider during the project in order to give a successful outcome:

1.       Safety: We should ensure that the whole operation of the product was safe, minimize the possible chance of damage or injuries.

2.       Ease of use: Since the major target user of the product was office workers, the operation of it should be as simple as possible.

3.       Size: As our product was assumed to be used mainly in indoor environment, the size of the product should be as compact as possible to minimize the space it takes.

4.       Effectiveness: The goal of designing this product was to improve the efficiency of replacing bottles.

5.       Appearance: In order to increase its market value, we wished our product to be attractive aesthetically.

6.       Capacity: We required our product to be able to lift up at least the weight of a 5 gallon water bottle.

7.       Ease of manufacturing: There was a possibility that our product may undergo mass production if it was successful, so its production should also be as simple as possible.

8.       Mobility: The product would be more valuable if it was movable and could apply to multiple stations.

9.       Cost/Price: We should design and choose the material for the product based on the requirement of budget HKD$1,500, while also minimizing the price to increase its market competitiveness.

 

 

1.3   Analysis (House of requirement)

 

1.4  Project statements

 

 

1.5 Design Specification

1.       Safety: The product  should be regarded as low risk in risk assessment

2.       Ease of use: The product should be operated by 1 person only and the whole process of changing the water bottle should not take up more than 5 minutes.

3.       Size: The size of the water dispenser bottle changer should not exceed 1200mm x 40mm.

4.       Effectiveness: A person should not applied more than 50N to change the 200N water bottle.

5.       Appearance: In order to increase its market value, we wished our product to be attractive aesthetically.

6.       Capacity: We required our product to be able to lift up at least the weight of a 5 gallon water bottle.

7.       Ease of manufacturing: The number of manufacturing processes involved should not exceed five.

8.       Mobility: The product should be able to move easily within 800 feet.

9.       Cost/Price: The price should not exceed $1000.

 

1.5  Project workflow

Microsoft project was used to draw the Gannt chart in the design stage and was shown as following.

 

 

 

 

 

 

SECTION TWO Design stage

 

2.1  Brain storming -  possible mechanism

 

At the very beginning of the conceptual design stage, our group brainstorm about the mechanism that could be used to lift up things, we borrowed concepts from existing products.

Such as pulley system from elevator; Hydraulic system from ______, torque concept from_____ and tracking system from roller coaster.

With these 4 mechanisms in mind, we tried to think about how to apply them on our product.

 

 

2.2  The alternative designs

Before actually designing the device, we have come up with several design criteria that we want to achieve: Safe to use, simple operation steps, compact size, easy to manufacture

Also, studying the process of changing the bottle by hands, we had defined 5 essential steps involved:

·       Removing the emptied bottle

·       Lifting the new water bottle (~20kg)

·       Turning the bottle upside down

·       Aligning the bottle to the dispenser

·        Inserting the bottle

During brainstorming, we proposed 4 alternative designs considering these factors: 

 

2.2.1 The guiding track

Description: This design looked like a roller coaster track which surrounded the water dispenser. The whole guiding track was combined by three short tracks. In each short track, there are three holding pins to hold the water bottle’s neck on the track. So the user can take a rest when they lift up the water bottle a little bit.

Steps to use: Remove the emptied bottle by hands before operation. Firstly, users had to place the water bottle on to the track. Next they had to push the water bottle up around the track until it reached sufficient height. Finally, fit the mouth of the water bottle into the hole on the water dispenser by hands, and then inserted the bottle.

 

Review: The guiding track solved the lifting problem but it could not help user to turn the water bottle upside down and did the alignment of the water bottle and the dispenser before insertion.  Besides, there was a risk on turn upside down the water bottle if the user is strong enough. The water bottle may fall down.

 

2.2.2 The hydraulic press

Description: The design looked like a box with three layers. It could lift up the water bottle by pressing the hydraulic press installed with the device. In addition, it could store three water bottles at a time. In each layer there were four locking plates to hold the water bottle. Those locking plates allowed movements of the bottle upwards and block downward movements. The belt and plate on the top of device was to secure the water bottle. The plate on the top was movable so as to aid the alignment of the water bottle to the dispenser before insertion.

Steps to use:  Removed the emptied bottle by hands before operation. Firstly, user had to push the water bottle in to the bottom of the box, lying horizontally. Then stepping on the hydraulic press to provide force to lift the bottle up until it was secured on upper level by the locking plates. Next, put another bottle in the bottom level of the box and lift up the water bottle again. After repeating the steps 3 times, one of the bottles would reach the highest layer. Secured the lower part of water bottle using belt, slide the top plate forward to align the bottle. Finally, released the belt and plate to insert the bottle.

Review: The hydraulic press solved the problems of large amount of force needed to lift, turn and align the bottle. However, it would be complicate to incorporate hydraulic press system to the device since approval from government department was required. Also, despite the assist by hydraulic press, it was quite hard to lift up three water bottles stacked up in the device. The material should be strong enough to withstand the weight of three bottles at the same time. This aroused the concern of cost purchasing high strength material.

 

2.2.3 Ferris wheel Torque
Description: The idea came from torque motion using leveling system. We imagined the design works like a Ferris wheel. Three main components of the design: Base, Transporting rod and locking system. The base included a 50kg ground pad and a pole which was used to connect the transporting rod. There were handle and clamping equipment for clamping the water bottle. The working principle of this design was based on the utilization of the power from user to cause a rotational motion.

Steps to use: Originally, the handle was on the top and the clamping equipment was at the bottom. After the water bottle was clamped firmly on the clamping equipment, we could apply force to the handle to cause rotation. As the handle rotated downwards, the bottle would go upwards. The locking system was used for securing the bottle and preventing drop down during operation. We incorporated locks at every 45 degree of the rod’s rotation. This could also prevent the situation that the rod rotated in a reverses direction and hurt the user.
Review: There were some restrictions to this design. The user must be strong enough and heavy

enough since the device
was worked by forcing rotation. Light-weighted users may have difficulties using it since it could not work properly with insufficient torque. Another disadvantage of this design was that it needed a large amount of space for rotation of the transporting rob. That meant it would occupy space for about 3 times more than the dispenser. This was a problem for some companies which do not have enough space. Besides, it was difficult to keep the device steady during the whole operation since the moment kept changing during the rotation.

 

2.2.4 The ladder
Description: This design borrowed the concept of a ladder.
The water dispenser was supposed to place in the middle of the ladder stand. On the left of the ladder was a track guiding the movement of the water bottle; while on the right was a hand wheel. A pulley system was found at the top of the ladder. A wire would be the medium connecting the three systems as a whole. The ladder stand helped the users to change the water bottle by tying the bottle at the track end, with the pulley system, when the hand wheel was turned, the bottle would climb up the track automatically.
Steps to use: The bottle would be placed horizontally somewhere near the stand. A rubber cover with a hole in the central would be inserted in the bottle neck. The cover would have some extension wires, the extension wires would be wrapped around the bottle and joined together at one point of the back of the bottle. When the water bottle was securely mounted on the wire connection with the pulley system the user could turn the hand wheel. The bottle would then move along the guide track. The profile of the track was changed at the top part, when the bottle was pulled nearly touching the top, the bottle could swing into the center of the ladder and placed in the center of the water dispenser. 

 

To evaluate the alternative design, firstly we should first weight each requirement’s importance.
The weighting was shown as followings:

Requirement

Weighting (%)

Safety

30

Ease of use

15

Effectiveness

10

Capacity

5

Cost/price

5

Size

15

Ease of manufacturing

5

Mobility

5

Appearance

10

 

The following table showed the evaluation of different design:

Requirement

Track

Press

Wheel

Ladder

Safety (30%)

4

7

3

7

Ease of use (15%)

6

7

5

7

Effectiveness (10%)

3

4

5

5

Capacity (5%)

5

7

5

6

Cost/price (5%)

2

1

7

5

Size (15%)

2

4

3

5

Ease of manufacturing (5%)

6

3

6

5

Mobility (5%)

0

5

5

6

Appearance (10%)

1

5

4

5

Final Score

3.45

5.45

4.15

6.00

 

Therefore ladder was chosen as out final design.

 

File:Pulley3a.svg

2.3 Detail Design stage

2.3.1 Pulley system
To save effort of pulling the water bottle all the way up the track, instead of simply using one pulley to sever the function, a double tackle were used. A double tackle had two pulleys in both the fixed and moving blocks with four wire parts supporting the load.

 

Mechanical advantage

The mechanical advantage of double tackle was 4.

Separation of the pulleys in the double tackle showed the force balance that results in wire tension of W/4in our case, the weight of the water bottle was 200N. The user can lift up the water bottle by 200/4 = 50N

 


2.3.2 Hand wheel Ratchet and Pawl

To avoid the bottle from dropped suddenly when releasing the hand wheel, we used a ratchet and pawl mechanism in the turning hand wheel, such that the wheel could only be turned in one the direction. When the force acting on the wheel was release, the ratchet and pawl would be automatically locked, so as to prevent the dropping of the bottle and hurt the user.

 

2.3.3Testing and verification results of the ultimate design

This picture showed the stress on the pulley system, we could see that the stress was in blue region which meant the stress was rather low and the pulley could totally support the weight added on it.





 

 

 

 

 

 

 

 

 

 

 

Dimension in mm scale

D=diameter, L=length

 

 
2.4 Bill of Material and cost estimation

 

The frame

 

Material use

Quantity

Unit

Total material cost($)

Specifications

Body part (19x19)

Aluminum steel

14

meter

n/a

1.           High hardness

2.           Good stability

 

 

The pulley system

 

Material use

Quantity

Unit

Total material cost($)

Specifications

Double Pulley (d=50, l=80)

Gray cast iron

2

EA

20

1.     Weatherproof for anti-rusting

2.       Relatively cheap

Wire (d=30)

AISI 1010 Steel

1

roll

20

1.       strong transmission power

2.       anti-wearing out

Pulley casing (100x120x20)

1060 alloy

2

EA

30

1.       Light in weight

Pulley shaft (d=12, l=120)

AISI 4340 steel, annealed

2

EA

15

1.       High toughness

Ring screw (d=8,l=20)

AISI 1010 Steel

2

EA

10

n/a

Hook

AISI 4340 steel, annealed

1

EA

15

1.       High strength

Hook screw (d=4, l=25)

AISI 1010 Steel

1

EA

10

n/a

 

The bottle carrier

 

Material use

Quantity

Unit

Total material cost($)

Specifications

Belt ( 450x30)

Nylon 6/10

4

EA

50

1.       Flexible

2.       Durable

Top holder (d=85mm)

PP homopolymer

1

EA

35

n/a

Fasteners (60x40)

PVC rigid

4

EA

30

1.       Rigid enough for clamping

 

 

 


The hand wheel

 

Material use

Quantity

Unit

 

Total material cost($)

Specifications

Handling bar(d=28,

Cast Iron with chrome

1

EA

25

1.       High luster

2.       Better Gripping

Ratchet and Pawl (151x96x23)

Aluminum alloy, 1060-H16

1

EA

40

1.      Easy for tail-making

2.       Light in weight

Single pulley (d=50, l=25)

Gray cast iron

1

EA

10

n/a

Spring (d=6, l=14)

1060 aluminum alloy

1

EA

15

n/a

Screw pawl (d=5, l=10)

AISI 1010 Steel

2

EA

10

n/a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SECTION THREE Manufacturing stage

 

3.1 Manufacturing workflow

 

3.1.1 Profile (use as the skeleton of the water dispenser water changer)
Sawing machine was used  to cut the approximate length of the profiles, followed by using milling machine to cut the exact length of the profiles and drilling holes on it for screws’ insertion.

With the holes drilled, thread was made inside the holes.

Fig. 3.1 Showing the profile  manufacturing process