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Hausübung
Fertigungstechnik

PolyU HK

2013

Maximilian L. ©

0.37 Mb
sternsternsternstern_0.2stern_0.3
ID# 39382








Content


  1. Introduction

  2. Existed Product Design Problem Analysis

  3. Expectation of New Hanger Design

  4. House of Quality

  5. Engineering Design Specification

  6. Project Schedule

  7. Finalized Hanger Design

  8. Instruction of New Hanger Operation

  9. Conclusion

  10. Appendix

- A. Assembly Drawing

- B. Engineering Design Specification

  1. Reference









Introduction


In 1869, O. A. North at the United States, had invented the first shoulder-shaped wire hanger, which is being popular used nowadays. Hanger has being very important of household usage in our daily. It can be used to hang coat, shirt, jacket or dress for drying, displaying or storing.


Hanger characteristics can be classified into two parts, which are material and size. The material usage of hanger includes wire, wood and plastic. There are two standard ranges of size for different customers, which are 30cm to 52cm in length for adult and 25cm to 41cm in length for child.


Hanger has been designed in different size or shape for different types of clothing. For instance, wooden hanger is normally used for hanging suit or coat, and the wire hanger can be applied for light weight clothing. However, we have experienced that the hanger is difficult to hang the sweater or T-shirt directly. We often need to put it inside through the bottom. Therefore, our project has to make a design that improving the normal hanger which can fit to any collar.


Existed Product Design Problem Analysis


  1. Normal Hanger

We have observed that the collar size of normal clothing cannot afford a hanger passing through it. The normal hanger is unable to hang the sweater or T-shirt directly. If we thrust it inside through the collar, it will lead to a collar loose. It will be inconvenience if we put it inside through the bottom.


Sometimes we may put the hangers together with a basket for storing. We may face a problem that the hock of the hangers may clasp each other and hence it will be inconvenience to take it out every time. It may have to spend a lot of time to take apart from the clasped hangers.




  1. Pinch Hanger

The concept of this design is to pinch the hanger with the two shoulders to fold and make it straighter. By reducing its size, it can be easier to put it inside through the collar. The design is based on the characteristic of plastic. Some of the plastic, such as Polyethylene and Polystyrene, has a higher elasticity that can be twisted. This product has applied Polyethylene for its material, which is ductile and available to afford the burden of bending. Besides, the hanger is designed in one piece.


The problem is the hanger has to be twisted to fold. The middle of the hanger will bear the highest load of twisting. Therefore, the material should be flexible enough to afford the bending, otherwise it may break. However, it may affect the performance of hanging clothes. When a shirt is hanged by this product, the shoulders will be sagged by the load, so it cannot handle some heavier clothing such as coats and jackets. Another problem is the hanger will deform after many times of bending, so it is not durable enough.




  1. Folding Hanger

The design problem of this hanger is the material usage of the joints. The hanger has applied metal for the jointing parts. Sometimes we may use hanger for hanging wet clothes. If the metal joints often contact with water without well coated, there will be an opportunity that the joints get rusted after a period of time. The metal joints may lose its function and make the whole structure be loose. It may affect the durability of the hanger.



  1. Umbrella Hanger

The product has applied the concept of umbrella design. The structure of this product is a trunk connected with certain amount of branches. The branches are able to swing through the paths of the bracket. Clothes can be hanged on the branches when they spread.

However, the size of this product is too large. The hanger may occupy much space when using it. We have observed that user may find it difficult to put it out of the window since the size leads the hanger stick on the window frame. Consequently, the users have to close the branches to make it smaller whenever they need to put it through the window frame, and it will bring the users much inconvenience.

Also, the hanger cannot lies on the wall since the branches are propped to the wall. It has restricted the application of this hanger.



Expectation of New Hanger Design


By the analysis of the current existed hanger product, we can conclude that the convenience is the first factor that we have to consider. For the new design, we expect that its size can be small enough to pass through the collar. At the same time, it should be able to hang the clothing completely. We do not allow any complicated process of usage. We hope that the user can feel easy and directly to use it. Also, our hanger product should not be allowed to damage or affect the quality of clothing, especially preventing the loose of collar.


The size of the hanger is not just predicting the collar, but also predicting if carry on or storage. We expect that some users may bring along their own hangers when traveling, or may want to save place of his/her housing. In fact, the current existed hangers are almost fixed size. Their sizes are typically 25cm to 52cm in length and 17-24 cm in height. If the quantity is large, it may occupy many spaces for storage and hence difficult to carry them for traveling. Therefore, the hanger should be allowed to adjust in a smaller size.


Another major consideration is its efficiency of hanging clothes. We hope that the new design can maintain the hanging ability of typical hanger, which can afford to hang the heavier clothing such as jackets or coats, but also able to change its size at the same time. It’s a difficult part that the structure should be well organized for bearing the load and maintaining the whole structure.


We also consider the environmental factors, such as temperature and humidity. Since the users may use it to hang either wet or dry clothing, the metal parts of this product should be well coated or organized without any waterish contact.




House of Quality


House of Quality (HOQ) is a group method that used to do the analysis between the voice of the customers and the corresponding engineering requirements. We try to determine the direction of hanger design by this method.


We have collected the customer responses of hanger product and try to understand their need for the later evaluation. We also need to estimate the importance weights of the specified requirements. Then we have to give some suitable and feasible ideas corresponding to different needs. Afterward, we can use HOQ to evaluate their importance by scoring the levels of relation and correlation. Finally, we can conclude the specification of the new design by the data and establish the path of design.


By the previous design problem analysis of the existed hanger product, we can conclude the regular customer requirements: 1. Able to hang the clothing directly, 2. Smaller size, 3. Low price, 4. Durable, 5. Antirust parts and assemblies, 6. Easy to use, 7. Light weight, 8. Easy to carry on, 9. Easy to store and 10. No clasping of numerous hangers. Target customers are mostly concerning in whether the hangers can be allowed to hang the cloth through the collar, and the size of the product. The other considerations are whether the hanger can be easy to store and carry on. But in fact, these two problems can be solved by minimizing the size of hanger, so these kinds of problem can be terminated at the same time. We try to design a folding hanger which can cross the collar easily. The folding feature and a simple structure of hanger design can also solve the size problem. Therefore, HOQ is very helpful in product analysis since it can minimize these kinds of repeated factors and focus to the major considerations.






Engineering Design Specification


By giving the specified index of importance in different customer requirements and scoring the relations and correlations of the requirements, we now can identify the design direction by referring the HOQ result. The estimated result shows that simple structure and adjustable size are most important to develop, and we have set them to be the targeted objectives. To form a simple structure, the amount of parts and assembles should be reduced to least. We suppose to make a hanger within ten parts, and the parts will be simply designed without any complicated shape and texture. It purposes to reduce the difficulty of manufacturing, which may lead to a higher production cost and increase customers’ financial burden.


There are different ways to make the hanger adjustable in its size, even folding, twisting or pinching. It is just a consideration of which can be applied and perform the best hanging efficiency. Folding is the most popular design concept that the designers ever use, but we should consider the strength of the joints. It is because folding design may include two or above parts, and the parts may not bear the load equally. Twisting and pinching concepts are adaptable in one piece design, and the load evaluation is much easier than folding design. However, their hanging ability may also be affected. Therefore, for engineering design, it is very important to make judgment among the advantages and disadvantages.


Material selection is also very important in hanger design. Different kinds of plastic own different strength and deform level. Plastic can be brittle but hard, or deformable but soft. Plastic selection depends on what product we are designing and what features the design predicated to be. Additionally, we try to create a hided hock design to avoid the probability of clasping the hangers. Engineering Design will consider all these factors and summarize a specified design proposal.






Project Schedule


The project schedule consists of fourteen tasks, including the start and finish dates and the different responders. The tasks are estimated with the duration, resource and budget.


In the beginning, the Marketing collects the customer requirements and passes them to the Design and the Engineering. The Design will do the hanger appearance design, and then pass it to the Engineering. The Engineering will determine the product specification with considering the customer requirements. After collecting the product appearance design by the Design, the Engineering will do the engineering design with the product specification.


If the customer accepts the finalized design, a prototype will be prepared for reviewing the hanger features. In the meantime, the Marketing will provide a preliminary quotation to the customer. If the prototype has been confirmed by the customer, the Manufacturing will do the tool design for production. At the same time, the Design will start the artwork and packaging design. The design will be passed to the Marketing and seek the customer’s confirmation.


According to the schedule, the tools will be prepared after two weeks. The Manufacturing will do the production and check the off tool sample with testing. The off tool sample should claim the Design and Engineering verification. The Marketing will provide the finalized quotation to the customer. If all tasks are verified, the Production will start the mass production.








Hanger Development Schedule



Week


Tasks

1

2

3

4

5

6

7

8

9

10

11

12

Responders

Receive the customer requirements and do the product appearance design

 

 

 

 

 

 

 

 

 

 

 

 

 

Design & Marketing

Determine the product specification and do the engineering design


 

 

 

 

 

 

 

 

 

 

 

 

Engineering

Prepare the preliminary quotation to the customer

 

 

 

 

 

 

 

 

 

 

 

Marketing

Finalize the product design and seek the customer confirmation

 

 

 

 

 

 

 

 

 

 

 

 

Design, Engineering & Marketing

Make the prototype

 

 

 

 

 

 

 

 

 

 

 

 

Manufacturing

Review the prototype and seek the customer confirmation

 

 

 

 

 

 

 

 

 

 

 

 

Engineering , Design & Marketing

Tool designing and making

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Manufacturing

Packaging design

 

 

 

 

 

 

 

 

 

 

 

Design

Artwork design and seek the customer confirmation

 

 

 

 

 

 

 

 

 

 

 

Design & Marketing

Check the off tool sample and testing

 

 

 

 

 

 

 

 

 

 

 

 

Manufacturing

Off tool sample verification












Design & Engineering

Prepare the finalize quotation to the customer and seek the customer confirmation

 

 

 

 

 

 

 

 

 

 

 

 

Marketing

Prepare mass production material

 

 

 

 

 

 

 

 

 

 

 

 

 

Production

Mass production

 

 

 

 

 

 

 

 

 

 

 

Production

Finalized Hanger Design


Our final design is a folding hanger with eight parts. The design concept of the hanger is making a path in the middle of the shoulders that allow the shaft to move along which creates a folding feature. The shaft is fixed on the right shoulder. To stabilize the shoulders, we have designed a lockable shaft to fix them when the hanger is fully extended. The shaft is composed by two plates with latch, spring and screw. The screw is used to fix the plates on the shaft. The spring purposes to push the latch upward. The shoulders will be locked when the latch has pushed inside the notch of the left shoulder. The hock and left shoulder are fixed among the plates and right shoulder. The hock is able to rotate about the shaft, which is purposed to hide the hock between the two shoulders.


Front View

Back View

Exploded View



Bill of Material

Item no.

Part name

Material Type

Material name

Amount

1

Hook

Plastic

Polycarbonate

1

2

Left Shoulder

Plastic

Polycarbonate

1

3

Right Shoulder

Plastic

Polycarbonate

1

4

Front Plate

Plastic

Acrylonitrile Butadiene Styrene (ABS)

1

5

Bottom Plate

Plastic

ABS

1

6

Latch

Plastic

ABS

1

7

Spring

Metal

Steel

1

8

Screw

Metal

Steel

1


When designing the parts which are made with plastic, it is not only considering the magnitude of load, but also considering their types and durability. Plastic has different performance which depends on different load and environmental condition. It is very difficult to predict the parts’ performance, so it is recommended to make a prototype and test it in different applications, and evaluate the durability of the critical parts.



The cross sectional diameter of the shaft is 14mm and the maximum load that it can bear is 5kg. The definition of strength is the weight divided by the cross sectional area:


= P / A = (5*9.81) / (3.14*(7)2) = 7.32 Nmm2=1061.7psi


The following table lists the typical values of different materials:


The tensile strength of Polycarbonate is 10,000 psi. Therefore, the material can afford the above stress.


Instruction of New Hanger Operation


When you want to hang your clothing, you just need to put the folded hanger inside through the collar and press the button to release the lock. The left shoulder of hanger will slip along the path and extend. The shoulder will be locked when the hanger is fully extended. Finally, a completed hanger is already formed. The cloth can hang the cloth without any damage to the collar. If you wish to take the cloth, you just need to release the lock and let the left shoulder slip back to the original position. Afterward, you can take the folded hanger out of the collar.



When the hanger is not be used, you can hide the hook to avoid any clasping between the hangers.


Conclusion


Hanger is simple but it can be variety. Actually, there are lots of things that can be improved of typical hanger. We found that there are many types of hanger existed in the market. To create an outstanding design, understanding the competitive products’ weakness is very important. Therefore, we have spent much in analyzing the existed product with understanding their design concepts and problems. Our product is a variant design that we try to do more improvement based on the typical one, including the shape, size and appearance.


By this report, we can deeply understand the flow of product realized process. We have to handle each of the parts with considering the realistic needs in marketing, designing, engineering, etc. We believe that our product can fulfill the customer need and compete in the market.













Appendix A



Assembly Drawing









Appendix B



Product Requirement Specification



Hanger



Version: 1.0










Authorization

Department

Name

Signature

Sales and Marketing

Jackie Chan


Design


Engineering

Karl Lam


Manufacturing

John Lee




Date: 5th April, 2013










































Product Image

 

Product Features

 

Color

Pink

Materials

Plastic

Packaging

Box

Dimension

 

    Length (mm)

489.5± 1.0

    Width (mm)

27.4 ± 0.5

Height (mm)

167.5± 0.5



Customer Requirements:

  1. Can hang the cloth directly through the collar

  2. Smaller size

  3. Low price

  4. Durable

  5. Antirust parts and assemblies

  6. Easy to use

  7. Light weight

  8. Easy to carry on

  9. Easy to store

  10. No clasping of numerous hangers



Company Requirements:

  1. Simple product structure

  2. Easy to manufacture

  3. Can be mass-produced

  4. Low cost



Reference


Hanger Picture -


Hanger Size and Dimension –


House of Quality –


Material Characteristics –



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