Need Knower - Mrs. Nimali Bandara


About Her

Name: Nimali Bandara
Age: 46
Background: She is a housewife, and there are five members in her family. She has a daughter and two sons(Schooling). Her husband is a policeman.

Interests/Strength

She wants to be independent in eating. As she is a housewife, she loves to prepare meals for her family.

Characteristics - Physical

Diagnosis: Left-hand crush injury with thumb and little finger amputated. Limited finger flexion, with the index finger being most functional. Wrist flexion/extension possibly present. No sensation on the palmar surface. Flap graft done, and a pressure garment applied. Communication is verbal.

Characteristics - Mental

She is very comprehensive and motivated.  She is worried about being unable for doing her household work and selfcare works. Her family is very supportive.

Targeted Activities

  • Cutting Vegetables
  • Grasping Objects
  • Writing
  • Eating

Present Difficulties

Reasons: The thumb and little finger are amputated. So she can't grasp objects. Limited movements in the remaining three fingers due to muscle stiffness.

Methodology

We listed all the needs and requirements of the need-knower.
• Cutting Vegetables
• Grasping Objects
• Writing
• Eating
• Extracting Coconut Milk
• Riding the motorbike
• Sweeping the Floor
• Washing Clothes

Initial Concept

By considering the overall scope we came up with a concept.
Based on the following factors, we decided to take another approach.
  • complexity & Feasibility of design
  • Limited time
  • Resources
  • Cost 


Multi-Criteria decision-making for concept-selection

Using the multi-criteria decision-making concept we got a rating for factors (qualitative) and we considered design feasibility. In here we gave more weight to customer opinion as the voice of customer is more important.

Selected Concepts


Concept 01: For writing


Concept 02: For Cooking


Concept 03: For Supporting


Concept Selection

In concept selection, we identified the best concepts.

Design and Development


Quality Function Deployment (QFD)

Mapped customer requirements to technical specifications when designing the product and then rated the relationship between the voice of  customer and design requirements on a 1-9 scale.

Limitations in Concept 3

Complex geometry in the hand (palmar surface) and no uniform dimensions. So, we need  3-D scanning facilities. Unfortunately, we cannot develop this concept and time limitation. 

Prototyping

Software - SolidWorks , UltiMaker Cura , Bambu Lab  

1.Concept 1 – Writing device

Prototype – According to her actual situation we got exact and comfort dimension. Target the middle and index fingers. By getting her feedback we identify the index finger is more suitable for this concept.

Material

PLA 

Mechanism

Simple 

Advantages

  • Easy to use
  • Re-usable
  • Low manufacturing cost
  • Lightweight

Ergonomics

  •   Gripping part for easy handling
  •   Customizable length and shape as required
  •   The Index finger is prioritized over the middle finger for better usability
 

2.Concept 2 – Cutting device


Material

PLA

Mechanism

  •  simple mechanical movement device  

Advantages

  •   Easy to use
  •  Low manufacturing cost 
  • Portable
  • Lightweight
  • The blade can be replaced easily

Ergonomics

  • Provide the required force with minimum effort, therefore palm stand is designed
  • Maintains the forearm hand in a neutral position 
  • Ability to operate the machine by standing position
  • Pressing mechanism should not force wrist extension or flexion beyond 15°

Testing


1.Concept 1

 

1st Testing


  • Conducted using the index and middle fingers, we got need-knower ratings and feedback. Since her index finger is more functional, it is most suitable for this concept. It was determined that the pen should be approximately the same length as the finger to function effectively.

2nd Testing

  • The second test revealed that the shape of the stand did not fit well on her finger. We plan to adjust and improve the fit.

2.Concept 2


1st Testing

We were trying to come up with a design that could do the cutting using her palm. We decided to come up with the spring effect. Also, our device can fixed to a table.

Stress Analysis


Concept 2-Stress Analysis


Concept 2-Displacement Analysis


Results and Conclusion


Final Concepts


Concept 01 – Writing device


Concept 02 - For Cooking


Sustainability Analysis

  • Life-cycle assessment (LCA) for filaments

References

  • Openshaw, S. and Taylor, E. (2006). Ergonomics and design : a reference guide. New York: Diane Publishing.
  • Rishi Kumar et al. / Procedia CIRP 107 (2022)
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Project in a Minute