Design Realization/Detailed Design - Medical Device Design: Innovation from Concept to Market - page 188

For example, if you have components that look the same but are different, how are they
supposed to know? The classic failure here is knobs that look the same but which have
slightly different threads.

Do they need special tools to assemble your device? Are there critical components that can be
misassembled?

As you can imagine, if you have assembly at point of use then your risk analysis has to be
robust. Hence thinking about this in a DFA analysis actually makes your life a lot easier.

Some questions to consider when performing a DFA analysis are:

l

How many different components do we have? Are they all necessary?

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How many fixings do we have? Are they all necessary?

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Do we have any components that look the same and hence can be confused?

l

Are any jigs and fixtures required?

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Is the assembly logical and easy to perform?

l

Is assembly dependent on highly skilled technicians?

Table 8.9: 6 σ Seven Wastes Applied to DFDA

Waste Description/Question

1. Waste of overproduction

l

Poor joining methodology leads to excessive scrap?

2. Waste of waiting

l

How long does it take to disassemble?

l

Will you need to wait excessively for specialist materials/
services?

l

Is significant training required?

3. Waste of transporting

l

Will it need multiple subcontractors to complete?

l

Are numerous site visits required?

4. Waste of inappropriate processing

l

No. of variations?

l

Ill-conceived joining leading to inappropriate unjoining
methods?

l

Have you used adhesive where nonpermanent fixings
would suffice (or vice versa)?

5. Waste of unnecessary inventory

l

Too many items required for replacement post-
disassembly?

6. Waste of unnecessary motion

l

Ill-conceived protocol?

l

No thought of person doing disassembly?

l

Fiddly process?

7. Waste of defects

l

Too complex?

l

Designed in issues?

l

Disassembly leads to scrap?

“New” Waste
7(b) Waste of untapped human potential

l

Have you spoken to the people who will disassemble it?

l

Have you sought advice from those who may understand
the usual processes in situ?