sunbar, I'm a mechanical engineer and have worked on vehicle BIW structures previously.
When my wiper linkage failed, I too was astounded when it was removed to find how poorly designed it was.!!! It was as though it was intentionally done to fail after several thousand cycles... I mean, how can any engineer with a right frame of mind design a plastic bracket to hold a steel tube, with a narrowing feature (like a nozzle) into the tube. The ribbings added there were also insufficient, in my opinion, to improve any real structural rigidity, as the torque experienced at that junction is no doubt too much!
In overall, a poor design. Almost all 147 owners I know have seen this bracket fail - averag lifespan about 2-3 years.
The problem I think is that Bosch have directly copied the design in plastic, where in my experience for over ten years it was made from zinc alloy or aluminium.
Having said that I also know the amount of test and development that Bosch carry out on wipers (and other parts). They would have proved the design over a number of years and almost certainly on other applications other than Alfa. Bosch's resources in test and development would be greater than most other suppliers.
That does not mean they cannot make a mistake. I have also seen it go horribly wrong in the past for large companies.
I expect the designer had a string of qualifications, as long as your arm, but was it ultimately long term serviceable, no way. Put him in the stocks and pelt him!
: In a word, absolute cheap rubbishy material, for the intended job it didn't do!
Yes all of the German designers and engineers would have been very well qualified and experienced.
Bosch would also be contracted to make year-on-year savings to reduce the cost by Fiat/Alfa like all car companies. This is where the need to use plastics come from, so that we can all afford to own ever more complex cars at little extra cost and to compete with Asian labour costs.
Maybe down to just lack of use
ie wiper blades sticking to windscreen (not in my case as my car was washed regularly(at least weekly) and wiper blades cleaned as well.
Not so I'm afraid the examples of warranty failures from Australia that I had experience of were excessive wear. However although they were not associated with the exact 147 type problem being discussed here the evidence was that the linkages had seen similar use to that in Europe. A hotter climate would be one difference. Also although overall the rainfall in the UK is higher (particularly lately with the floods we have been having) in recent years there have been a lot of months where conditions have been dry and wipers would have little continuous use for weeks at a time.
My conclusion without actually seeing the 147 plastic parts would be that although the linkages would have been tested fully and proved to be an acceptable (cheap) design, manufacturing variables in the plastic mouldings could have resulted in some batches of parts being inferior. I'm afraid it could be another case where the cost of the plastic mouldings means the supplier changes the processing cycle to reduce costs down to border-line strength.
Aluminium and Zinc castings can also have their manufacturing problems but substituting plastics needs a lot more control in processing.
I'm just waiting to see it my wipers are going to need replacing as I'm unlikely to be selling my Alfa for some years.