General comments on the development of anything:
In order to develop something (with the purpose of ending up with a finished product), one needs to know as accurate as possible what one wants to develop.
How else would one know when the goal is achieved?
One needs to know in much detail as possible the criteria of function and performance. What is the process of obtaining such detail? Two essentials: the design brief and the establishment of function criteria.
The Design Brief
In detail, I have explained the purpose of the design brief in my article Design Innovation. In short (briefly), it is a collection of mostly measurable performance data and criteria, which have been established through a company’s tradition and market research. Part of the latter is the placement of the new product within the marked field through determining the priority sequence of a product’s attributes. This to determine is the management’s chief task.
After the establishment of the design brief, ingeneering’s most important job, next to the actual design project, is the development of quantifiable design criteria, which can be tested and measured.
For this, one must know, which performance criteria determine, why a fountain pen is considered a good fountain pen. Market opinion decides the latter. The priority list determines the degree of importance the design ingeneer places on a particular characteristic.
It is essential of such qualification to be based is on function criteria. Here are some (by far not all) examples, relating to fountain pens:
- Expressiveness of intended write characteristic
- Comfort of writing and holding
- Constancy of ink flow
- Prevention of drying out (how long does the pen remain immediately usable after a time of rest)
- Dripping (under what circumstances)
- Ease of refilling
- Ease of cleaning (and how often)
It is part of the design brief to rank these criteria, according to their importance for the customer during the purchase decision-making. Then, the product will be situated in the predetermined market location.
The Idea turns solid
Criteria need to be translated into technical, physical terms.
This short sentence takes the highest priority during development and design of a product. Here is where the ingeneer’s ingenuity shows its talent and quality. If they are shoddy about this, they miss the point… miss their market.
From this, test rigs are developed with the aim to find a correlation between assessed performance and physical quantities.
The requirement in the brief states: — The fountain pen should have a good resistance against shock.
What does good mean in the opinion of the user/purchaser? This must be discussed and formulated in the design brief. The translation into factual terms could look like this: — “Only after the fountain pen (with a cap on) has dropped (with nib downwards) five times in a row onto a carpeted floor from one meter height, ink may drop off the nib.”
Based on this requirement a test rig is designed and built. It would have a clamping means to hold the fountain pen. The impact of the drop on carpet must be simulated without damaging the fountain pen. A means is provided to assure the particular height of drop and an area for a piece of paper to show when a drop has fallen off the nib.
In general: a test rig must be of a certain quality so that it can provide results within the expected range, with a necessary accuracy and relevance. If the range of expected variation is smaller than the accuracy of the test rig, it is useless.
Once all the test rigs are adjusted and completed, relevant fountain pens obtainable from the market will be tested. According to their test results, they will be ranked. This ranking must correlate with their evaluation in the market.
Correlation validates the test rigs.
Only now, sensible research and design development can start. During this time, ideas are prototyped and tested. Ideas need to quantitatively demonstrate, whether they have and to what degree they have achieved the intended goal. Possible improvements, which are inside the range of inaccuracy of the test must be validated or discarded. One needs to be brutally honest.
In the next chapter, I will specifically discuss the impact of temperature and pressure variation on the feed.