Fountain Pen Design

Function, Development, Construction and Fabrication

2.6 Development of the Feed

Let me start with fundamental comments on the development of anything (If it has not been there in the first place, it has been designed!):

In order to develop something (with the purpose of ending up with a finished, useful product), one needs to know as accurately as possible what one wants to develop. How else would one know how to find the item, furthermore, when the goal is achieved?

One needs to know in much detail as possible the criteria for function and performance.  What is the process of obtaining such detail?  Two essentials:  the design brief and the establishment of functional criteria. Searching for such criteria and establishing them reduces the field of possible solutions. Hence, the more criteria are known, the nearer one is to the solution.

The Design Brief

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.  Some major tasks of market research is the product’s placement in the market, the definition of the product scenario, the target group of users, the expected quantity of sales (production) and finally the arrangement of the product’s attributes and rank of priority.

Function Criteria

After the establishment of the design brief, during the planning and advancing of the actual design project, ingeneering’s most important job is the development of quantifiable design criteria, which can be tested and measured.

For this, one must know which performance criteria determine a fountain pen to be considered a good fountain pen.  Marketing decides the latter based on sales quantities, price, status and assumed high-profit margin, however, this placement is not supported by clear function criteria. Let’s say, the comment was “starts writing quickly” the ingeneer needs to know what “quickly” means. For example, the time in seconds or the length of a line before ink marks the paper.  The ingeneer’s task is to define the requirements through measurable data, the most arduous task being to get marketing to agree to these requirements and their technical definitions.
Once this priority list is completed with data, the ingeneer can establish links amongst the criteria and recognise the significance of particular characteristics.

It is essential for such qualification to be based is on measurable function criteria.  Here are some (by far not all) examples, relating to fountain pens:

  • Expressiveness and characteristic of the intended writing style
  • Comfort of writing and holding
  • Constancy of ink flow
  • Prevention of drying out
    How long does the pen remain immediately usable after a rest period? (exact duration!)
  • Dripping (unavoidable) (under what circumstances may it occur?)
  • Leaking (unavoidable) (under what circumstances may it occur?)
  • Ease of refilling (what method)
  • Ease of cleaning (unavoidable) (under what circumstances 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.  If marketing’s predictions were correct and ingeneering realised them, then, the product will be situated in the predetermined market location. There is no doubt.

The Idea turns Real

Criteria need to be translated into technical, physical terms.

This short sentence takes the highest priority during the early stages of the development and design of a product.  Here is where the ingeneers’ ingenuity shows its talent and quality.  If their attention to this process is shoddy, they miss the point of their main task… miss their market.

After having sussed out the nitty-gritty, special tests and their rigs are developed with the aim to find a correlation between qualitative performance assessed by the market/user, and physical quantities. How many tests? As many as needed to cover the significant criteria. If one cannot measure a detail, how could one assess the effectiveness of changes when varying parameters of an item? Above all, during the invention and establishment of the tests, one learns a lot about the item to be tested.

For example:

The requirement in the brief states:   — The fountain pen should have an acceptable resistance against shock.

What does “acceptable” mean in the opinion of the user/purchaser? This must be discussed and formulated in the design brief.  The translation of “acceptable” would need to be described in technical terms like this:  — “Only after the fountain pen (with a cap on) has been dropped (with nib downwards) five times in a row onto a carpeted floor from one-meter height, the ink may drop off the nib.”

Based on this requirement, a test rig is designed and built.  It would have a clamp to hold the fountain pen.  The impact of the drop on the carpet must be simulated without damaging the fountain pen.  The rig must provide a means to assure a particular height of drop and an area for a piece of paper (for example) to show when a drop has fallen off the nib.

With this rig, I also tested the top competitors of my fountain pen, and I found out whether my test criteria were placed at a reasonable amount above them. As more and more tests were established, permitting me to check out “the others”, I developed a performance matrix and within it, fields of criteria and their absolute values. Somewhat they correlated with what the market called a “good” fountain pen, and it gave me a sense of what this meant.

According to the test results, I ranked the fountain pens which were important in my pen’s market range.  In most cases, my ranking correlated with their evaluation by the market.  However, there is no technical correlation for kudos, but it certainly compensates for lack of performance.

In general: a test rig must be of a certain quality so that it can provide results within the expected range, with a necessary exactness and relevance.  If the expected variation of test results is smaller than the accuracy of the test rig, then it is pretty useless.


Correlation validates the test rigs.

Only now, sensible research and design development can start.  During this time, ideas are prototyped and tested.  They need to quantitatively demonstrate, whether they have and to what degree they have achieved the intended goal.  Possible improvements, which are within the range of inaccuracy of the test, must be validated further or discarded if that was not possible. One needs to be brutally honest, even if it has been one’s pet idea.


In the next chapter, I will specifically discuss the impact of Temperature and Air-Pressure variation on the feed.


Amadeus W.

3 April 2016

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