Rapid Manufacturing in Practice: Using RM at the Early
   Development and Design Stages of Production

     by Reinhold Rutks

Biography

Reinhold Rutks studied chemical engineering at the Royal Institute of Technology in Stockholm at the end of the 1970’s. Specialising in distillation technology he was immediately given an opportunity to start work as a technical consultant with his own company, AB Destila. In early projects the market aspects were introduced into the work and accidentally lead to a diversion into the world of electrostatics. In 1985 he started working with technical sales and marketing of electrostatic equipment with a certain emphasis on new customised technical applications. Swedish Electro Static AB was founded in 1994 as a specialist company in electrostatics which both offers a wide range of standard products for charging, discharging and measuring of static electricity, as well as tailor made equipment and applications. A consultancy service is being offered and with the 2003 founding of a separate UK company, Swedish Electrostatics Ltd, an international expansion has started. If a background in chemical engineering is not provoking enough he often asks during lectures – ”what happens when static goes dynamic??” The innovative work needed for developing new products and applications for virtually all branches of industry calls for close co- operation with customers and co-workers and a static approach is not fruitful.



Abstract

When Gutenberg revolutionised the production of books by making a printing press it was only the first step towards today’s ever faster development of machines and methods. In the graphics industry digital printing has made an irreversible entry in a short period of time, making personalisation easy and the production of one single book economically possible. Rapid prototyping has been regarded as a toy or luxury but once you realise that it is for production the real advantage lays it is quickly being adopted by many specialist technicians to both speed up the development and design processes as well as making it possible to manufacture small numbers or even one-off products at reasonable costs.

It will be made obvious that old truths are just old and that the main obstacle to overcome is not the limitations to the technique itself, but rather the state of our minds. Most of us are comfortable with what is mainstream and want to relay on what is regarded as common ground. In the presentation there will be practical examples from fast production of customised one-off products as well as the use of rapid manufacturing as the ground for development and design work from start of project to final production.

Rapid manufacturing has just begun to make its entry in industry. Although there are few people who dare use the technique at an early stage, the use will explode as it will be cost driven. The ability to make customised products with very short lead time from specification to finalised products and the manufacturing of single parts for spares or repeat orders will make traditional production methods left with volume production.

Once you get a basic understanding of how to use this new powerful tool – there will be a technological shift.

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Introduction

It is easy to lose perspective when being introduced to new developments, new techniques or new influences in society. A very crude way of defining members of modern society is by how we handle change in our lives and using this information to predict how we would be willing to accept new technological developments.

We may be divided into three groups – the first two more clearly defined than the last. The first of groups would be those people who love change and are drawn towards anything new, exciting and challenging; not wanting to wait another minute to get started. The second group is made up of the people who are averse to change and absolutely hate everything new or strange. Members of this group are threatened by anything that they have not previously seen, done or heard of.

The third group, which is probably the largest, would then consist of the people who are not easily labelled and who may generally speaking not want to be bothered too much – the people that may be influenced but would not want to make the effort to get too involved one way or the other.

In the battle between the two more extreme groups, powerful clashes happen and life can get a bit rough. It is when the third group of people have incorporated the technique into their everyday lives that the biggest change has taken place and there has been a technological shift.

Which group do you fit into? What is your personal relationship with new technological advancements? And what about your colleagues, customers and suppliers? Is there some sort of rule as to finding out who can be expected to belong to which group?

A little anecdote;

In the early 1970s, one of my fellow students almost bursting with pride showed us his new electronic pocket calculator made by the Japanese company Citizen. He especially wanted to impress on our old mathematics and physics teacher who was still teaching us how to work the slide rule and, when greater accuracy was needed, mathematical tables. What was the “old” (60+) man’s reaction? He laughed a very hearty laugh and told us that he personally was in no hurry.

He said that the technological development is so fast that, in a few years time, he would to get a simple calculator like the student’s free at the super market, just for spending a certain amount of money on groceries. He was right!

A journey from scratch to making use of the technique and wishing for more

Once you have learned to master something that you initially thought was difficult or even seemed impossible, you tend to rationalise and forget about the problems and feelings of insufficiency.

As my wife wanted me to teach her the basics of downhill skiing, this fact became painfully clear to me; “Please help!! – How do I stop?” …”Well…um…you just stop!?” Obviously, there was a need to sit down and try to analyse how to stop in a more theoretical way to determine what was going on as the process started and what consecutive steps needed to be followed and in what order.

Before getting into what use we make of direct digital manufacturing (DDM) at present and what we expect to achieve in the future, here is a description of our journey from first learning of the existence of the technique.

The first time I actually saw rapid prototyping -- which has evolved into rapid manufacturing or DDM -- was in England in the mid 1990s. It was used to build a scale model of a suspension bridge that was being built to be used in simulations in a wind tunnel. Although I had read about the technique of rapid prototyping, it was strange to see a steel tank with some mysterious fluid that was polymerised at the precise position where beams of light intersected. I almost expected someone to come out of the next room to ask me to smile, as I felt like I was on candid camera.

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As with everything new and not aimed at a mass market, the mysterious contraption seemed to be both fairly unreliable and very user unfriendly. If you add onto that a price tag in parity with the user unfriendliness it did not seem likely I would see this technique in my company.

Some years later at a Gothenburg plastics exhibition, a company was exhibiting and running one of its rapid prototyping machines at a stand near our own. They were primarily a service provider and offered to make prototype models using more traditional techniques as well as using the machine. The rapid prototyping machine was not a big box containing a magic fluid, but a machine which had a small box filled with a white powder that looked like flour, but seemed to be heavier.

After returning from the Gothenburg exhibition, we actively searched information and visited machine suppliers to get a basic understanding of the technique and to get samples made. Among those we saw was a machine that squeezed something that looked like a thick fishing line through a hot nozzle, thus building the model layer by layer from bottom to top until it was complete finished.

A combination of laziness, a restricted budget and the fact that we work with high voltage -- and therefore are afraid of water -- made it easy to choose a machine that could create a component that was relatively clean.

When we received two orders that required speed and efficiency of the machine, we picked up with phone and immediately ordered the Stratasys FDM! After that “life has never the same”.

How could we calculate a return on investment?

When you want to get a new piece of equipment into your business there will always be someone asking the unwanted and stupid questions like; who will pay for it? - or - What is the payoff time for the investment?

In our case we made a very interesting discovery when we started to lay out a new type of products that needed to be designed individually according to every customers own individual need.

The cost of machining a specific component with irregular shapes and preferably as one piece, and furthermore from an insulating polymer material, can be worked out and compared to the cost of making the same component using DDM. We did come up with some very convincing arguments for getting our own machine. Some of these are:

• Cost per component
• Availability
• Delivery time
• New shapes previously not possible
• A new approach to solving problems

Calculations showed that with one complicated object per month, the investment in an FDM machine would make a profit.

It was very difficult not to make the investment!

Is this salvation? Will everything be made by rapid manufacturing?

Is it possible to find a back entrance to paradise, or are there still some obstacles that we need to consider? Well, you never stay entirely happy, and usually not for very long!

As with most human activities, we also need to use all our communications skills to make sure that the work we do makes sense to other people involved. There is a danger of blindly using the new technique without taking into account that it need be integrated in systems with constraints related to different techniques.

Today one may laugh at old timers still using ink and a drawing set lining up a drawing on their big and heavy drawing board. Not only does the drawing board occupy a huge floor space, it is too heavy to

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move, and your work is stationary. How on earth could I survive if I cannot bring my work home, or out into the garden?

There are some skills that we tend to lose with the new advancements. With CAD software you very often get drawings with angles never heard or thought of, and very accurate measurements with four digits after the decimal point. This, in my experience is often the work of a true artist and it gives you all reason to be prepared for excitement not asked for!

In order to get maximum value from your additive fabrication machine you need to have a broad general knowledge which makes it possible to interact with other people from other technological fields, thus making the integration of the technique smooth and practical.


So, how are we working with DDM today?


Although we did refer to the machine as a rapid prototyping machine for a few years, we make very few models or prototypes. The machine was bought as a rapid manufacturing machine with the very clear purpose of being able to manufacturing one offs at an affordable price and short delivery time. Today we have just begun producing small series of standard products by rapid manufacturing, since the traditional production methods are more expensive, considering tool costs, batch sizes, delivery times, complex shapes etc.

Our way of thinking has completely changed. It has all happened in many small steps over a long period of time, but when you look at it over the time span the change is dramatic.

Today, we would start by thinking about what can be best made with the FDM machine and what must be made some other way. We have learned a little about how to combine the different construction materials that we use to get the tolerances, how to get a good bond, how to integrate electronics and pneumatics components and how to get a nice surface finish.

Some products may also have a critical weight which may not be exceeded. At the same time there may be very specific demands for strength, meaning that a hollow construction can be the solution if the construction and design are made correctly.

As one starts to use the machine for series production the construction must also consider how to minimize machine time and material consumption.

The next step for our company will be to start looking at machines that can build us the metal parts that we need and how to integrate them into our current technique and designs.

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