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From the "witches's kitchen" to serial production – Brugg Cables

Company coverage

For more than 100 years the company Brugg Cables has been serving the world market with high-voltage and maximum-voltage cables up to a voltage category of 550 kV. Founded in 1886 as Suhner AG and trading since the 1930s as Kabelwerke Brugg, the enterprise has grown dynamically. The ever increasing export share, at this time amounting to 70 %, led to the international market appearance as "Brugg Cables" in 2001.

Around 1,800 employees are working across the group. Apart from the cable production, there are also the business units "rope technology" and "Brugg pipe systems" for district heating technology and safety pipes for the construction of filling stations. The core business in the electrical area is high-voltage and maximum voltage cables, complete high-voltage plants as main contractor, undersea cables and cable mountings. The most important markets are the Asian regions and the Middle East with its petro-chemistry.

The field of cable mountings is a quite young business unit that is set up and headed by Mr Hans Rudolf Mueller.

DNR - Team:
Mr Mueller, would you please tell us something about your work over the past years in the field of the cable mountings production?

Hans Rudolf Mueller:
Until the mid-1990s we had a close cooperation with the company Cossonay, also based in Switzerland that already sold the so-called slip-on joints. We therefore bought these at that time quite simple cable mountings in addition. Due to various restructuring measures at Brugg, this cooperation was finished. We realized, however, that important new projects got lost without cable mountings made by Brugg itself. Hence, a new project called "Independent" was launched to stand here on our own two feet.

As project manager in charge, I started a corresponding feasibility study and developed together with another employee mould concepts and production methods. After all, we are talking about very large rubber mouldings which have to be produced absolutely free from trapped air and with very exact transitions.

DNR - Team:

What equipment was at your disposal?

Hans Rudolf Mueller:
In short, a witches`s kitchen and many ideas. Nevertheless, we were able to design first slip-on joints and to produce prototypes. It was a real manufactory. But in 1997 we passed the sample testing for our 170-kV joint body. This was the first great success which, however, was kept secret.

»To produce large-sized conrol electrodes and slip-on joints without any air entrapments and with perfect transitions from the conductive layers to the insulation ones is very demanding«

On the left: Hans Rudolf Mueller
Serial production of "control electrodes" on the DESMA 968.250 T

DNR - Team:
Why?

Hans Rudolf Mueller:

We still were exclusively manufacturers of cables, and production capacities were actually not available. In the back room we kept on projecting and developed a 300-kV joint body, produced prototypes, passed the sample testing. Everything still secretly... Much to the industry's surprise, we then presented our 300-kV joint body including all performance characteristics at the INELTEC show in Basel. It was a brilliant success - and we received an initial order to deliver 50 joint bodies.

DNR - Team:
And how did you manage to execute this order - without any production capacities ...?

Hans Rudolf Mueller:

It was the hangover after the party - this was of course the question we had to ask. The order was carried out by taking a "sledgehammer approach", with a laboratory extruder with rubber screw manufactured as pump, and delivery was on schedule! Afterwards, we were all wondering how to carry on. On my own initiative, I prepared a business plan and a project presentation of a possible "production cell" and presented it to the supervisory board. The core statement was: how could a serial production look like and what can we achieve in three years from now?

DNR - Team:

What was the response to your initiative?

Hans Rudolf Mueller:

I was very lucky - Mr Otto Suhner, the chairman of the board, immediately decided to realize this project. I could start and "went shopping".

DNR - Team:
That meant the end of the witches`s kitchen?

Hans Rudolf Mueller:

Yes, one could say so. Now we were looking for, if possible, a universal injection machine for HTV and LSR silicones that should also fit into an existing hall assigned to us for the production of cable mountings. I visited a lot of machine manufacturers in order to obtain detailed information. We decided on a DESMA 968.250 ton-machine with injection into the split line. Reason of this decision was that with the split line injection and a deflection block it was feasible to carry out an injection from top and from bottom or into the split line. Moreover, this machine enabled the combination of a relatively large injection volume of approx. 6,000 cm³ with a relatively small clamping force (2,500 kN). And above all, the machine - of 3.50 metres height only - fitted perfectly into my hall.

DNR - Team:

Were there any other arguments that influenced your choice?

Hans Rudolf Mueller:
The technical competence for the processing of HTV and LSR silicones was in any event given at DESMA. They had references to many projects already implemented that confirmed my purchase decision. Especially the possible process support as well as the experiences in constructing moulds were very important to me. Also, a variety of special procedures to process silicone has already been available in the machine control system as a standard, so that I did not have to set a limit to my demands. At any rate, I wanted to include as many options as possible for future articles and production methods in my purchase. Although DESMA has been and still is an "expensive" supplier, the order was placed with them in 1998. The same year our tailor-made machine was delivered. To this day, the machine technology has been convincing us!

DNR - Team
:
From a manufactory to a serial producer - have things always been going smoothly?

Hans Rudolf Mueller:

We had a plane now, but had to learn to fly first. During the start-up phase we produced 4 control electrodes and 2 joint bodies per day. Hence, a production on a laboratory scale, but of very high quality. The range of products was very quickly extended and the voltage categories 220 kV and 420 kV followed. We used new low-module material types which were optimized jointly with the material supplier. The breakthrough was achieved with a large order from Asia. We delivered 300 kV joint bodies in big quantities.

DNR - Team
:
How did business develop afterwards?

Hans Rudolf Mueller
:
Since this large order we have been in a position to obtain annual growth rates between 20 - 25 %. Business is doing very well and we already had to invest in further machines.

DNR - Team:
You have recently decided on a DESMA 968.400 ZO Benchmark 750 with FlowControl+ nozzle technology. What about your experiences after more than 6 months of production?

Hans Rudolf Mueller:
We decided on a 400-ton machine, because we wanted to produce these large-sized cable joints in multi-cavity moulds to cope with the increased demand. This machine provides in addition to the very ergonomic ease of operation the advantage of large opening strokes which of course is crucial for our products. The overall height of the machine of 4,40 metres just fits into our hall.

DNR - Team:

What did you expect from the usage of the FlowControl+ nozzle technology and what did prove true?

Hans Rudolf Mueller:
The FlowControl+ nozzle technology was convincing from the very first moment on, and I knew that a great cost-saving potential was given. In pretests at DESMA in Fridingen we were very quickly able to achieve savings between 30 and 50 %, i.e. cure time could be halved from 900 to 450 seconds! This saving was fully confirmed in the serial production. We are saving at least 30 % of the cure time and are aware that considerable potential is yet available. Article quality is absolutely identical with a conventional production.

DNR - Team:
What about your further plans for 2010?

Hans Rudolf Mueller:
We want to continue growing. In March 2010 we are going to move to a completely new hall which is especially being built for the production of cable mountings. This relatively new business segment is becoming a big competitive edge. We are independent of supplies and develop our own optimally designed product for our requirements. There are no compromises to make. The days of the witches`s kitchen are far behind us. We are in top form.

DNR - Team:
Mr Mueller - we thank you very much for this discussion and wish you all the very best of success for the future.