When automatic electroplating machines moved into German electroplating plants The further development of rectifier technology triggered a surge in automation in electroplating plants in the Federal Republic of Germany in the 1960s and 70s, particularly with automatic electroplating machines. The development in this country was so successful that even the former technological role model, the USA, sought licenses for the efficient machines.
In terms of equipment, the period from around 1890 until after the First World War was characterized above all by the rapid replacement of the galvanic elements used as a power source by
Dynamo machine in upright design from 1876 - Photo: Siemens Dynamomaschinen. This meant that electricity was now available everywhere and in practically any quantity. While the electrical current for motor and heating purposes was used as alternating current or three-phase current, as supplied by the public grid, the direct current for electroplating had to be generated by converting the alternating current itself, whereby the most common type of converter in 1920 was the motor generator. As is often the case in technology, the serious competitor for the dynamo machine appeared at the moment when the motor generator seemed to have finally conquered the field. The competitor was the rectifier based on modern semiconductors, which replaced the dynamo machine in almost all galvanic plants after the end of the Second World War. Initially, selenium rectifiers dominated. The tendency to use other semiconductors, such as silicon and germanium rectifiers, which originated in the USA, was initially unable to establish itself in Germany [1]. Germanium rectifiers were considered to be too heat-sensitive and unsuitable for the harsh operating conditions in electroplating [1], despite their excellent efficiency. The selenium rectifier, especially the air-cooled one, was the cheapest to buy. The decisive factor in the choice between a germanium or silicon rectifier was the availability of a cooling water system [2]. A very important advance in electroplating was achieved by the increasing availability of automatic current and voltage stabilization, with which the rectifiers could be equipped, whereby the controlled rectifiers were replaced by regulated rectifiers in the 1970s. This was an essential prerequisite for production with automatic electroplating machines.
The revolutionary developments in the field of power sources began after the end of the Second World War, an extremely difficult post-war period for the electroplating industry [1]. After the forced break caused by the war, electroplating technology in Germany not only had to catch up with the technical level, especially that of the USA, but, like the entire German economy, was faced with an almost impossible task in view of the shortage of raw materials. The research and production facilities had also been largely destroyed. Initially, the focus was therefore on repairing and overhauling old equipment and supplying electrolytes, anodes and other auxiliary materials. It was only when supplies began to return to normal that the situation slowly began to improve, so that working conditions could once again be created that allowed production to run smoothly.
The automation of pre-treatment also progressed. Here is an advertisement for the so-called Automatikus from the MSV, as the magazine Galvanotechnik used to be called
Schlötter advertisement for mass electroplating systems
In addition to the traditional systems, the first automatic electroplating machines, new processes and modern tools came onto the market a few years later. This also opened up good sales opportunities for the electroplating industry, which brought considerable increases in turnover for all those involved in the electroplating industry over the course of time, particularly due to the onset of full employment and the associated demand for rational processes and automatic systems. Sales of systems, equipment and accessories from German suppliers of electroplating technology increased extraordinarily from 5.4 million German marks (DM) in 1950 to around 59 million DM in 1964 [3].
Automatic machine for electroplating aircraft wings from the Leonberg-based company Stohrer
The automotive industry has traditionally been one of the major customers of electroplating technology. At that time, it was already using galvanized parts to a large extent, the durability of which was increased despite the greatest stresses and increased external influences. This was made possible by the increased corrosion protection provided by galvanic processes, which had improved considerably in the meantime. The high-performance galvanic coatings could hardly be surpassed by other surface coating processes. In 1964, 1,850 tons of nickel were processed in the automotive sector alone, which corresponded to around 46% of the nickel consumption in electroplating in the Federal Republic of Germany at the time [3]. The increase in car sales in the Federal Republic of Germany from approx. 1.7 million cars in 1960 to 2.65 million cars in 1964 shows how decisively business with the automotive industry had developed, with nickel consumption in the electroplating sector practically doubling from 930 tons (1960) to 1,850 tons (1964) [4].
In addition to the automotive sector, the extraordinary expansion of the electrical industry, mechanical engineering, precision mechanics and optics, the metal, sheet metal and jewelry industry and, last but not least, the construction industry contributed to the annual growth in sales volumes for electroplating.
At this time, the general trend towards the automation of processes in German industry could not be overlooked. Electroplating, especially in industrial electroplating, could not escape this general trend, which is why the most important manufacturing companies turned their attention to this area. Far-sighted contract electroplating companies also followed the demands of increasing industrialization and began to use automatic electroplating machines [5].
Stohrer and the Dürr company jointly set up the VW electroplating plant with automatic electroplating machine in Brazil in the early 1960s. - Photo: Stohrer
The strong development in the field of automation of electroplating systems, especially in the 1960s to the end of the 1970s, was mainly due to the users of electroplating systems, manufacturers of electroplating systems and the electronics industry [6].
Users demanded plant utilization, personnel savings, better quality, minimum maintenance and maximum operational reliability at the lowest possible price. Manufacturers promoted the interests of users through fierce competition by introducing new chemicals, process technologies and electronic controls.
The electronics industry made many automation concepts possible through the rapid development of inexpensive components such as diodes, transistors, integrated circuits (ICs) and computers.
In the USA, which was regarded as the benchmark for German electroplating technology at the start of reconstruction after the Second World War, electroplating companies had preferred to use electroplating machines with mechanically rigid systems until the early 1960s, in which the electrical engineering component for the control system was very small and their adaptability to changes in production was correspondingly limited. In view of the requirements in the USA, universal systems were still in little demand at this time [7].
The increasing capacity of the German economy, triggered by the German "economic miracle", very soon brought with it a shortage of labor and, on the other hand, ever shorter working hours. Automation was therefore necessary [1].
The control cabinets of the Brazilian VW electroplating plant. - Photo: Stohrer
Within an unusually short period of time, automatic electroplating machines of all sizes were launched on the market in Germany in the field of automation of electroplating systems in a wide variety of technical modifications that were able to fully meet industrial requirements. Despite the dominance of the USA in the 1960s, licenses were already being granted from Germany to the USA in the electroplating sector [1].
A decisive step in the development of electroplating machines was the introduction of the so-called cell machines, in which the transport equipment was largely adapted to the requirements of the control technology. When this type of automatic machine appeared on the market and was characterized by the fact that it could be switched more variably than carousel and long automatic machines with the same assemblies, this has led to a strong response in electroplating circles since its appearance [8].
Automatic system for pickling steel and brass parts before electroplating at Schering - Photo: Schering AG
An important step towards automation was taken in 1969 when Schering [6] first developed a model for reading product program information without information indicators on the "automatic bookkeeping" product carrier. Around the same time, mechanical and magnetic limit switches were replaced by contactless inductive proximity switches for many applications. With the construction of two complex automatic electroplating machines at WMI Westfälische Metall Industrie (Paderborn) and WMF Württembergische Metallwaren Fabrik (Geislingen), these companies laid the foundation for the first computer-controlled electroplating systems in Europe. These plants were a joint venture between Kampschulte, Schering and Siemens. In 1971, the computer took over process control in both plants. The hardware and software of the WMI control system was developed by Siemens in Erlangen, that of the WMF by Schering in Feucht. In contrast to the WMI system, the computer of the WMF machine already had a mini-computer and structured user software, which had a positive effect on the price-performance ratio.
For the future development of electroplating machines, it can be predicted that the major developments in the field of automation, including the associated technical accessories, have certainly not come to an end, as some experts believed in 1965 [1]. In particular, it is not yet possible to predict the extent to which the networking of electroplating machines with industrial peripherals (keyword: electroplating 4.0) and the use of artificial intelligence (AI) will successfully and comprehensively find their way into electroplating, for example to support electroplating in the major issue of reducing energy consumption. Certainly, there are those today who see little prospect of such developments. However, they should be reminded that negative predictions about the introduction of electroplating machines also proved to be inaccurate in the past, for example when "clever" trade journalists commented that electroplating machines worked sluggishly, step by step, inhibited the work process and would deliver poor quality goods [4], as electroplating specialist author Max Schnellenkamp critically reported in 1965 in a market report about colleagues in his trade. History has shown that the exact opposite was the case, as optimum productivity was exploited and realized while taking into account the highest quality requirements.
Literature
[1]Galvanotechnik special issue Export: German electroplating today (1965) 75-105
[2]Stiassny, W.: Galvanotechnik 56 (1965) 14-19
[3]Galvanotechnik special issue Export: German electroplating today (1965), 61-74
[4]Schnellenkamp, M.: Galvanotechnik 56 (1965) 195-200
[5]The importance of contract electroplating: Galvanotechnik, 56 (1965) 33 -36
[6]Sturm, K. H.: Galvanotechnik (1976) 41-51
[7]Strecke, H.: Galvanotechnik 57 (1966) 611-614
[8]Strecke, H.: Galvanotechnik 56 (1965) 736 - 746
