Immediately after the end of the war, Peter Schmetz founded the company PETER SCHMETZ – Elektroindustrieofenbau in Neuenrade.
Reconstruction of hardened buildings destroyed during the war was an urgent task. The focus was on the two-wheeler industry with companies such as Dürkoppwerke Bielefeld, Ardi, Zündapp and Triumph in Nuremberg.
Relocation from Neuenrade to Menden on Unnaer Landstraße in a newly constructed office and production building. This was followed by the construction of furnaces for enameling tank columns, kitchen stoves and bathtubs.
The manufacturers of stainless steel wires ordered wire drawing annealing furnaces.
The same type of system was also used for soldering refrigerator evaporator plates or for soldering components for cash registers.
The company Ankerwerke / Bielefeld, manufacturer of cash registers, reported to Peter Schmetz Senior on problems with gas-shielded continuous brazing. The edge decarburization of steel parts led to costly reworking, decarburization and recarburization.
SCHMETZ has been familiar with the construction of vacuum annealing furnaces for the wire industry since 1954. This gave rise to the idea of brazing the steel parts in a vacuum as well.
The tests that followed quickly showed that this was the solution to the problems with edge carburization on steel parts. This led to the development and construction of the first vacuum brazing furnace in Germany.
This brazing furnace was used to carry out the first contract brazing orders for Ankerwerke. This gave rise to two business ideas for SCHMETZ. On the one hand, the construction of high-temperature vacuum brazing furnaces and, on the other, contract brazing on behalf of customers.
A second, larger brazing furnace was built in order to meet the demand for vacuum brazing that had arisen in the meantime.
Ankerwerke was convinced of the quality during the time of contract brazing and ordered its first vacuum brazing furnace from SCHMETZ for its own production. This first system was delivered that year and was followed by others over the next few years.
Klaus Schmetz moves from plant engineering to the high-temperature vacuum brazing technology division. His task was to organize contract brazing as an independent area alongside plant construction and to make vacuum brazing known on the market.
Milestones
Up to this point, only E-Cu solders were used.
An inquiry from the BBC / Baden company in Switzerland (now ABB) as to whether SCHMETZ could carry out high-temperature soldering with Ni-based solders resulted in the first contact with these special solders. High-temperature soldering with these Ni-based solders was developed in the USA and England for tasks in the aerospace industry and for reactor construction.
This request from BBC / Baden (CH) was the impetus for SCHMETZ to build the first high-vacuum brazing furnace in retort shaft design. This plant was then used to braze Comprex rotors for BBC / Baden and heat exchangers for Autokühler / Hofgeismar. The Ni-based solder came from Dewrance Metals Ltd. in England. Later, such solders could also be obtained from the USA. The company Lurgi / Frankfurt distributed the solders of the company Wall-Colmonoy from Detroit.
Further demand from the market prompted the construction of a second high-vacuum brazing furnace. The company MAN-TURBO / Munich (today MTU) wanted to have engine compressor guide rings and other engine parts brazed.
Further tasks for this system came from, among others:
- Sulzer / Winterthur (CH):
Hip joint prostheses - Siemens / Reactor Center Erlangen:
Spacers for fuel rods - Interatom / Bensberg:
Sodium cooling cassettes for the fast breeder reactor - Lufthansa Workshop Hamburg:
Diffuser tubes, stator segments, combustion chambers
The company BBC / Mannheim ordered the brazing and tempering of compressor impellers for gas liquefaction turbines.
Major problems occurred during soldering and subsequent quenching.
The vertical cooling gas flow from above favored the cooling of the cover disk over the hub disk. The resulting tensile stress tore the soldering of the two disks apart again. The solution to the problem was a device for distributing the cooling gas flow to all impeller surfaces.
The temperature curves on the impeller were almost identical and the soldering result was perfect. Au/Ni 80/20 was used as the solder.
In conversation with Peter Schmetz junior, Klaus Schmetz presented the problem and solution and initiated the development of a brazing furnace with demand-controlled cooling gas flow for SCHMETZ-Ofenbau.
More than 10 years were to pass before it was possible to realize this in terms of oven construction. Graphite building materials came onto the market, which made completely new designs possible for the stove engineers at SCHMETZ.
Also in 1968, Klaus Schmetz took part in an international soldering conference in London.
Under the impression of this conference, Klaus Schmetz and Mr. Iversen from the company Interatom initiated the foundation of a German working group for vacuum high-temperature brazing with the aim of exchanging experiences. First meeting at Lurgi / Frankfurt, then twice a year.
First presentation of a SCHMETZ RN 100 vacuum brazing furnace at the Schweißen + Schneiden trade fair in Essen.
SCHMETZ vacuum brazing furnace type RN 100 at the trade fair in Essen
In the same year, the first contact with tempering channel systems for record pressing molds was made.
The press molds consisted of an upper and lower part into which the channel system was inserted. Both parts were then joined by high-temperature vacuum brazing.
The channel systems were used to heat the molds to pressing temperature with steam in just a few seconds. After the pressing process, the steam was displaced by cooling water and the mold was cooled to the removal temperature of the record. The total cycle time per process was 15 seconds. That meant over 5000 cycles per day. Soldering customers included EMI-Elektra / Cologne, Bertelsmann / Gütersloh, Telefunken – Decca / Neumünster.
This year, Klaus Schmetz took part in an international conference for soldering technology in Cleveland, USA, for the first time. The event was organized by the American Welding Society – AWS. The annual meeting, which took place in different cities each year, lasted two weeks and consisted of two parts.
1st week: Lectures and discussion on problems of high-temperature soldering and exchange of experience.
2nd week: Visit to well-known users of high-temperature brazing technology with a tour and insight into applications for brazing technology.
Companies such as NASA in Pasadena and Cleveland, BOEING / Seattle, Pratt & Whitney / San Diego, Rockford / Chicago and Stanford University / Los Angeles were of particular interest as they had many years of experience with Ni-base, gold and palladium solders. The insights and impressions gained by Klaus Schmetz at this conference were of great value for the further development of Schmetz soldering technology. Further participation in these conferences therefore followed in the years that followed.
The brazing of hard metals on carrier materials was a key topic in the following period. Chain teeth for chainsaws were tipped with carbide for Stihl / Waiblingen.
Krupp-Widia / Essen and Barmag / Remscheid each had hundreds of hard metals soldered onto pelletizing discs with a diameter of 500 mm.
Brazing tests on carbide rock drills were carried out with Hilti / Liechtenstein.
Result: An exclusive contract was concluded between SCHMEIZ-Ofenbau and Hilti:
SCHMETZ-Ofenbau did not deliver to Hilti’s competitors; in the following years, Hilti ordered at least one soldering system per year from SCHMETZ-Ofenbau.
This agreement proved its worth over many years.
SCHMETZ-Ofenbau moves from Unnaer Landstraße to Holzener Straße.
This freed up space that could be used for the further growth of SCHMETZ-Löttechnik.
A cooperation between SCHMETZ-Ofenbau and the vacuum furnace manufacturer Ipsen / Kleve resulted in the purchase of a large Ipsen brazing furnace with a usable chamber diameter of 1200 mm and a height of 1200 mm.
This significant expansion of the soldering possibilities now allowed the soldering of components with corresponding dimensions. The soldering of exhaust valve baskets for large diesel engines now played an important role in the spectrum of different tasks. These large diesel engines were mainly intended as marine propulsion systems.
The previous major manufacturing problems of a casting and welding nature were quickly solved by the soldering technique, and the constructive division of the baskets into three segments resulted in pieces that were manageable in terms of casting technology, which were then joined using soldering technology.
Customers were found throughout Europe.
The first bottom load furnace built by SCHMETZ-Ofenbau was installed in this new building. The increase in tasks for contract soldering made this capacity expansion necessary.
2. demand-controlled (∆t) cooling gas flow 2-R system
During this time, SCHMETZ-Ofenbau was confronted by the market with the demand for vacuum furnaces with overpressure gas quenching for bright hardening. In order to be able to realize distortion-free hardening of tools using an overpressure cooling system, the experience gained in 1968 with the brazing of impellers was used.
A ∆t-controlled cooling gas flow was set as the development goal.
The graphite building materials, sheath thermocouples and program controls that were now available offered the best prerequisites. At SCHMETZ-Ofenbau, intensive development work was carried out under the direction of Peter Schmetz in the years 1978 – 1980.
The result was the System-2R with overpressure gas quenching. The first system in this series was installed in the now completed
Technical center installed at SCHMETZ-Löttechnik.
This system served SCHMETZ-Ofenbau as a demonstration object, but was also used by SCHMETZ-Löttechnik for soldering tasks.
A high-vacuum laboratory furnace was also set up in the technical center for tests and small orders.
The following years were characterized by the growth of the two divisions and the expansion of their market position. Appropriate marketing was of particular importance here. A quality assurance system was also installed in the area of soldering technology. TÜV certification and regular audits have enabled the company to meet the increased demands of the market.
Close-contour cooling channel system for plastic injection molds Contura® system
Reiner Westhoff, son-in-law of Klaus Schmetz, started at SCHMETZ-Löttechnik. He had just graduated from the University of Applied Sciences in Iserlohn as an engineer for plastics technology. After a training period in soldering technology, he gained two years of professional experience in Switzerland.
In the course of market development, he came into contact with plastics processing companies, among others. Manufacturers of injection-molded parts told him about their problems in being able to control the temperature of the injection molds correctly. The available techniques (mostly drilling) could not produce the necessary duct systems. Ejectors, breakthroughs and ribs showed the limits of straight-line drilling technology.
In an interview, Reiner Westhoff explained the problems and their effects on cycle times and the quality of the molded parts to Klaus Schmetz.
Good mold temperature control is a prerequisite for optimum molded part quality and economical production (cycle time).
Reiner Westhoff was familiar with these connections from his studies. Injection molding was new territory for Klaus Schmetz. His specialty was high-temperature brazing technology. He referred Reiner Westhoff to the possibility of manufacturing the mold inserts from two or more segments, whereby the temperature control channels could then be inserted close to the contour by machining. The individual segments could then be fully joined to form a single unit using high-temperature vacuum brazing technology.
Reiner Westhoff responded to these comments: “Do you know what that would mean for the users?”
Klaus Schmetz couldn’t get this sentence out of his head. Here, the combination of two specialist areas brought an interesting idea to light.
INNOVA was founded to put this idea of “tools with optimum temperature distribution” into practice.
In line with the company concept, INNOVA concentrated on engineering. Suppliers should create the hardware.
The key technology was high-temperature vacuum brazing. The solders used were mainly the nickel-based solders known from the aerospace industry. The soldering process was easy to combine with the necessary tempering treatment of the tools.
The modern vacuum brazing systems with overpressure gas quenching and gas flow direction change (2R) were the best prerequisite for these joining and heat treatment tasks.
The company INNOVA reported on 16.10. In 1992, the company applied for a patent under file number P4234961 for “Temperable tool or mold for the production of plastic molded parts and process for the production of such tools or molds”. Klaus Schmetz was registered as the inventor.
INNOVA registered the “CONTURA” brand to give this contour-following temperature control system the best attention on the market. This trademark was registered on 11.11.1993 under the number 20 49 385.
The German patent is granted under the above number on July 25, 1996.
Industry insiders, above all BAYER/ Leverkusen, were convinced by the Contura® system. In BAYER’s opinion, it was the best innovation in injection molding technology for 15 years. The company HUF Velbert (automotive supplier) spoke of a “quantum leap* in temperature control technology following test results. The Kunststoffinstitut Lüdenscheid (KIMW) was of the opinion that INNOVA had a license to print money with the Contura® system.
These and similar assessments contributed to INNOVA’s subsequent expansion of its engineering and market development capacity in order to take advantage of this “opportunity”.
However, bringing the Contura® system to market proved to be more difficult than expected.
Many companies worked with fixed budgets for machines and tools. There was often no room for new technologies such as System Contura®.
Even guarantees for cycle time reductions and quality improvements did little to change this situation.
The established tool manufacturers also saw INNOVA as a serious competitor and were on the lookout for errors and defects on the part of INNOVA. These inevitably arose, as with any new technology. There were delivery delays and errors in project planning as well as manufacturing problems at the suppliers for mechanical production and soldering technology.
This provided suitable arguments for negative advertising.
The fact that both toolmakers and injection molding machine manufacturers were not interested in INNOVA establishing itself on the market with the Contura® system was ultimately understandable. Both sectors benefited from long injection molding cycles (more demand for tools and machines).
Despite all the difficulties, INNOVA believed in the market success of System Contura®. And so attempts were made to counteract the hesitant attitude of the market with increased sales efforts.
A thermal camera was purchased to visually support the case for the Contura® system.
Thorsten Müller-Schmetz, son-in-law of Klaus Schmetz and also employed at INNOVA after studying engineering for plastics technology, was able to provide a lot of evidence of poor mold temperature control with this camera.
Thermal images taken immediately after the injection-molded parts had been produced showed the often serious temperature differences on the molded parts. Too few companies have been persuaded by this evidence to equip their injection molds with System Contura.
This approach and other measures did not bring the desired success for INNOVA in order to achieve the economically necessary results.
The successes achieved since INNOVA was founded were not sufficient to cover the costs and ensure INNOVA’s continued existence.
The company had to file for insolvency in June 2003.
The main reasons for this insolvency were:
1. that the System Contura® product had to displace existing solutions from the market and that the resistance to something new was enormous.
2. that INNOVA had no experience of how much time and effort was required to make this process successful.
3. the overly optimistic assessment of the chances of success, which led to a prematurely overestimated cost apparatus.
unforeseeable problems in technical order processing, both in mechanical production and in high-temperature brazing and tempering.
However, the idea of producing contour-following tempering of injection molds using high-temperature brazing had not lost its appeal and was therefore not affected by the insolvency.
In the same year, 2003, the company was founded under new management.
CONTURA MTC (Mold Temperature Control) was founded in Menden Sauerland.
Within ten years, the CONTURA brand had achieved a high level of recognition in the market. It therefore made sense to go into the future with this brand as the company name.
The technical know-how acquired over the past few years was fully available to the management team with Thorsten Müller-Schmetz and Reiner Westhoff. The patents were still valid for 10 years.
The task now was to incorporate the experience gained with INNOVA into a new, realistic and cost-conscious business concept.
Some of INNOVA’s customers were happy to work with CONTURA MTC in the future in order to benefit from the advantages of contour-following temperature control for injection molds.