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March 2010 Powder Injection Moulding International



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Company visit: Parmaco Metal Injection Molding AG

Parmaco Metal Injection Molding AG: High tech MIM manufacturing in a Swiss rural retreat Fischingen, the most southerly community in eastern Switzerland’s Canton Thurgau, nestles in rolling green and wooded hills. The small community is renowned for its former Cisterian monastery and the region, which borders Canton Zürich, is a hikers’ paradise only 40 minutes from Zurich Airport. Less well known is that Fischingen is the home to Parmaco Metal Injection Molding AG, one of Europe’s leading and most innovative MIM producers since 1992. Bernard Williams reports on his recent visit for PIM International.

Georg Breitenmoser, Parmaco’s Managing Director, is a native of this part of Canton Thurgau and studied at the Swiss Federal Institute of Technology, Zürich, where he graduated with a degree in Materials Engineering in 1981. He had chosen metallurgy in his final year because he felt it gave him more options for travel and career opportunities in a country which he stated is dominated by chemical and pharmaceutical giants. His first job after graduating was with Oerlikon, near Zürich, a company specialising in producing welding machines and

welding consumables such as pressed stick electrodes coated with flux and alloy steel powders. Initially he worked in the R&D department but was later made responsible for providing technical support to Oerlikon’s many licensees around the world, thus helping him to fulfil his wish to travel. In 1984 he was given the opportunity to work for a licensee in Lima, Peru, where he developed alloy steel (13Cr steel) welding electrodes used to refurbish turbine parts used in hydroelectric power plants.

Fig. 1 Georg Breitenmoser, managing director of Parmaco AG in Fischingen, Switzerland



Powder Injection Moulding International March 2010

A new chapter in Georg Breitenmoser’s life started in 1987 when he decided to embark on a MBA at California State University in San Luis Obispo and it was during his stay in California that he made a visit in 1988 to Carl Zueger, a fellow Swiss and co-founder of one of the world’s first metal injection moulding companies, Parmatech Corp. based in Petaluma near San Francisco. The visit made sufficient impression on Breitenmoser to convince him of the future potential for MIM technology and he was offered a manufacturing license to use Parmatech’s patented technology in Switzerland. It took four more years, however, before Breitenmoser’s ambitions to set up a MIM plant in Switzerland could be realised. He first undertook, together with his father and two other partners, to set up a small manufacturing plant to produce central heating radiators from sheet steel in the nearby town of Münchwilen in 1989. Then in 1992 he founded Parmaco. He rented part of a modern building in Fischingen which suited his initial needs for a small MIM operation - one of the first in Europe. The company purchased a 50 ton Arburg Allrounder injection moulding machine, a planetary mixer and a solvent debinding unit. Breitenmoser built his own furnaces for thermal debinding and sintering based on

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Company visit: Parmaco Metal Injection Molding AG

Fig. 2 Good tool maintenance is critical to the success of metal injection moulding

Parmatech specifications. The first person employed was a toolmaker and the young team at Parmaco focused first on getting MIM part design and process stability under control. “We found the MIM process relatively unstable so we designed our own production cells in order to achieve the desired control of temperature in debinding and sintering

Fig. 3 Injection moulding of MIM parts at Parmaco.The six axis robot gripper is picking two parts

part. “This was a ‘breech lock holder’ (Verschlusshalter) used in a Swiss made air pistol produced by Hammerli, then located in Lenzburg, Switzerland, and we were able to make this as a single MIM part from an FeNi alloy against an assembly of machined parts previously used”, said Breitenmoser. The second MIM part was developed together with Festool, a leading

‘We prefer to focus on small or extremely small and complex MIM parts where material cost is a comparatively minor factor’ and as a consequence control of dimensional accuracy in the MIM parts. It’s one thing being able to achieve dimensional accuracy in a lab furnace, but it’s another to achieve the same in a production environment”, Breitenmoser said. An additional challenge was that very few design engineers knew about MIM in the early 1990s. “We had no MIM parts in production when we first exhibited at the Hannover Trade Fair in April 1993”, said Breitenmoser. The company’s stand which promoted examples of MIM applications in armaments, office machines, computers, etc., did, however, manage to generate quite a few enquiries one of which turned into an order for its first MIM

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producer of professional power tools, in 1993. This part was also made from FeNi alloy and was used in a jig saw blade holder assembly in the then PS200 model jig saw. Parmaco was able to beat investment casting on price, tolerances and finish. Today, Parmaco has some 250 active MIM parts in production ranging in weight from 0.05g to as heavy as 90g, although the preferred upper weight range is put at 50 to 60g and Breitenmoser puts the ‘ideal’ MIM part size at under 20g. “Because of the complexity of MIM parts and the associated high tooling costs for injection moulding, our production quantities tend to start at a minimum of 10,000 parts/year with an upper range of 3 million parts/year

depending on MIM part size and weight,” said Breitenmoser. Around 60% of Parmaco’s MIM production is based on low alloy steels (NiFe), and the rest is dominated mainly by various stainless steel grades but also some controlled expansion alloys, soft magnetic parts, tungsten heavy alloys and a limited number of tungsten carbide wear resistant MIM parts. Over the past 18 years the company has gradually taken over the whole of the building it rents in Fischingen. However, it remains a relatively small to medium size operation employing some 50 people, and Breitenmoser emphasised that the company was not geared to very high volume MIM production. “We prefer to focus on small or extremely small and complex MIM parts where material cost is a comparatively minor factor, and where the MIM process can achieve up to 100% material utilisation through the elimination of any secondary machining steps. In this way we can successfully compete with parts produced by competitive technologies which require extensive secondary machining”, said Breitenmoser. “Our strategy is to sell high quality service and design solutions to our customers, and not to compete for high volume parts with depressed prices. Our batch furnaces are in any case more suited to medium volume production”. This strategy and Breitenmoser’s passion for MIM technology has, he

March 2010 Powder Injection Moulding International



Company visit: Parmaco Metal Injection Molding AG

Fig. 4 A dimension on a housing part cover is being measured in Parmaco’s quality control department

stated, paid handsome dividends with applications over a wide range of end user sectors including fire arms, medical, power tools, textile machines, telecoms, optical and automotive. Approximately 80% of production is exported with a large proportion going to German customers – an indication perhaps of the success of exhibiting every year at the Hanover Trade Fair. In recent years annual growth has averaged 10 to 15% requiring 3-shift working in the MIM plant. In 2008 Parmaco saw sales surge by 30% as new MIM parts were put into production. “This high level was maintained until March 2009 when there was a sharp downturn in demand and 2-shift working was introduced”, said Breitenmoser. Order volumes started to pick up again in the second half of 2009, and the company was expecting to consume around 50 tonnes/year of MIM feedstock in the last year.

Expertise in MIM feedstock

Fig. 5 MIM parts being loaded into the combination debinding and sintering furnace at Parmaco

Parmaco produces all of its own MIM feedstock, which was originally based on the formulae licensed from Parmatech in the USA, but which has in many cases been changed or modified to suit production of a particular component or material. Mixing is done in 50 kg lots in planetary mixers using a soluble wax binder and a non-soluble thermoplastic backbone binder with elemental metal powders such as carbonyl iron, nickel and other metals as required, as well as water and gas atomised stainless steel powders. Process controls are in place to ensure a consistent dispersion of metal powder particles and binder throughout the feedstock. Parmaco uses a weighing station where each ingredient material is accurately weighed, based on the specified formula kept on a database. The mixed binder/metal powder feedstock, which typically has a 55 to 60% powder loading, is then processed into pelletised feedstock and stored in 20 kg drums ready for injection moulding.

Moulding / debinding

Fig. 6 A line of batch sintering furnaces



Powder Injection Moulding International March 2010

MIM tooling is now mostly produced by outside contractors with only tool maintenance done in-house. Tooling tolerances are critical to the success of the injection moulded parts and Parmaco can achieve an accuracy of better than +/- 0.3% in its MIM

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Company visit: Parmaco Metal Injection Molding AG

Fig. 7 Selection of small and micro-MIM parts in production at Parmaco

Fig. 9 MIM part having extremely intricate shape and thin walls for a mounting unit used to position a glass prism in an optical lens system

Fig. 8 Award winning Micro-MIM high torque planet-carrier produced by Parmaco

Fig. 10 MIM part used in a nut tightener system for special self drilling flat head screws for facade construction

process, which means that even for extremely small and complex parts moulding accuracy can be in the range of hundredths of a millimetre. Surface finish of better than Ra 3.2 is attainable without the need for polishing. In the case of micro-MIM parts, Parmaco’s toolmakers are expected to produce tools capable of close to zero tolerances. Some moulds contain up to eight die cavities. “It is very important to create a good design of MIM parts and the associated moulding tools in order to avoid problems in production”, said Breitenmoser. “Our part designers and toolmakers work closely with customers as early as possible in the design process to avoid such problems”, said Breitenmoser. Parmaco operates a total of eight injection moulding machines including a Netsal 60 ton hydraulic press, a line of 50 ton Arburg machines of which some are fully electric and a Battenfeld 5 ton machine which is used for injection moulding extremely small and so-called micro-MIM parts. Moulding pressures are in the range of 800 to 1600 bar.

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Many of the injection moulding cells are fully automated using robotic devices to remove runners from the moulded parts and to place the parts onto trays for debinding. On one machine seen producing a gun hammer part, the robot placed the parts onto a tray and when the tray is full the robot’s gripper is automatically changed to allow it to place the tray onto a stack. The whole stack can then be taken to the solvent debinding unit. As already mentioned, Parmaco’s binder systems are based on a soluble wax and an insoluble backbone thermoplastic. The first step in the debinding process involves solvent extraction whereby the moulded parts are immersed in a hexane bath. This dissolves the wax binder element and leaves the parts with around 20% porosity having interpenetrating pore channels which are needed for the second stage of the debinding process. The ‘solvent extraction’ stage is relatively short and there is no change in size of the parts at this stage, stated Breitenmoser. The next ‘thermal debinding’ stage

is more critical in terms of temperature control during the evaporation of the backbone thermoplastic binder from the parts. Parmaco uses four batch thermal debinding furnaces which the company has designed in-house with each furnace having a loading capacity of 1m3 and operating at temperatures up to 300°C. To ensure uniform debinding the company is able to maintain temperature accuracy to +/-1°C in its furnaces where the gradual heating of the parts attacks and evaporates the binder constituent without loss of shape. The ‘brown’ parts which emerge from the thermal debinding furnace have still more or less the initial size but have gained more porosity.

Custom-built sintering furnaces Equally impressive to the furnace units seen for thermal debinding are the sintering furnaces which Parmaco has also designed in-house. There are four top loading batch furnaces with integrated fan cooling used for sintering low alloy steels in hydrogen atmos-

March 2010 Powder Injection Moulding International



Company visit: Parmaco Metal Injection Molding AG

phere at temperatures up to 1300°C. Gas flow is said to be critical in these furnaces and temperature sensors placed strategically help to control the temperature throughout the working zone of the furnace. A horizontal loading atmosphere batch furnace is also available for sintering up to 1300°C, and Parmaco has developed know-how on the optimum tray materials on which the MIM parts are placed in the sintering furnace. In addition there are three front loading custom designed vacuum furnaces used for sintering stainless steels, and the company prides itself on its acquisition of an Elnik Systems combination debind and vacuum sinter furnace. The Elnik furnace provides temperature control accuracy to within +/-5°C in the six zones around the retort and can process a variety of metal/binder mixtures in a one-step debinding and sintering cycle. This is achieved through the use of a gastight refractory metal retort with a gas management system which allows laminar gas flow to occur thereby sweeping out the evaporated binder, CO2 and water, followed by the sintering cycle in vacuum or partial vacuum. The furnace can be automatically controlled for gas flow, temperature and partial pressure. Backing up the impressive production facilities is a machine shop with CNC milling, grinding, and calibrating equipment although it is the company’s objective whenever possible to produce MIM parts which do not require secondary operations. Heat treatment of MIM parts, plating, etc. is done by outside contractors. The company was accredited with ISO 9001:2000 in 1998, and its quality control section is responsible for the rigorous controls at every stage of the manufacturing process with data being fed into a PC-based data collection system for future reference or cross checking. This guarantees batchto-batch accuracy for MIM part weight and dimensions, said Breitenmoser.

Fig.11 MIM receptor part for jig saw power tool in various stages of production.

Innovative MIM products

Fig.12 Functional areas of the MIM slide used in jig saw blade holder assembly.

Parmaco has been successful in convincing design engineers of the merits of MIM through its ability to work with them in developing the optimum designs for the MIM process, ideally eliminating or minimising secondary operations. It has also demonstrated the potential of cost savings by the ability to achieve in one part design what might have

Fig. 13 A selection of parts for various industries such as locking systems, textile, medical, stepping motor gears and fire arms



Fig. 14 This print wheel is the heart of a 24 dot matrix printer head manufactured of 3% silicon iron soft magnetic alloy

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Company visit: Parmaco Metal Injection Molding AG

previously required an assembly of two or more parts as outlined in some of the examples below. Breitenmoser, however, is not complacent about the need to do even more to promote MIM technology and to educate and inform design engineers who still remain unaware of the potential of the process. There is no better way of doing this than by giving design engineers examples of successful MIM applications and innovations, and in this respect Parmaco is one of the few MIM producers in Europe which has been open about some of its MIM product developments. Parmaco follows a strong Swiss tradition of precision manufacturing and as already mentioned the company is able to achieve tolerances in its MIM parts of +/- 0.3% of blueprint dimensions without reworking and can achieve a surface finish, without polishing, of better than Ra 3.2. Even the so-called micro-MIM parts where the weight of the parts is only in the range of 0.01 to 0.3g, Parmaco is able to offer tolerances of 0.01mm. Examples of such tiny MIM parts are given in Figs.7 and 8. Fig. 8 shows a micro-MIM high torque planet-carrier with a sun gear for planetary gear boxes used in an opening and closing mechanism of mobile (cell) phones. The high volume part could be produced as one piece by MIM instead of assembling 5 parts. This MIM part received recognition in the EPMA Awards for Excellence in 2008. An example of where Parmaco was able to push the boundaries of MIM technology was a part having extremely intricate shape and thin walls (Fig. 9). The part is for a mounting unit used to position a glass prism in an optical lens system in order to deflect a laser beam. The part has to work accurately under different temperatures ranging from -20°C to +50°C which required a NiFe alloy having the required coefficient of expansion. It has a diameter of 43mm and all cross sections are between 0.5 and 0.7mm thin. Distortion and uneven shrinkage in thermal debinding and sintering were the key problems that needed to be overcome in this application, which is considered to be a masterpiece of MIM capabilities. The part was recognised in the EPMA’s Innovation Awards in 2003. Yet another example of Parmaco’s capacity for innovation was rewarded with an EPMA award in 2004 for a small MIM part used in a newly introduced

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Fig. 15 MIM housing cover made from 316L stainless steel for a sensor casing. (As presented in the EuroPM2009 keynote paper “Key Areas for Development in PM Technology”, Dr Olle Grinder, PM Technology AB, Sweden)

nut tightener system for special self drilling flat head screws for façade construction (Fig. 10). In comparison to the machined part which it replaced, MIM provided an 85% cost saving to the customer. The part is made from Fe-7Ni low alloy steel sintered at 1200°C to >7.8 g/cm3 density, and it has to survive 2000-5000 nut tightening operations. The staying power of MIM was demonstrated through Parmaco’s long standing relationship with power tool producer Festool, which gave the company its second MIM part for a jig saw power tool model back in 1993. Breitenmoser stated that in 1999 Parmaco became involved in the development of the new PS300 jig saw model which was introduced to the market in 2001 and which was to include two MIM parts in the jig saw blade holder assembly. The two MIM parts used in the PS300 jig saw holder assembly are the receptor shown in different stages of production in Fig. 11 and the slide whose functional requirements are shown in Fig. 12. The MIM receptor weighs 10.28g and is made from 7%NiFe whereas the MIM slide weighs 6.37g and is also produced from the 7%NiFe alloy powder. This part is coined to achieve the required dimensional tolerances. Key to the success of MIM in this application was the good sliding characteristic of the slide part and the fit of the MIM slide in the receptor. Both parts are case hardened. The final examples of successful applications developed by Parmaco are shown in Figs. 13 to 15. Fig. 15 is

a MIM housing cover made from 316L stainless steel for a sensor casing. It is very thin walled and therefore distortion was a critical issue. The large diameter is made to hold an O-ring and must fit tightly into a tubular sensor casing also made of stainless steel. The spring latch on the large diameter secures the electrical contact between housing and cover. The moulded thread on the upper side of the housing cover allows for securing an air tight connector to the device. This casing cover is just one of a variety of casings Parmaco is producing. Georg Breitenmoser is confident that Parmaco will continue to achieve above average industry growth in the coming years, and given that the company has almost outgrown its present facilities in Fischingen there are plans to establish a new purpose built larger MIM facility nearby. Whilst the land for the plant has been purchased, the timescale for the move is as yet not fully clear; however it is expected to happen within the next year or two. PIM International wishes the company well in its move and looks forward to a revisit in the not too distant future to report on progress.

Contact Georg Breitenmoser Parmaco Metal Injection Molding AG Fischingerstrasse 75, CH-8376 Fischingen, Switzerland Tel: +41 71 977 21 41 Fax: +41 71 977 21 22 Email: [email protected] www.parmaco.com

March 2010 Powder Injection Moulding International



Hannover Messe (Germany) 2010, 19-23 April Hall 4, Booth C12/15

Parmaco Metal Injection Molding AG Fischingerstrasse 75, CH-8376 Fischingen Switzerland Tel: +41 71 978 78 78 www.parmaco.com