With more than ten years of experience producing Ceramic Injection Moulded parts in the Czech Republic, Vibrom s.r.o., a small family run company, has over the past two years also introduced Metal Injection Moulding production to the country. PIM International profiles the challenges the company has faced in introducing both Ceramic Injection Moulding and Metal Injection Moulding and its ambition to become a significant player in the European PIM industry.
Vibrom s.r.o. is a small, family-run company based in Trebechovice pod Orebem, a small town of around six thousand inhabitants near the city of Hradec Kralove in the Czech Republic. The company was originally established in 1993 under the name ‘Ing. Ivan Jebavý – Vibrom’ to design and produce vibration mills. Two years later, in 1995, the company started the production of ceramic yarn guides for the textile industry using the hot casting process. This involved preparing a ceramic slip comprising a fine powder and binder and hot casting the liquid slip into a complex mould under pressure.
Alžběta Jebavá, one of the daughters of the founder with responsibilty for process engineering and marketing, told PIM International, “We used a homemade moulding machine for the process and the technology worked perfectly. However, it was the success of this process that led us to venture into Ceramic Injection Moulding. My father had seen some articles on Ceramic Injection Moulding in magazines and we investigated how we could produce CIM parts, initially using our own homemade equipment to produce prototypes. However, whilst the process worked well we quickly realised that we needed more modern equipment for high quality components and we invested in the necessary injection moulding machines and furnaces.”
Alongside the investment in modern production equipment, the company also decided to move to larger and more suitable premises. In 2003 the move was made to a renovated old boiler house in Trebechovice pod Orebem (Fig. 1)and the company name was changed to Vibrom s.r.o. The new premises housed the Arburg 270 injection moulding machine purchased in the same year for CIM production. Two more Arburg machines have since been purchased for CIM production and a fourth is used for the plastic overmoulding of sintered CIM parts. Modern debinding and sintering furnaces were also added.
Alžběta told PIM International that the biggest challenge in the early days of CIM production was to find the correct ratio of ceramic powder and binder. “We are still producing our own Ceramic Injection Moulding feedstock for white ZrO2 and Al2O3 because we have developed the know-how for these powders and this option is cheaper than bought-in feedstock. However, we do buy in ready-to-use feedstock for black ZrO2, mainly from BASF.” Other significant challenges included injection moulding tools. Alžběta commented, “Every new tool is unique and requires tuning. This needs experience, time and determination. PIM tools are generally made by companies that are more experienced with moulds for plastics. It is really difficult to find good precision tool manufacturers so we rely on suppliers from outside our region. It takes a lot of driving to finish the mould but it’s worth it!”
The introduction of MIM
In 2012 Vibrom started to investigate the production of components by Metal Injection Moulding. As with ceramics, Ivan Jebavý had seen reports in the literature about MIM technology and decided to purchase a trial lot of MIM Catamold feedstock from BASF to produce some prototype parts. “At first we used our existing moulding equipment and furnaces and, following a few production trials, we decided to venture into MIM production and to obtain the best feedstock material and equipment available on the market. For us this was a combination of BASF’s Catamold feedstock, fully automatic Arburg 370 moulding machines (Fig. 2) and an Elnik Systems debind and sintering furnace. We presently use a range of metal feedstocks including low alloy steels, stainless steels and tungsten. We also have ambitions to produce titanium MIM parts, which are currently being tested,” stated Alžběta.
Both thermal and catalytic debinding methods are used depending on the feedstock being processed. “We did not consider preparing our own feedstock because there is such a wide variety of materials already available in the form of ready-to-mould feedstock and we wanted to focus on developing applications,” explained Alžběta.
A new Metal Injection Moulding production hall was opened in the summer of 2014 (Fig. 4) and, to supplement the newly installed production equipment, Vibrom also installed a tumbling machine to surface finish MIM parts as necessary. The company has initiated a system of 100% quality control for both its MIM and CIM parts, including a 3D measurement and defectoscopy station for non-destructive testing. Each finished injection moulded part is checked for defects. Some products have their functional surfaces polished and a number of sub-assembly operations are undertaken, such as pressing parts into plastic holders or glue bonding with other components, depending on the customers’ requirements. The company is accredited with ISO 9001:2001.
Low volumes, high quality
Alžběta Jebavá explained that Vibrom’s key focus is quality rather than quantity. The company is focusing on complex shaped MIM and CIM parts with high dimensional tolerances but with lower than typical production volumes, typically starting at around 5,000 pieces. “As a small company with just twenty employees we can be flexible and react quickly to customers’ demands. We are open to all technical components, but we pay particular attention to parts requiring high quality in smaller batches.”
Vibrom has a number of customers in the Czech Republic who take around 50% of current production. The balance of production is exported to customers in Denmark, Germany, Slovakia and as far afield as China. Sectors served include the textile industry, firearms, medical instruments and the electro-mechanical goods industry.
The potential for new MIM and CIM applications
The management team at Vibrom believes that there is still enormous potential for new CIM and MIM applications, not only in the industry sectors it currently serves but also in many other sectors. However, it was stated that awareness of Powder Injection Moulding is extremely poor at many Czech companies and academic establishments and that much more should be done to educate future material and design engineers. “It helps to be able to show design engineers and students real parts in real applications in order to allay their fears about porosity and the performance of MIM parts. We are trying to reach out to new customers by giving them presentations about how MIM and CIM technology works, and we try to convince part designers that metal parts can be designed using plastic moulding concepts and not just machining. It is important to emphasise the point that although the input cost of materials for PIM is higher than conventional metal forming processes and that tool costs can also be high, the price of complex MIM parts with high dimensional tolerances is usually three times lower than an equivalent machined part,” stated Alžběta.
“We have ambitions to grow as a company and we plan to promote our technology and expertise at more exhibitions. We are particularly keen to develop new parts for customers using MIM titanium powders, but there is a big variety of MIM materials on the market that we can also offer.”