Metallized injection moulded components: an automated approach
04 April 2013
Injection moulding of reflectors is a highly complex process where any imperfections reduce the performance of the end product. In a bid to improve profitability without outsourcing overseas, injection moulding specialist IV Group has invested in a new type of metallization plant that works in tandem with the injection moulding machine in an unmanned cell, coating reflectors as they come off t
Injection moulding is a highly competitive industry and many manufacturers have moved their production to China in an effort to cut costs. However, such a move comes at a price. In addition to higher shipping costs, decision making takes longer and valuable customer feedback can be difficult to implement in practice.
Injection moulding company IV Group has managed to keep production at home by using a high degree of automation. The company specialises in production of technical and advanced plastic parts; reflectors for light fittings is a major product group. “Keeping production at home gives better control over the operation, reduces quality costs and simplifies the co-operation with customers,” says team leader Sten Anders Lian.
The company is located in Norway, a country renowned for its high cost levels. IV Group is based in Leksvik in the central part of the country, about one hour drive from Trondheim and about eight hours’ drive from the main commercial centre of Oslo and even further from the markets in central Europe. Yet it has managed to maintain profitability through investment in efficient production technology.
Equally profitable in the west
The company also has a factory in China, with higher staffing levels, but this caters mainly to Asian markets and there is very little transfer of product between the different markets. Still, the operation in Norway is just as profitable as the one in China. Mr Lian takes up the story:
“Materials and machinery cost about the same in China and in Europe. The savings available are on manpower, but with a higher degree of automation we can make up for this in Norway, ensuring that our production here is just as viable as in China.
“By staying in the area where we’ve always been, we ensure we have loyal and knowledgeable staff at all times. This translates into low downtime and a profitable operation. We also remain close to our main customer and can respond quicker to its requirements. With the flexible and highly automated production system we recently implemented, we are now able to provide a better customer service.”
Lian is referring to the new production cell for reflectors that IV Group has just commissioned. Here, the reflectors are metallized immediately after injection moulding. A six axis Motoman robot removes the reflector from the die and places it directly into the metallization chamber.
Dry process metallization
The metallization system is a PlastiCoater 400 from Swedish company Impact Coatings; the machine delivered to IV Group is the largest from this range ever made by the company.
The metallization takes place by physical vapour deposition (PVD), an entirely 'dry' process, unlike traditional 'wet' processes. The production flow from the injection moulding machine and through the PVD coating process is continuous, with all machines involved working at the same output rate.
Before the installation of the Plasticoater 400, IV Group used to send reflectors to a subcontractor for metallization, many hours away by road. This meant that it could take a long time to discover any imperfections, as a whole batch had to be metallized and returned before it could be inspected. Now, the production cycle is much shorter and no more than four items are metallized at any one time, which means this is the maximum volume that has to be discarded if an imperfection is discovered. This enables Lian and his staff to respond rapidly, keeping quality costs low.
Coated in vacuum
PVD works by bombarding the object with metal atoms inside a vacuum chamber. The PlastiCoater 400 has several chambers where different processes can take place, including the application of a final transparent layer to protect the metallized surface before it is exposed to the atmosphere.
In the vacuum chamber, a process known as magnetron sputtering takes place. Using a powerful magnetic field, atoms are eroded from a ‘target’ - the material where the metal comes from, and released onto a 'substrate' - the object to be coated. A plasma cloud is formed inside the chamber and directed towards the object, forming the coating. Impact Coatings’ CEO, Torsten Rosell takes up the story:
“PVD as a process has been around for some time, so it is a tried and tested method. However, traditional PVD metallization is carried out in batches, using machinery that is separate from the production line. Our system enables manufacturers to integrate PVD metallization into the production line and use the method on an industrial scale.
At the moment, the reflectors manufactured by IV Group are coated with aluminium, but it would be possible to use a material with higher reflection. This could enable production of smaller reflectors that give more light from a given surface area.
Coating round the clock
According to Mr Lian, IV Group used to operate two shifts per day, but with the new equipment, the company has moved to production around the clock.
The largest customer is Glamox, based nearby. Glamox is a Norwegian industrial group that develops, produces and distributes professional lighting products for the global market. IV Group supplies the company with reflectors in series from a few hundred to several thousand, typically in polycarbonate. Mr Lian concludes:
“We aim to be total supplier of the whole production chain, from tool making to injection moulding and metallization. With the new PVD equipment, that sequence is complete and we can send the finished reflectors directly to Glamox. The objective is to have a production plant that is as flexible as possible, producing the right quality within the agreed time frame. The new equipment helps us reach that goal.”