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Particle-free production for low fault rates

News International-French

17 Apr 2019

Injection moulding expert addresses growing requirements for the circuit-board industry.

Particle-free production for low fault rates

Particle-free production for low fault rates

Dirt particles increase the risk of faults in electronic components. In its guideline “Technical Cleanliness in Electronics” the German Central Association of the Electrical Engineering and Electronics Industry (ZVEI) names nine possible faults, including short circuits and electrical isolation, that can lead to non-functioning conditions. The causes are easily overlooked, everyday contaminants that can get onto electrical contacts - hairs, flakes of skin, pollen. To prevent this, manufacturers are steadily tightening their cleanliness requirements, both for themselves and for suppliers like injection moulding specialist Hans Geiger Spritzgießtechnik GmbH. The company’s products are used in circuit boards that must meet the highest quality standards. The company has responded to these requirements by developing an enclosed production line which meets all the criteria of a cleanroom efficiently and in a small space. This enables it to do clean manufacturing to individual specifications, without added costs or time for additional parts cleaning. These savings are passed on to customers.

Particle-free production for low fault rates: Injection moulding expert addresses growing requirements for the circuit-board industry

Eva Söhnlein, senior manager of Hans Geiger Spritzgießtechnik explains:

“Particle-free production is already common in many industries. It is not a new criterion in the electronics industry, but the demands placed on components for installation in circuit boards have risen considerably in recent years. Since more and more plug connections are used on circuit boards, our products need to be particle-free as well. High-quality final products are possible only with the use of essentially particle-free components.”

The main cause of contamination in the injection moulding process is ambient air. Depending on the surroundings, air can contain a variety of particles and fibres, such as dust, hair, pollen or flakes of skin. Another possible source of contamination is the mould itself, for example in the form of metallic particles caused by friction. If these particles get on the components they can cause serious faults, such as changed friction and shorter clearances and creepage distances. To prevent this and produce injection-moulded parts in cleanroom quality, in October 2017 Hans Geiger Spritzgießtechnik GmbH added a clean production line.


Clean production without added time expenditure
The company had the idea in 2016 as Söhnlein remarks:

“Initially our sales team and Process Engineering department analysed the growth in application areas for technically clean components in the foregoing years. They identified many future applications for this kind of product. So the next logical step was to invest in the production technology”

There are several ways to make technically clean products. Often, part of a building will be converted into a cleanroom. Industrial parts cleaning following production is another method that is often preferred. But instead, Geiger decided to enclose a production line in Plexiglas.

Söhnlein explains: 

“We rejected the usual methods as it would have been extremely expensive to fit out an entire building, and washing would mean an additional process step that ultimately would have cost our customers time”

Two laminar flow boxes on the sealed enclosure create a constant overpressure, and a steady air current prevents particles from settling in the clean area.

Söhnlein notes:

“Since the line is closed and has its own filter units, there are no further special needs that need to be met during production”

The line merely needs to be comprehensively cleaned before the start of production and after a tool change. To prevent particles being generated during production by the line itself, for example by friction, all sliding and moving elements of the moulds are specially coated and operate lubricant-free.

Particle-free production for low fault rates

Ability to meet individual customer requirements
The line is a complete, compact production system with injection moulding machine, removal robot and packaging station. This makes it possible to make parts, remove them by robot and place them on the cooling line without danger of contamination. The finished products are then automatically counted and packed, ensuring that they reach the customer in clean condition.

Söhnlein says:

“The manufacturing process on this line is controlled, reproducible and audit-safe. With each order, we carefully examine the customer’s individual criteria and evaluate our ability to meet them”.

All told, it enables a cleanliness level corresponding to cleanroom class 7. But Geiger decided against standard categorisation, since many of the company’s large customers have their own standards of technical cleanliness. If a purchase agreement is reached, during production each batch is examined by an external test laboratory for compliance with the required specifications prior to delivery to the customer.

Since commissioning last year the production line has amply demonstrated its value.