Economy and ecology combined

More efficiency and sustainability – this is the target KB Kunststofftechnik has set itself for investing in new injection molding technology. Its most recent project – three automated production cells from WITTMANN to produce highly complex technical components – is a prime example.

“Efficiency and reproducibility were the decisive criteria in making our choice”, reports Iris Langenberg, CSR Manager at KB Kunststofftechnik in Gummersbach, Germany, during our visit. We are standing in front of three brand-new production cells from WITTMANN with precisely these attributes to strengthen the contract manufacturer’s competitiveness.

At the heart of each of the three units are servo-hydraulic SmartPower injection molding machines, two with 38 tons and one with 60 tons clamping force. Moreover, two of the machines are equipped with the new WX90 sprue removal system fitted with rotary servo axis. The third cell operates with a Primus 16 pick-and-place robot – here in telescopic design, as the production hall offers only limited space for up-ward movements.

High-precision machine movements for premium-quality parts
KB Kunststofftechnik supplies a wide range of different components to numerous industries. The customer base for its products includes door and window manufac-turers, as well as laboratory and dental technology, mechanical engineering and au-tomotive industries.

Iris Langenberg is holding a particularly complex component in her hands. To be pre-cise, a complete assembly consisting of 68 individual components. With few excep-tions – such as circuit boards and switching elements – these are all thermoplastic parts, which are injection-molded in Gummersbach and subsequently assembled manually, together with the electronic components supplied by the customer. As a central part of winch drives in crane systems, this assembly is an important safety feature. These devices known as geared limit switches control the positioning of the crane hook. Depending on the type and size of the crane, the crane hook must be able to carry loads of up to 120 tons reliably. Therefore, every geared limit switch is examined on a test stand for correct functioning and then provided with a code via which the test documentation and all subsequent servicing activities can be traced.

Accordingly, the demands on injection molding processes for the individual compo-nents of the assembly are particularly stringent. “Drive systems only function if the cogwheels are kept strictly within tolerance limits”, says Langenberg. Multi-stage planetary gears, small axes and mounting elements for circuit boards and switches are molded mostly from two materials – ASA and POM.
Inside the SmartPower machines, the main elements providing high process stability and reproducibility for even extremely delicate part geometries are high-precision injection units and a combination of fast-response servo-hydraulic motors with high-performance constant displacement pumps. Consequently, there is no more produc-tion scrap.

The machines’ “Drive-on-Demand-2.0” technology also minimizes their energy re-quirements. During cooling and handling phases, the motor is shut off and consumes no energy. “Depending on the application, Drive-on-Demand 2.0 reduces energy consumption by up to 35 per cent compared to machines with modern variable dis-placement pump systems”, explains Daniel Müller, Regional Sales Manager at WITTMANN BATTENFELD in Germany.

A further contribution to the high level of energy efficiency is made by the kinetic en-ergy recovery system, abbreviated KERS, patented by WITTMANN. It transforms the deceleration energy of the moving mold platen into electric energy and transfers it to other consumers – for example the barrel heater.
 

Daniel Kaufmann, responsible for initial sampling and maintenance work at KB Kunststofftechnik

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