Proven heat and surface treatment systems from one source

Maschinenfabrik NIEHOFF has more than six decades of experience in engineering and production of wire drawing and processing machinery. Exemplary results of the long lasting development processes are the inductive annealers of the RI series and the WPT galvanic wire plating lines developed in cooperation with Steuler Anlagenbau.

Wire annealing: The RI inductive annealers and the new RI 120 N model

Versatile application

Above all, the RI annealers are intended for wires made of brass (CuZn), tin bronze (CuSn), German silver (CuNiZn) as well as low-alloyed copper alloys such as CuMg, CuBe, CuCr and CuSiMn. Also wires made of heating conductor and resistance alloys on the basis of nickel, nickel chrome and copper nickel can be optimally annealed. The same applies to wires made of precious metals and their alloys, wires made of metallic compounds and last but not least bare or plated copper wires.

Good forming properties, high-quality surface

Because of the inductive wire annealing and the rapid wire cooling, a very fine-grained, homogeneous microstructure is generated that gives the wire excellent processing and forming properties. Due to the contactless heating, these wires have also a high surface quality. By means of a special calculation software NIEHOFF specialists are able to simulate the annealing of wires made of different materials and with different dimensions. In this way consumption values, annealing velocities, wire temperatures and other parameters can be determined in advance for each application.

Easy handling

The RI annealers are characterized by a simple and clear design. The wire path is achieved using two deflections only. The position of the short-circuit pulley is adjustable to allow exact alignment of the wire path into the cooling section. The few wear parts of the annealer have a long service life. The individual elements can be taken out easily and quickly for cleaning or for replacement using with minimal tooling. The short circuit pulley is motor-driven in order to reduce the drag forces acting on the heated wire.

Energy efficiency

Because of the contactless energy transfer principle, RI annealers can achieve high energy efficiencies of up to 90%. RI annealers can be combined with rolling lines, drawing lines and combined lines and are suited for round, flat and profile wires with a simple cross-section.

Wire plating: The WPT galvanic plating lines

Certain applications in the wire and cable industry require the use of plated copper wires. The plating process realized in continuously working galvanic plating lines must generate a concentric layer with homogeneous physical properties and a high surface quality along the whole wire length. Therefore, modern plating lines must meet demanding technical but also ecological and economical requirements. The WPT wire plating lines meet all these requirements. The lines work according to the Wire Plating Technology (WPT) which has been developed by Maschinenfabrik NIEHOFF and Steuler Anlagenbau. The WPT lines are built in several sizes for different combinations of base metal and plating metal. The WPT 300.SN.1.3000 model, e.g., is designed for tinning copper wires with a diameter of 1.2 to 2.6 mm, and generates a plating layer adjustable between 1.0 and 20.0 µm thickness. The line, which is foreseen for medium production outputs, can be operated with a line speed of up to 420 m/min.

Efficient and environment-friendly

The wire passes one after another the processes electrolytic degreasing, rinsing with water in a cascade rinsing system, chemical neutralization of the wire surface in the pickling bath, electrolytic plating in the galvanic bath and repeated cleaning. The cascade rinsing system ensures that the wire is cleaned with complete removal of all residue while using the minimum amount of water. At the same time this also contributes to a long service life for the plating bath and low consumption of chemicals. 
The working process includes automatic dosing of chemicals (additives) and supply of water which results in stable operating conditions, consistent surface quality with excellent adhesion of the metallic coating and low manpower requirement. The WPT lines offer several advantages like minimized consumption of energy, water and chemicals, practically up to 100% usage of anode materials and high reliability. If the rinsing water, e.g., is distilled with a vacuum evaporator, more than 90% of the cleansing water can be returned to the process and re-used. All these measures ensure minimized production costs and meet environmental regulations.

Modular design

Due to a modular construction concept, the WPT lines can be individually adapted to the customer-specific situation on site and easily adapted to changing market conditions by replacing modules. All aggregates are easily accessible and easy to maintain. In this way the service and maintenance effort are reduced to a minimum. The modern lines are operated by means of the new NMI (NIEHOFF Machine Interface) color touch-screen display with color user interface and simplified navigation structure.
The WPT wire plating lines can be combined with other NIEHOFF products – such as pay-offs, drawing machines, annealers, spoolers or barrel coilers – into complete, synchronized manufacturing lines.