Maschinenfabrik Niehoff has been designing and building rotating machines for processing non-ferrous wires into automotive, power, data and special cables since the 1960s. Typical machines resulting from this development are the double twist bunching and stranding machines of the D series that includes eight differently sized models, among them the D 632 version (above on the right the interior, and below the full-length picture).
In the picture above: the D 632 double twist bunching machine
Three particular features
The D 632 double twist bunching machine is characterized by three special features which make its application very rewarding for the user:
1. Single-bow design with the Eco-Bow energy-saving bow.
2. Automatic traverse system NBAT.
3. Adjustable and controlled wire tension, regardless of the spool filling.
Perfect bunching and spooling
The D 632 is able to produce strands with 0.09 to 6.00 mm² cross section and a steplessly variable lay length of 6 to 100 mm. The maximum number of twists is 7000 twists/min and the maximum production speed 300 m/min. Due to the adjustable and controlled winding tension and the automatic traversing, each spool is perfectly filled. Thus, the strands can be payed-off smoothly in downstream processes even at high speeds causing less scrap and preventing complaints.
Ideal for copper alloy fine wires
The D 632 is ideally suited for processing copper alloy fine wires such as CuSn0.3 or CuMg0.2 into strands for automotive wires. Using the “Stretch Forming and Straightening technology”, the machine avoids the crowning and spiraling effect typical for copper alloys.
Machine condition monitoring such as monitoring of the temperatures of the main bearings and cradle vibration are also Niehoff standard.
For process monitoring, parameters such as winding tension, lay length and number of twists can be documented, so that the user of a D 632 can prove in writing top quality to his customer.
- Material costs
- Energy costs
- Labour costs
The main advantage of the machine is that it helps to reduce operational costs. Additional costs can be saved if the machine produces strands with very tight tolerances. This means that only the minimally required copper cross-section is used – not more!
Also the reduced power consumption of a D 632 type double twist buncher equipped with an Eco-Bow results in energy cost savings. For the production of e.g. a 7 x 0.254 mm strand with 6000 twists/min, energy costs of 10,000 €/year can be saved.
The automatic mode of operation allows to reduce labour costs as one operator is sufficient to look after up to 20 machines. Considering the high production reliability of the machine, the purchase of a D 632 pays itself back relatively quickly.
Please contact Niehoff for calculating your real ROI – you will be surprised.
New D type double twist stranding machines
Niehoff is also developing further double twist stranding machines for the manufacture of conductors for energy cables with up to 500 mm² cross sections. The D 1252 double twist stranding machine, a further development of the D 1251, is one of these new models. It is foreseen for stranding and compacting (round and sector) class 2 conductors for energy cables up to 19 wires with a cross-section of up to 120 mm². The machine is also capable of stranding Cu & Al alloy wires, bunching flexible conductors up to 120 mm² and laying up LV insulated conductors. The machine can reach a maximum rotating speed of 2000 twists/min and a line speed of 300 m/min.
In the picture above, the D 1252 double twist stranding machine.
Below, the interior of the D 1252.
The D 1252 enables the most efficient manufacturing method of compacted 19 x 2.17 mm = 70 mm² class 2 conductors – fast as well as energy and material saving.
Machine, production and process data can be collected in the machine and used according to Industry 4.0.
The next largest model D 1602 will be intended for conductors with a 19 wire design, and the D 2002 for a spool size of 2000 mm and
cable designs beyond. For even bigger cable constructions, the Niehoff rigid stranders (NRS) are going to be developed.