For the first time in the field of screw head forming, inductive heating is being used, which Aachener Maschinenbau (Amba) has integrated into its machines. The first machine in the new series will produce fastening elements between 160mm and 1,500mm/6.30 - 59.06 inches in length with diameters of up to 18mm/0.71 inches directly from the wire.

Since very high forces are required when forming large-volume heads, Amba is transitioning from cold to hot forming for the first time and integrating a system for inductive heating.

This machine produces square-head bolts used in power transmission applications and manufactured in quantities of millions. With this development, one customer has succeeded in replacing two older machines arranged in series.

A complete enclosure of the machine significantly reduces noise emissions and allows emulsion vapours to be extracted. At the same time, it forms the core of the safety concept, enabling the system to be operated in full compliance with CE requirements.

New approach: integrated hot forming

The new series of bolt machines is designed to cold-form wire with diameters of up to 12mm/0.47 inches as before and to hot-form material up to 18mm/0.71 inches thick. When moving from 10mm to 12mm/ 0.39 to 0.47 inches, forming forces increase by approximately 40 % compared to the predecessor model “BM 10”.

To manage these forces, hot forming has been fully integrated. This required a fundamental redesign of each individual station – from the wire feeding system through straightening and cutting the blanks, pressing the heads and rolling the threads.

In addition, the forming tools must be cooled and other components protected from intense heat radiation. The bearing shells of the transport spindles are also cooled to minimise expansion effects.

System function in detail – from wire to bolt

The rolled wire is fed from the coil via a drawing unit to the target diameter, pre-straightened in a rotating wire straightening system, cut to length and placed in the transport system.

Before the first pressing stage, the ends of the blanks are heated over a length of 450mm/17.72 inches within approximately 13s from room temperature to over 1,000°C/1,832°F. The temperature is monitored inline using a pyrometer to ensure the required minimum temperature.

The screw head is formed in two stages: first a preform volume is created, then the finished square head is produced. The upsetting heads operate with forces of up to 100t.

The newly developed thread rolling station is designed for tools longer than 400mm/15.75 inches in accordance with industry standards. The Amba tool concept enables synchronous thread rolling as well as forming a large chamfer at the bolt tip.

Compact drive with high power

The new compact press drive is specifically designed for the system. In addition to the required drive power at maximum production speed, a high energy capacity with good controllability during setup operation is a key parameter.

Despite a reduction in external dimensions of more than 50 percent, the drive is significantly more powerful due to high flywheel speeds and provides power reserves. In addition, the “BM 12” is equipped with an integrated mechanical overload clutch to protect the drive unit.

The system also features optional process monitoring and remote maintenance capabilities. If signs of tool wear are detected, the machine is automatically stopped to prevent damage and scrap.

wire 2026, hall 16 booth H 55

Aachener Maschinenbau GmbH

Werner-von-Siemens-Strasse 17-19

52477 Alsdorf/ Germany

Contact person is Frank Kronmüller

Tel.: +49 2404 551 289 - 11

frank.kronmueller@amba.de

www.amba.de