20 ELECTRONICS
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“After just a few days of familiarisation, the system’s production was outstanding. The dancer regulator functions simply and enables precise winding,” reports the Technical General Manager of Alcotec, Volker Wandelt (on left), who directs the company together with Eckard Schmitz (on right). Source: Alcotec Aluminium Coil Technology GmbH
expertise of the manufacturer,” explains Schmitz. Special cutting and coiling system for strips greater than 3mm The core of the system is the shearing mechanism, which is able to position exactly thanks to the exact pre-tensioned rolling bearings and clearance-free line guide. The integrated knives feature a diameter of 130mm and may be combined with rubberised or steel ejector rings. In a single run, an operating speed > 100 m/min may be applied for a maximum of six cuts up to five times, depending on material strength and thickness. A gauge featuring 0.01mm precision indicates the plunging depth of the knives during the process. Because the widths of the cut strips differ and a tidy coil was required, various winding mechanisms were integrated to accept the strips; three for 3 to 30mm and one each for 30 to 100 and 30 to 200mm. The two 4 to 8mm wide edge strips are coiled and sorted out separately. The strips are separated in a controlled manner via a deflecting separator mechanism, which also features rolling bearings. To enable convenient conversion of the system for diverse order requirements, the winding shafts may work with coils as well as sleeves, which may easily be replaced thanks to the quick-change clasp on the spool shaft. Six dancer regulators for fine but constant belt tension control The precision of the knife alone would not have been sufficient to deliver the required cutting quality, especially for the production of the narrow strips. In this November/December 2015
ELECTRICAL Alcotec.indd 2
case, equal belt tension adjusted to the sensitivity of the thin aluminium panel was also decisive, which is why Burghardt + Schmidt integrated sensitive dancer systems on both the in-feed and the outfeed. The swivel-mounted rollers provide exact, smooth running and balance out even the slightest fluctuations in tension. The first regulator on the in-feed side of the deflection roller between the unwinding spool and the shears enable fluid regulation of the tension between 6 and 500 N. Additional dancers are located prior to the winding spools according to the various strip types. As such, the thin strips are only subject to 0.72 to 72 N, while the tension on the wide strips may be between 20 and 600 N. Integrated encoders ensure secure position recording in both areas.
The desired belt tension may be set conveniently for the electrical motors via the system’s control panel, and additional control of the five dancers at the winding spools takes place automatically. “In this case, a single reference positioning run must be completed for the system. Afterwards, it’s sufficient to specify the material parameter, e.g. thickness, width at in-feed, specific belt tension and strip width at the coiling spools, at the main control panel, and the dancers adjust themselves independently,” explains Thomas Baral, General Manager at Burghardt + Schmidt. The belt edge controller also corrects the position of the material running off of the unwinding spool in order to create the best-possible initial conditions for cutting. The system includes an opto-electrical sensor unit including measuring light barrier, an electronic control amplifier, and the actual control device, which is used to control the electrical and mechanical linear drive for the positioning. Controls For easy operability, a central control panel uses a Siemens touch display, which displays fault messages, system speeds, and similar information in addition to data entry. Additional auxiliary control panels are provided at the unwinding spool, the splitting machine shears, and at three locations at the coiling spools. This enables important values for quality and operating safety to be adjusted everywhere as required in order to ensure problem-free production in spite of the difficult raw production material. The high-precision splitting machine is currently still operating in single shifts, but expansion to two to three shifts is already planned. Contact www.alcotec.com
The clearance-free roller bearing sheers enable up to six very exact simultaneous cuts for strip widths greater than 3 mm. It is suitable for rubberised or steel ejector rings. Source: Burghardt + Schmidt GmbH
Aluminium International Today
10/21/15 11:53 AM