Patent EP-2273567-A1 (EP)
Inventor: NOWAK ANDREAS
IPC: B21F1/02
Filed: 2009-06-30
Abstract: The method for stretching a solder wire (1) such as a ribbon-shaped solder connector for solar cells, comprises winding and stretching the stored thin solder wire to a reeling device and then feeding to a cutting device for cutting to length of the solder connector, permanently determining the traction force of the solder wire by a measuring device (2) during the stretching process, and continuously adjusting a counter force, which is produced in a braking device (4), to a predetermined target value of the traction force by a computer (3) with the determined measurement values. The method for stretching a solder wire (1) such as a ribbon-shaped solder connector for solar cells, comprises winding and stretching the stored thin solder wire to a reeling device and then feeding to a cutting device for cutting to length of the solder connector, permanently determining the traction force of the solder wire by a measuring device (2) during the stretching process, and continuously adjusting a counter force, which is produced in a braking device (4), to a predetermined target value of the traction force by a computer (3) with the determined measurement values, where the target value of the traction force is exactly adjusted to the yield value of the material type of the solder wire. The method further includes forming a buffer wire (8) in the form of a loop of the winded solder wire, seizing the wire from the buffer wire at one end and pulling the wire ends with a predetermined traction force by a gripping device processable by a feeding unit in a wire running direction up to an end position against the counter force applied to the wire by the breaking device, continuously measuring the traction force with a force measuring device during the pulling step, forwarding the measurement values to the computer for evaluating the traction force and permanently regulating the breaking device to the selectable target value of the counter force during pulling by the gripping device, clamping the wire with a clamping device as soon as the gripping device reaches its end position, and separating the solder connector by the cutting wire with the cutting device, where simultaneously the buffer wire is filled and the process steps are repeated. The length of the solder connector is freely regulatable by the selection of the end position of the gripping device. The target value of the counter force of the breaking device is freely adjustable over the computer. The solder wire is clamped at a position and is stretched so long by pulling the solder wire against the clamped position under permanent measurement of the stretching force until the target value is reached corresponding to the yield value of the solder wire, where the measurement values is fed to the computer, which compares the measurement values with the yield value of the solder wire and controls the cutting device for separating the solder connector during reaching the target value. The method further includes forming the buffer wire in the form of the loop of the winded solder wire, seizing the wire ends from the buffer wire by the gripping device and moving the wire ends up to a predetermined length of the solder connector, clamping the wires with the clamping device as soon as the gripping device reaches the preselected length, pulling the clamped solder wires in direction to the end position predetermined by the feeding unit with the gripping device up to the target value of the predetermined stretching force by a continuous measurement of the traction force during pulling with the force measuring device is detected, forwarding the measurement values to the computer for evaluating the stretching force and controlling the cutting device, and separating the solder connector by the cutting wire with the cutting device, where simultaneously the buffer wire is filled and the process steps are repeated. An independent claim is included for a device for stretching a solder wire such as a ribbon-shaped solder connector for solar cells.