Optical measurement in cable and wire production processes

Velocity measurement on roll-fed material and piece goods

Velocity measurement is indispensable for process control and optimization in many industrial processes. It is the basis for many other applications such as cutting length control, length measurement and velocity difference measurement. In these processes velocity is measured using the laser Doppler technique.

Laser surface velocimeters (LSVs) from Polytec are ideally suited because they can conduct measurements on almost any surface and they are not susceptible to contaminated surfaces. The non-contact measuring technique makes it possible to eliminate any negative influences on accuracy, such as slippage and wear, in one go. The product being subjected to the measurement also remains intact.

Another benefit of Polytec systems is the flexible interface concept – it enables velocity readings via encoder output, serial interfaces, LAN, Profibus and Profinet.

Practical examples:

Polytec LSVs are used for a variety of velocity measurement processes in the cable and wire industry:

• dwell time determination in coating systems, e.g. for fiber optic cables
• cutting device control in cut-to-length processes
• coil synchronization when winding cables and wires

Cut length control on roll-fed material

Determining the length and velocity provides the basis for controlling the cut length. If the sheet materials are not to be stopped in order to perform the cut, then the cutting device must move along with the sheet material for a straight cut, in other words it should be a "flying cutting device". The speed of the sheet material is measured for velocity synchronization.

Laser surface velocimeters (LSV) from Polytec are ideally suited for cut length control because they measure both velocity and length at the same time and can display the values on different interfaces. The LSV works on almost any surface and is not susceptible to contaminated surfaces. The non-contact measuring technique makes it possible to eliminate any negative influences on accuracy, such as slippage and wear, in one go. The product being subjected to the measurement remains intact too.

The Polytec LSV offers increased cutting precision compared to other methods and therefore allows reduced safety margins to be added to the preset cut length. This will save costs on every cut.

Another benefit of Polytec systems is the flexible interface concept – it enables length and velocity readings via encoder output, serial interfaces, LAN, Profibus and Profinet. The digital outputs feature a pre-warning signal that indicates when the cutting length is about to be reached, as well as the cut signal for triggering the cutting process.

Practical examples:

Polytec LSVs are used in the cable and wire industry to control cutting lengths in cut-to-length processes on cable, wire, sheathing and insulation materials.