Background
Just how important is wire in today’s world? Look inside the average home or office electronics product, such as a TV, CD or DVD player, cell phone, PC, or indeed any other item of electronics and at first glance all you seem to see are circuit boards. But look again and you will find ribbon cables and individual wires providing a myriad of interconnections. Modern electronic devices, as well as the communications systems that link them, are full of wire. From the enormous conductors that route local-area-network data around microwave communications systems to the miles and miles of wiring that connect all the critical control and communications systems on aircraft and other transportation systems, to the minute strands that provide interconnections in microelectronic systems or carry the signals in medical implants, wires are indispensable for moving signal and power about.
The traditional method of mechanical wire stripping employs metal blades to cut through the insulation, enabling it to be pulled away over the end of the conductor. However, even though modern mechanical stripping equipment incorporates shaped blades, automatic wire handling and precise blade control, it still shares one thing with the handyman’s wire stripper: both need careful attention to avoid wire damage.
Historically, designers and manufacturers had to accept a degree of damage to the wire conductor from the use of mechanical blades for stripping. To accommodate this, the electrical resistance of the wire is often specified with a higher tolerance than would otherwise be necessary; which essentially means specifying a larger conductor; this makes the whole wire larger and more costly.
In critical manufacturing applications such an approach is unacceptable and, where quality is all-important, damage free laser wire stripping comes into its own. For state-of-the-art applications it is critical to be able to strip insulation precisely from wire without damage to the conductor. Laser-based wire strippers accomplish this simply, by relying on the ability of light to selectively remove non-metallic insulating materials while leaving the metallic conductor completely untouched.
Wire stripping is simply the removal of the insulation, which covers the electrically conducting wires, in order to make the wire ready for termination. Conventional wire stripping techniques have developed including mechanical, abrasive, chemical and thermal methods. But each method has its associated problems such as conductor damage, slow processing speed, and a lack of precision or poor quality.
Manual or semi-automatic mechanical, chemical or thermal wire stripping methods have well known quality assurance problems. The mechanical blade is the most widely used tool to strip wires. It is best suited to cutting through the insulation on a regular shaped circular cross-section wire; i.e. the humble single core wire. Even so, damage to the conductor may result from the use of blades that are worn or that do not fit the shape of the wire correctly or from inadequate control of the stripping process. Furthermore, mechanical methods are not well suited to stripping twisted or shielded cables that do not have a regular, circular cross-section.
Very long process times and environmental issues impair chemical wire stripping techniques. These chemical processes often use hot sulphuric acid or hydrogen peroxide, which are difficult to use and control. In addition the chemicals are quite reactive and require careful handling and disposal must be carried out with due regard to the environment and current legislation.
Thermal methods require very fine process control and frequent calibration in order to maintain quality. Thermal processes also often require a secondary operation to remove any remaining strands of insulation from around the conductor.
Laser wire stripping, in contrast has a fast process time, excellent precision and outstanding process control. Most importantly, laser wire stripping eliminates contact with the wire and by using the correct laser type it is possible to completely eliminate the risk of damage to the conductor or shield.
