19 October 2007

Automotive Cutting Applications with Rofin's StarDisc

Laser cutting in itself is not a new process, and for many industries and applications such as sheet metal cutting and profiling, lasers operate reliably and efficiently in the background, being accepted as an everyday part of the production process.

Within the automotive industry, lasers are now becoming the preferred method for cutting and trimming of vehicle interior trim components such as door panels, roof linings and load space trim components etc. As for any cutting or machining process however, there have always been limitations, and whilst lasers are used on interior components and also on body in white applications, lasers have not been used on finished or painted and lacquered surfaces, due to the potential for marking or damage to the surface finish and cut edge from the heat generated during the conventional laser cutting process.

High Material Removal Rates with Low Heat Input

The conventional laser cutting process removes the molten material from the cutting path in one pass. With heat sensitive or non-homogeneous materials, this high heat input can lead to problems of the edge melting and the creation of burrs. These process problems are now eliminated by the StarDisc Laser, thus broadening the application range of the laser considerably.

The operation of the StarDisc is greatly enhanced by the use of a Galvo Deflection Head, which ensures rapid and precise beam positioning in two dimensions. The material is ablated at impressive speed using multiple passes, with very high peak laser power, achieving rapid material removal rates. The StarDisc laser does not normally require assist gas and the multiple pass process provides efficient material removal, which is expelled upwards with minimal melt creation. As a result, the StarDisc laser can be used to process a much wider range of materials, and can be applied to application areas previously considered unsuitable for laser cutting.

New Applications

One application, now made possible by StarDisc, is the customising of Car, Van or Truck bodies by laser after final painting and lacquering.

Many vehicles have a large number of optional accessories, and whilst most of these are easily fitted during the vehicle build process, some such as additional Aerials or Body Styling Kits & Spoilers are fitted at the end of the production process, when the vehicle is fully painted and lacquered.

When the StarDisc laser is applied to cutting applications on painted and lacquered automotive body panels, a cutting speed of approximately 2.0mm/second is achieved on a typical material thickness of 0.68mm. The result is a clean cut on the panel, with no damage to the painted surface, and no dross or debris on the inside of the panel which has been cut. The colour of the panel being cut has little or no impact on the performance of the laser cutting process.

Another major benefit provided by StarDisc, is the fact that the cut component does not fall inside the panel, but remains attached to the parent material, ready for removal using a vacuum or magnetic gripper.

The benefits of a clean cut with no internal debris will enable the StarDisc laser to be used on a wide range of thin sheet metal cutting applications not only within the automotive industry, but also in applications such as the production of electronic enclosures where metal particles within the panel are unacceptable.

Laser Specification

StarDisc is a Q-switched disc laser and provides material removal rates which are unrivalled by any other laser source. This is achieved by high average power, excellent beam quality, (TEM00 Gaussian Mode), and an unusually long Q-switch pulse length.

Technical Background

The performance capability of the StarDisc can be illustrated by making a comparison of this laser with another Rofin Laser PowerLine E-20. Both are Single Mode / TEM00 / Gaussian lasers, with Average and Peak power levels as follows :-

  Average Power Peak Power
StarDisc 60W 2kW ( Approx )
PowerLine E-20 18W 250kW (Approx)

If average power levels are considered, one might expect the StarDisc to outperform the PowerLine Laser, as the StarDisc has the higher average power level. This assumption is then reversed if the peak power levels are considered, with the PowerLine laser having a much greater peak power level than the StarDisc Laser.

However it is the unique combination of the high average power, together with the unusually long pulse duration, which enables the StarDisc Laser to achieve ablation rates which are an order of magnitude greater than other Q-switched lasers of a similar power.

Contact: Dave MacLellan

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