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Graphic element Research > Growth > Research projects > Materials & technologies projects > Making tools laser sharp
Graphic element Making tools laser sharp

Historically, the manufacturing sector has used metal for cutting tools and components that has been hardened by heating it to high temperatures. This is not only expensive, but also treats a much larger part of the surface than necessary. CRAFT-funded research has resulted in a laser method of hardening, which can be focused accurately on the part of the tool or component that needs it. Large-scale testing of fully operational tools and products in industrial settings has perfected the technique, which is now being offered as a service world-wide by the participating firms and two newly created companies.

Hardening tools by heating

Cutting tools which are used to carve out intricate metal parts for manufacturing industry suffer rough punishment. The materials they cut are themselves durable and tough, and tools of this sort must withstand repeated abrasion without wearing out. It is common practice to harden cutting tools by heating the metal that is used to make them to temperatures of up to 1000°C. This changes a normally ductile metal, making it much harder but more brittle. The process is called transformation hardening and has been used reasonably successfully for several years.

However, hardening the whole tool is expensive - heating a complete sheet of metal uses a significant amount of energy. It also makes the metal difficult to work with, as a tool made entirely of hardened metal can become stressed, and can break.

As alternatives, fine flames and plasma arcs have been used to try to heat only the cutting part of the tool, but it has proved difficult to direct the heat onto cutting edge with enough precision to obtain a consistent level of hardening. If a more accurate technique could be developed, the result would not just be better tools: there is a whole range of high-performance metal components which need hard, wear-resistant surfaces.

The laser approach

By the mid-1990s, the USA and Japan were developing hardening techniques using lasers, but European expertise lagged behind. Metallurgy research organisations found they were being approached simultaneously by many SMEs, desperate to use parts hardened using the latest laser techniques.

Individual SMEs, however, did not have the research facilities or financial resources to develop the process themselves. The University of Twente and TNO Industry, both in the Netherlands, and the Laserzentrum of the Fachhochschule Münster in Germany, which already had good working relationships with companies specialising in laser technology, realised that a European project could be the way forward.

The three laboratories worked with Demar Laser and LaserProdukt to develop a CRAFT project proposal, which included seven SME and three large company component producers, from Belgium, Germany and the Netherlands.

Dr WG Essers, a Dutch scientific research consultant, co-ordinated the consortium's efforts. "The first step was to guide the partners towards the right sort of research and to plan the proposal for CRAFT funding," he explains. "Each company had its own priorities and the decision making process was quite lengthy. We had to choose the research route that seemed most likely to lead to a commercially exploitable process."

  From test pieces to finished parts

The proposal was selected and the CRAFT project began. Initially, individual component producers made small test pieces and delivered them to Demar Laser, LaserProdukt and the research organisations for various laser treatments. They used two main techniques.

1. Laser heat only was used to achieve consistent transformation along the cutting edge of the tool.
2. The surface of a component was coated, or clad, with a layer of hardening material.

Cladding had previously been carried out by plasma spraying with a hot gas flame - an imprecise technique, which coats more of the surface than necessary. By contrast, the new technique uses a powder coating, which is laser heated. The powder melts on the surface of the metal, but only where the laser beam is focused. The molten coating formulation clads the surface evenly and precisely.
Some techniques worked better than others, but there were some outstanding successes. These were rapidly scaled up for further testing. Real components were made, treated and then tested in simulated and then genuine industrial conditions.

"Not all the techniques worked, but we produced some very good results. Some of the partners were able to develop tools that were far superior to any that they had produced before," comments Dr Essers. The laser technique is also able to harden other parts, such as tools for producing complex gear rims used within moving machinery. The precision of the lasers can easily cope with intricate shapes.

  Providing a hardening service worldwide

Demar Laser felt that the results were so good that they, together with another SME, have recently formed two separate companies. These are dedicated to applying the technology tested in this project and providing a hardening service to industry world-wide. NedClad Technology BV and NedClad Production BV opened in early 2000. The two companies are up and running, and although it is too early to predict sales figures, the owners are confident of commercial success. The other partners are either already exploiting the results, or plan to do so.

Laser technology moves very fast, and the team are ready to test their methods using a new generation of diode lasers. "These will be much more powerful than the lasers we have been using. In the next couple of years we could develop state-of-the art laser technology that will produce even better quality tools and machine parts," predicts Dr Essers.


Hardening tools by heating
The laser approach
From test pieces to finished parts
Providing a hardening service worldwide

Key data

Development of improved materials is part of the New materials and production technologies generic action. A CRAFT project has developed the use of laser hardening both for industrial cutting tools that must withstand rough treatment and for metal machine parts that need a specially treated surface which resists wear.

Project: Laser surface treatment for extended lifetime of parts for combustion engines, tools for sheetmetal working and small machine parts (BRST-CT96-5029)

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