Fraunhofer IWS researchers have developed a device that measures the flow of metal powder during laser cladding.
The powder flow meter will make it possible to measure exactly which metals flow in what quantity into the focus of the laser beam.
This will help reduce the costs of powder-based laser cladding, improve the quality of the components produced and make the entire production process precisely repeatable – a particularly important requirement in high-tech industry.
Known as POWDERscreen, the device combines modern sensor technology with special software, a screen, and interfaces for data transfer. Photo sensors count the particles in the powder stream, and the software uses them to calculate the feed rates. The screen displays the processed data to the machine operator.
POWDERscreen can be mounted on any process head for powder laser cladding. It shows its strengths particularly well when combined with Fraunhofer IWS’ COAXquattro nozzle, which can feed up to eight different powders or wires in separate channels into the laser focus to produce in-situ alloys. COAXquattro supports up to 30 grams per second per channel, meaning significant powder rates can be achieved. The combination of technologies is particularly suitable for high-performance processes in which large and complex components have to be produced, coated or repaired with high quality, reproducibility and speed.
‘So far, powder-based laser cladding still falls short of its potential,’ said Rico Hemschik, the engineer who developed POWDERscreen. ‘With the powder flow meter, we are taking a big step towards a more efficient, controlled and automated additive manufacturing process.’
Via its interfaces, POWDERscreen can be integrated together with other process monitoring systems into modern industrial environments or solutions for the Industrial Internet of Things. In the future, such combined process monitoring systems could independently generate digital twins of additively produced components. The information about where the laser melted, alloyed and shaped which powder and in what quantity can in principle also be automatically merged into a virtual computer model.
The Fraunhofer IWS researchers see great application potential for POWDERscreen in the aerospace industry, where it could be used to reproduce and repair intricately shaped turbine blades with additive processes in consistently high quality. The same applies to stamping tools in automotive manufacturing or prototype production across almost all sectors of industry.
Systems such as POWSERscreen could mean that machine operators no longer have to set up powder-based laser cladding systems ‘freehand’ and with numerous trials, but instead on the basis of precisely recorded and repeatable process parameters. This would shorten the run-in curve and reduce the reject rate at the start of a small series.