Birth of a new machine

Changes in design philosophy and product trends in the industry can often leave manufacturing unprepared to produce new designs. These changes are usually slow and subtle but occasionally they are dramatic and obvious. Recently, this has been the case for industrial laser material processing.

Laser system programming and process development

For aerospace manufacturers to derive the full benefit of laser processing using a particular system and laser, training of the process engineers and programmers is increasingly done using real or representative workpieces. Programs for processing these workpieces and the laser processes themselves are developed cooperatively by the end user and laser system manufacturer to ensure that the relevant machine capabilities are both fully understood and fully utilised. The capabilities of the latest laser systems are increasing rapidly and relying on experience from previous generations of laser systems can lead to significant missed opportunity.

One area of focus in the growth of laser systems and laser processing technology is in the production of effusion cooling holes in advanced turbine designs. Effusion cooling holes are small (typically 0.5-0.75mm diameter) positioned at increasingly acute (as small as 10 degrees) compound angles to the surface of the engine component. New cooling holes continue to challenge laser processing’s state-of-the-art for both the drilling process and expanded laser system capability. Similarly, component designs have called for increasing levels of precision.

Speculation with lasers to achieve more advanced components

Throughout the early use of laser systems in aerospace manufacturing, the number of applications was quite varied. Often, manufacturers invested in laser systems based on speculation about their ability to extend the processing benefits achieved on one or more test components to more difficult to process components.

That drove laser system design flexibility, in other words, the ability of the system to handle a wide range of workpiece sizes, shapes, material thicknesses, and lot sizes. The large work envelope of systems like the LASERDYNE 795XL were developed to fill this need. These laser systems allowed processing three dimensional workpieces while remaining stationary. This permitted multiple setups reducing changeover time between small lot sizes.

Environmental friendliness is a driver in aerospace engine and laser system design

Today’s laser technology is proven and is now the basis for the next generation of aircraft and aircraft engines. An adjunct to this is the aerospace industry’s long history of commitment to environmental friendliness – to ever increasing fuel efficiency and to reducing air pollutants and noise. This commitment continues to be evident in statements from industry spokespersons and trade groups and from new product announcements made by aerospace manufacturers. According to the International Air Transport Association, “modern aircraft are 70% more efficient than 40 years ago and 20% more efficient than 10 years ago. The goal of the next generation of aircraft is to be another 25% more efficient by 2020.”

Smaller aerospace components require smaller laser systems

Laser processing is a key part of the strategy to realising these efficiency increases and emissions reductions. For laser processing to be viable for the volume production of these new engines, it must be capable of cost effectively laser processing the smaller components that will make up the next generation of engines.

Taking into account the growing number of holes, the new designs and the projected volumes of new engines coupled with replacement parts required for regular engine maintenance, the highly flexible, large work envelope laser processing systems that have so long dominated this market are no longer the best solution for every situation.

One key to increasing the fuel efficiency for aircraft engines is to use only enough of the air passing through the engine for cooling as required -- the rest is used for combustion and thrust. This has created ever increasing need for precision in both the airflow through laser drilled cooling holes and in the position of laser cut and drilled features. The result of this is seen throughout the design of the newest laser systems – from the volumetric precision of the motion axes to the control loop that ensures dynamic precision and smooth motion.

In response to these emerging needs, Prima Power Laserdyne has introduced the LASERDYNE 430 BeamDirector. This system incorporates the capability unique to the BeamDirector rotary tilt laser processing head for producing precise effusion cooling holes at shallow and complex angles into a smaller, more floor space efficient system platform.

A modern 3D laser system must include controls that are faster (higher bandwidth), are more intelligent and able to support the faster processing rates and more intricate holes and feature patterns. The robust structure of these systems ensures component rigidity to maintain precision throughout complex contours as the individual machine axes accelerate/decelerate throughout a higher speed range.

Since the part program, (sometime generically referred to as the NC program), that drives the laser system is also a factor influencing the precision that is actually realised, LASERDYNE has developed programming utilities. These utilities produce integrated laser and motion control that is optimised for the specific laser system. They include ShapeSoft for programming shaped holes and CylPerf for automatic programming of patterns of holes on cylindrical workpieces by trepanning, percussion drilling, and drilling on the fly.

The user of the laser system need only provide information about the particular workpiece to be drilled because the details of the laser system required to optimise throughput, quality, and repeatability of the process are embodied in these routines. As indicated previously, a key design objective for the 430 BeamDirector was to make performance independent of operator (and programmer) skill and knowledge of details of the system design. Process control and verification are important requirements for today’s manufacturing environment. SPC (Statistical Process Control) Data Acquisition provides a tool for system control to monitor and record, as a part program is executing, key process, and system information. The part program contains codes that specify data to be collected by the SPC Data Acquisition feature. The system monitors key parameters (i.e. time, date, temperature, position, commanded and/or actual laser power, pulse conditions, etc.) and stores the data as a text file. Data from the text is easily retrieved for further analysis and/or archived to provide a permanent process record.

As previously mentioned, process development must not be overlooked in order to realise the highest performance and quality from the system. With the new aerospace component designs, there are new challenges in motion, feature type and positioning. The laser process and part program development is increasingly being provided by the system manufacturer. This trend goes beyond the desire to prove the worthiness of the system. In part, it is due to the newer types of lasers being used.

While they offer advantages in cost of operation and capability, the user is not familiar with processing with this new laser technology. Consequently, the system manufacturer must be able to guide the customer’s development process utilising the latest generation of hardware and software features, and oversee all facets of the system use to train and achieve maximum productivity. This dual approach -- providing an innovative laser system together with full process development -- ensures that system users derive the full productivity and reliability of their new systems.

In the future, the use of laser processing will continue to grow. The older, large scale laser processing systems that are appropriate for small batch manufacturing of medium to large size components will continue to be bought and used. Newer system designs will take a larger portion of the system installations in the future. It is the natural evolution of equipment design to favour more efficient use of floor space while producing to higher tolerances. This is the real definition and meaning of value.