A clear path for AFP

With many smart and creative people involved in the automated fibre placement (AFP) industry it’s no surprise it’s changing so quickly. However, addressing the need to economically produce small and complex parts using fibre placement is critical to it future success. The complex process currently used has to be simplified and stabilised to become practical for lower tier suppliers. Until then, AFP will remain a specialised manufacturing method only available on high-end products from larger companies. CGTech provides machine independent AFP programming and simulation software to help demystify the process, making it more approachable for smaller companies. Recent advances in AFP machines are generating much excitement, with highly productive automated composite lay-up machinery fast becoming a reality. In the same way as cutting speed in ‘centimetres per minute’ is boasted by manufacturers of high-speed CNC machines, manufactures of AFP machines promote composite material application rates of ‘kilograms per hour’, while often ignoring other significant process complexities that must be addressed in order to lay-up parts quickly. However, the parallels don’t end there; just as CAD and CAM software must continually evolve with new machining techniques, the software for programming AFP machines must also evolve to handle advances in technology. Software that narrowly supports one supplier or specific model of AFP machine will quickly become obsolete. Today’s automated composite lay-up technology is difficult to adopt for all but the largest manufacturers, because of the high initial investment and infrastructure costs. CGTech aims to help clarify the process of programming automated composite machinery by introducing the key components of machine independent off-line programming software through its Vericut software product. Software developed for one specific brand of machine is only exposed to the small set of users of that machine, and is limited to the requirements of that specific machine. Alternatively, software exposed to a broad range of user demands with varied processes and machine requirements, with good channels of two-way communication with those users and the ability to synthesize comments, requirements, and requests, allows software developers to include new product features applicable to the whole industry. Additionally, off-line AFP programming software dedicated to a single machine brand is simply not economical or realistic. The costs and risk associated with implementing multiple off-line NC programming products tend to lock businesses into a single machine supplier, rather than allowing the selection of the best and most current machine for a specific job. Universal CAD/CAM software that can be used on any CNC metalcutting machine is what allows a manufacturer the freedom to choose the best production machining solution available, without the time and cost constraints of having to retrain manufacturing engineers with new software each time. And, the inevitable appearance of new AFP machine suppliers will make the old approach even more unattractive. The three elements Machine independent off-line programming and simulation software for AFP and tape laying machines from CGTech consists of three components that can be used individually or together: Vericut Composite Paths for Engineering (VCPe), Vericut Composite Programming (VCP) and Vericut Composite Simulation (VCS). VCPe provides the user access to the same software tools NC programmers use to create AFP NC program paths that are subsequently used in the workshop to lay-up a composite part. Using these tools the part designer or engineer can easily create and experiment with various AFP path options and evaluate the effects AFP manufacturing has on a composite component’s design intent. By producing actual AFP tape courses the user can measure and evaluate the effects of AFP path trajectory, material steering, surface curvature, course convergence and other process constraints as they would be applied in manufacturing. VCPe provides product manufacturability analysis for the fibre angle based on the curvature of the part, as well overlap and gaps needed for structural analysis. It contains a subset of standard VCP features, and presents a subset of choices in the user interface. Those features associated with post-processing and writing AFP NC programs are not available. However, VCPe files containing AFP tape courses are compatible with standard VCP and can be used as a starting point for AFP off-line NC programming. VCP adds the ability to post-process linked paths for specific machine requirements. The resulting NC programs include configurable machine-specific events with safe start and restart sequences. Multiple path trajectory methods are available to address specific engineering requirements and part topology. Sequences are then output as NC programs for the selected automated lay-up machine. NC programs can contain partial, full or multiple plies and the user can analyse material limits prior to program creation. Paths or tows can be exported as CAD geometry for further engineering analysis of how the material is actually applied. VCS reads CAD models and NC programs from composite lay-up path generating applications, such as VCP. It then simulates the sequence of NC programs on a virtual machine. Material is applied to the lay-up form via NC program instructions in a virtual CNC simulation environment. NC program tow add/cut commands are read and acted-on to add or drop the simulated applied material. The simulated material applied to the form can be measured and inspected to ensure the NC program follows manufacturing standards and requirements. The purpose of simulation is to validate the CNC lay-up process. All machine components can be checked for collisions and near misses. The simulation is run directly from ISO NC programs and tow material is applied by NC program commands - commonly referred to as ‘G-codes’. At any point during the simulation the user can measure applied material: gap/lap; steering and roller conformance; thickness and more. The three components of machine independent software combine to allow manufacturers to select the best machine for a specific part or manufacturing process, without having to introduce a different piece of software into the process for each different machine brand. With machine independent software the manufacturer learns and uses one application for programming and simulating all AFP machines, regardless of the brand. Finally, bear in mind machine tool manufacturers are not software development companies. They focus on advances in machine and materials technology. As a result, they tend to fall behind the curve on commercial computer hardware and software advances because it’s not core to machine tool manufacturing. Looking to the future, it’s apparent that many manufacturers are still struggling to apply current AFP technology to complex high-curvature part shapes. It often seems as though the machine currently used is not designed to meet the necessary requirements. However, it appears there are new AFP machine technologies being developed to specifically apply material over complex shapes. Innovative NC programming approaches such as those offered by CGTech are needed to successfully and reliably create complex fibre-placed parts while achieving the structural requirements of the laminate. www.cgtech.co.uk