Toolcraft AG, Georgensgmünd, Germany, has established AMbitious, a new business area that offers training and individual project support to companies looking to utilise Additive Manufacturing. Building on Toolcraft’s experience in achieving Nadcap certified aerospace components, the company is keen to see its customers benefit from its wealth of knowledge in AM.
Since its beginnings over thirty years ago, the company has steadily expanded into machining, robotics, injection moulding and mould making before its 2011 entrance into the AM sector. This was shortly followed by the construction of an additional factory building with its own lab so that Toolcraft could focus on AM technology in more depth.
Since 2017, Toolcraft has been using Siemens NX software to support its AM work, in an effort to ensure consistency throughout its entire process chain. Two years ago, Toolcraft invested in a bespoke Additive Manufacturing machine from Trumpf with horizontal and vertical rotary axes. At present, Toolcraft has twelve Powder Bed Fusion (PBF) machines and a machine with a powder nozzle.
In order to be Nadcap certified, companies must have numerous conditions in place in order to be certified to produce additively manufactured components. After companies have examined the entire process, staff must receive in-depth training and be given the required authorisations (e.g., authorisation to work as machine operators, project managers or visual inspectors).
Pre-processing also involves a number of challenges: to meet the required standard, maintenance plans need to be drawn up for machinery & screening stations and defined maintenance intervals need to be adhered to and documented. Procurement specifications and incoming goods inspections play an important role in maintaining powder quality. An appropriate powder sampling method must be defined to allow particle-size distribution and oxygen and nitrogen content to be analysed. This must include access to a lab – either through a service provider or an in-house lab.
Toolcraft’s in-house lab has enough space that three materials technicians carry out various analyses. The qualification of build jobs is also highly important during the certification process; this plays a key role when inspecting a machine for the first time or when using a new material and also forms a crucial part of regular quality control. When preparing AM build jobs, it is important to pay attention to both the component’s design and its arrangement and orientation in the manufacturing space. In certain circumstances, it may be necessary to undertake a simulation to rule out any potential delays in advance and to ensure optimum component quality. A document accompanying the manufacturing process must be created and maintained so that all the steps performed and the people involved can be retraced.
To ensure that quality assurance is conducted adequately, components must be manufactured in a suitable environment where crucial factors – such as ambient temperature and air humidity – are continuously monitored. The manufacturing process must be described in detail and followed by everyone involved. Numerous monitoring tools (e.g., camera systems to monitor the powder bed) are also needed to record the oxygen content, air humidity and heating in the manufacturing space. Monitoring tools are indispensable and their high precision allows minimal deviations in the process to be detected, but Toolcraft has expressed that the human eye is also essential for performing visual inspections during manufacturing.
Traditional and AM-specific quality assurance methods are both useful during post-processing; traditional methods include optical measuring techniques, which are used to optimise and determine the quality of the component quickly and precisely. There is also the possibility of using tactile measuring techniques, where the component’s dimensions, angles, symmetry and parallelism are felt using machines to reliably rule out any discrepancies. Non-destructive surface testing can be conducted in an evaluation cubicle under UVA light to detect even microscopic cracks. AM-specific quality assurance methods include both the static and dynamic analysis of material strength. In addition to oxygen and nitrogen content, these methods can be used to analyse a material’s thickness, porosity and structure.