Quality Intelligence - Part 3

Dimensional Measurement and Inspection:

Better, faster is mantra of every manufacturer, especially when it comes to components such as aerospace and power generation blade measurement and inspection. These blades require 100-percent dimensional inspection for each new part. The process involves verifying every feature on the part and comparing it to a customer-supplied component drawing and or 3D CAD model. First-article inspections are done prior to full production release and often while a part is in development

These new processes require higher through puts and data collection which necessitates the need for the replacement of existing CMM technology for high speed 3D structure light solutions. which capture and calculate precise 3D coordinates for up to 1.3 million points in about seven seconds dramatically reducing inspection time. Accuracy, repeatability and traceability matter, so using globally-respected 3D measurement systems to provide a complete solution for all types of blade inspection is important. The captured component blade data is then used to analysis and compared to the master CAD model. Quality Inspection: “Reporting and Analysis” In addition, user-defined reports containing sections, labels and much more, support the interpretation and the understanding of the analysis results. At any time, also after measuring is completed - specific points on the object may be determined, and the deviations for these points can be documented in tables or evaluated statistically with repeated measurements of parts that are identical in construction.

Various methods are available to align the measured data to the nominal geometry. Best-fit algorithms, applied to certain areas of the components, allow for analysing local geometry deviations but also visualise torsion or deformations of partial areas with respect to each other.

If the alignment is made to the aerodynamic part (aerofoil) of the blade, the actual deviations in these areas can be analysed. If, however, best-fit registration is performed to the root of the blade, torsion of the airfoil with respect to the root can be detected.

All blade inspection project, the alignment and inspection criteria varies vastly from OEM to OEM’s specifications. The industry experience a competent highly-trained measurement engineers, linked with the highly intuitive and detailed sensors software, makes the creation of the even the most demanding inspection report easy and concise. Multiple alignments and additional registration or coordinate transformation rules like 3-2-1 or RPS registration which uses reference elements like planes, holes, cones, cylinders can be easily generated and is a representation of the engineering intent. Inspection reports are generated for each component, providing an un-broken tractability chain including documentation of the sensors accuracy and quality assurance.

Batch inspection and multi blade using automated 3D scanning cell

Component Holding fixtures and reference frames created using 3D printing and fabrication solutions, enabling families of components to be held in locations during the measurement cycle. The fixture and reference frames include targets which enables the use of photogrammetric workflows to be applied

The photogrammetry system works by calculating the centre of the circular reference points using several images captured using a high resolution DSLR camera. Coded reference target markers are used to bundle the images together in conjunction with the positions of un-coded markers in a digital point cloud.

Component fixtures, measured with photogrammetry (TRITOP), guarantee a reproducible positioning of these parts during measurement and allows the individual scans to be referenced within the coordinate transformation matrix for the component. The measurements are directly in the defined coordinate system using the reference point markers of the fixture.

For analysis, components can be measured completely or partially with the system for each production step in order to, Determine the initial geometry of component blank. This guarantees that subsequent processing can be carried out correctly. In addition, it is also possible to consider the blank geometry when creating CAM processing programs (e.g. milling paths) reducing processing time.  

Other example of multi part measurement advantages include:

·        Dimensional / surface checks consistency after cutting processes.

·        Dimensional consistency or the deformation after heat treatments.

·        Measure and Inspection to assess dents and bumps on aerofoils surface.

·        Layer thickness checks when applying protective and insulating layers.

o  The comparison of measurements before and after coating, aligned to the root of the turbine blade, result in the layer thickness.

·        Dimensional check for the mounting of multiple components, e.g. the mounting of individual blades to a Disc or complex Blisk (consists of a single part, instead of an assembly of a disk and individual, removable blades) also known as IBR. (Integrally Bladed Rotors)

Traditional Co-ordinate Measurement systems (CMMs), methods come close to their technical limits because of the increasing requirements regarding quality in production such as larger amount of measuring points, flexible measuring solutions for a variety of products as well as precise measuring equipment and the generation of application and component programming. Optical measuring workflows, however, provide high flexibility and very dense measuring point data.

To measure large quantities of components, an automated solution supported by a robot and combined with a rotation table provides a totally flexible platform, extensive macro programming to automate the entire measuring procedure including the control of the handling systems and evaluation up to generating a Go/No-go statement or SPC reporting.

Optical measurement of components offers new possibilities in product and production development as well as in production quality control. Providing:

·          time saving during measurement,

·          complete measuring,

·          support of new manufacturing processes,

·          increase the competitiveness of the user due to a higher quality and shorter development times.