Product category:
Vision and scanning systems
News Release from: NVision | Subject: Scanner
Edited by the Manufacturingtalk Editorial
Team on 12 July 2007
One scanner makes BLISK measurments fast
Machining a BLISK is one thing, but measuring it afterwards is awkward, but a UK gas turbine maker now scans them using one scanner instead of a number of CMMs.
Instead of using a coordinate measuring machine (CMM) to carry out 97% inspections on gas turbine turbine blades, Centrax is using a Maxos optical scanning system supplied by NVision Centrax produces gas turbines and gas turbine components
This article was originally published on Manufacturingtalk on 13 Jun 2008 at 8.00am (UK)
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At its UK plant, Kevin Vickers said: "We originally planned to purchase several touch probe CMMs to keep pace with production during a ramp up of our BLISK (blade integrated disk) manufacturing programme." He went on to say that they had discovered that the Maxos system was so much faster than the other machines we had considered.
One Maxos scanner handles Centrax's planned output of BLISKs.
Centrax's Turbine Components Division produces compressor and turbine aerofoils, discs, shafts, casings, associated hardware including sub assemblies and engine modules.
Further reading
Non-contact system outperforms CMMs
A turnkey non-contact inspection system is claimed to outperform coordinate measuring machines by an average of 8 to 1 in terms of inspection speed and offers greater accuracy.
Existing clients maintain new CMM is fastest
NVision has introduced MAXOS, the multi-axis optical CMM, offering a significantly faster way to measure high-value precision components in an automatic production environment.
The BLISKs consist of rotor disks with integral blades or vanes for gas turbines.
Compared with conventional disk and blade arrangement a BLISK offers a potential weight saving by eliminating of the fixings that secure the blade root to the disk.
However, when manufacturing closely toleranced BLISKs the big problem is that of inspecting them.
Usually, BLISK makers use touch probe CMMs that are moved from point to point.
This technique is very slow because the touch probe must make actual physical contact with each point that it measures.
Just how quickly a touch probe can be moved around each blade limits the speed of the whole measurement cycle.
Non-contact scanners are faster, but their weakness lies in that they cannot scan freshly machined or highly polished surfaces.
To overcome this, the surfaces can be coat but it takes time, raises the risk of contaminating the blades and introduces dimensional inaccuracy.
On the other hand, The Maxos scanner uses a proprietary non-contact probe with a point of white light.
This arrangement allows the scanner to collect individual points at a rate of 70/s.
Like a touch probe CMM it collects individual points, but unlike a conventional CMM it continues on its path at high speed without a pause.
The Maxos has an exceptionally high accuracy of +/-2 micron on matt surfaces and +/-10 micron on polished metal.
It can achieve a point spacing resolution of 0.2 micron without pausing.
Additionally, since it has no ball probe and measures a single point at a time, it is not limited by ball-offset geometry.
The Maxos can inspect radii of under 0.2mm.
This feature is key to the measurement of leading and trailing edges on turbine blades.
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