{{Short description|Bladed disk; machine part}} {{About|blisks in aviation mechanics|blisks in the Destroy All Humans! series|Destroy All Humans! 2}} thumb|A CNC-milled, single piece axial compressor blisk A '''blisk''' (portmanteau of '''bladed disk'''), also known as an '''integrally bladed rotor''' ('''IBR'''), is a turbomachinery component consisting of a rotor disk and blades made as a single part instead of a disk assembled with individual removable blades. Blisks generally have superior aerodynamics than conventional rotors with single blades and are lighter. They may be made by additive manufacturing, casting, machining from a solid piece of material, or welding blades to a rotor disk. The term ''blisk'' is used mainly in aerospace engine design.
== History == Blisk manufacturing has been used since the mid-1980s. It was first used by Sermatech–Lehr (now known as GKN Aerospace<ref>{{Citation | title = GKN Aerospace | url = http://www.gknaerospace.com/}}.</ref>) in 1985 for the compressors of the T700 helicopter engine. Since then, its use has continued to increase in major applications for both compressors and fan blade rotors. Examples include the Rocketdyne RS-68 rocket engine and the General Electric F110 turbofan.
The F-35B variant of the Joint Strike Fighter uses blisks to achieve short take-off and vertical landing.<ref>{{Citation | url = http://www.theengineer.co.uk/in-depth/rolls-royces-liftsystem-for-the-joint-strike-fighter/1008008.article | title = Rolls-Royce's LiftSystem for the Joint Strike Fighter | first = Ellie | last = Zolfagharifard | newspaper = The Engineer | date = 28 March 2011 | access-date = 18 April 2011 | archive-date = 19 December 2013 | archive-url = https://web.archive.org/web/20131219050153/http://www.theengineer.co.uk/in-depth/rolls-royces-liftsystem-for-the-joint-strike-fighter/1008008.article | url-status = dead }}.</ref>
Engine manufacturer CFM International is using blisks in the compressor section of its LEAP-X demonstrator engine program, which has completed full-scale rig testing.<ref>{{Citation | title = Optioning the Future | newspaper = Aviation Week & Space Technology | volume = 170 | issue = 10 | date = 9 March 2009 | page = 37}}.</ref> The compressor sections of PowerJet SaM146 engines which power Sukhoi Superjet 100 aircraft are also equipped with blisks.<ref>{{Citation | url = http://www.aviationweek.com/aw/generic/story.jsp?id=news/om/2010/11/01/OM_11_01_2010_p28-260528.xml&channel=mro | title = Powering Up Next-Gen Engine MRO | first = Bill | last = Burchell | newspaper = Aviation Week | date = 2 November 2010 }}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}.</ref>
General Electric's Passport (formerly "TechX") engine uses blisks for both its main {{cvt|52|in|cm}} fan as well as for five of its ten high pressure compressor stages.<ref name="passport_freeze">{{cite press release |author=<!--Not stated--> |url = https://www.geaviation.com/press-release/business-general-aviation/ge-aviation-freezes-design-passporttm-engine |title=GE Aviation Freezes Design of Passport Engine |publisher=GE Aviation |date=2012-05-13 |access-date=2022-05-13}}.</ref><ref name=TypeCert>{{cite web |url= http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/78ad2acef2ea44b986257fb00067591d/$FILE/E00091EN_Rev_0.pdf |publisher= FAA |title= type certificate data sheet E00091EN, revision 0 |date= 29 April 2016}}</ref> The GEnx engines already use blisks in some stages.
== Advantages == [[File:First stage Allison axial compressor blisk.jpg|thumb|A blisk used in a gas turbine engine compressor.]] Instead of making bare compressor disks and attaching the blades later, blisks are single elements combining the two. This eliminates the need to attach the blades to the disk (via screws, bolts, etc.), thus decreasing the number of components in the compressor, while at the same time decreasing drag and increasing efficiency of air compression in the engine. The elimination of the dovetail attachment found on traditional turbine blades eliminates a source for crack initiation and subsequent propagation.<ref name=RAND>{{Citation | first = O | last = Younossi | title =Military Jet Acquisition: Technology Basics and Cost-Estimating Methodology | publisher = RAND Corporation | ISBN = 0-8330-3282-8 | pages = 29–30 | year = 2002|display-authors=etal}}.</ref>
Efficiency improvements of up to 8% are possible.<ref>{{Citation | url = http://www.flightglobal.com/articles/2010/10/21/348755/nbaa-ge-techx-fan-blisk-is-all-the-buzz.html | title = NBAA: GE TechX fan blisk is all the buzz | first = John | last = Croft |website= Flightglobal.com |date= 21 October 2010}}.</ref>
== Disadvantages == Any damage to blades on integrally bladed rotors beyond minor dents and scratches requires the rotor to be replaced, or for the damaged blades to be cut off and replacement blades welded on. Maintenance of this nature is often extremely difficult to perform on the flightline and often requires the engine or compressor to be fully removed and shipped to a specialized repair facility. Integrally bladed rotors must also undergo much more rigorous harmonic vibration testing and dynamic balancing than traditional rotors, since the inherent natural damping that traditional rotors' dovetail attachments provide is no longer present.<ref name="RAND" />
== Process == === General === Blisks can be produced with several different manufacturing processes, including CNC milling, investment casting, electrochemical machining, 3D printing, or welding. Research is being conducted to produce them using friction welding of "near net" part shapes that are then machined down to the final blisk shape.<ref>{{Citation | date = Jun 5, 2013 | newspaper = Aviation Week | url = http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_05_06_2013_p42-574844.xml&p=2 | title = Metallics Make Comeback With Manufacturing Advances | access-date = February 23, 2022 | archive-date = April 27, 2015 | archive-url = https://web.archive.org/web/20150427133615/http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2FAW_05_06_2013_p42-574844.xml&p=2 | url-status = dead }}.</ref>
=== Measurement and inspection === thumb|Sample blisk in ATOS ScanBox The measurement and inspection of blisks, crucial for guaranteeing engine performance, is carried out at the end of the manufacturing processes. Traditionally this has been achieved using tactile devices, like coordinate-measuring machines (CMM), but as geometries and requirements increase, the trend in modern factories is to carry out 3D scanning inspection systems.<ref name=":0">{{Cite web|url=https://www.gom.com/industries/aerospace/aero-engine/blisk-inspection.html|title=Blisk Measurement & Inspection using GOM, ATOS 5 for Airfoil, 3D Scanners|last=|first=|date=|website=|url-status=live|archive-url=https://web.archive.org/web/20201029212524/https://www.gom.com/industries/aerospace/aero-engine/blisk-inspection.html |archive-date=2020-10-29 |access-date=}}</ref> This has advantages of the speed of measurement compared to tactile devices, whilst collecting 3D data to relate back to design characteristics. Using 3D data, parts can be catalogued in this way, often called digital twin, allowing monitoring of the product through its life-cycle.
=== Blisk repair using adaptive machining === Engine-run blisks pose their own set of unique requirements. After parts have been in service in the engine, noticeable amounts of damage and wear will be observed. Provided that the damage and wear are within thresholds set by the design authority, it is possible that the blisks can be repaired. Repair of blisk components is very complex and first requires an accurate 3D representation of the component. The quickest way to do this is by 3D scanning the product.<ref name=":0" /> After the part is scanned, an STL file (stereolithograph) can be passed to a CNC code generating software such as NX CAM. The tool paths are regenerated to suit the measured geometry and not the nominally generated CAD in a process known as adaptive machining.<ref>{{Cite web|url=https://www.ttl-solutions.com/en-gb/our-services/adaptive-machining/blisks-impellers/|title=Overview of an Adaptive Machining Process|last=|first=|date=|website=|url-status=live|archive-url=https://web.archive.org/web/20160725090420/http://www.ttl-solutions.com:80/en-GB/our-services/adaptive-machining/blisks-impellers |archive-date=2016-07-25 |access-date=}}</ref>
The processes would typically involve removing part or all of a blade(s), followed by a weld back to approximate size before finishing by final machining back to the airfoil shape.<ref>{{Cite web|url=https://www.rolls-royce.com/media/our-stories/discover/2019/meet-the-robots.aspx|title=Rolls-Royce Blisk Repair Process|last=|first=|date=|website=|url-status=live|archive-url=https://web.archive.org/web/20210111025311/https://www.rolls-royce.com/media/our-stories/discover/2019/meet-the-robots.aspx |archive-date=2021-01-11 |access-date=}}</ref>
== References == {{Reflist}}
== External links == {{Commons category|Blisks}}
* {{Citation | publisher = Rolls-Royce | title = LiftFan blisk | date = March 2003 | url = http://www.rolls-royce.com/press/assets/images/defence/tech_blisk.jsp }}{{dead link|date=July 2017 |bot=InternetArchiveBot |fix-attempted=yes }}. * {{Citation | publisher = Rolls-Royce | url = http://100.rolls-royce.com/facts/view.jsp?id=283 | title = Facts | url-status = dead | archiveurl = https://web.archive.org/web/20061019182354/http://100.rolls-royce.com/facts/view.jsp?id=283 | archivedate = 2006-10-19 }}. * {{Citation | publisher = Rolls-Royce | url = http://www.rolls-royce.com/media/showPR.jsp?PR_ID=1342 | title = Media | url-status = dead | archiveurl = https://web.archive.org/web/20060921063732/http://www.rolls-royce.com/media/showPR.jsp?PR_ID=1342 | archivedate = 2006-09-21 }}.
Category:Gas turbine technology Category:Engine technology