GB2243320A - Laser drilling. - Google Patents
Laser drilling. Download PDFInfo
- Publication number
- GB2243320A GB2243320A GB9009343A GB9009343A GB2243320A GB 2243320 A GB2243320 A GB 2243320A GB 9009343 A GB9009343 A GB 9009343A GB 9009343 A GB9009343 A GB 9009343A GB 2243320 A GB2243320 A GB 2243320A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cavity
- weight
- ptfe
- laser drilling
- backwall
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/18—Working by laser beam, e.g. welding, cutting or boring using absorbing layers on the workpiece, e.g. for marking or protecting purposes
Description
2::27 -1-3 -i 0 1 - i Laser Drilling This invention relates to the
drilling of holes, using laser radiation into components having an internal cavity.
Laser radiation is often used for the precision drilling of small holes in components used, for example, in the aerospace industry.
methods for producing such holes with laser radiation are available; direct drilling and trepanning. Direct drilling involves the use of a "pulsed" laser wherein material is removed little by little by individual pulses of laser radiation concentrated on a small area. The general technique involves directing a number of pulses of laser radiation to burn through the material plus one or more subsequent pulses to "clean out" the interior of the hole and to remove the rough edges left on the hole as the laser emerges through the material.
Trepanning involves direct drilling of a small hole through the material which is then enlarged by moving the laser source and the component relative to one another such that the edges of the hole are gradually removed. During this enlargement process a significant proportion derived from the laser passes straight not incident upon the of the energy through the hole made and is material it is desired to remove When drilling holes, by either of the above methods, into components having an internal cavity, a major problem is the prevention of damage to the internal back wall of the cavity upon break through by the laser beam. Such damage is especially prevalent when drilling by the trepanning method during which, only around 50% of the laser energy is incident on the material being removed, the majority of the rest of the energy passing down the already drilled hole which acts as a "light pipe", maintaining a constant beam width and so tending to maximise the backwall damage.
It is known to use paraffin wax containing up to 60% by weight PTFE as a "laser-stoppery' material to fill the cavity of such components prior to laser drilling. Such PTFE-filled wax disperses the laser energy incident upon 1 it and thereby prevents or reduces damage to the cavity backwall. However, problems associated with the use of PTFE-filled wax are that the wax tends to melt as the component heats up and may drip out of the holes already drilled; since laser drilling is often carried out in an oxygenrich atmosphere the wax is prone to burning as it drips out of the component. Furthermore such waxes also tend to leave a carbon-rich deposit or 'tchar" on the component which may chemically combine with the remelted metal at the hole edges and can lead to cracking and general weakening of the component.
It is an object of the present invention to provide an improved cavity filling material, for use in the laser drilling of holes in components having 21.nternal cavities, to minimise damage occurring to the backwall of the cavity when the laser beam breaks through the component surface.
It is a further object to minimise the other undesirable chemical side effects which occur with known filling materials.
According to a first aspect of the present invention there provided a material for use in the laser drilling of components having at least one internal cavity to minimise damage occurring to the cavity backwall due to the laser beam, said material comprising an acrylic resin monomer 4 and polytetrafluoroethylene (PTFE), incorporating a suitable initiator.
polymerisation of the liquid monomer to polymer.
the monomer to promote form a solid In one embodiment of the material the acrylic resin monomer may preferably comprise methylmethacrylate (MMA).
The resulting polymethylmethacrylate (PMMA) has many advantageous features for the purposes of the present invention; it leaves little or no char on degradation, it has a relatively high melting point and a low oxygen index and therefore does not tend to melt and drip out of the component during drilling or to burn in an oxygen-rich atmosphere. Furthermore PMMA has good powers of dispersion to laser light and also acts as a type of "fibre optic", that is to say PMMA lights up when the laser light hits it; this feature is useful in detecting breakthrough of the laser into the cavity.
The proportion of PTFE dispersed in the resin may range from very low levels of less than 0.5% by weight to very high levels of over 70% by weight but is effectively determined by the accessibility of the internal cavity in the particular component to be drilled and the ease with which the filler may be introduced. Increasing the proportion of PTFE in the mixture also increases its I viscosity hence high PTFE contents may not be suitable for use when drilling components having very small and/or complex cavities to which access is limited.
For the purposes of the present invention the PTFE is preferably present in the range 0.5% by weight to 30% by weight, more preferably 1% by weight to 10% by weight and still more preferably 2% by weight to 6% by weight.
The initiator used to promote polymerisation of the liquid monomer may be any free radical initiator known in the art for such purposes. Examples of such initiators include azobisisobutyronitrile and peroxides.
According to a second aspect of the present invention a method for preventing damage to the internal backwall of a within a component during laser drilling of holes into said component comprises the steps of at least partially filling the cavity in the component with a material according to the first aspect of the present invention and allowing said material to polymerise in situ in the cavity prior to laser drilling.
cavity The invention will now be described more particularly by means of the following Example and drawing which shows a section through a turbine blade being laser drilled in 0 accordance with the invention.
are produced In the drawing the turbine blade 10 has two simple internal cavities, a front cavity 12 and a rear cavity 14 separated by an internal wall 16 the front face 17, of which forms the backwall of the front cavity 12. Holes 11 in the front surface, 15 of the blade by means of pulses of radiation 13, incident upon the blade front produced by a laser (not shown). The front cavity 12 is completely filled with a material 18, which acts to disperse the laser energy after it breaks through the front surface and thereby prevent or minimise any damage to the backwall 17.
EXAMPLE
A turbine blade to be laser drilled contained a complex cavity, from the root almost to the top, 70mm long tapering down to a small crosssectional area of 2mm2. Numerous pillars spanned the cavity thereby making the use of a solid PTFE laser barrier impossible.
annroximatelv The barrier material comprised 19g of methyl methaerylate, 1.Og of Fluon L169 (trade mark) PTFE powder and 0.5g of azobisisobutyronitrile. These components were stirred together for 30 seconds and drawn into a syringe to which a lmm diameter flexible tube was then attached to direct the liquid to the bottom of the blade cavity. The blade was filled, in the upright position, to overflowing.
J 4 - 7 After one hour the barrier material had set and the blade could be handled; after 24 hours at ambient temperatures the blade was ready for drilling.
Drilling was carried out using a Nd-YAG (1064nm) pulsed laser using oxygen gas fed through an axial jet to the turbine blade surface to assist molten metal and vapour removal.
The following laser parameters were used:- Nozzle to workpiece gap = 10 mm 0 2 pressure = 100 psi Lens setting 50 mm Energy per pulse Pulse width Lamp power Joules 0.6 msec, 3 Kw (xZ') = 12 After drilling was completed the barrier material was removed from the blade by burning out in a furnace at 700 0 C for 3 hours.
Examination of the blade showed that good hole shape and quality had been obtained with no damage to the backwall of the blade cavity and no chemical reaction between the filling material and the metal adjacent to the hole walls.
Claims (1)
- A material for use in the laser drilling of components having at least one internal cavity to minimise damage occurring to the cavity backwall due to the laser beam, the material comprising an acrylic resin monomer and polytetrafluoroethylene (PTFE), the monomer incorporating a suitable initiator to promote polymerisation.A material according to claim 1 wherein the acrylic resin monomer is methylmethacrylate.A material according to either claim 1 or claim 2 wherein the PTFE is present in the range 0.5% by weight to 30% by weight.4. A material according to claim 3 wherein the PTFE is present in the range 1% by weight to 10% by weight.5. A material according to claim 3 wherein the PTFE is present in the range 2% by weight to 6% by weight.6. A method for preventing damage to the internal backwall of a cavity within a component during laser drilling of holes into said component, the method comprising the steps of at least partially filling t 1 - 9 the cavity in the component with a material according to any one of claims 1 to 5 and allowing said material to polymerise in situ in the cavity prior to laser drilling.A material for use in the laser drilling of components having at least one internal cavity t minimise damage occurring to the cavity backwall due to the laser beam substantially as hereinbefore described with reference to the accompanying specification and drawing and to the Example.0 8. A method for preventing damage to the internal backwall of a cavity within a component during laser drilling of holes into said component substantially as hereinbefore described with reference to the accompanying specification and drawing and to the Example.1 Published 1991 at The Patent Office, Concept House, Cardiff Road. Newport. Gwent NP9 I RH. Further copies may be obtained from Sales Branch, Unit 6. Nine Mile Point, Cwmfelinfach, Cross Keys. Newport. NP1 7HZ. Printed by Multiplex techniques ltd, St Mary Cray, Kent.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9009343A GB2243320B (en) | 1990-04-26 | 1990-04-26 | Laser drilling |
DE69101171T DE69101171T2 (en) | 1990-04-26 | 1991-04-17 | Laser drilling. |
EP91200906A EP0454223B1 (en) | 1990-04-26 | 1991-04-17 | Laser drilling |
US07/688,138 US5227098A (en) | 1990-04-26 | 1991-04-22 | Laser drilling |
JP3095070A JPH04270750A (en) | 1990-04-26 | 1991-04-25 | Material for preventing damage on the surface of wall of space by laser beam, and method for preventing the damage by using this material |
CA002041356A CA2041356C (en) | 1990-04-26 | 1991-04-26 | Laser drilling |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9009343A GB2243320B (en) | 1990-04-26 | 1990-04-26 | Laser drilling |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9009343D0 GB9009343D0 (en) | 1990-06-20 |
GB2243320A true GB2243320A (en) | 1991-10-30 |
GB2243320B GB2243320B (en) | 1993-08-25 |
Family
ID=10675003
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9009343A Expired - Fee Related GB2243320B (en) | 1990-04-26 | 1990-04-26 | Laser drilling |
Country Status (6)
Country | Link |
---|---|
US (1) | US5227098A (en) |
EP (1) | EP0454223B1 (en) |
JP (1) | JPH04270750A (en) |
CA (1) | CA2041356C (en) |
DE (1) | DE69101171T2 (en) |
GB (1) | GB2243320B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0768140A1 (en) * | 1995-10-11 | 1997-04-16 | SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION -Snecma | Process for drilling works with a laser and barrier material used herewith |
Families Citing this family (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ATE162469T1 (en) * | 1991-10-31 | 1998-02-15 | Canon Kk | INK JET HEAD AND ITS MANUFACTURING PROCESS |
GB9514447D0 (en) * | 1995-07-14 | 1995-09-13 | Rolls Royce Plc | Laser barrier material and method |
US5844200A (en) * | 1996-05-16 | 1998-12-01 | Sendex Medical, Inc. | Method for drilling subminiature through holes in a sensor substrate with a laser |
US5855835A (en) * | 1996-09-13 | 1999-01-05 | Hewlett Packard Co | Method and apparatus for laser ablating a nozzle member |
US5773790A (en) * | 1997-01-21 | 1998-06-30 | General Electric Company | Beam blocking material and method for beam drilling and inspecting cooling holes |
JP3233060B2 (en) * | 1997-02-26 | 2001-11-26 | 株式会社デンソー | Laser processing method for resin products |
US6054673A (en) * | 1997-09-17 | 2000-04-25 | General Electric Company | Method and apparatus for laser drilling |
US6172331B1 (en) | 1997-09-17 | 2001-01-09 | General Electric Company | Method and apparatus for laser drilling |
US5837964A (en) * | 1998-01-16 | 1998-11-17 | Chromalloy Gas Turbine Corporation | Laser drilling holes in components by combined percussion and trepan drilling |
DE19832774B4 (en) * | 1998-07-22 | 2008-01-24 | Siemens Ag | Protective device for producing minute holes in tubular components and method for producing bores opening into a cavity |
US6533376B1 (en) * | 1999-01-29 | 2003-03-18 | Spectra, Inc. | Conditioning ink jet orifices |
DE19908630A1 (en) * | 1999-02-27 | 2000-08-31 | Bosch Gmbh Robert | Shielding against laser beams |
US6547645B2 (en) * | 2001-08-27 | 2003-04-15 | General Electric Company | Method and backer inserts for blocking backwall water jet strikes |
FR2834659B1 (en) * | 2002-01-17 | 2004-04-02 | Snecma Moteurs | STOP MATERIAL FOR LASER BEAM MACHINING |
US20050248060A1 (en) * | 2002-06-28 | 2005-11-10 | 3M Innovative Properties Company | Manufacture of valve stems |
US7290860B2 (en) * | 2004-08-25 | 2007-11-06 | Lexmark International, Inc. | Methods of fabricating nozzle plates |
GB0426780D0 (en) * | 2004-12-07 | 2005-01-12 | 3M Innovative Properties Co | Pressurized inhalation devices |
GB0427281D0 (en) * | 2004-12-14 | 2005-01-12 | 3M Innovative Properties Co | Methods of providing medicinal metal components having through holes |
GB0428169D0 (en) * | 2004-12-23 | 2005-01-26 | 3M Innovative Properties Co | Pressurized inhalation devices |
DE102006061444A1 (en) * | 2006-12-23 | 2008-06-26 | Mtu Aero Engines Gmbh | Method and device for applying a protective medium to a turbine blade and method for introducing cooling holes in a turbine blade |
EP2093011A1 (en) * | 2008-02-22 | 2009-08-26 | National University of Ireland Galway | A method and apparatus for detecting hole breakthrough in a laser drilling process, using an optical fibre |
DE102009015401A1 (en) | 2009-03-27 | 2010-09-30 | Mtu Aero Engines Gmbh | Covering device for a workpiece to be machined by means of a laser |
EP2335855A1 (en) * | 2009-12-04 | 2011-06-22 | Siemens Aktiengesellschaft | Filler material when drilling passageway holes in hollow components, method and device for same |
JP5787555B2 (en) * | 2011-03-07 | 2015-09-30 | 三菱日立パワーシステムズ株式会社 | Method for manufacturing gas turbine member |
JP6165163B2 (en) | 2011-12-07 | 2017-07-19 | ジェネラル アトミックス | Method and system for use in laser processing |
DE102013211047B4 (en) * | 2013-06-13 | 2015-04-30 | MTU Aero Engines AG | Method for closing cooling air holes |
US9278462B2 (en) | 2013-11-20 | 2016-03-08 | General Electric Company | Backstrike protection during machining of cooling features |
JP6455021B2 (en) * | 2014-08-22 | 2019-01-23 | オムロン株式会社 | Manufacturing method of bonded structure |
WO2016201278A1 (en) | 2015-06-10 | 2016-12-15 | Ipg Photonics Corporation | Laser beam energy modification to reduce back-wall strikes during laser drilling |
KR102291087B1 (en) * | 2018-03-19 | 2021-08-18 | 두산중공업 주식회사 | Protecting device |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3656988A (en) * | 1969-02-27 | 1972-04-18 | Watch Stones Co Ltd | Method for the fabrication of holes in a workpiece by means of laser-beams and apparatus for the performance of the aforesaid method |
FR2482495B1 (en) * | 1980-05-16 | 1984-04-13 | United Technologies Corp | SUPPORT FOR DRILLING ELECTRON BEAM HOLES |
US4539463A (en) * | 1984-02-24 | 1985-09-03 | Continental Packaging Company, Inc. | Trimming of polyester containers using a laser |
DE3767890D1 (en) * | 1986-02-14 | 1991-03-14 | Amoco Corp | TREATMENT OF SHAPED SURFACES WITH ULTRAVIOLET LASER. |
US4904529A (en) * | 1986-02-18 | 1990-02-27 | Kurabe Industrial Co., Ltd. | Heat and oil resistant insulating composition |
JP2507397B2 (en) * | 1987-03-09 | 1996-06-12 | 日特エンジニアリング株式会社 | Wire clamp device for winding machine |
DE68907527T2 (en) * | 1988-06-13 | 1993-10-28 | Rolls Royce Plc | Laser drilling of components. |
CA1324821C (en) * | 1988-08-04 | 1993-11-30 | Milan Brandt | Manufacture of finely perforated sheet material |
US4954256A (en) * | 1989-05-15 | 1990-09-04 | Pall Corporation | Hydrophobic membranes |
JPH0712632B2 (en) * | 1990-02-23 | 1995-02-15 | 秀俊 横井 | In-mold vibration finishing removal method |
-
1990
- 1990-04-26 GB GB9009343A patent/GB2243320B/en not_active Expired - Fee Related
-
1991
- 1991-04-17 EP EP91200906A patent/EP0454223B1/en not_active Expired - Lifetime
- 1991-04-17 DE DE69101171T patent/DE69101171T2/en not_active Expired - Fee Related
- 1991-04-22 US US07/688,138 patent/US5227098A/en not_active Expired - Fee Related
- 1991-04-25 JP JP3095070A patent/JPH04270750A/en active Pending
- 1991-04-26 CA CA002041356A patent/CA2041356C/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0768140A1 (en) * | 1995-10-11 | 1997-04-16 | SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION -Snecma | Process for drilling works with a laser and barrier material used herewith |
FR2739797A1 (en) * | 1995-10-11 | 1997-04-18 | Snecma | METHOD FOR DRILLING LASER PARTS AND STOPPING MATERIAL USED |
Also Published As
Publication number | Publication date |
---|---|
DE69101171T2 (en) | 1994-06-30 |
US5227098A (en) | 1993-07-13 |
CA2041356A1 (en) | 1991-10-27 |
JPH04270750A (en) | 1992-09-28 |
DE69101171D1 (en) | 1994-03-24 |
EP0454223A1 (en) | 1991-10-30 |
CA2041356C (en) | 1997-11-25 |
GB2243320B (en) | 1993-08-25 |
GB9009343D0 (en) | 1990-06-20 |
EP0454223B1 (en) | 1994-02-16 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20000426 |