EP0403537B1 - Ultraschall-polierung - Google Patents

Ultraschall-polierung Download PDF

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Publication number
EP0403537B1
EP0403537B1 EP89903596A EP89903596A EP0403537B1 EP 0403537 B1 EP0403537 B1 EP 0403537B1 EP 89903596 A EP89903596 A EP 89903596A EP 89903596 A EP89903596 A EP 89903596A EP 0403537 B1 EP0403537 B1 EP 0403537B1
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EP
European Patent Office
Prior art keywords
workpiece
tool
configuration
abrasive
slurry
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.)
Expired - Lifetime
Application number
EP89903596A
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English (en)
French (fr)
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EP0403537A1 (de
EP0403537A4 (en
Inventor
Lawrence J. Extrude Hone Corporation Rhoades
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Extrude Hone LLC
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Extrude Hone LLC
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Publication date
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Priority to AT89903596T priority Critical patent/ATE96071T1/de
Publication of EP0403537A1 publication Critical patent/EP0403537A1/de
Publication of EP0403537A4 publication Critical patent/EP0403537A4/en
Application granted granted Critical
Publication of EP0403537B1 publication Critical patent/EP0403537B1/de
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
    • B24B1/04—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes subjecting the grinding or polishing tools, the abrading or polishing medium or work to vibration, e.g. grinding with ultrasonic frequency
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B35/00—Machines or devices designed for superfinishing surfaces on work, i.e. by means of abrading blocks reciprocating with high frequency
    • B24B35/005—Machines or devices designed for superfinishing surfaces on work, i.e. by means of abrading blocks reciprocating with high frequency for making three-dimensional objects

Definitions

  • the present invention relates to a method of polishing a workpiece according to the preamble of claim 1 (see US-A-2 850 854).
  • the present invention is particularly adapted to polishing compound surfaces and complex shapes having fine or intricate detail where a reduction in surface roughness is needed without loss of resolution or detail.
  • Ultrasonic machining is a well known machining process whereby the surface of a workpiece is abraded by a grit contained in a slurry circulated between the workpiece surface and a vibrating tool adjacent thereto, vibrating at frequencies above the audible range, i.e. typically within the range 19,500 to 20,500 cycles per second.
  • the amplitude of vibration is less than 0.01 mm, and typically within the range 0.001 to 0.005 mm.
  • the tool is made of a material having high strength and good ductility, in order to impart a high degree of impact resistance to minimize abrasion of the tool itself.
  • the abrading tool face is provided with a three-dimensional form, while a negative compliment thereof is machined onto the workpiece surface.
  • the tool Since the tool does not contact the workpiece, the actual cutting is done by the abrasive particles suspended in the slurry. These particles are driven with a percussive impact against the workpiece surface by the tool, ultrasonically vibrating perpendicular to the workpiece surface.
  • This process finds particular utility in its ability to work difficult materials, such as glass, ceramics, calcined or vitrified refractory materials and hard and/or brittle metals, which are not susceptible to machining by any other traditional technique, or even such nontraditional techniques such as electrical discharge machining, electro-chemical machining or the like.
  • Ultrasonic machining has proved particularly advantageous for reproducing complex shapes which could not be obtained by traditional machining, or by non-traditional techniques such as electrical discharge machining, electro-chemical machining, or the like because of the nature of the materials to be worked.
  • Ultrasonic machining imparts some abrasive erosion of the tool as well as the workpiece, so that there is an ongoing and increasing loss of fine detail and resolution as the tool is used and worn. For this reason it has been considered rather important that the tool material be one that is comparatively tough and ductile, i.e. not readily abradable by ultrasonic machining, so as that the tool will be abraded to a much lesser degree than the workpiece.
  • tools are commonly made of materials such as cold rolled steel, austenitic stainless steel, copper, aluminum and the like.
  • ultrasonic machining in its normal practice, only abrades areas of the workpiece which are most adjacent to the tool face surfaces. Therefore, if ultrasonic machining is to be used on a workpiece that is already formed, or formed in part, as in a polishing operation, it is very important that the tool and workpiece be aligned and registered as accurately as possible, least the workpiece be abraded or polished nonuniformly and possibly even destroying the workpiece as desired. Setting-up the tool and workpiece with the necessarily accurate indexing and registration is a time consuming and laborious procedure .
  • polishing by any method requires the removal of a very small amount of workpiece material, and ideally a very uniform removal thereof. Manual polishing, vibratory finishing, buffing, brushing and even extrusion honing cannot remove the workpiece material to the extent of uniformity often desired, particularly in the case of complex workpiece surfaces. Burnishing, on the other hand, tends to redistribute the workpiece surface material causing dimensional changes.
  • the invention consists in the method of polishing a workpiece surface having a configuration preformed therein without adversely effecting the configuration detail and resolution, comprising:
  • U.S. Patent 2850854 shows a method for removing material by ultrasonic grinding.
  • the ratio of stock removed to tool wear shall be at least 1:1, varying up to 100:1.
  • the tool is abraded but only "polishing" amounts of material are removed from the workpiece, so that the ratio of "stock removed” to "tool wear” would be much less than 1 to 1, a difference of kind rather than mere degree.
  • Japanese Patent No. JP-A-54-133697 also relates to a grinding process, but in which a molded shaped head is utilised to grind a subsequent workpiece. Minimal tool wear for a given grinding performance is desired, the opposite of the present invention.
  • a method for ultrasonic polishing of a workpiece by means of a tool which is significantly more ultrasonically abradable than the workpiece and therefore, need not be preformed to provide a complement of the surface of the workpiece. Instead, a blank tool face can be used.
  • the tool When the tool is vibrated, imparting its vibrations to an abrasive slurry disposed in the gap between the tool and workpiece, the tool is quickly eroded in such a fashion that it quickly develops a complementary form of the workpiece with a high degree of resolution and detail.
  • the tool will continue to be abraded at a comparatively high rate while continuing to maintain its high degree of resolution and detail, while at the same time the surface of the workpiece is abraded to a much lesser degree so that it is merely polished while the tool is being progressively abraded down, but at all times maintaining its high resolution and detail complimentary work surface.
  • the present invention may be employed to polish any material more resistant to ultrasonic erosion than the material of which the tool is made.
  • the tool will be re-dressed continuously and inherently to the complementary form of the workpiece, by virtue of the fact that the tool will be eroded to a greater extent than the workpiece.
  • the preferential working of the tool results in a constant or even increasing conformity to the fine detail and resolution of the workpiece, so that as polishing of the workpiece occurs, there is no loss of resolution.
  • ultrasonic polishing is made applicable even to relatively soft and easy to work materials, such as bronze, brass, or gold, to polymeric materials, and a wide diversity of other materials which were not heretofore thought to be appropriate for ultrasonic techniques, in addition to very much harder materials, including those where ultrasonic machining techniques have been employed previously, as discussed above.
  • ultrasonic polishing in accordance with the present invention, surface finishes can be attained, depending on the extent of polishing, of substantially any desired degree, regardless of the material and in any degree of intricacy and fineness of detail without substantial change in detail or resolution.
  • Surface roughness can be reduced to as low as about 0.1 microns Ra, although such high degree of polish may not always be required and a lesser extent of polishing may often suffice for a given application.
  • the process of this invention does remove a very uniform layer of material from a workpiece surface, the process is also ideally suited to the removal of thin layers of unwanted material from a workpiece surface, such as an EDM recast layer of material which is normally 0.003 to 0.006 mm thick.
  • the process of this invention can be used to remove burrs from a workpiece surface or to radius the edges thereof.
  • FIG. 1 An ultrasonic machine tool as employed in the present invention is shown schematically in Fig. 1.
  • Figs. 2 and 3 are "before” and “after” photomicrographs of a carbide compacting die illustrating the effectiveness of this invention.
  • Ultrasonic machine tools are known to the art and the present invention is generally applicable for use with any such machine, utilizing typical parameters for vibrational frequency, amplitude and abrading particles.
  • such equipment comprises a frame 10 adapted to hold a workpiece 4 and a tool holder 1 including an ultrasonic driver which vibrates the tool 2 at a frequency typically of about 20 KHz but in some applications from 10 to 40 KHz, most often about 19 to 22 KHz.
  • the tool holder 1 is adapted at 11 to advance the tool from a retracted position into working position and, during working, into the workpiece.
  • the equipment will ordinarily be furnished with abrasive slurry handling means 6,7,8,9 so that the slurry can be disposed between the tool 2, and the workpiece 4.
  • the slurry will often be pumped through the gap between the tool and workpiece to continuously provide fresh, unworn abrasive to the working surface and to flush away eroded material and debris.
  • the slurry may be processed to remove debris and recirculated.
  • the transducer will most typically be an electronically driven stack of piezoelectric element or a magnetostrictive transducer.
  • the abrasive slurry will ordinarily be formed of hard abrasive particles disposed in a liquid carrier.
  • the abrasives are typically tungsten carbide, silicon carbide, aluminum oxide, boron carbide, boron nitride, diamond and the like, although it should be noted that when polishing softer materials in the present invention, softer abrasives may be used, such as alumina, corundum, garnet, and the like.
  • the liquid carrier must be one capable of transmitting ultrasonic vibrations and should be chosen to be compatible with the workpiece and the electrode materials. Water is the best such transmitters, although other liquids such as cutting oil or fluid and the like may be used. When water is used, it may be necessary to add rust inhibitors.
  • liquids other than water such as cutting oil, can be used to effect a low amplitude particle movement, or in the alternative a lower power can be used with the water as the transmitter.
  • the particle size of the abrasive is not critical as long as the particle size is such that it can be held in suspension. It is generally preferred, therefore, to use small particle sizes, less than 0.075 mm (200 mesh), and preferably, 0.025 to 0.015 mm (600 to 1000 mesh), with a particle concentration of from 10 to 20 volume percent of the fluid to attain the highest levels of polish.
  • the workpiece to be polished can be substantially any material which, contrary to prior art practices, is ultrasonically harder than the tool material, typically, a metallic workpiece.
  • the extent of polishing required will be determined by the initial surface roughness of the workpiece and the finish required after polishing. Both an advantage and a limitation of the procedure of the present invention resides in the fact that the configuration of the workpiece will not be altered during the polishing operation. It is thus important to recognize that the present invention will not improve resolution of fine detail, and the quality of the final product will, except for surface finish, be determined by the initial workpiece.
  • the tool must be formed of a material that is considerably more ultrasonically abradable than the workpiece material.
  • An ultrasonically more abradable material does not mean one that is softer, but usually one that is more brittle.
  • ultrasonic abradability it should be realized that in the ultrasonic machining of a surface, the tiny abrasive particles suspended in the fluid are impinged against the workpiece surface at an ultrasonic velocity, so that the tiny particles microscopically chip-away at the workpiece surface. To be chipped away in this fashion, the workpiece must have some degree of brittleness, whether or not the material is hard.
  • an ideal tool material would be a material having a significantly greater degree of ultrasonic abradability, such as graphite, glass, quartz and other such materials which have normally been considered ideal workpiece materials but not normally tool materials.
  • the tool When employed with suitable equipment, the tool may be provided with passages (5) communicating with the gap through which the abrasive slurry may be pumped to provide flushing of debris from the gap.
  • the debris will predominantly be tool material particles eroded from the tool combined with minor amounts of material polished from the surfaces of the workpiece.
  • the pumping will serve to provide fresh abrasive slurry to the gap so that cutting edges are not excessively worn during use.
  • the surface contour of the workpiece first serves to shape the tool surface into very exact registration therewith.
  • the tool is continually eroded and will perpetually generate and maintain very exact registration in situ .
  • the preferential erosion of the tool is the feature of the present invention which permits a high polish on the workpiece surface by a very thin, highly uniform surface removal.
  • the process of this invention is also ideally suited to the removal of any undesired layer of material from a workpiece surface.
  • an EDM recast layer typically from 0.003 to 0.006 mm (0.0001 to 0.0002 inch) thick can readily be removed by the practice of this process with the result that the recast layer is removed without any loss of resolution of detail in the workpiece surface.
  • workpieces coated with material such as ceramic can be processed as described herein to remove or selectively remove the ceramic coating therefrom without any loss of resolution of detail in the workpiece surface.
  • the process of this invention can be used to remove burrs which protrude from the workpiece surface, or to radius sharp corners on the edges of the workpiece. Either of these objects can be readily effected by using such an ultrasonically abradable tool without losing any of the workpiece detail.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Claims (16)

  1. Verfahren zum Polieren einer Oberfläche eines Werkstücks (4), welche eine vorgeformte Form aufweist, ohne die Formeinzelheiten und die Auflösung negativ zu beeinflussen, mit:
    A. Ausbildung eines Werkzeugs (2);
    B. Montieren des Werkzeugs (2) in einer schwingungsfähigen Beziehung (1) zu einem Werkstück, so daß eine Bearbeitungsoberfläche des Werkzeuges von der Werkstückoberfläche mit der genannten Form beabstandet ist;
    C. Einbringen einer flüssigen, Schleifmittel-Aufschlämmung zwischen das Werkzeug und das Werkstück;
    D. Hervorrufen einer Schwingungs-Relativbewegung bei einer Ultraschallfrequenz zwischen dem Werkzeug und dem Werkstück; und E. Anhalten der Schwingungs-Relativbewegung, wenn die Form auf der Oberfläche des Werkstücks poliert wurde;
    dadurch gekennzeichnet, daß das Werkzeug (2) aus einem Material besteht, welches besser durch Ultraschall abtragbar ist als das Werkstück, und daß die Schwingungs-Relativbewegung
    a) bei einer Ultraschallfrequenz und -amplitude durchgeführt wird, die dazu ausreichen, die Bearbeitungsoberfläche des Werkstücks dazu zu veranlassen, daß sie zu einer Negativ-Komplementärform der Form abgetragen wird, die auf der Oberfläche des Werkstücks vorgeformt ist; und
    b) weiter durchgeführt wird, um das Werkzeug abzutragen, während das Werkzeug damit fortfährt, die Negativ-Komplementärform der Form auf der Oberfläche des Werkstücks umzuformen und aufrechtzuerhalten, während zur selben Zeit eine Polierwirkung auf die Form auf der Oberfläche des Werkstücks ausgeübt wird.
  2. Verfahren nach Anspruch 1, bei welchem die Schwingungsbewegung bei einer Frequenz zwischen etwa 10 KHz und etwa 40 KHz durchgeführt wird.
  3. Verfahren nach Anspruch 1, bei welchem der Vorgang dazu eingesetzt wird, eine ungewünschte Materialschicht von der Werkstückoberfläche zu entfernen.
  4. Verfahren nach Anspruch 1, bei welchem der Vorgang zur Entfernung irgendwelcher ungewünschter Grate von der Werkstückoberfläche eingesetzt wird.
  5. Verfahren nach Anspruch 1, bei welchem der Vorgang zum Abrunden der Kanten des Werkstücks (4) eingesetzt wird.
  6. Verfahren nach Anspruch 1, bei welchem das Werkzeug (2) zu einer Form vorgeformt wird, welche eine allgemeine Entsprechung zur vorgeformten Oberfläche des Werkstücks aufweist.
  7. Verfahren nach Anspruch 1, bei welchem das Schleifmittel in der Aufschlämmung eine Teilchengröße von weniger als 0,075 mm (Maschenweite 200) aufweist.
  8. Verfahren nach Anspruch 7, bei welchem das Schleifmittel eine Teilchengröße von 0,025 bis 0,015 mm (Maschenweite 600 bis 1000) aufweist.
  9. Verfahren nach Anspruch 7, bei welchem das Schleifmittel in der Aufschlämmung in einer Konzentration zwischen 10 und 20 Vol.-% vorhanden ist.
  10. Verfahren nach Anspruch 1, bei welchem das Werkzeugmaterial aus der Gruppe ausgewählt ist, die aus Graphit, Glas und Quarz besteht.
  11. Verfahren nach Anspruch 1, bei welchem das Werkzeugmaterial ein ungeformter Block aus Graphit ist.
  12. Verfahren nach Anspruch 1, bei welchem das Werkzeugmaterial ein ungeformter Block aus Glas ist.
  13. Verfahren nach Anspruch 1, bei welchem die flüssige Schleifmittel-Aufschlämmung ständig durch den Spalt zwischen dem Werkzeug und dem Werkstück fließt.
  14. Verfahren nach Anspruch 1, bei welchem die flüssige Schleifmittel-Aufschlämmung Werkzeugteilchen und Teilchen, die von dem Werkstück abgetragen wurden, aus dem Spalt wegspült.
  15. Verfahren nach Anspruch 1, bei welchem das Schleifmittel in der Aufschlämmung ein aus der Gruppe ausgewähltes Mitglied ist, die aus Wolframcarbid, Aluminiumoxid, Siliziumcarbid, Borcarbid, Bornitrid, Tonerde, Korund, Diamant und deren Mischungen besteht.
  16. Verfahren nach Anspruch 15, bei welchem das Werkstück (4) aus einem Material besteht, welches aus der Gruppe ausgewählt ist, die aus Bronze, Messing, Gold und Polymermaterialien besteht.
EP89903596A 1988-03-10 1989-03-10 Ultraschall-polierung Expired - Lifetime EP0403537B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89903596T ATE96071T1 (de) 1988-03-10 1989-03-10 Ultraschall-polierung.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US166502 1980-07-07
US16650288A 1988-03-10 1988-03-10
US30576889A 1989-02-03 1989-02-03
US305768 1994-09-13

Publications (3)

Publication Number Publication Date
EP0403537A1 EP0403537A1 (de) 1990-12-27
EP0403537A4 EP0403537A4 (en) 1991-09-11
EP0403537B1 true EP0403537B1 (de) 1993-10-20

Family

ID=26862319

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89903596A Expired - Lifetime EP0403537B1 (de) 1988-03-10 1989-03-10 Ultraschall-polierung

Country Status (7)

Country Link
EP (1) EP0403537B1 (de)
JP (1) JP2691787B2 (de)
KR (1) KR930012261B1 (de)
AU (1) AU619263B2 (de)
DE (1) DE68910115T2 (de)
RU (1) RU1836206C (de)
WO (1) WO1989008535A1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5245796A (en) * 1992-04-02 1993-09-21 At&T Bell Laboratories Slurry polisher using ultrasonic agitation
DE4447698B4 (de) * 1994-02-27 2005-04-14 Hahn, Rainer, Dr.Med.Dent. Medizinisches Werkzeug
KR100299975B1 (ko) * 1998-02-19 2001-10-27 이정기 플라즈마챔버의전극제조방법
DE19817863A1 (de) * 1998-04-22 1999-11-04 Lzh Laserzentrum Hannover Ev Verfahren zum Glätten einer Oberfläche eines Werkstücks, insbesondere einer optischen Funktionsfläche
CN102615554B (zh) * 2012-04-15 2014-08-20 长春中俄科技园股份有限公司 一种微型球面或非球面透镜阵列的加工方法
CN110509123A (zh) * 2019-08-31 2019-11-29 巩义市宇通新材料科技有限公司 一种超声波研磨机的抛动装置

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2774193A (en) * 1955-10-10 1956-12-18 Thatcher Tools for ultrasonic cutting
US2804724A (en) * 1956-02-24 1957-09-03 Charles J Thatcher High speed machining by ultrasonic impact abrasion
US2850854A (en) * 1956-08-20 1958-09-09 Levy Sidney Method for removing material
US3593410A (en) * 1967-11-21 1971-07-20 Robert A Taylor Method for casting and finishing tools or dies
US4071385A (en) * 1976-05-19 1978-01-31 Arthur Kuris Ultrasonic inlaid article
JPS54133697A (en) * 1978-04-07 1979-10-17 Matsushita Electric Ind Co Ltd Supersonic method
JPS5741151A (en) * 1980-08-25 1982-03-08 Nippon Steel Corp Process for machining injection nozzle of molten metal
DE3125316A1 (de) * 1981-06-27 1983-01-13 Volkswagenwerk Ag, 3180 Wolfsburg Vorrichtung zum herstellen einer raumformelektrode aus graphit mit hilfe einer dreidimensionalen formfeile

Also Published As

Publication number Publication date
KR930012261B1 (ko) 1993-12-28
KR900700238A (ko) 1990-08-11
AU3219389A (en) 1989-10-05
AU619263B2 (en) 1992-01-23
WO1989008535A1 (en) 1989-09-21
RU1836206C (ru) 1993-08-23
DE68910115T2 (de) 1994-02-17
JP2691787B2 (ja) 1997-12-17
DE68910115D1 (de) 1993-11-25
EP0403537A1 (de) 1990-12-27
EP0403537A4 (en) 1991-09-11
JPH03504108A (ja) 1991-09-12

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