EP0635334A2 - Eine von Schleifteilchen enthaltendem Harz imprägnierte Scheibe, Verfahren zum Herstellen der Scheibe und Läppenverfahren - Google Patents

Eine von Schleifteilchen enthaltendem Harz imprägnierte Scheibe, Verfahren zum Herstellen der Scheibe und Läppenverfahren Download PDF

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Publication number
EP0635334A2
EP0635334A2 EP94830368A EP94830368A EP0635334A2 EP 0635334 A2 EP0635334 A2 EP 0635334A2 EP 94830368 A EP94830368 A EP 94830368A EP 94830368 A EP94830368 A EP 94830368A EP 0635334 A2 EP0635334 A2 EP 0635334A2
Authority
EP
European Patent Office
Prior art keywords
disc
discs
abrasive
resin
wheel
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
Application number
EP94830368A
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English (en)
French (fr)
Other versions
EP0635334B1 (de
EP0635334A3 (de
Inventor
Massimo Sommaruga
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.)
TESSITURA LANDINI Srl
Original Assignee
TESSITURA LANDINI Srl
Priority date (The priority date 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 date listed.)
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Publication date
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Publication of EP0635334A2 publication Critical patent/EP0635334A2/de
Publication of EP0635334A3 publication Critical patent/EP0635334A3/de
Application granted granted Critical
Publication of EP0635334B1 publication Critical patent/EP0635334B1/de
Anticipated expiration legal-status Critical
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
    • B24D18/0027—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for by impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D13/00—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor
    • B24D13/02—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by their periphery
    • B24D13/12—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by their periphery comprising assemblies of felted or spongy material, e.g. felt, steel wool, foamed latex
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/20—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially organic
    • B24D3/28—Resins or natural or synthetic macromolecular compounds

Definitions

  • This invention concerns the mechanical surface treatment by which the untreated surface is lapped and eventually buffed in the final treatment stages.
  • This type of surface treatment can be carried out on metals, painted or varnished surfaces, cast or injection-molded plastics and the like.
  • cloths or plaits used are usually made of natural fibres such as cotton, agave sisal, flax, hemp, wool and jute, on account of these natural fibres' higher resistance to overheating during treatment.
  • a wide range of cloths and abrasive pastes selections may create operating conditions ranging from highly abrasive lapping to almost purely buffing treatments. As experienced operators know, there may be several intermediate stages of leveling/buffing through which abrasive properties are progressively reduced and viceversa buffing/polishing properties increased.
  • the work area is the wheel outer periphery. Therefore, the air radially flowing from the wheel center towards the periphery - accelerated by appropriately-shaped holes or air intakes in the wheel truing plates - "cools down" the peripheral work area of the wheel, thus allowing non-stop machining.
  • the abrasive paste is intermittently distributed on the work area, by injecting it through appropriately oriented nozzles.
  • the intermittent feeding of abrasive paste in the work area entails periodic, even drastic changes in the operating conditions.
  • the work run shows performance "peaks” alternating with performance "drops", "synchronized” through repeated feeds of fresh abrasive paste during treatment.
  • a lot of the abrasive paste is inevitably lost due to the centrifugal force. Losses increase when the disc or wheel work area gets overheated, since the paste tends to become more fluid as the temperature rises.
  • the lost abrasive paste cannot be recovered, nor can it be recycled. Therefore, the lost paste not only represents an important cost item in the working process, but its disposal also causes environmental problems.
  • Buffing discs and wheels are essentially expendable materials, since they undergo progressive wearing. Ventilated wheels are to be replaced when their outer diameter has decreased below a certain limit, which in many cases can be as low as 60 ⁇ 70% of the original wheel diameter.
  • a widely-used technique to increase the cloth or plait wear resistance is to provide "rigidity" to the cloth of which the wheel or disc are made by impregnating it with special emulsions of an acrylic, vinyl, epoxy or oily resin. If necessary, the resin impregnating the cloth is then submitted to a polymerization heat-treatment.
  • the cloth is vacuum-impregnated by placing it in a special evacuable "autoclave" into which the impregnating emulsion is poured. After draining the emulsion from the vacuum chamber, the buffing discs or wheels are removed and then heated in the oven, to eliminate possible traces of solvent, till the temperature reached and the time elapsed are sufficient to allow resin polymerization.
  • this new techinque consists in impregnating a buffing disc or wheel with an emulsion-suspension containing both a polymerizable resin and an abrasive powder and successively polymerizing the resin.
  • This treatment of the textile discs or wheels brings about an unexpected series of highly positive effects.
  • the abrasive powder (of a given particle size) incorporated in the resin with which the lapping/buffing disc/wheel cloth is impregnated produces an extra source of lapping agent (e.g., a metal oxide) "in situ".
  • lapping agent e.g., a metal oxide
  • the abrasive powder incorporated in the impregnating resin of the disc/wheel cloth is gradually released onto the surface or work area.
  • This extra abrasive powder rather than merely adding to the intermittently fed abrasive paste, tends to supplement it during the intervals between intermittent distributions of abrasive paste on the work area, so as to make up for and decrease the occurrence of abrasive powder shortages occurring between two successive distribution cycles of fresh abrasive paste.
  • this not only helps maintaining suitable lapping properties, but it also reduces overall treatment time and allows a drastic reduction in the amount of abrasive paste to be progressively distributed during the entire working cycle.
  • this technique reduces cloth disc overheating and wearing, during the abrasive paste shortage phases between two subsequent abrasive paste feeds, thus prolonging the life of the ventilated disc or wheel.
  • Fig. 1 shows a buffing disc 1 consisting of a "pack” or pile of cloth discs (2), piled up one on top of the other and joined by concentric seams (3). Hub (4) allows the disc to be installed on a rotating spindle.
  • the disc may also include two side strengthening discs (5) made of cardboard or other suitable material.
  • Fig. 2 shows a ventilated buffing disc (or wheel) obtained by placing together a certain number of strips (2') of slanting cloth folded into a "V". Cloth strips are anchored to a metal hub (4') which may include two side discs (5'), provided with openings or air intakes (6) to let cooling air flow from the hub core towards the peripheral work area of the wheel, through air passages.
  • the cloth may be made up of cotton, agave sisal, wool, flax, hemp, jute, or similar fibres with adequate resistance against overheating.
  • the fabric may be made up of a single type of fibre or may be obtained by combining different fibres in different amounts.
  • Cotton and sisal are among the most widely used fibres. The latter is particularly suitable for roughing discs. This fiber can in fact generate a higher abrasive power and is therefore recommended for preliminary surface lapping.
  • abrasive power is gradually reduced and buffing conditions are enhanced by using increasingly "softer" (e.g., cotton) buffing discs and increasingly thinner abrasive pastes.
  • the type of cloth or plaited cord used for these discs may change depending on the characteristics required. Therefore, besides combining different fibres, more or less "napped" cloths are used to adjust the abrasive and/or buffing power of the disc.
  • An abrasive powder suspension of the required particle size and characteristics is prepared in a special tank - fitted with a stirrer - containing a liquid mixture consisting of an aqueous dispersion of a soluble resin, which may be an acrylic, vinyl, or epoxy resin, together with emulsifying agents, such as fatty acids obtained from tallow or other oily compounds.
  • a liquid mixture consisting of an aqueous dispersion of a soluble resin, which may be an acrylic, vinyl, or epoxy resin, together with emulsifying agents, such as fatty acids obtained from tallow or other oily compounds.
  • the mixture is kept homogeneous through continuous stirring.
  • the discs are removed from the autoclave and centrifuged in a special centrifugal chamber (centrifuge) until they reach a substantial dynamic balance.
  • This centrifugation process besides eliminating the impregnating mixture in excess, ensures a substantially uniform distribution of the impregnating substance.
  • the impregnated and centrifuged discs are finally oven-treated by progressively raising the temperature of the oven up to about 140°-170°C.
  • the impregnating mixture is dried by evaporation of the aqueous solvent and the resin is polymerized and fixed onto the cloth fibres incorporating the particles of the abrasive material contained in the impregnating suspension.
  • the mixing ratio between the resin and the abrasive powder usually ranges in weight between 0.5:1 and 1.5:1. Tests show that if aluminum oxide (Al2O3), with a 50% to 98% ⁇ -alumina content, in terms of overall weight, is used as abrasive material together with an acrylic resin, the ratio between the abrasive material absorbed and the incorporating resin should be about 1:1.
  • the particle size of the abrasive powder incorporated in the cloth-impregnating resin may range between 20 and 100 ⁇ m.
  • the particle size is selected according to the type of disc required. A coarse particle size is recommended for the preparation of "roughing" discs, whereas a finer size is more suitable for discs to be used at the lapping/buffing stage, to get extremely leveled and buffed surfaces.
  • fatty acids or similar emulsifying compounds in percentages ranging from about 10% to 20% of the overall mixture weight facilitates the dispersion and suspension of the abrasive particles in the mixture.
  • the discs produced according to the procedure of this invention hereinafter referred to with acronym I.R.A. (Impregnazione Resistenza Abrasiva, i.e. Abrasive Resistance Impregnation) prove to be unexpectedly effective and long-lasting as compared to the discs impregnated according to the traditional technique, i.e. without incorporating abrasive particles in the dressing resin.
  • a basic feature of the discs manufactured according to this invention is the improvement in the overall performance of the mechanical surface treatment, as compared to the discs produced according to the former technique.
  • This important advantage has been quantified through a series of tests comparing I.R.A. discs with discs having the same features but without abrasive particles incorporated in the impregnating resin.
  • This study was carried out for buffing processes on rotary tables mainly using discs of the so-called ventilated type.
  • the highly automated and continuously operated type of treatment actually provides ideal conditions, on the one hand for detecting the effects produced by the treatment as a function of time, according to observable "indexes", and on the other, for comparing the actual effectiveness of the treatment.
  • this treatment provided for a timed feed of abrasive paste in the work area at preset intervals.
  • the lapping performance was assessed according to an empiric 0 to 100 scale. Efficacy was rated by observing the ability of the disc to level off grooves created on the surface of brass and stainless steel workpieces by sanding it with a 80 to 360 grain size sanding paper.
  • the buffing discs used in a first comparative test series were ventilated discs made of agave sisal cloth and with a configuration similar to that shown in Fig. 2.
  • the impregnating mixture of I.R.A. discs manufactured according to this invention was the following:
  • a second set of test discs had the same configuration as the one shown in Fig. 2, but made with cotton cloth strips.
  • the impregnating mixture was the following:
  • Impregnation was carried out after a 25 Torr vacuum was created in the autoclave.
  • the impregnated discs were centrifuged at about 1,400-2,800 r.p.m. for about ten seconds.
  • the drying-polymerization process was carried out by gradually heating the discs from room temperature up to 150°C in one hour, and by keeping the 150°C temperature constant for a further 30 minutes.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
EP94830368A 1993-07-22 1994-07-20 Eine von Schleifteilchen enthaltendem Harz imprägnierte Scheibe, Verfahren zum Herstellen der Scheibe und Läppenverfahren Expired - Lifetime EP0635334B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT93VA000014A IT1265984B1 (it) 1993-07-22 1993-07-22 Disco o ruota di materiale tessile impregnato con resina contenente particelle di materiale abrasivo, procedimento di preparazione e
ITVA930014 1993-07-22

Publications (3)

Publication Number Publication Date
EP0635334A2 true EP0635334A2 (de) 1995-01-25
EP0635334A3 EP0635334A3 (de) 1995-05-24
EP0635334B1 EP0635334B1 (de) 2002-06-05

Family

ID=11423242

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94830368A Expired - Lifetime EP0635334B1 (de) 1993-07-22 1994-07-20 Eine von Schleifteilchen enthaltendem Harz imprägnierte Scheibe, Verfahren zum Herstellen der Scheibe und Läppenverfahren

Country Status (3)

Country Link
EP (1) EP0635334B1 (de)
DE (1) DE69430715T2 (de)
IT (1) IT1265984B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997018059A1 (en) * 1995-11-16 1997-05-22 Minnesota Mining And Manufacturing Company Surface treating articles and method of making same
CN102794715A (zh) * 2012-08-03 2012-11-28 河南工业大学 一种纤维增强砂轮基体及其制备方法
CN104260004A (zh) * 2014-08-06 2015-01-07 翁博川 一种具有光亮剂的抛光轮及其加工方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH417387A (fr) * 1961-02-06 1966-07-15 Carborundum Co Objet abrasif et son procédé de fabrication
JPS6128573A (ja) * 1984-07-18 1986-02-08 Mitsubishi Mining & Cement Co Ltd 研磨パツド及びその製造方法
DE8430781U1 (de) * 1984-10-19 1987-07-23 Brand, Jack, Toronto, Ontario, Ca
EP0400658A2 (de) * 1989-05-31 1990-12-05 Norton Company Umhülltes Schleifmaterial, sein Herstellungsverfahren und seine Anwendung
EP0446871A1 (de) * 1990-03-12 1991-09-18 Kurt Koch Gmbh Verfahren und Vorrichtung zum Schleifen bzw. Schärfen der Schneide eines Materialbearbeitungswerkzeugs
US5129919A (en) * 1990-05-02 1992-07-14 Norton Company Bonded abrasive products containing sintered sol gel alumina abrasive filaments
US5224968A (en) * 1992-07-07 1993-07-06 Ramron-Bancroft, Inc. Method for making abrasive wheels

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH417387A (fr) * 1961-02-06 1966-07-15 Carborundum Co Objet abrasif et son procédé de fabrication
JPS6128573A (ja) * 1984-07-18 1986-02-08 Mitsubishi Mining & Cement Co Ltd 研磨パツド及びその製造方法
DE8430781U1 (de) * 1984-10-19 1987-07-23 Brand, Jack, Toronto, Ontario, Ca
EP0400658A2 (de) * 1989-05-31 1990-12-05 Norton Company Umhülltes Schleifmaterial, sein Herstellungsverfahren und seine Anwendung
EP0446871A1 (de) * 1990-03-12 1991-09-18 Kurt Koch Gmbh Verfahren und Vorrichtung zum Schleifen bzw. Schärfen der Schneide eines Materialbearbeitungswerkzeugs
US5129919A (en) * 1990-05-02 1992-07-14 Norton Company Bonded abrasive products containing sintered sol gel alumina abrasive filaments
US5224968A (en) * 1992-07-07 1993-07-06 Ramron-Bancroft, Inc. Method for making abrasive wheels

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 8612, Derwent Publications Ltd., London, GB; AN 86-079162 & JP-A-61 028 573 (MITSUBISHI MINING CEMENT) 8 February 1986 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997018059A1 (en) * 1995-11-16 1997-05-22 Minnesota Mining And Manufacturing Company Surface treating articles and method of making same
US5996167A (en) * 1995-11-16 1999-12-07 3M Innovative Properties Company Surface treating articles and method of making same
US6251002B1 (en) 1995-11-16 2001-06-26 3M Innovative Properties Company Surface treating articles and method of making same
US6514363B2 (en) 1995-11-16 2003-02-04 3M Innovative Properties Company Surface treating articles and method of making same
CN102794715A (zh) * 2012-08-03 2012-11-28 河南工业大学 一种纤维增强砂轮基体及其制备方法
CN102794715B (zh) * 2012-08-03 2015-07-15 河南工业大学 一种纤维增强砂轮基体及其制备方法
CN104260004A (zh) * 2014-08-06 2015-01-07 翁博川 一种具有光亮剂的抛光轮及其加工方法

Also Published As

Publication number Publication date
ITVA930014A0 (it) 1993-07-22
EP0635334B1 (de) 2002-06-05
DE69430715T2 (de) 2002-09-26
IT1265984B1 (it) 1996-12-16
ITVA930014A1 (it) 1995-01-22
EP0635334A3 (de) 1995-05-24
DE69430715D1 (de) 2002-07-11

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