SE192579C1

SE192579C1 -

Info

Publication number: SE192579C1
Authority: SE
Publication date: 1964-01-01

Description

Uppfinnare: L A Williams Prioritet begard Iran den 14 september 1959 (USA) Foreliggande uppfinning avser en apparat for elektrolytisk slipning, vilken innefattar en elektriskt ledancle, roterbar slipskiva med slippartiklar, yilka bilda en slipyta p0. en ringformig yta ay slipskivan, en hallare for arbetsstycket och en baranordning for hallaren, Aiken baranordning är rorlig i en riktning yinkelratt mot slipskivans rotationsaxel far att fOra det av hallaren fasthallna arbetsstycket tvars over slipytan, en anordning far tillforsel ay elektrolyt till spalten mellan slipskivan och arbetsstyeket och en anordning for anslutning av slipskivan och arbetsstycket till en elektrolytisk stromkrets, sa. att slipskivan bildar katod. Inventor: L A Williams Priority requested Iran, September 14, 1959 (USA). The present invention relates to an electrolytic grinding apparatus which comprises an electrically conductive, rotatable grinding wheel with grinding particles, which form a grinding surface p0. an annular surface of the grinding wheel, a holder for the workpiece and a bar device for the holder. The bar device is movable in a direction perpendicular to the axis of rotation of the grinding wheel to move the workpiece held by the holder across the grinding surface. the workpiece and a device for connecting the grinding wheel and the workpiece to an electrolytic circuit, said. that the grinding wheel forms a cathode.

Elektrolytisk slipning bestar i stora drag dari, att ett arbetsstycke ansattes mot ytan pa en. roterande metallbunden slipskiva under sadana betingelser, att en. likstrom med lag spanning passerar genom en elektrolyt melIan arbetsstycket och slipskivan under slipningen for avlagsnande av material frau arbetsstycket genom .elektrolytisk verkan. En anordning och ett forfarande for genomfarande av denna grundprocess aro utforligt beskrivna i det arnerikanska patentet 2 826 540. Electrolytic grinding consists largely in that a workpiece is applied to the surface of one. rotating metal-bonded grinding wheel under such conditions, that a. low voltage direct current passes through an electrolyte between the workpiece and the grinding wheel during grinding to remove material from the workpiece by electrolytic action. An apparatus and method for carrying out this basic process are described in detail in U.S. Patent 2,826,540.

Uppfinningen har till andamal att mojligOra Okning ay materialavverkningshastigheten Yid bearbetning av ett arbetsstycke, pa vilken en plan yta utformas, varyid den stone avverkningshastigheten bör uppnas yid forhallandevis lag fkbrukning av elektrisk en:ergi. Uppfinningen liar darfOr till Andamal att asta:dkomma en apparat, yid vilken ett arbetsstycke fares tvars Over ytart pa. slipskivan sadant satt, att kontaktareart mellan arbetsstycket och slipskivan har en i huvudsak maximal storlek. The object of the invention is to make it possible to increase the material felling speed by machining a workpiece on which a flat surface is formed, and the stone felling speed should be achieved by relatively low consumption of electrical energy. The invention therefore aims to provide Andamal with an apparatus in which a workpiece is passed across the surface. the grinding wheel so set that the contact type between the workpiece and the grinding wheel has a substantially maximum size.

Den for uppnaende ay uppfinningens andamal konstruerade apparaten ay den inled ningsvis definierade typen kannetecknas i huvudsak daray, att slipytan an svagt konvex och har formen av mantelytan hos en trubbig stympad kon, vilken yta har en svag lutning relativt ett mot slipskivans axel vinkelratt plan, varvid lutningsvinkeln fir tillrackligt stor men ej yasentligt storre an att arbetsstycket med sakerhet gar klart for slipskivans periferi, nar del Hires mot och tvars Over slipskivans slipyta i en riktning vinkelratt mot den radie hos derma yta, langs vilken slipytan under slipturen arbetar sig djupast in i arbetsstycket. The apparatus for achieving the object of the invention of the type initially defined can be characterized mainly in that the grinding surface is slightly convex and has the shape of the mantle surface of a blunt truncated cone, which surface has a slight inclination relative to a plane perpendicular to the axis of the grinding wheel. the angle of inclination is sufficiently large but not significantly greater than that the workpiece is certainly ready for the periphery of the grinding wheel, when part Hires towards and across the grinding wheel grinding surface in a direction perpendicular to the radius of this surface, along which the grinding surface works deepest into the workpiece .

Enligt ett foredraget utforande Or den stympat koniska slipytans lutning relativt den mot slipskivans axel vinkelrata ytan c :a 2°. According to a preferred embodiment, the inclination of the truncated conical grinding surface relative to the surface perpendicular to the axis of the grinding wheel is about 2 °.

Uppfinningen beskrives narmare i det fOl- junder hartvisning till bifogade ritning, pa vilken fig. 1 visar en schematisk Yertikalprojektionsyy ay en slipapparat med de for uppfinningen kannetecknande konstruktiansdragen, fig. 2 Or en Ty, som schematiskt visar ett parti air slipskivans yta och arbetsstycket, vilket i askadliggorande syfte visas i ett lage, da det fores tyars Over slipskivan med ett parti I kontakt med denna pa ett f8r uppfirmingen typiskt salt, och fig. 3 är en tyarsektionsvy, tagen i huvudsak langs linjen 33 i fig. 2 och sett i den genom pilarna antydda riktningen. The invention is described in more detail in the following reference to the accompanying drawing, in which Fig. 1 shows a schematic vertical projection of a grinding apparatus with the construction features of the invention, Fig. 2 or a Ty, schematically showing a portion of the grinding wheel surface and the workpiece, which is shown for ash-making purposes in a layer, when the grinding wheel is lined over a grinding wheel with a portion in contact therewith on a typical salt for the invention, and Fig. 3 is a tire sectional view, taken substantially along line 33 in Fig. 2 and seen in the direction indicated by the arrows.

Under en ordinar slipoperation, cla en plan yta skall framstfillas pa ett arbetsstycke uteslutande genom slipning, fares vanligtvis arbetsstycket fram och Ater trans Over periferikanten pa den roterande slipskivan' i sficlan riktning, att arbetsstycket nalkas slipskivan tangentiellt. Den remsa air arbetsstyckets metallyta, som ãr i kontakt med slipskivans yta, har darfor en Magi, som är ekirivalent med slipskivans tjocklek, och en bredd av hogst nagra hundradels millimeter. I vane ogon- 2— — blick ãr salunda slipskivans och arbetsstyckets kontaktarea ytterst begransad, om icke slipskivor med opraktiskt stora diametrar anvandas. During an ordinary grinding operation, if a flat surface is to be produced on a workpiece exclusively by grinding, the workpiece is usually moved forward and transversely over the peripheral edge of the rotating grinding wheel in the direction of the workpiece so that the workpiece approaches the grinding wheel tangentially. The metal surface of the strip air workpiece, which is in contact with the surface of the grinding wheel, therefore has a Magi, which is equivalent to the thickness of the grinding wheel, and a width of a few hundredths of a millimeter. In the usual eyes, the contact area of the grinding wheel and the workpiece is extremely limited, unless grinding wheels with impractically large diameters are used.

Nar denna konventionella slipmatning anvandes vid en slipapparat for elektrolytisk slipning är elektrolysverkan mellan arbetsstycket °eh den av slipskivan bildade elektroden nara pa helt begransad till denna ytterst smala zon. Avverkningshastigheten fir darfor relativt lig, eftersom for varje sarskild spanning i elektrolysstromkretsen strOmflodet och foljaktligen avverkningshastigheten är direkt proportionell mot anodens och katodens effektiva area, och denna area fir i sin tur begransad i huvudsak till den zon, Mom vilket avstandet mellan slipskivans elektriskt ledande yta och arbetsstycket ãr konstant och vii-ken uppgar till endast nagra fa hundradels millimeter. When this conventional grinding feed is used in an grinding apparatus for electrolytic grinding, the electrolytic effect between the workpiece and the electrode formed by the grinding wheel is almost completely limited to this extremely narrow zone. The felling speed is therefore relatively similar, since for each particular voltage in the electrolytic circuit the current and consequently the felling speed are directly proportional to the effective area of the anode and cathode, and this area is in turn limited mainly to the zone between the electrically conductive surface and the workpiece is constant and the volume amounts to only a few hundredths of a millimeter.

Anstrangningarna att Oka avverkningshastigheten vid elektrolytisk slipning genom att Oka spanningen och darmed Oka stromtatheten aro av begransat varde bade dad& att otillatna spanningar kunna resultera i Over-slag mellan elektrodelementen och darfar aft Rat stromflode till priset av okad spanning i alltfor hog grad okar kostnaden for den elektriska energin. Det kan sasom exempel namnas, att om stromstyrkan i kretsen fordubblas genom att spanningen fordubblas, blir effekten i watt sasom ett matt pa kostnaden fyra ganger stone, varemot varje atgard som kan resultera i Okning av stromstyrkan i kretsen utan Mining i spanningen endast okar kostnaden fOr elektrisk energi sasom en direkt funktion av stromstyrkenningen. Eftcrsom Oven awerkningshastigheten Or en direkt funktion av stramstyrkan, sa hojer icke okningen av stromstyrkan kostnaden for elektrisk energi per avNerkad enhet, sa lange som spanningen forblir densamma. Den totala kostnaden vid Wining av stromstyrkan reduceras emellertid pd grund av att maskintiden per enhet blir minskad. The efforts to increase the felling rate in electrolytic grinding by increasing the voltage and thus increasing the current density are of limited value & that impermissible voltages can result in overlaps between the electrode elements and therefore the current current at the price of increased voltage increases the cost of electrical energy. It can be mentioned, for example, that if the current in the circuit is doubled by doubling the voltage, the power in watts becomes like a measure of the cost four times stone, whereas any action that can result in an increase in the current in the circuit without Mining in the voltage only increases the cost of electrical energy as a direct function of the current increase. Since above the rated rate is a direct function of the current, the increase in current does not increase the cost of electrical energy per de-charged unit, as long as the voltage remains the same. However, the total cost of Wining the current is reduced due to the reduction in machine time per unit.

Det bor med dessa fundamentala fakta i minnet inses, att stor kontaktarea Indian slipskivan och arbetsstycket Or synnerligen Onskyard vid elektrolytisk slipning, och dot Or pa detta problem, i farening med planslipning sasom motsats till kolvslipning, som uppfinningen Or inriktad. Mera speciellt medgiver tillampandet av nppfinningen langt stone ingreppsarea mellan slipskivan och arbetsstycket On som Or mojlig vid konventionell omgangsslipning, och detta utan namnvard Caning av slipskivans storlek och utan okning av graden av slipskivans inmatning i arbetsstycket vid varje sliptur. It is with these fundamental facts in mind that it is realized that the large contact area of the Indian grinding wheel and workpiece is particularly Onskyard in electrolytic grinding, and dot Or on this problem, in conjunction with face grinding as opposed to piston grinding, as the invention is directed. More specifically, the application of the invention allows a long stone engagement area between the grinding wheel and the workpiece On as possible in conventional round grinding, and this without naming Caning of the size of the grinding wheel and without increasing the degree of grinding wheel feed in the workpiece at each grinding trip.

Med hanvisning i forsta hand till fig. 1 visas schematiskt en med 10 betecknad metallbunden slipskiva, som Or monterad pa. en i ett hus 14 lagrad spindel 12. Huset Or fast vid en haltare 16, som uppbar en elektrisk motor 18 och som i sin tur Or fast vid slipmaskinens stativ 20. En isolerande dyna mellan huset 14 och hallaren 16 mojliggor, att dessa element kunna ha skiljaktig elektrisk potential. Spindeln 12 och slipskivan 10 Oro anordnade att drivas medelst motorn 18 via en eller fkra remmar 22. En ledare 24 med lag negativ potential for elektrolysframkallande likstrom Or ansluten till borstar 26, vilka anligga mot en slapring 28, som Or monterad pa spindeln 12. Slipskivan liar darfor negativ elektrolyspotential, varemot motorn 18 och maskinstativet kunna ha jordpotential. Referring primarily to Fig. 1, a metal-bonded grinding wheel designated 10 is schematically shown, on which Or is mounted. a spindle 12 stored in a housing 14. The housing is attached to a holder 16, which carried an electric motor 18 and which in turn is attached to the stand 20 of the grinding machine. An insulating pad between the housing 14 and the holder 16 makes it possible for these elements to have different electrical potential. The spindle 12 and the grinding wheel 10 are arranged to be driven by the motor 18 via one or several belts 22. A conductor 24 with low negative potential for electrolysis-inducing direct current Or connected to brushes 26, which abut against a slip ring 28, which Or is mounted on the spindle 12. The grinding wheel therefore has a negative electrolysis potential, whereas the motor 18 and the machine stand may have earth potential.

I foreliggande fall fasthalles arbetsstycket inedelst en magnetisk chuck 30, som Or ansluten till jord och till elektrolyskretsens positiva ledare 32. Chucken 30 Or fast vid ett bord 34, som Or anordnat att forskjutas langs maskinbadden 36 pa styrningar 38. In the present case, the workpiece is held inwardly by a magnetic chuck 30, which is connected to ground and to the positive conductor 32 of the electrolytic circuit. The chuck 30 is fixed to a table 34, which is arranged to be displaced along the machine bath 36 on guides 38.

Det Or underforstatt, att en lamplig, vanligtvis hydraulisk mekanism, vilken icke är visad, eftersom sadana anordningar Oro vanliga, Or anordnad att fora bordet 34 fram och ater med en vald hastighet och onskad slaglangd. Vidare Or en mekanism anordnad for matning av badden 36 uppat mot slipskivan i lamplig grad mellan bordets 34 slag. This implies that a suitable, usually hydraulic, mechanism, which is not shown, since such devices are common, is arranged to advance the table 34 at a selected speed and desired stroke. Furthermore, a mechanism is provided for feeding the bath 36 upwards against the grinding wheel to an appropriate degree between the strokes of the table 34.

Slipskivan 10 arbetar med sin yttre yta 46, Aiken sasona visas i fig. 1 och 3, icke ãr en ringformig plan yta utan bildar en trubbig stympad kon. I fOrtydligande syfte Or lutningen av denna yta visad vaserttligen Overdriven. Arbetsytan Or foretrademis en rotationsyta med en lutningsvinkel av cirka relativt ett mot spindelns 12 axel vinkelrat plan. Denna yta Or konvex genom att dess parti nat.- mast slipskivans centrum stracker sig nagot langre utat On dess periferi. The grinding wheel 10 works with its outer surface 46, Aiken as shown in Figs. 1 and 3, is not an annular flat surface but forms a blunt truncated cone. For the sake of clarity, the slope of this surface is shown to be exaggerated. The working surface Or is represented by a rotating surface with an angle of inclination of approximately relative to a plane perpendicular to the axis of the spindle 12. This surface Or convex in that its part nat.- mast the center of the grinding wheel extends somewhat further out On its periphery.

Slipskivan skall normalt vara monterad i ett nagot lutande lage, sd att dess axel lutar relativt vertikalplanet i en mot slipskiveytans lutning svarande grad. I foreliggande exempel Or salunda lutningsgraden cirka 2°. Vid ett stalle Or (WET en radiell linje tvars slipskivans yta horisontell, och vid detta stalk har avstandet mellan slipskivans yta och chuckens oversida sitt minimum. Detta stalle Or i fig. 2 och 3 antytt medelst linjen 50. Monteringen Or sa utford, att denna linje 50 Or belagen ovanfor chucken och stacker sig ratvinkligt relativt dennas rorelseriktning langs styrningarna 38. Det bOr namnas, att denna linjes lage bestammer planet for den p0. arbetsstycket slipade ytan vid slutet av varje tur av bordet 34. The grinding wheel should normally be mounted in a slightly inclined bearing, so that its axis is inclined relative to the vertical plane to a degree corresponding to the inclination of the grinding wheel surface. In the present example, the degree of inclination is about 2 °. At a stall Or (WET a radial line the surface of the grinding wheel is horizontal, and at this stalk the distance between the surface of the grinding wheel and the upper side of the chuck has its minimum. This stall Or in Figs. 2 and 3 is indicated by line 50. The assembly Or said challenge that this line 50 Or coated above the chuck and stacked at right angles to its direction of movement along the guides 38. It should be noted that the position of this line determines the plane of the surface ground on the workpiece at the end of each turn of the table 34.

PA omse sidor om den centrala linjen 50 sluttar emellertid slipskivans yta gradvis frau detta plan, varigenom Oven vid en liten slipskiva arbetsstycket kommer att forsiktigt och gradvis ingripa med slipskivan, nar det framfores medelst bordet 34 till ett sa.dant lige relativt badden 36, att ett lampligt tunt skikt av metallen avlagsnas, for att nar arbetsstyckets framre kant nar fram till den radiella, — —3 centrals. linjen 50, slutligen ingripa over ett synnerligen stort ytomrade. Elektrolysverkan (sasom visas tillfOres elektrolyt genom en ledning 51 sá att den bringas att gramma Over slipskivans yta) ager dad& rum Over ett stort omrade av arbetsstyckets yta, vilket ãr synnerligen Onskvart, sasom tidigare beskrivits. On the opposite side of the central line 50, however, the surface of the grinding wheel gradually slopes from this plane, whereby even with a small grinding wheel the workpiece will gently and gradually engage the grinding wheel as it is advanced by means of the table 34 to such a position relative to the bath 36 that a suitably thin layer of the metal is removed, so that when the front edge of the workpiece reaches the radial, - —3 centrals. line 50, finally intervening over an extremely large surface area. The electrolytic effect (as shown is supplied with electrolyte through a line 51 so that it is caused to grind over the surface of the grinding wheel) acts as a space over a large area of the workpiece surface, which is particularly uneven, as previously described.

Fig. 2 och 3 visa ingreppet mellan slipskivan och arbetsstycket under typiska forhallanden ehuru i fortydligande syfte slipskivans lutning och foljaktligen tjockleken av den me-tall, som avldgsnas, dr visad overdrivet stor. Kontaktarean mellan arbetsstycket och slipskivan, dar elektrolysverkan sker, visas liggande mellan de streckade linjerna 50 och 52 och har en bredd ekvivalent med arbetsstyckets bredd. Nar arbetsstycket narmar sig slipskivan frail vanster med avseende pa fig. 2 bear det icke slipskivan forran det nar fram till punkten 54. Det foreligger salunda icke nagon risk f6r fastklamning. Vid nagon ytterligare frammatning (till punkten 56) astadkommes fullstandig kontakt tvars Over arbetsstycket och detta ingrepp fortsatter, tills arbetsstycket passerar forbi slipskivans yta vid den centrala linjen 50. Figs. 2 and 3 show the engagement between the grinding wheel and the workpiece under typical conditions, although for the purpose of clarification the inclination of the grinding wheel and consequently the thickness of the metal which is deposited, there is shown excessively large. The contact area between the workpiece and the grinding wheel, where the electrolysis action takes place, is shown lying between the dashed lines 50 and 52 and has a width equivalent to the width of the workpiece. When the workpiece approaches the grinding wheel from the left with respect to Fig. 2, it does not bear the grinding wheel until it reaches point 54. There is thus no risk of clamping. In the event of any further feed (to point 56), complete contact is made across the workpiece and this engagement continues until the workpiece passes past the surface of the grinding wheel at the central line 50.

Det bor namnas, att vid anvandningen av apparaten enligt uppfinningen stor kontaktarea mellan arbetsstycket och slipskivan och foljaktligen effektiv och snabb elektrolysverkan kan erhallas vid: slipning i turer aven vid sma slipskivor, och detta kan ske under sakerstallande av gradvis ingrepp mellan arbetsstycket och slipskivan och utan risk for att det frammatade arbetsstycket stoter eller klammer emot slipskivans kant. It should be mentioned that when using the apparatus according to the invention large contact area between the workpiece and the grinding wheel and consequently efficient and fast electrolysis effect can be obtained by: grinding in turns even with small grinding wheels, and this can be done by gradual engagement between the workpiece and the grinding wheel and without risk of the fed workpiece bumping or clamping against the edge of the grinding wheel.

Vid det speciella utforandet av uppfinningen, som är visad p5. ritningen och ovan beskrivits, är slipskivans axel anordnad med endast svag lutning relativt vertikalplanet. Det bor emellertid namnas, att den geometriska axeln for slipskivans barorgan bestfimmes i stort sett av den typ av slipmaskin, medelst vilken slipningen skall utforas. Utforandet enligt fig. 1 är vanligt, eftersom det medgiver, att den yta av arbetsstycket, som skall slipas, fir placerad horisontellt relativt bordet, men det Sr givet, att relationen mellan arbetsstyckets yta och slipskivan icke skulle andras om bade slipskivans axel och arbetsstyckets yta lutades fran detta lage i sal-lima grad, och for en del arbeten kunde detta mojligen vara mera lampligt. Det viktiga i detta sammanhang är givetvis slipskivans kontur samt placeringen och orienteringen av slipskivans yta relativt arbetsstyckets yta samt arbetsstyckets rorelseriktning relativt slipskivans yta. In the particular embodiment of the invention, which is shown p5. drawing and described above, the axis of the grinding wheel is arranged with only a slight inclination relative to the vertical plane. It should be mentioned, however, that the geometric axis of the bar member of the grinding wheel is largely determined by the type of grinding machine by means of which the grinding is to be performed. The embodiment according to Fig. 1 is common, since it allows the surface of the workpiece to be ground to be placed horizontally relative to the table, but it is obvious that the relationship between the surface of the workpiece and the grinding wheel would not change on both the axis of the grinding wheel and the workpiece surface. was tilted from this layer to a sal-lima degree, and for some works this could possibly be more appropriate. The important thing in this context is, of course, the contour of the grinding wheel and the placement and orientation of the surface of the grinding wheel relative to the surface of the workpiece and the direction of movement of the workpiece relative to the surface of the grinding wheel.

Av ovanstaende beskrivning av ett foredraget utforande enligt uppfinningen bor det tydligt ha framgatt, att olika modifikationer aro mojliga mom ramen for uppfinningen, sasom denim Sr definierad i de bifogade patentanspraken. From the above description of a preferred embodiment according to the invention, it should have been clear that various modifications are possible within the scope of the invention, such as denim Sr defined in the appended patent claims.

Claims

Patent claim:

Apparatus for electrolytic grinding, comprising an electrically conductive, rotatable grinding wheel (10) with grinding particles, which form a grinding surface (46) ph an annular surface of the grinding wheel, a holder (30) for the workpiece and a bar device (34) for the holder , which bar device is movable in a direction perpendicular to the axis of rotation of the grinding wheel (10) to move the workpiece held by the holder (30) across the grinding surface (46), a device for supplying electrolyte to the slot Indian grinding wheel (10) and the workpiece and a device (32) for connecting the grinding wheel and the workpiece to an electrolytic strain circuit, so that the grinding wheel forms a cathode, drawn wire drive, that the grinding surface (46) is slightly convex and has the shape of the mantle surface of a blunt truncated cone, which surface has a slight inclination relative a plane perpendicular to the axis of the grinding wheel, the angle of inclination being sufficiently large but not substantially greater than that the workpiece is securely ready for the periphery of the grinding wheel when flares towards and twists over the grinding surface of the grinding wheel in a direction perpendicular to the radius of this surface, along which the grinding surface during the grinding trip works deepest into the workpiece.

2. Apparatus according to patent claim 1, Milne-characterized in that the inclination of the truncated conical grinding surface (46) relative to the surface Sr about 20 perpendicular to the axis of the grinding wheel.