CA1066108A - Production of shaving foil - Google Patents
Production of shaving foilInfo
- Publication number
- CA1066108A CA1066108A CA256,140A CA256140A CA1066108A CA 1066108 A CA1066108 A CA 1066108A CA 256140 A CA256140 A CA 256140A CA 1066108 A CA1066108 A CA 1066108A
- Authority
- CA
- Canada
- Prior art keywords
- face
- front face
- foil
- etching
- dished
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B26—HAND CUTTING TOOLS; CUTTING; SEVERING
- B26B—HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR
- B26B19/00—Clippers or shavers operating with a plurality of cutting edges, e.g. hair clippers, dry shavers
- B26B19/38—Details of, or accessories for, hair clippers, or dry shavers, e.g. housings, casings, grips, guards
- B26B19/384—Dry-shaver foils; Manufacture thereof
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/02—Local etching
Abstract
PRODUCTION OF SHAVING FOIL
ABSTRACT OF THE DISCLOSURE
The invention concerns a method for producing foils for dry shavers.
The method of the invention includes forming a layer of photosensitive material on each side of a metal plate, exposing each side to light to produce a pattern of exposed and unexposed areas, corresponding to per-forations at one side and recesses in the backs of the bars of the foil on the other side, etching each side, then removing photosensitive material from the front side and carrying out further etching until the foil is completely perforated.
The invention is especially suitable for forming foils for battery operated dry shavers.
ABSTRACT OF THE DISCLOSURE
The invention concerns a method for producing foils for dry shavers.
The method of the invention includes forming a layer of photosensitive material on each side of a metal plate, exposing each side to light to produce a pattern of exposed and unexposed areas, corresponding to per-forations at one side and recesses in the backs of the bars of the foil on the other side, etching each side, then removing photosensitive material from the front side and carrying out further etching until the foil is completely perforated.
The invention is especially suitable for forming foils for battery operated dry shavers.
Description
1066,108 FIELD OF THE INVENTION
. .
This lnvention concerns a method of producing per-forated foils for dry shavers.
The cutting head of a dry shaver conventionally comprises a perforated stationary outer shear ~oil and an inner movable cutter contacting the rear face of the shear foil. The cutter can either comprise a plurality of separate blades or it can itself be made from a perforated foil.
Our copending Canadian Application No. 256,141 (now Canadian Patent 1,041,753 issued 7 November, 1978) provides a shearing foil for a dry shaver, made from a sheet of metal or alloy, having perforations extending through the sheet with bars between the perforations, the bars being dished in transverse cross-sectional profile, the base of the dished profile being substanti-ally flat and of uniform thickness(t), and the edges of the dished profile extending at an obtuse angle to the base to terminatewith coplanar faces disposed parallel to the base, said face having a width(_) in the transverse direction which is not greater than (t).
STATEMENT OF PRIOR ART
Various forms of foil have been proposed in the lit-erature, or employed in practice. For instance, British Patent Specification No. 845,832 describes a foil whose thickness(from front to rear surfaces) immediately adjacent to the apertures exceeds the thickness at those portions between apertures.
Heretofore, a variety of methods has been proposed and employed for producing shaving foils. For instance, electrodeposition techniques have been proposed in U.S.
t~
610~3 Patcnts NG. 3,~ ]. 3,655,528; 3,655,529; and 3,695,927.
Stamping tec~ln.Jqucs have also beerl desc.ribed, for instance ~n U.S. ~atcnt No. 3,216,286. British l'atent No~ 1,056,038 provides a met:hod involving co,ting a flat stainless steel plate with a photoresist, exposing through a mask with the r desired apertures, removing the unhardelled parts of the resist to bare the steell bending tllc plate to the desired shape and etching through the stcel and rcmoving the hardene~d parts by burning off to obtain the shear plates. Preferably, the shear plate is hardened by heating to 1,020C, cooled rapidly, immersed in liquid air and tempered at 200C. ~!
An earlier method described in.British Patent Specification No. 845,832 involves: etcl-ing a sheet by a chemical or electrochemical process, so as to produce apertures surrounded by rims which project from the inner surface of the plat:e which is contacted by the cutting member. ~pertures in a resist on the outer side are in groups, and resist on the inner side forms a pattern of .
islands each corresponding to such a group. Etching is carried out until less than half the thickness of metal has been removed, then stopped, and resist applied over all the inner side including the etched depressions, then etching iS re-started so as to etch holes through from the outer sidc, and continued until each group of aper-- tures merges into a single hole surroundcd on the inner side by a crenate rim.
There.has, however, been a continued search for ncw methods of producing foil$.
OBJECT OF TIIE INVENTION -r __ The object of the present inventicn is to provide ...
P~)66~08 a novel rnet}lod of producing a per,.oratcd foil for a dry shaver.
STATEMENT OF l`~E INVENTION
_ _ _ _ _ _ .
rrhe prescrlt invcntion providcs.a mcthod of producing a sheariny foil for a dry shaver from a shee~ of metal, said foil having a front facc and a back face, and exhibit-ing perforations extending through the shcet from said front face to said back face with bars bctwcen the perfor-ations, the bars being dished in transverse cross-sectional profile, the recessed base of the dished profile being sub-stantially flat and of uniform thickness, and -the edges of the dished profile extending at an angle to the base to terminate with coplanar faces disposed parallel to t:he base, which method comprises applying a layer of a photosensitivc material to each face of the sheet of metal, exposing the front face to radiation through a mask having a hole pat-tern corresponding to the desired pcrforations of the shaving foil, exposing the back face to radiation through a mask having a pattern corresponding to the recessed base of the dished profile, developing the photosensitive material in ordcr to generate a respective pattern of unprotected regions on each face of the metal sheet, etch-ing said unprotected regions of the front face and the back ' face, removing the photosensitive layer from the front face-foil, carryiny out a further etching of the front face until a predetermined quantity of metal is removed and the ridges of the bars are smoothly rounded off, and finally removing the remaining masking material.
DESCRIPTION OF DRAWINGS r The invention will be more particularly described ~ 8 , , .
with referhnce to ~hc ~ccompanying drawings in whlch:
Fig. i is a cross-section through a bar on a foiL
o conventior)al cor,struction;
Fig. 2 is a cross-section ,hrough a bar on a foi3 according to our above-mentioned copending ~ppllcation:
and Figs. 3 and 4 arc cross-sections illustrating two r stages during the mcthod according to thc invention.
PARTICULAR DESCRIPTION OF THE INVENTION
_ _ _ _ _ ___ _ ~eferrillg now to Figs. 1 and 2, a foil has apertures 1 and bars 2 between the apertures. Thc bars 2 are dished in cross-sectional profile, with a substantially flat base 3 of thickness t and edges 4 extending at an angle o~ to the base. The edges 4 terminate in faces 5 which are coplanar and parallel to the base 3, and have a width _.
The bars therefore, have recessed portions 6.
In-accordance with the conventional construction shown in Fig. 1, _ is greater than t, and the angle d~ is substantial]y a rig}lt angle.
In accordance with the invention of our copending Application shown in Fig. 2, _ is not greater than t.
In other words, ~ can be substantially the same as t, or it can b.e less than t.
The m~itcrial from which the foils are made is a single metal or alloy (e.g. steel). - r The usc of a single material in the construction of the foils according to the invention makes it possible to employ the advantageous etching technique according to the present invention. This technique will be described with r reference to Figs. 3 and 4 of the accompanying drawings.
--5~
106~108 In accordance with this method, a strip 10 of a suitable metal, e.g. laminated steel, is cleaned to remove grease and other contaminants from its surfaces, and is then provided by dip-coating with a layer of a suitable negative or positive photoresist on each surface. A pre-ferred negative photoresist is Waycoa~-450 sold by the Philip A. ~unt Chemical Corporation. Another suitable negative photoresist is KMER~of Kodak, and a suitable positive photoresist is AZ~lll of Shipley Chemicals Ltd.
The layers of photoresist 11 and 12 are hardened by baking' The strip 10 at this stage is shown in Fig. 3. Both layers are then exposed to ultraviolet radiation through approp-riate masks, such as exposed and developed photographic film having transparent areas and opaque areas. In the case of a negative photoresist, the mask adjacent the layer 11 will have opaque areas in correspondence to the desired position of the apertures 1, whilst the mask adjacent the layer 12 will have opaque areas in correspondence to the recessed portions 6. Care must of course be taken to -ensure that the masks are precisely registered, so that the positions of the apertures 1 and recessed portions 6 in the finished product will be accurate. After the exposure, the photoresist is developed and baked. The L
strip 10 will have on one side masking areas lla and on the other side, masking areas 12a (see Fig. 4).
The face of the workpiece provided with the masking areas 12a (which will provide the back face of the foil) is then subjected to spray etching, in order to form the recessed portions 6. Once these have been etched to the r correct depth, the workpiece is rinsed and dried, and the ~0661(~3 newly-etched face is protected by a protective film 13, for instance, of adhesive tape.
The face of the workpiece provided with masking areas lla (which will provide the front face of the foil) is then spray etched, the etching being halted when the metal has been eaten away to position 14, shortly before the apertures are completely formed.
After rinsing, the masking areas lla are removed, leaving the areas 12a and protective film 13 in place.
Alternatively, both the masking areas lla and 12a and the protective film 13 are removed, and a further protective film, for instance a layer of shellac, is applied over the face bearing the recessed portions. Further etching of the unprotected face (i.e. the front face) removes more metal and smoothly rounds off the edges of the bars 2, leaving a foil with apertures 1 and bars 2. Finally, after an optional chemical polishing step, the protective film is removed, and the finished foil is rinsed and dried.
The following Example illustrates one preferred manner in which a shaving foil according to the invention can be made.
EXAMPLE
A steel strip is subjected to an intensive cleaning involving firstly ultrasonic cleaning in a chlorinated solvent such as trichloroethylene, or preferably trichloro-ethane, at room temperature, followed by blow drying. This is followed by alkaline cleaning in a hot degreasing salt solution, with agitation, followed by rinsing with water.
A suitable degreasing salt for this purpose is Mete~ TS
40 A (from MacDermid) which can be conveniently employed at a temperature of about 40C. The plate is then subjected to electrolytic cleaning in a cold alkaline cyanide-free solution, e.g. Oxypre~ 285 of Oxy Metal Finishing Co., followed by water-rinsing. After neutralizing with dilute 18~ hydrochloric acid, washing with water, dionized water and isopropyl alcohol, the plate is finally dried in a vapour of a chlorinated solvent, such as trichloroethane.
Both faces of the plate are now provided with a layer of Waycoa~ 450 photoresist by dip-coating in Waycoat~
450 thinned with Waycoat PF thinner to a viscosity providing the required thickness of photoresist. After optional air-drying of the coated plate, the photoresist is provided with a pre-exposure baking, for 10 minutes at 95-100C in a convection oven, or for 2 minutes at 350C in an infra-red unit. The photoresist on each side of the plate is then exposed to ultraviolet light through masks made from exposed photographic film having transparent areas and opaque areas. On the side which will finally provide the front face of the foil, and which is provided with layer 11 (see Fig. 3) the transparent areas will correspond to areas lla (see Fig. 4), and on the side which will finally provide the back face of the foil, and which is provided with layer 12, the transparent areas will correspond to areas 12a. Optimum exposure is achieved by holding 6 to r 7 steps after exposure through a Stauffer 21 step sensitivity guide or a Kodak~ # 2 step wedge.
After exposure, development can be carried out by spraying and immersion. It involves contacting the exposed photoresist with Waycoa~ PF Developer, Waycoat PF r Thinner, and water, followed by air drying. The developed ,~ I
lQ~6las photoresist is then baked for 10 minutes at 120C in a convection oven or for 2 minutes at 350C in an infra-red unit.
Etching is then carried out, advantageously using a double-sided spray-etching apparatus, for instance the apparatus sold by Chemcut Corporation. Etching can be carried out using Waycoat PF Etchant, but it is advant-ageous to employ a 48 Beaume solution of ferric chloride, heated to a temperature of 52C.
The first etching stage is carried out for 20 to 40 seconds on the back face to provide the recessed portions 6 followed by rinsing with deionizedwater and blow-drying with nitrogen. A protective layer of adhesive cellulose acetate tape 13 is then applied. The second etching stage is then carried out on the front face to remove metal down i~
to position 14. This involves etching for 100 to 140 seconds, followed by washing withdeionized water and blow- ;
drying with nitrogen.
The masking areas lla are then removed using Kodak CP Stripper 13 LS, the recesses 6 and masking areas 12a being protected by the protective layer 13. A final etching is carried out on the front face using the same etching solution as before, at the same temperature as before. This final etching takes about 40 seconds, followed by washing withdeionized water and blow drying with nitrogen.
A chemical polishing step can then be carried out using a polishing solution suitable for the metal of the strip 10. Suitable solutions are described for instance r with Band 1/2 of "Handbuch der Galvanotechnik" by Dettner ~6~108 an~ Elze, Carl Hauser Verlag, Munchen.
Finally the protective layer 13 is removed and the remaining masking areas 12a are stripped off using Kodak L~ 13 stripper. After a final washing with water and blow-drying with nitrogen, the manufacture of the foil is complete.
. .
This lnvention concerns a method of producing per-forated foils for dry shavers.
The cutting head of a dry shaver conventionally comprises a perforated stationary outer shear ~oil and an inner movable cutter contacting the rear face of the shear foil. The cutter can either comprise a plurality of separate blades or it can itself be made from a perforated foil.
Our copending Canadian Application No. 256,141 (now Canadian Patent 1,041,753 issued 7 November, 1978) provides a shearing foil for a dry shaver, made from a sheet of metal or alloy, having perforations extending through the sheet with bars between the perforations, the bars being dished in transverse cross-sectional profile, the base of the dished profile being substanti-ally flat and of uniform thickness(t), and the edges of the dished profile extending at an obtuse angle to the base to terminatewith coplanar faces disposed parallel to the base, said face having a width(_) in the transverse direction which is not greater than (t).
STATEMENT OF PRIOR ART
Various forms of foil have been proposed in the lit-erature, or employed in practice. For instance, British Patent Specification No. 845,832 describes a foil whose thickness(from front to rear surfaces) immediately adjacent to the apertures exceeds the thickness at those portions between apertures.
Heretofore, a variety of methods has been proposed and employed for producing shaving foils. For instance, electrodeposition techniques have been proposed in U.S.
t~
610~3 Patcnts NG. 3,~ ]. 3,655,528; 3,655,529; and 3,695,927.
Stamping tec~ln.Jqucs have also beerl desc.ribed, for instance ~n U.S. ~atcnt No. 3,216,286. British l'atent No~ 1,056,038 provides a met:hod involving co,ting a flat stainless steel plate with a photoresist, exposing through a mask with the r desired apertures, removing the unhardelled parts of the resist to bare the steell bending tllc plate to the desired shape and etching through the stcel and rcmoving the hardene~d parts by burning off to obtain the shear plates. Preferably, the shear plate is hardened by heating to 1,020C, cooled rapidly, immersed in liquid air and tempered at 200C. ~!
An earlier method described in.British Patent Specification No. 845,832 involves: etcl-ing a sheet by a chemical or electrochemical process, so as to produce apertures surrounded by rims which project from the inner surface of the plat:e which is contacted by the cutting member. ~pertures in a resist on the outer side are in groups, and resist on the inner side forms a pattern of .
islands each corresponding to such a group. Etching is carried out until less than half the thickness of metal has been removed, then stopped, and resist applied over all the inner side including the etched depressions, then etching iS re-started so as to etch holes through from the outer sidc, and continued until each group of aper-- tures merges into a single hole surroundcd on the inner side by a crenate rim.
There.has, however, been a continued search for ncw methods of producing foil$.
OBJECT OF TIIE INVENTION -r __ The object of the present inventicn is to provide ...
P~)66~08 a novel rnet}lod of producing a per,.oratcd foil for a dry shaver.
STATEMENT OF l`~E INVENTION
_ _ _ _ _ _ .
rrhe prescrlt invcntion providcs.a mcthod of producing a sheariny foil for a dry shaver from a shee~ of metal, said foil having a front facc and a back face, and exhibit-ing perforations extending through the shcet from said front face to said back face with bars bctwcen the perfor-ations, the bars being dished in transverse cross-sectional profile, the recessed base of the dished profile being sub-stantially flat and of uniform thickness, and -the edges of the dished profile extending at an angle to the base to terminate with coplanar faces disposed parallel to t:he base, which method comprises applying a layer of a photosensitivc material to each face of the sheet of metal, exposing the front face to radiation through a mask having a hole pat-tern corresponding to the desired pcrforations of the shaving foil, exposing the back face to radiation through a mask having a pattern corresponding to the recessed base of the dished profile, developing the photosensitive material in ordcr to generate a respective pattern of unprotected regions on each face of the metal sheet, etch-ing said unprotected regions of the front face and the back ' face, removing the photosensitive layer from the front face-foil, carryiny out a further etching of the front face until a predetermined quantity of metal is removed and the ridges of the bars are smoothly rounded off, and finally removing the remaining masking material.
DESCRIPTION OF DRAWINGS r The invention will be more particularly described ~ 8 , , .
with referhnce to ~hc ~ccompanying drawings in whlch:
Fig. i is a cross-section through a bar on a foiL
o conventior)al cor,struction;
Fig. 2 is a cross-section ,hrough a bar on a foi3 according to our above-mentioned copending ~ppllcation:
and Figs. 3 and 4 arc cross-sections illustrating two r stages during the mcthod according to thc invention.
PARTICULAR DESCRIPTION OF THE INVENTION
_ _ _ _ _ ___ _ ~eferrillg now to Figs. 1 and 2, a foil has apertures 1 and bars 2 between the apertures. Thc bars 2 are dished in cross-sectional profile, with a substantially flat base 3 of thickness t and edges 4 extending at an angle o~ to the base. The edges 4 terminate in faces 5 which are coplanar and parallel to the base 3, and have a width _.
The bars therefore, have recessed portions 6.
In-accordance with the conventional construction shown in Fig. 1, _ is greater than t, and the angle d~ is substantial]y a rig}lt angle.
In accordance with the invention of our copending Application shown in Fig. 2, _ is not greater than t.
In other words, ~ can be substantially the same as t, or it can b.e less than t.
The m~itcrial from which the foils are made is a single metal or alloy (e.g. steel). - r The usc of a single material in the construction of the foils according to the invention makes it possible to employ the advantageous etching technique according to the present invention. This technique will be described with r reference to Figs. 3 and 4 of the accompanying drawings.
--5~
106~108 In accordance with this method, a strip 10 of a suitable metal, e.g. laminated steel, is cleaned to remove grease and other contaminants from its surfaces, and is then provided by dip-coating with a layer of a suitable negative or positive photoresist on each surface. A pre-ferred negative photoresist is Waycoa~-450 sold by the Philip A. ~unt Chemical Corporation. Another suitable negative photoresist is KMER~of Kodak, and a suitable positive photoresist is AZ~lll of Shipley Chemicals Ltd.
The layers of photoresist 11 and 12 are hardened by baking' The strip 10 at this stage is shown in Fig. 3. Both layers are then exposed to ultraviolet radiation through approp-riate masks, such as exposed and developed photographic film having transparent areas and opaque areas. In the case of a negative photoresist, the mask adjacent the layer 11 will have opaque areas in correspondence to the desired position of the apertures 1, whilst the mask adjacent the layer 12 will have opaque areas in correspondence to the recessed portions 6. Care must of course be taken to -ensure that the masks are precisely registered, so that the positions of the apertures 1 and recessed portions 6 in the finished product will be accurate. After the exposure, the photoresist is developed and baked. The L
strip 10 will have on one side masking areas lla and on the other side, masking areas 12a (see Fig. 4).
The face of the workpiece provided with the masking areas 12a (which will provide the back face of the foil) is then subjected to spray etching, in order to form the recessed portions 6. Once these have been etched to the r correct depth, the workpiece is rinsed and dried, and the ~0661(~3 newly-etched face is protected by a protective film 13, for instance, of adhesive tape.
The face of the workpiece provided with masking areas lla (which will provide the front face of the foil) is then spray etched, the etching being halted when the metal has been eaten away to position 14, shortly before the apertures are completely formed.
After rinsing, the masking areas lla are removed, leaving the areas 12a and protective film 13 in place.
Alternatively, both the masking areas lla and 12a and the protective film 13 are removed, and a further protective film, for instance a layer of shellac, is applied over the face bearing the recessed portions. Further etching of the unprotected face (i.e. the front face) removes more metal and smoothly rounds off the edges of the bars 2, leaving a foil with apertures 1 and bars 2. Finally, after an optional chemical polishing step, the protective film is removed, and the finished foil is rinsed and dried.
The following Example illustrates one preferred manner in which a shaving foil according to the invention can be made.
EXAMPLE
A steel strip is subjected to an intensive cleaning involving firstly ultrasonic cleaning in a chlorinated solvent such as trichloroethylene, or preferably trichloro-ethane, at room temperature, followed by blow drying. This is followed by alkaline cleaning in a hot degreasing salt solution, with agitation, followed by rinsing with water.
A suitable degreasing salt for this purpose is Mete~ TS
40 A (from MacDermid) which can be conveniently employed at a temperature of about 40C. The plate is then subjected to electrolytic cleaning in a cold alkaline cyanide-free solution, e.g. Oxypre~ 285 of Oxy Metal Finishing Co., followed by water-rinsing. After neutralizing with dilute 18~ hydrochloric acid, washing with water, dionized water and isopropyl alcohol, the plate is finally dried in a vapour of a chlorinated solvent, such as trichloroethane.
Both faces of the plate are now provided with a layer of Waycoa~ 450 photoresist by dip-coating in Waycoat~
450 thinned with Waycoat PF thinner to a viscosity providing the required thickness of photoresist. After optional air-drying of the coated plate, the photoresist is provided with a pre-exposure baking, for 10 minutes at 95-100C in a convection oven, or for 2 minutes at 350C in an infra-red unit. The photoresist on each side of the plate is then exposed to ultraviolet light through masks made from exposed photographic film having transparent areas and opaque areas. On the side which will finally provide the front face of the foil, and which is provided with layer 11 (see Fig. 3) the transparent areas will correspond to areas lla (see Fig. 4), and on the side which will finally provide the back face of the foil, and which is provided with layer 12, the transparent areas will correspond to areas 12a. Optimum exposure is achieved by holding 6 to r 7 steps after exposure through a Stauffer 21 step sensitivity guide or a Kodak~ # 2 step wedge.
After exposure, development can be carried out by spraying and immersion. It involves contacting the exposed photoresist with Waycoa~ PF Developer, Waycoat PF r Thinner, and water, followed by air drying. The developed ,~ I
lQ~6las photoresist is then baked for 10 minutes at 120C in a convection oven or for 2 minutes at 350C in an infra-red unit.
Etching is then carried out, advantageously using a double-sided spray-etching apparatus, for instance the apparatus sold by Chemcut Corporation. Etching can be carried out using Waycoat PF Etchant, but it is advant-ageous to employ a 48 Beaume solution of ferric chloride, heated to a temperature of 52C.
The first etching stage is carried out for 20 to 40 seconds on the back face to provide the recessed portions 6 followed by rinsing with deionizedwater and blow-drying with nitrogen. A protective layer of adhesive cellulose acetate tape 13 is then applied. The second etching stage is then carried out on the front face to remove metal down i~
to position 14. This involves etching for 100 to 140 seconds, followed by washing withdeionized water and blow- ;
drying with nitrogen.
The masking areas lla are then removed using Kodak CP Stripper 13 LS, the recesses 6 and masking areas 12a being protected by the protective layer 13. A final etching is carried out on the front face using the same etching solution as before, at the same temperature as before. This final etching takes about 40 seconds, followed by washing withdeionized water and blow drying with nitrogen.
A chemical polishing step can then be carried out using a polishing solution suitable for the metal of the strip 10. Suitable solutions are described for instance r with Band 1/2 of "Handbuch der Galvanotechnik" by Dettner ~6~108 an~ Elze, Carl Hauser Verlag, Munchen.
Finally the protective layer 13 is removed and the remaining masking areas 12a are stripped off using Kodak L~ 13 stripper. After a final washing with water and blow-drying with nitrogen, the manufacture of the foil is complete.
Claims (4)
1. A method of producing a shearing foil for a dry shaver from a sheet of metal, said foil having a front face and a back face, and exhibiting perforations extending through the sheet from said front face to said back face with bars between the perforations, the bars being dished in transverse cross-sectional profile, the recessed base of the dished profile being substantially flat and of uniform thickness, and the edges of the dished profile extending at an angle to the base to terminate with coplanar faces disposed parallel to the base,which method comprises applying a layer of a photosensitive material to each face of the sheet of metal, exposing the front face to radiation through a mask having a hole pattern corresponding to the desired perforations of the shaving foil, exposing the back face to radiation through a mask having a pattern corresponding to the recessed base of the dished profile, developing the photosensitive material in order to generate a respective pattern of unprotected regions on each face of the metal sheet, etching said unprotected regions of the front face, and of the back face, removing the photosensitive layer from the front face, carrying out a further etching of the front face until a predetermined quantity of metal is removed and the ridges of the bars are smoothly rounded off, and finally removing the remaining masking material.
2. A method as claimed in claim 1 wherein the photosensitive material is a positive photoresist.
3. A method as claimed in claim 1 wherein the photosensitive material is a negative photoresist and an additional masking layer is applied to the back face after etching the recessed base of the dished profile and before removing the photoresist layer from the front face.
4. A method as claimed in any preceding claim wherein the back face is first etched to provide the recessed base of the dished profile, and the front face is etched subsequently.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2842675A GB1511046A (en) | 1975-07-05 | 1975-07-05 | Production of shaving foil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066108A true CA1066108A (en) | 1979-11-13 |
Family
ID=10275457
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,140A Expired CA1066108A (en) | 1975-07-05 | 1976-07-02 | Production of shaving foil |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS603499B2 (en) |
| AT (1) | AT351900B (en) |
| CA (1) | CA1066108A (en) |
| CH (1) | CH612694A5 (en) |
| DE (1) | DE2629919A1 (en) |
| FR (1) | FR2317373A1 (en) |
| GB (1) | GB1511046A (en) |
| IT (1) | IT1070244B (en) |
| NL (1) | NL177231C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57183885A (en) * | 1981-05-07 | 1982-11-12 | Hitachi Maxell | Production of outer blade of electric razor |
| DE3526951A1 (en) * | 1985-07-27 | 1987-01-29 | Battelle Institut E V | Shearing blade for razors and method for the production thereof |
| NL8801017A (en) * | 1988-04-20 | 1989-11-16 | Philips Nv | METHOD FOR MANUFACTURING A SHAVING BLADE FOR A DRY SHAVER |
| JPH0750015Y2 (en) * | 1990-03-07 | 1995-11-15 | 株式会社小松製作所 | Panel vendor |
| US5343727A (en) * | 1990-03-07 | 1994-09-06 | Kabushiki Kaisha Komatsu Seisakusho | Panel bender |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3498891A (en) * | 1965-12-17 | 1970-03-03 | Gillette Co | Method of making shearing foils for dry shavers |
| US3679500A (en) * | 1970-08-07 | 1972-07-25 | Dainippon Screen Mfg | Method for forming perforations in metal sheets by etching |
-
1975
- 1975-07-05 GB GB2842675A patent/GB1511046A/en not_active Expired
-
1976
- 1976-06-02 IT IT6863476A patent/IT1070244B/en active
- 1976-07-02 CA CA256,140A patent/CA1066108A/en not_active Expired
- 1976-07-02 AT AT484876A patent/AT351900B/en not_active IP Right Cessation
- 1976-07-02 DE DE19762629919 patent/DE2629919A1/en active Granted
- 1976-07-02 NL NL7607306A patent/NL177231C/en not_active IP Right Cessation
- 1976-07-05 JP JP8031276A patent/JPS603499B2/en not_active Expired
- 1976-07-05 FR FR7620424A patent/FR2317373A1/en active Granted
- 1976-07-05 CH CH856776A patent/CH612694A5/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NL177231B (en) | 1985-03-18 |
| CH612694A5 (en) | 1979-08-15 |
| NL177231C (en) | 1985-08-16 |
| FR2317373A1 (en) | 1977-02-04 |
| FR2317373B1 (en) | 1980-09-05 |
| GB1511046A (en) | 1978-05-17 |
| JPS603499B2 (en) | 1985-01-29 |
| JPS529551A (en) | 1977-01-25 |
| NL7607306A (en) | 1977-01-07 |
| DE2629919A1 (en) | 1977-01-27 |
| IT1070244B (en) | 1985-03-29 |
| AT351900B (en) | 1979-08-27 |
| ATA484876A (en) | 1979-01-15 |
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