EP0973959A2

EP0973959A2 - Coating method for elongated metal blanks

Info

Publication number: EP0973959A2
Application number: EP98922654A
Authority: EP
Inventors: Horst PILGENRÖDER; Vincenzo Cavallaro
Original assignee: Inter Transtech sro
Current assignee: Inter Transtech sro
Priority date: 1997-04-11
Filing date: 1998-04-07
Publication date: 2000-01-26
Anticipated expiration: 2018-04-07
Also published as: AU7522698A; DE59801691D1; WO1998046806A3; DK0973959T3; JP2001518981A; EP0973959B1; ES2162444T3; CN1256718A; CN1121512C; US6299750B1; WO1998046806A2; JP4094681B2

Abstract

The invention relates to a method based on superfinishing for coating elongated metal blanks. Said blanks have at least two axially aligned sections with varying cross-sections, wherein particles of a hard substance protruding from the surface of the coating are embedded into a metal lining in a chemical electroplating bath on the surface of a first segment provided with indentations or the like. The exposed surfaces of a second section remain substantially devoid of hard substance particles. A plurality of blanks is thus freely circulated in a rotating drum in a dispersion which is suspended in the electroplating liquid so that the hard substance particles adhering to the exposed surfaces can be removed once again by rubbing the blanks against each other.

Description

00001 Coating process of elongated, metallic

00002 blanks 00003

The invention relates to a method for coating

00005 elongated, metallic blanks according to the generic term

00006 of claim 1. 00007

00008 In the book series "Production Technology Today" (published

00009 about Prof. Dr. Ing. H. J. Warneke) is published in volume 14,

00010 deburring, theory, processes, systems by F. Schäfer

00011 on pages 93 to 98 the so-called surface grinding

00012 described. A variety of in one rotary gear

Blank blanks 00013 NEN slide during the

00014 rotational movement of the drum against each other and against

00015 abben abrasives. The type of sliding together

00016 ens depends on the speed. At low turning

00017 numbers slide against each other. From one

00018 certain speed, the sliding zone collapses

00019 men, workpieces and grinding wheels described there

00020 beat aueinanader. This and the sliding together

00021 causes a surface removal. 00022

In the generic method blanks, the

00024 at least two axially consecutive sections

00025 have different cross-section treated. In

00026 a chemical electroplating bath will be on the surface

00027 of a first, notch valleys or the like

00028 section into a metallic edging layer

00029 hard material particles protruding from the layer surface

00030 beds. The exposed areas of a second section

00031 tes remain largely free of hard particles. The

00032 exposed areas, the lateral surfaces of a

00033 cylinders. The cylinder base can be a circular

00034 surface, an oval or a hexagonal surface.

00035 the cross-sectional area of the notch valleys 00036 the section can be tooth-shaped or star-shaped

00037 outline contour. The tooth or star flanks

00038 of this section are to be

00039 bedding. The application of hard material

00040 particles to reduce wear on workpieces or

00041 for increasing the frictional force is particularly

00042 ten machine parts and also known for tools. It

However, 00043 is also known to be stressed or pressurized.

00044 spoke sections of different metallic counterparts

Such measures would require less wear.

Design 00046. Areas of the workpieces that are not coated

00047 should be used in known methods

00048 means paint or the like can be covered. Beispiels-

00049 shows the OS 29 20 593 a method, such as

00050 local power particles in a metallic

00051 area are introduced. From PS 28 55 054 is a

Known in which the stator vane one

00053 turbine with a metal layer with embedded foreign

00054 particles is coated. There are coating-free

00055 only those covered by a jig

00056 sections of the bucket. 00057

The object of the invention is to provide a generic solution.

00059 solution to find without partial covers

00060 of the workpiece to produce coatings, in particular

00061 re diamond coatings that over the areas of

00062 workpiece are gradually different sizes. 00063

00064 This is achieved in that a large number of raw

00065 loosely in a rotating drum in such a way

00066 dispersion of in the electroplating liquid in Switzerland

Be kept hard material particles circulated that

00068 by sliding the blanks together

00069 particles of hard material adhering to the exposed surfaces

00070 be removed again. 00071 The pre-treated, degreased, rinsed

00072 and pickled blanks are in larger numbers

00073 filled the drum, the walls of which form openings

00074 den. These are smaller than the diameter of the raw

00075 ge, so that it is used as intended in the drum

00076 remain. The filled drum is placed in the

00077 km medium sunk and rotates within it.

00078 The drum carries the inside of the electroplating medium

00079 rotary movements from taking the pretreated

00080 blanks. The electroplating medium passes through the openings

00081 the drum in this and comes into contact with

00082 surface of the blanks. Regarding the electroplating medium

00083 it is a dispersi kept in motion

00084 on from hard material particles and a metallic component

00085 nente. Both the metallic component and the

00086 hard material particles settle on the surface of the

00087 blanks from. The drum movement leads to the fact that

00088 adhering to the exposed surfaces of the blanks

00089 hard material particles by mutual abrasion

00090 th of the blanks are removed again. In the area

00091 of the grooves flanked by the work surfaces

00092, however, the hard material particles remain. It

So there is no abrasion 00093, so that there

00094 desired friction compression is achieved. What general

00095 is considered disadvantageous in vibratory grinding, namely

00096 lent the unprocessed nests to the workpieces

00097 gene, is an advantage in the method according to the invention

00098 used. So that the hard particles in the same density

00099 occur in the electroplating medium and does not

00100 zen, the agitator is provided. This keeps the hard

00101 suspended particles in the electroplating medium. Farther

00102 the drum is cylindrical and around it

00103 driven in the horizontal axis of rotation.

00104 For example, the drum can have a cross section

00105 have polygonal outline shape, what when rotating the 00106 drum of a good circulation of the

00107 comes blanks. It is possible that

00108 to fill the drum about half full with blanks, so

00109 that a large during a coating process

00110 number of blanks is coatable. Is an advantage

It is that the rotating drum completely in the

00112 electroplating medium is immersed. The galva in question

00113 nikiquid has a nickel component which

00114 without electrical voltage itself in the form of metallic

00115 precipitates nickel on the surface of the blanks.

00116 The floating in the electroplating liquid

00117 tungsten carbide particles are preferably diamond grains,

00118 in particular in the order of 10 to 30 μm.

00119 That means that the diamond grains partially from the

00120 layer on the work surfaces

00121 protrude and, for example, an anti-slip

00122 layer or an abrasion-resistant layer.

00123 The nickel layer accordingly represents the border

00124 layer for these diamond grains. The larger the

00125 grain size of the diamond grains, the more the

00126 "cam-out effect". For an optimal coating of the

00127 work surfaces, it is advantageous that the movement of the

00128 drum with interposed breaks. To

00129 a correspondingly long rotational movement phase

00130 the drum takes a pause, in

00131 which the adhesion of the hard metal particles within

00132 of the electroplating medium happens. The added to the drum

00133 blanks are degreased before coating,

00134 pickled and in a nucleation bath (nickel strike)

00135 treated. The device for carrying out the process

00136 rens is characterized in that the drum one

00137 polygonal cross-section also has from the drum front

00138 walls bearing journals, one of which is in coupling

00139 connection can be brought to the rotary drive of the drum

00140 mel. By removing the drum from the electroplating bath 00141 is the coupling connection between the journal and

00142 rotary drive released while inserting the drum

00143 the coupling connection between these parts

00144 leads. The openings in the drum walls are for

00145 passage of the electroplating medium provided. This is

00146 is in the tub, which is equipped with an agitator

00147 is equipped to levitate the hard material particles in the

00148 to hold electroplating medium. The manufactured according to the procedure

00149 posed workpieces are such that the

00150 exposed areas are coated with hard particles

00151 with a surface density that is at least a tenfold

00152 ches is less than that in the range in the

00153 grooves. It is therefore guaranteed that the essential

00154 the hard material particle coating only in the intended

00155 area takes place, that is, on which the grooves flank

00156 surfaces. In some ways, the sliding

00157 abrasion also a partial area of the grooves

00158 so that the areal density of hard material particles

00159 groove base increases. The effective areas

00160 are not thereby disadvantaged, but rather

00161 more distant area. A saving on

00162 hard material particles is achieved in that the surface

00163 density of hard material particles on the web end faces

00164 is at least ten times smaller than that in the range

00165 of the groove base. The elongated blanks can be

00166 have such designs. For example,

00167 as the size of a pencil. The the

00168 notch valleys or the like having section

00169 a star-shaped or gear-shaped cross-sectional con

00170 tur. In the treatment of such blanks

00171 is essentially only the gear or star

00172 shaped section with the abrasion-resistant and / or abrasive

00173 ive surface coated. The exposed parts

00174 remain coating-free. If the procedure is carried out on

00175 bend driver inserts applied, so the second remains 00176 in particular as a hexagonal cross-sectional profile

00177 te section largely free of hard particles, while

00178 rend the working section having a cross profile

00179 receives a side coating. It is also from

00180 advantage that you can the finished products due to the

00181 gradually different hard particle density

00182 the different sections the manufacturing process

00183. It works when coating such blanks

00184 the slight coating of the web end face

00185 chen and the increasing hard material particle density to

00186 notch base favorably on the "came-out effect".

00187 Such diamond-coated blanks can be used for

00188 passivation of the surface be gold-coated. 00189

00190 The method, the device and

00191 the manufactured by the method of the device

00192 Product based on a graphically illustrated

00193 embodiment explained. It shows: 00194

00195 Fig. 1 is an enlarged view of a

00196 screwdriver bit with Phillips

00197 like to finish work, 00198

00199 Fig. 2 shows the section along the line II-II in Fig. 1, 00200

00201 Fig. 3 in extreme enlargement a detail

00202 sen cross section of the working end in the area

00203 a work surface, 00204

00205 Fig. 4 in a schematic representation a longitudinal

00206 cut through the device for implementation

00207 of the procedure and 00208

5 shows a cross section through the device. 00210 The device for carrying out the 00212 method according to the invention has a tub 1 with the 00213 tub opening pointing upward. The tub end walls 2, 3 carry bearing shells 4 and 5 which protrude into the 00214 tub interior. 00215 They serve to accommodate bearing journals 6 and 7, respectively, in which the drum end faces 00217 walls 8, 9 of a drum 10 extend in coaxial alignment. The 00218 of the drum 10 is inserted from above, the bearings 00219 journals 6, 7 being received 00220 by the bearing shells 4 and 5, respectively. A fuse, not shown, causes 00221 that the bearing pins 6, 7 remain in the bearing shells 4 and 5 00222, respectively. 00223 00224 The drum 10, in turn, can be set in rotation by means of a rotary drive 00225 bes 11, for which purpose the drive pin 11, which faces the rotary drive 00226, can be brought to the rotary drive 11 in coupling connection. The latter is overlaid 00228 by a hood 12 00229 attached to the end wall 3 of the tub. The cylinder-like drum 10 00230 is thus driven about its horizontal axis of rotation 00231 se. The drum 10 itself has a 00232 polygonal cross section. In the exemplary embodiment, a 00233 octagon shape is selected. The drum walls 13 have openings 14 for the passage of an electroplating medium 15, 00235 which passes through the openings 14 of the drum 10 00236. Furthermore, the drum 10 is completely immersed in 00237 in the electroplating medium 15. Regarding the same 00238, it is a dispersion held in motion. This is done using a schematically illustrated stirrer 16 which is accommodated inside the tub 1. 00241 00242 The coating of a screwdriver bit is given as an example of the use of the method 00243: 00244 00245 In the device described above, hard material

00246 particles 17 in a metallic bezel layer 18

00247 on the work surfaces F one with grooves 19 and expo-

00248 designated surfaces provided working end 20 of a screw

00249 driver insert 21 applied such that the hard

00250 material particles 17 from the layer surface

00251 se protrude, cf. see Fig.3. The end of work 20

00252 is cross-shaped in cross-section and is used for

00253 Attack on Phillips screws. They are flanked

00254 grooves 19 of webs 22, which in the direction of the shaft

00 255 23 Rise in the shape of a truncated cone. On the shaft 23

00256 is followed by a polygonal section 24, which in

00257 cross-section is hexagonal. 00258

00259 Before applying the hard material particles 17 in the

00260 metallic edging layer 18, the relevant

00261 subjected the blanks to a pretreatment. This

00262 shoots in the drum 10 removed from the tub 1. In

00263 the blanks are entered until the cover

00264 lockable drum 10 approximately to half with raw

00265 gene is filled. The level of the drum 10 can

00266 between one third and two thirds of the drum

00267 mel volume vary. It then takes place in special

00268 baths an alkali degreasing, an electrolytic

00269 Degreasing and rinsing the blanks. After that

00270 the blanks are removed, rinsed and then

00271 treated in a nucleation bath (nickel strike).

00272 As a result, the blank receives a

00273 before nickel strike layer 25. Then the filled

00274 Drum 10 of a cascade rinse with fresh water

00275 suspended. Once this has been done, the insertion takes place

00276 the drum 10 with the correspondingly pretreated

00277 blanks in the tub 1 with the production of the coupling

00278 lungs connection of the journal 7 with the rotary drive

00279 11. That is the drum 10 fully receiving L. 00280 a galvanic liquid, which is a nickel component

00281 owns. In this the hard material particles 17 are

00282 means of the agitator 16 kept in suspension. In terms of

00283 of the hard material particles 17 are diamond particles

00284 ner with a size of 10 to 30 microns.

00285 After inserting the drum 10 into the tub 1 runs

00286 the drum 10 with interposed breaks. The

00287 means that after a rotational phase of the drum

00288 a pause is activated at intervals in which

00289 rather the nickel component of the electroplating liquid itself

00290 with the hard material particles 17 in the form of metallic

00291 kels (edging layer 18) on the surface of the

00292 blanks down. Then after the break

00293 Rotation of the drum 10 continued by the

00294 drum movement and the thereby revolving blanks

00295 on the exposed surfaces of the same adhering hard

00296 particles of material 17 by mutual abrasion

00297 ten removed from which removal the grooves

00298 19 and thus the work surfaces F located there

00299 are largely excluded. In the course of a cycle

00300 then takes the coating thickness on the work surfaces

00301 Chen F to. From Fig. 1 it can be seen that the surface

00302 density of hard material particles 17 in the finished treatment

00303 screwdriver bit 21 increases towards the groove base 19 '.

00304 The reason for this is that the

00305 the groove cross section adjacent blanks during the

00306 circulating in the drum 10 a slight abrasion

00307 fen can cause. This removal in the grooves 19

However, 00308 extends in the zone which is for the

00309 screw insert is irrelevant. In the area of the

00310 beitsendes 20 are the relevant, in area

00311 work surfaces F stepping towards the screw in undiminished

00312 ter layer thickness available. 00313 00314 It can also be seen from FIG. 1 that the expo-

00315 ned surfaces of the clamping end (polygonal section

00316 24) are coated with hard particles. The existing there

00317 denen density is at least ten times

00318 less than that in the area of the grooves 19 of the

00319 end of work 20. This slight areal density

00320 hard material particles acts in the area of the clamping end

00321 does not adversely affect the insertion of the screw

00322 lathe insert in a corresponding holder. In

00323 inserted position in the holder leads the low

00324 compliant hard particle coating even to one

00325 improved fit of the screwdriver bit in the

00326 recording. Fig. 1 further illustrates that the areas

00327 marriage density on hard material particles 17 on the web end faces

00328 chen 22 'is also less than that in the range of

00329 groove base. On the web end faces, the surface

00330 density of the hard material particles 17 at least ten times

00331 smaller than that in the area of the groove base 19 'of

00332 end of work 20. This slight areal density

00333 hard material particles 17 on the web end faces 22 '

00334 even improves the fit of the working end 20 in the

00335 slot of a screw to be turned. 00336

00337 After the corresponding dwell time in

00338 the electroplating medium 15 to achieve the coating

00339 of the working end 20 is the drum from the tub 1

00340 to lift out. Now there is a rinse with fresh water

00341 ser. Then the diamond-coated raw

00342 to passivate the surface in a hard

00343 gold-plated gold bath. The gold coating

00344 device is designated by the number 26 in FIG. 3. 00345

00346 All disclosed features are essential to the invention. In

00347 the disclosure of the application is hereby also the

00348 disclosure content of the associated / attached priori 00349 full documents (copy of the pre-registration)

00350 included, also for the purpose of characteristics of this

00351 documents in claims of the present application with

00352 to record.

Claims

00353 00354 ANS P RUCHE 00355 00356 1. Method for coating elongated, metallic 00357 blanks, which blanks have at least two axially mutually lying sections of different cross-sections 00359, 00360 in a chemical electroplating bath on the surface of a first, notched valleys or the like Hard metal particles protruding from the section into a metallic encasing layer protruding over the layer surface, and the exposed surfaces of a second section being largely 00365 free of hard material particles, characterized in 00366 that a large number of blanks loosely rotate in a drum in such a dispersion 00367 in a dispersion of in of the 00368 electroplating liquid in the suspended hard material 00369 particles that adhering hard material particles adhering to each other on the exposed surfaces are removed again by sliding against each other 00372 we rden. 00373 00374 2. The method according to claim 1 or in particular according thereto, 00375 characterized in that the hard material particles (17) 00376 are kept in suspension in the galvanic medium (15) by means of an agitator (16). 00378 00379 3. The method according to one or more of the preceding00380 the claims or in particular according thereto, characterized gekenn00381 that the drum (10) is cylindrical in design and is driven about its horizontal 00003 axis lying in the horizontal. 00384 00385 4. Method according to one or more of the preceding00386 claims or in particular according thereto, characterized 00387 shows that the drum (10) is about half filled with 00388 the blanks. 00389 00390 5. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the drum (10) is completely immersed in the 00393 electroplating medium (15). 00394 00395 6. Method according to one or more of the preceding00396 claims or in particular according thereto, characterized gekenn00397 that the electroplating liquid has a Nickelkorπpo- 00398 nente which 00399 without electrical voltage in the form of metallic nickel (bezel layer 18) on 00400 the surface of the Blanks precipitates 00401 00402 7. Method according to one or more of the preceding00403 claims or in particular according thereto, characterized in that the hard particles (17) are diamond grains 00405, in particular in the order of 10 to 30 00406 μm. 00407 00408 8. The method according to one or more of the preceding00409 claims or in particular according thereto, characterized gekenn00410 that the movement of the drum (10) takes place with interposed breaks. 00412 00413 9. The method according to one or more of the preceding00414 claims or in particular according thereto, characterized gekenn00415 in that the blanks are removed before coating00416 tet, decapitated and treated in a nucleation bath (nickel 00417 strike). 00418 00419 10. The method according to any one of claims 1 to 9, characterized 00420, characterized in that the drum (10) has a polygonal cross section 00421 with the drum end walls (2, 3) 00422 outgoing bearing journal (6, 7), one of which (7) in 00423 coupling connection can be brought to the rotary drive (11) 00424 of the drum (10). 00425 00426 11. The method according to claim 10 or in particular da00427 according to, characterized in that the drum walls (13) 00428 are equipped with openings (14) for passage of the electroplating medium 00429 (15). 00430 00431 12. The method according to one or more of claims 10 00432 to 11 or in particular according thereto, characterized gekennzeich00433 that a tub (1) receiving the drum (10) 00434 is provided with an agitator (16). 00435 00436 13. The method according to one or more of the preceding00437 claims or in particular according thereto, characterized gekenn00438 that the blanks are screwdriver bits 00439, the exposed surfaces being formed by the polygonal surfaces of a hexagonal profile and the notch valleys by the 00441 clearances of a cross profile. 00442 00443 14. The method according to one or more of the preceding00444 claims or in particular according thereto, characterized gekenn00445 that the hard material density on the flanks of the 00446 notch valleys increases towards the bottom.