US 3278409 A
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Description (OCR text may contain errors)
ELECTROPLATING MACHINE Filed July 25, 1962 TRANSFER MECHANISM STATION I ENTRANCE TANK STATION 2 SOAK CLEAN TANK TAN K STATION *4 WARM RINSE STATION 5 COLD RINSE ANK STATION 6 ELECT. ACID STATION 7 COLD RINSE STATION 8 COLD RINSE TANK STATION it 9 COPPER STRIKE TANK STATION IO COPPER PLATE TANK STATION II RECLAIM RINSE TAN K STATION I2 COLD RINSE TANK STATION I3 ELECT CLEAN STATION I4 COLD RINSE 14 Sheets-Sheet l TANK STATION I6 COLD RINSE STATION *I'i IDLE TANK STATION T i8 DOUBLE NICKEL STATION IS TANK DOUBLE NICKEL STATION 2O IDLE STATION 2I COLD RINSE STATION 22 COLD RINSE STATION 23 TANK ACID STATION 2A COLD RINSE TANK STATION 25 CHROME PLATE STATION 2e TANK RECLAIM RINSE STATION 27 TANK CHROME PLATE TANK STATION T as RECLAIM RINSE STATION 29 COLD RINSE STATION 30 TANK I-IOT RINSE STATION SI ,NVENTORS DRY gag! :Zaegzkv az, sTATION 32 a 9% EXIT @4222 6! @evflezzsgzg fiaziazf/g fipa'zz/af ga BY @kdaza/J Z 220 Oct. 11, 1966 E. T. BARRINGER ETAL 337 9 ELECTROPLATING MACHINE v Filed July 25, 1962 14 Sheets-Sheet 2 ll ATTORNEY Oct. 11, 1966 E. T. BARRINGER ETAL 33 m ELECTROPLATING MACHINE Filed July 25, 1962 14 Sheets-Sheet s Oct. 11,
Filed July 25, 1962 E. T. BARRINGER ETAL ELECTROPLATING MACHINE 14 Sheets-Sheet 4 Oct. 11, 1966 E. T. BARRINGER ETAL 3, 7 9
ELECTROPLATING MACHINE Filed July 25, 1962 .14 Sheets-Sheet 5 ATTORNEY Oct. 11, 1966 E. T. BARRINGER ETAL 337,409
ELECTROPLATING MACHINE l4 Sheets-Sheet 6 Filed July 25, 1962 S R 0 T N w m f WZMM/ 6490/ ATTOFZ/VE Y 14 Sheets-Sheet 7 ELECTROPLATING MACHINE E. T. BARRINGER ETAL Oct. 11, 1966 Filed July 25, 1962 Oct. 11, 1966 E. T. BARRINGER ETAL ELECTROPLATING MACHINE Filed July 25, 1962 14 Sheets-Sheet 8 A TTORA-TY Oct. 11, 1966 E. T. BARRINGER ETAL 3,278,409
ELECTROPLATING MACHINE Filed July 25, 1962 14 Sheets-Sheet 9 17V ETNIUAS Oct. 11, 1966 E. T. BARRINGER ETAL 3,278,409
ELECTROPLATING MACHINE 14 Sheets-Sheet 10 Filed July 25, 1962 Z/VVENTORS' 595/ 72?? Vii/x7584 find r/A? 5 (211/ kgq &
ATTORNEY Oct 11, 1966 E. T. BARRINGER ETAL 3, &
ELECTROPLATING MACHINE 14 Sheets-Sheet 11 Filed July 25, 1962 INVENTORS 'az/ Z'fiazz/ Oct. 11, 1966 E. T. BARRINGER ETAIL, 3378,40
ELECTROPLATING MACHINE Filed July 25, 1962 14 SheetsZ-Sheet 12 ENTRANCE I SOAK CLEAN 2 ELECT. CLEAN 3 WARM RINSE 4 COLD RINSE 5 ELECT. ACID 6 COLD RINSE 7 COLD RINSE 8 COPPER STRIKE 9 COPPER PLATE IO RECLAIM RINSE II COLD RINSE I2 ELECT. CLEAN I3 COLD RINSE I4 ACID DIP I5 COLD RINSE l6 IDLE I7 DOUBLE NICKEL I8 DOUBLE NICKEL I9 IDLE 2O COLD RINSE 2| COLD RINSE 22 ACID COLD RINSE CHROME PLATE RECLAIM RINSE CHROME PLATE zgwm A TTORNEXS Oct. 11, 1966 E. T. BARRINGER ETAL. 3,278,409
ELECTROPLATING MACHINE Filed July 25, 1962 14 Sheets-Sheet 13 A TTORNIEY 1966 E. T. BARRINGER ETAL 3,
ELECTROPLATING MACHINE Filed July 25, 1962 14 Sheets-Sheet 14 ill! W h 1 ATTOR/Viy United States Patent 3,278,409 ELECTRGPLATING MACHINE Earl T. Barringer, Lathrup Village, Mitchell Choly, De-
troit, Carl C. Christensen, Birmingham, Robert A. Spaulding, Huntington Woods, and Richard L. Teno, East Detroit, Mich, assignors to General Motors Corpoi-anon, Detroit, Mich, a corporation of Delaware Filed July 25, 1962, Ser. No. 212,321 9 Claims. (Cl. 204198) This invention relates to electroplating machines and more particularly to a process and apparatus for circulating an electroplating electrolyte from a reservoir through a composite movable plating cell.
The invention is specifically directed to a means for expeditiously securing a source of electroplating solution to the pallet portion of the composite movable plating cell described and claimed in United States patent application Serial No. 212,318, entitled High Speed Plating Method and Apparatus, which is assigned to the assignee of the present invention and which has been concurrently filed herewith.
The plating machine disclosed in the aforementioned United States patent application Serial No. 212,318 is an in-line plating machine in which a plating cell, or cell part, is shuttled through a series of processing stations to treat the part. In its preferred embodiment, the plating cell is formed of two parts, a work carrier and a cover part, with only the work carrier being shuttled through the machine. A nonshuttled mating cover part is used at each processing station to form a complete cell with the shuttled work carrier for processing of the work. Thus, the work carrier forms a cell with the cover part present at each successive processing station. Hence, the treatment, or plating, cell moves progressively through the machine.
More specifically, the Work carrier is preferably in the form of a palletized plating fixture which is movable on a conveyor means from station to station in the machine. The palletized plating fixture is designed to accommodate individual workpieces and to retain the individual workpieces in a predetermined position throughout the plating process. Individual workpieces are supported during each portion of plating operation within individual plating cells to which various plating solutions and plating preparation solutions may be alternately applied without removal of the workpiece from the particular palletized plating fixture within which it is originally received. The prior commercially available part conveying apparatus, requiring immersion of workpieces within particular tanks, is
replaced so that the necessary operations are performed within individual plating cells at each of the work stations. In this manner, cleaning solutions and plating solutions are forced through the plating cell at the various stations without any repositioning of the workpiece relative to its initial position in the palletized plating fixture. A predetermined spatial relationship between anode means and each workpiece is maintained throughout the plating process.
It is an object of the invention to provide a rapid, reliable, effective process and apparatus for communicating the pressively moved plating cell with a source of processing solution.
This and other objects of the invention are attained by locating both a processing solution source conduit and a reservoir return drain at the processing station so as to register with solution inlet and outlet parts, respectively, in the plating cell. The cell and cell conveyor segment are lowered into positive engagement with the source conduit and drain .to obtain processing solution flow through the cell. In the two part cell, the cell cover at the proc- 3,278,409 Patented Oct. 11, 1966 essing station forms a support for a section of the work carrier conveyor. As the cover is lowered, so is the segment of the conveyor it supports, to allow the work carrier to engage the source conduit and reservoir return drain.
Other objects, features and advantages of the invention will become more apparent from the following detailed description, wherein reference is made to the accompanying drawings, in which:
FIGURE 1 shows a diagrammatic view of an illustrative plating process station sequence for copper, nickel and chrome plating an automobile bumper part or the like;
FIGURE 2 contains a side elevational view of a portion of a plating machine embodying individual plating process stations shown in FIGURE 1;
FIGURE 3 shows a plan view, partly in section, of the portion of the plating machine shown in FIGURE 2 and taken along the line 3--3;
FIGURE 4 shows a cross-sectional view taken along the line 44 in FIGURE 2;
FIGURE 5 contains an enlarged cross-sectional view taken along the line 5-5 in FIGURE 2;
FIGURE 5a shows a schematic elevational view in perspective of the conveyor frame section and associated housing shown in FIGURE 5;
FIGURE 6 also contains an enlarged cross-sectional view. This view shows the conveyor driven mechanism provided for the machine taken along the line 66 in FIGURE 3;
FIGURE 7 shows an enlarged cross-sectional view of the conveyor mechanism taken along the line 77 in FIGURE 6;
FIGURE 8 illustrates a detail plan view, partly in section, of a portion of the conveyor mechanism shown in FIGURE 6;
FIGURE 9 shows a cross-sectional view taken along the line 9-9 in FIGURE 7;
FIGURE 10 shows a cross-sectional view taken along the line 10-10 in FIGURE 8;
FIGURE 11 shows a cross-sectional view taken along the line ll-11 in FIGURE 7;
FIGURE 12 shows an enlarged sectional partial view of a palletized plating fixture in processing position as shown at station 2 in FIGURE 2;
FIGURE 13 also has an enlarged cross-sectional view of a plating cell formed at station 2 in FIGURE 2;
FIGURE 14 contains a cross-sectional view of a portion of the apparatus shown in FIGURE 13 and taken along the line 1 414 in FIGURE 13;
FIGURE 15 illustrates a cross-sectional view of a portion of the apparatus shown in FIGURE 13 and taken along the line llS-15;
FIGURE 16 shows a cross-sectional view taken along the line 1616 and showing a portion of the apparatus in FIGURE 13;
FIGURE 17 shows a cross-sectional view of a portion of the apparatus shown in FIGURE 13 and taken along the line 1717;
FIGURE 18 diagrammatically illustrates the method of transferring palletized plating cells :from station to station;
FIGURE 19 diagrammatically illustrates the method of transferring palletized plating cells from station to station;
FIGURE 20 contains a plan view of a pallet for a plating cell;
FIGURE 21 illustrates an enlarged sectional view of a portion of the apparatus shown in FIGURE 5 and taken along the line 21-21; and
FIGURE 22 shows a cross-sectional view of an alternative embodiment of the cathode fixture shown in FIG- URE 13.
3 MACHINE OPERATION Serving as a specific example of the invention is the following description of the operation and structure of a machine in which it is incorporated. This is a plating machine having a plurality of aligned processing stations through which a palletized plating fixture is to be moved by conveyor means provided on the machine. Processing means are provided at each of the stations to direct plating solution, cleansing solution or other processing materials into processing contact with an individual workpiece mounted in each of the palletized plating fixtures. At some stations a plating cell is formed by association of an anode fixture with the palletized plating fixture to form a sealed cell in which electrolytic processing can be accomplished. In order to minimize the number of anode fixtures required, other types of fixtures, for forming a sealed cell, are provided at certain processing stations where non-electrical processing is accomplished. Thus, instead of providing a single palletized plating cell of anode type construction, which would be moved from station to station; the preferred embodiment of this invention comprises a palletized plating fixture associated with various cover fixtures at the different processing stations to form various types of processing cells depending on the pi'ocessing operation at a particular station. In the apparatus shown for illustrative purposes, thirtytwo working stations are provided. However, it is to be understood that the number of processing stations may be varied and the position of various stations relative to one another may also be varied depending on the particular workpiece being processed, and on the particular type and sequence of processing desired to be applied to a particular workpiece or part. A sufficient number of palletized plating fixtures are utilized to provide a plating cell for each of the Work stations when the machine is in operation and to provide a sufficient number of palletized plating fixtures in addition to the number of work stations so that a continuous plating operation may be maintained. In other words, several palletized plating fixtures at any particular time in the complete plating cycle will be in the process of having the workpiece contained therein unloaded subsequent to the plating operation and loaded prior to re-entry into the plating machine to begin another plating process. Conveyor means are provided to carry each palletized plating fixture from the final station of the plating machine to an unloading station whereat an operator, or suitable automatic mechanism, may be utilized to remove the finished workpiece; and whereat, another workpiece may be mounted on the palletized plating fixture. The conveyor mechanism thereafter carries the palletized plating cell from the loading station to the first station of the machine whereat the palletized plating fixtures are fed onto a pallet conveyor mechanism which is actuable to move the palletized plating fixtures step by step from station to station. In some cases, the normal step by step movement of the palletized plating fixtures between successive stations is changed so that a station may be skipped or the formation of a cell at a particular station may be maintained for longer than a standard or normal processing period between transfer movement. In this manner, stations which require a longer processing time, compared to the other stations, may be accommodated without disrupting a standard stop period between transfer movement. The particular process solutions at each station are pumped or otherwise delivered under pressure within the processing cell formed thereat to cont-act the workpiece carried by the palletized plating fixture in a predetermined manner and to accomplish a predetermined result during the standard stop time. At each work station, a particular process solution is applied to the part within the plating cell and subsequently removed from the plating cell before the palletized plating fixture is transferred to the next work station. A plurality of tanks are provided adjacent each work station and suitable pumping means may be provided to convey the fluid from the tanks to the plating cells. In addition, at some stations, a processing material such as rinse water is applied from a central source through retractable shroud housing type fixtures provided at such working stations to form a processing cell with the palletized plating fixture. Suitable tanks are provided below the processing cell to collect rinse water or the like delivered through the retractable heads. The processing cycle is arranged so that suitable rinsing stations separate processing stations in which activated processing solutions are used. In this manner, the palletized plating fixtures are completely washed and cleaned between applications of plating solutions so that a solution applied at a particular station is completely washed or rinsed away before the palletized plating fixture arrives at another plating or similar process station. The operation of the machine is continuous and the different process solutions are applied to the individual parts supported within the processing cells in a manner in which the application of plating solution to the individual workpiece can be rigidly controlled and in which the position of an anode fixture relative to the surface of the workpiece to be plated is also rigidly controlled and maintained. The capacity of the machine is limited only by the time each individual workpiece must remain at a particular processing station. In order to increase the plating rate of the machine as a whole, special methods of applying the plating solutions are provided which increase the plating rate substantially relative to previously known methods of plating similar parts on a mass production basis. In this manner, although individual workpieces are plated as compared to plating of a multiplicity of workpieces at a particular station as known in the prior art, the plating rate capable of being achieved with the machine and methods provided by this invention is greatly increased over the plating rate which could be achieved in previous apparatus. In addition, plating quality is also increased. The control of the plating cycle is facilitated by providing work stations that are equally spaced from one another and by providing equal stop intervals for the palletized plating cells at each of the work stations. In general, each of the palletized plating fixtures is moved an equal distance between each station and remains at each station an equal time. Any necessary deviations from the standard stop time are accommodated by the special transfer mechanism provided which permits an increased process time at particular process stations, such as a plating station, without disrupting the continuous overall operation of the machine.
The preferred plating process is embodied in a machine comprising thirty-two separate in-line stations and transfer mechanism to successively move individual palletized plating fixtures from station to station. As shown in FIGURE 1, several of the stations are provided with individual solution tanks from which various process solutions are applied to processing cells formed by association of cover heads at each station with the palletized plating fixtures. The process sequence for a particular part comprises the preliminary steps of loading the part or workpiece on a cathode mounting fixture which is associated with a pallet to form a palletized plating fixture, and moving the palletized plating fixture to machine entrance station No. 1 whereat the palletized plating fixture is associated with transfer mechanism which controls move ment of the palletized plating fixtures from station to station through the machine. As previousely discussed, an individual palletized plating fixture will be located at each processing station during normal full scale production runs. The transfer mechanism moves each individual palletized plating fixture simultaneously from station to station and a standard stop time is utilized for forming a processing cell and applying processing solution at each station. After a palletized plating cell has been loaded with a part and positioned at entrance station No. 1 durthe part is passed in one end of the chamber and out the other. The velocity of the solution flowing through the chamber in this manner is equal to about 7.1 feet per second for each 100 gallons being pumped through per minute (g.p.m.). Hence, for a rate of flow of 200 g.p.m. the solution velocity in the chamber is about 14.2 feet per second, for 400 g.p.m. the solution velocity is about 28.4 feet per second, for 600 g.p.m. the solution velocity in the chamber is about 42.6 feet per second, etc. Thus, the process shown in FIGURE 1 also involves:
Station 1 An automatic loading station whereat the palletized plating fixture is automatically loaded on the machine transfer mechanism.
Station 2 A spray cleaning station whereat foreign matter, such as oil, dirt, bufling compound, etc., on the surface of the part to be plated is removed. The cleaning solution applied will usually be an alkaline type of cleaner of conventional composition comprising alkali, such as caustic soda, phosphate, carbonate, etc., emulsifiers, wetting agents and other soil removing aids. The stop interval is 30 seconds and the cleaning solution is pumped to the part at a rate of approximately 200 g.p.m. at a temperature of approximately between 100 F. and 200 F.
Station 3 An electrolytic cleaning station whereat electrolysis is used to aid in removing foreign matter on the part which was not removed at station 2. The part is electrified and an alkaline type cleaning solution is pumped to the part at approximately 300 g.p.m. and at a temperature of between approximately 100 F. and 200 F. The stop interval is 30 seconds.
Station 4 A warm water rinse station whereat residual alkali fihn remaining on the part is removed by spraying water over the part at a rate of approximately 100 gallons per minute at a temperature of approximately 100 F. to200 F. The stop interval is 30 seconds.
Station 5 A cold water rinse station whereat additional residual alkalies are removed from the part by spraying tap water at line pressure over the part. The stop interval is 30 seconds.
Station 6 An electrolytic acid station which may be optionally used as an acid dip to neutralize any residual alkaline film or as an electrolytic acid for electrolytic polishing of the part. Sulfuric acid or other suitable acid solution, which may vary from less than 1% to more than 50% concentration, is used in our preferred process. It is pumped to the part at an approximate rate of 300 gallons per minute and an approximate temperature of 75 F. to 200 F. A current density, anodic or cathodic, of about a.s.f. can be concurrently imposed on the part. This station can also be used for electropolishing, if desired. The stop interval is 30 seconds.
Station 7 and 8 Cold rinse stations whereat any residual acid solution is removed by tap water at line pressure. The stop interval is 30 seconds at each station.
Station 9 A copper strike station whereat a flash of copper is deposited on the part to provide a base for subsequent operations that will promote adhesion. A conventional cyanide copper solution is pumped to the part at an approximate rate of 600 g.p.m. and at an approximate temperature of between 100 F. and 200 F. The part is electrified. The stop interval is 30 seconds.
Station 10 A copper plate station whereat sufiicient copper is deposited to provide a suitable surface for subsequent bright nickel plating. The part is energized and may be cathodic or periodic reverse plating may be used. The solution is pumped to the part at an approximate rate of 600 gallons per minute and at a temperature of approximately F. to 190 F. The stop interval is 30 seconds.
Stations 11 and 12 Cold water rinse stations whereat any cyanide alkaline film residue on the part is removed by tap water pumped at an approximate rate of 100 gallons per minute. The stop interval is 30 seconds at each station.
Station 13 An electrolytic cleaning station which provides a supplementary cleaning to insure a clean surface prior to nickel plating. The part is electrified and an alkaline type cleaning solution is pumped to the part at a rate of approximately 300 gallons per minute and at a temperature of approximately F. to 200 F. The stop interval is 30 seconds.
Station 14 A cold water rinse station identical to station 5.
Station 15 An acid cleaning station whereat any alkaline film residue remaining from station 13 is removed. An acid solution of sulfuric acid, hydrochloric acid, or any other suitable acid, is pumped to the part at an approximate rate of 100 gallons per minute and at approximately room temperature to 200 F. The stop interval is 30 seconds.
Station 16 A cold water rinse station identical to station 7.
Station 17 An idle station whereat the part may be located for a stop interval of 30 seconds without any processing to accommodate a stop interval of 60 seconds at stations 18 and 19.
Stations 18 and 19 Station 20 An idle station to accommodate stop intervals of 60 seconds at stations 18 and 19.
Stations 21 and 22 Cold water rinse stations whereat residual nickel plating solution on the part is removed by tap water sprayed thereon at an approximate rate of 100 gallons per minute. The stop interval is 30 seconds.
Station 23 An acid dip station, whereat the nickel surface on the part is activated prior to chromium plating by application of an acid solution, such as sulfuric acid, and other conventional additives which form an activated nickel surface. The acid solution is sprayed over the part at an approximate rate of 100 gallons per minute at room temperature. The stop interval is 30 seconds.
Station 24 A cold water rinse station, whereat residual acid solution is removed. The station is identical to station 5.
ing a standard stop time, the next movement of the transfer mechanism carries the loaded palletized plating cell from station 1 to cleaning station 2. When the palletized plating cell is in position at station No. 2, a shroud housing is positioned around the workpiece and a cleansing solution is pumped from an adjacent tank to spray apparatus in the shroud housing from which the cleansing solution is sprayed over the workpiece. The cleansing solution flows over the workpiece and returns to the tank through a drain opening extending through the palletized plating fixture and a collection sink provided thereunder. The application of the cleansing solution is completed within the standard stop time and the shroud housing is disassociated from the palletized plating fixture before the next movement of the transfer mechanism which carries the palletized plating fixture from station No. 2 to electrical cleaning station No. 3. The apparatus provided at station No. 2 and the operation thereof is similar to the apparatus provided at stations Nos. 4, 5, 7, 8, 11, 12, 14, 15, 16, 21, 22, 23, 24, 26, 28, 29, 30 and 31. Therefore, only the process variations are hereinafter described in detail.
After the palletized plating fixture is properly positioned at station No. 3, an anode housing is positioned in sealing engagement therewith to form a processing cell and the palletized plating fixture is simultaneously positioned in sealed engagement with a solution applying passage and a solution receiving sink. At the same time, an electrical connection is obtained between the cathode mounting fixture and an electrical source provided at station No. 3. The anode fixture may be permanently electrically connected since it is permanently located at station No. 3. Cleansing solution is then pumped at a high rate of How from an adjacent tank through the solution applying passage and into a flow cavity formed between a contoured lower surface of an anode fixture within the anode housing and a parallel closely spaced surface of the workpiece on the palletized plating fixture. The flow cavity encompasses the entire surface to be plated of the workpiece and the cleansing solution flows completely over the outer surface of the workpiece. The anode fixture is electrically energized and the workpiece is electrically energized through contact with the cathode mounting fixture during the cleansing process' The cleansing solution flows through an outlet port extending between the palletized plating fixture and the solution receiving sink to the adjacent tank. At the end of the solution applying cycle and before the elapse of the standard stop time, the pumping of cleansing solution is discontinued and the palletized plating fixture is disengaged from the solution applying passage, the solution receiving sink, the electrical source and the anode housing to prepare the palletized plating fixture for transfer to the next station when the standard stop time has elapsed. It is to be understood that the shroud housings and anode housings at the various stations are simultaneously raised and lowered during the standard stop time and therefore no further reference to the positioning of the housings need be made in this brief description of the processing steps. The apparatus provided at station No. 3 and the operation thereof is similar to the apparatus provided at the subsequent electrical processing stations Nos. 6, 9, 10, 13, 18, 19, 25 and 27 whereat anode housings are provided. Accordingly, only the process variations are hereinafter described in detail.
The next movement of the transfer mechanism carries the palletized plating fixture from station No. 3 to warm rinsing station No. 4. After a shroud housing is associated with the palletized plating fixture, warm rinsing solution is pumped from an adjacent tank containing a heating element and applied to the workpiece. Before the stop time elapses, the solution application is discontinued and the shroud housing is disassociated from the plating fixture. The next movement of the transfer mechanism carries the palletized plating fixture from station No.
4 to cold rinsing station No. 5. Station No. 5 is identical to station No. 4 except that the solution is maintained at a lower temperature. The cold rinse solution may be supplied directly from a central water source and drained to a sewer connection rather than being pumped from and collected in an adjacent tank as at station N0. 2 The processing at stations 7, 8, 12, 16, 21, 22 and 29 is similar.
At station No. 6, an anode housing is associated with the palletized plating fixture and an acid solution of suitable composition is applied to the workpiece at a suitable rate of flow and current density.
The palletized plating fixture then passes through successive cold rinse stations Nos. 7 and 8 which are provided to insure a thorough removal of the cleansing acid applied to the palletized plating fixture at station No. 6 without disrupting the standard stop time. In other words, when a longer processing time is required than the standard stop time, a plurality of similar stations may be provided to enable the application of processing solution for the required processing time without unnecessarily increasing the stop time at other processing stations which require a lesser processing time.
Station No. 9 is a copper strike station whereat a processing solution of suitable composition is applied at a suitable fiow rate and current density.
Station 10 is a copper plate station whereat the workpiece is copper plated by the application of a processing solution of suitable composition at a suitable flow rate and current density.
Station 11 is a reclaim rinse station whereat copper is reclaimed from the rinse solution.
After a cold rinse at station No. 14, the palletized plating fixture is moved to acid dip station No. 15 whereat an acid solution of suitable composition is sprayed over the workpiece to additionally clean the copper plated workpiece.
After a cold rinse at station No. 16 to remove acid, the palletized plating cell is moved to either station No. 17 or No. 18 depending on whether station No. 17 is empty. Thus, by the provision of another idle station No. 20, the palletized plating cells can remain at stations Nos. 18 and 19 for two standard stop periods and each palletized .plating cell stops only at one or the other of stations 18 and 19. At nickel plating stations No. 18 and 19, a nickel plating solution of suitable composition is applied to the workpieces at a suitable fiow rate and current density for a suitable period of time.
The palletized plating fixture is next moved to cold rinse station No. 21 from station N0. 19 or from idle station No. 20 depending on the machine cycle. A second cold rinse station No. 22 insures complete rinsing of the nickel plating solution.
An acid solution of suitable composition is applied to the nickel plated workpiece at station No. 23 to prepare the nickel surface for a chrome plating operation. The acid is washed away at station No. 24.
The chrome plate is applied at stations No. 25 and No. 27 at suitable flow rates and current densities. Some of the chrome plating solution is reclaimed at rinse stations Nos. 26 and 28.
The chrome plated workpiece is then washed and rinsed at rinse stations Nos..29 and 30, and dried at station No. 31 prior to association of the palletized plating fixture with overhead conveyor means or the like at exit station No. 32 for movement of the palletized plating fixture to an unloading station and thereafter to the loading station and back to station No. 1 as previously described.
In summation and by way of further detail, the process shown in FIGURE 1 has been practiced on the left corner bar, or wing, of the 1961 Chevrolet front bumper. The conforming anode used in treating this part is spaced approximately one-half inch from the surface of the wing to form a rather extended treatment chamber therebetween. As previously indicated, the solution used to treat Station 25 A chromium plating station, whereat the chromium plating solution is pumped over the part at approximately 400 gallons per minute and at an approximate temperature of 100 F. to 200 F. The part is cathodically energized. The stop interval is 30 seconds.
Station 26 A reclaim rinse station, whereat residual chromium plating solution adhering to the part is removed by room temperature rinse water that is reclaimed. The stop interval is 30 seconds.
Station 27 A chromium plating station identical to station 25.
Stations 28 and 29 Cold water rinse stations whereat residual chromium plating solution is removed. The stations are identical to station 11.
Station 30 A hot water rinse station whereat the rinse water is heated to an approximate temperature of 180 F. to facilitate subsequent drying of the part. The station is otherwise identical to stations 28 and 29.
Station 31 A part drying station whereat hot air is blown over the part. The stop interval is 30 seconds.
Station 32 An unloading station whereat the palletized plating fixture is removed from the transfer mechanism and connected to a conveyor for removal to a part unloading station. The stop interval is 30 seconds.
GENERAL MACHINE STRUCTURE Since the machine apparatus is duplicated at many tations, only the first five stations are shown. Furthermore, the various stations are, in general, provided with one or two types of processing apparatus. One type of apparatus is provided at stations where the processing step requires no electrical energization of any of the parts and such stations may be referred to as non-electrical stations. The other type of apparatus is provided at stations where the processing step requires cathodic energization of the workpiece and the energiza-tion of an anode member. Such stations may be classified as electrical stations. Nonelectrical stations include a shroud housing in which spray apparatus is mounted and electrical stations include an anode housing in which an anode fixture is mounted. The two types of stations are hereinafter referred to, respectively, as shroud station and anode stations, and one of each type of station will be described in detail by reference to the details of the apparatus at shroud station No. 4 and the details of the apparatus at anode station No. 3, which are exemplary.
Referring now to FIGURES 2, 3 and 4, stations 1, 2, 3, 4 and of the plating machine are shown in detail, and it is to be understood that the other stations are similarly constructed. The machine comprises a frame of structural steel construction having a lower tank section which supports process solution tanks, an intermediate section which supports conveyor apparatus and an upper section which supports plating cell forming housings. As shown in FIGURES 2 and 4, the frame comprises a base formed by spaced horizontally extending lower structural members 50, 52, 53. A plurality of lower vertical structural members 54, S5, 56, 57, 58 extend upwardly from the base and form two spaced longitudinal rows of similarly positioned members. The vertical structural members in each row are spaced to define tank accommodating compartments 59, 60, 61 for each of the processing stations. Intermediate horizontally extending structural members 62, 63 are secured to the upper ends of the vertical structural members at each row and support a conveyor platform plate 66 which extends the length of the machine. A row of upper vertically extending structural members 67, 68, 69, 70 extends longitudinally along one edge of the conveyor platform 66 and another parallel row of identically located structural members 71, 72 extends longitudinally along the opposite edge of the conveyor platform 66. It is to be understood that similar upper vertical members extend the length of the machine. Upper horizontally extending support members 74, 75 are supported on the tops of the upper vertical structural members. Cross support structural members 76, 77 and cross support plates 78, 79', 80 extend transversely between the longitudinally extending structural members 74, 75. In addition, bracket plate members 81, 82 are secured to the top of the cross supports 76, 77 and extend longitudinally of the frame. As shown in FIGURES 4 and 5, bracket support plates 83, 84 may be secured to the inner side surfaces of the upper vertical members and extend longitudinally of the frame. A transfer mechanism support frame 85 is positioned adjacent one end of the machine frame and supports a transfer mechanism support platform 86 in substantial alignment with the conveyor platform 66.
Solution tanks, such as tanks 89, 90, 91, illustrated at stations 2, 3 and 4, are provided at some of the stations and are seated in the tank compartments. Conventional pump mechanisms 92, 93, 94 are mounted adjacent each of the tanks as shown in FIGURE 3. At some of the stations, such as station No. 5, an outlet pipe 64 is provided in place of a tank to conduct processing solution to a central drain system. In addition, at the several plating stations, electrolyte regenerating tanks (not shown), are also provided adjacent the apparatus and are connected by suitable piping to the tanks provided beneath each station.
Referring now to FIGURE 3, a longitudinally extending conveyor track is centrally located on the support platform 66 and comprises spaced rows 87, 88 of horizontally aligned roller members 95, 105. The rollers at each nonelectrical station may be mounted on individual support frames 96, 97 which are directly connected to the support platform 66. The rollers at each electrical station are specially mounted and will be hereinafter described in detail. The rollers 95, and roller frame sections 96, 97 of adjacent work stations are parallelly aligned so that a continuous roller conveyor is provided for the palletized plating fixtures. For purposes of illustration, each section of rollers is shown to comprise three individual roller members. Referring now to FIGURE 4, the spaced sections of rollers at each of the nonelectrical stations, such as station No. 4, comprise base plates 98, 99 which are secured to the support platform 66 in any suitable manner. Spaced side support plates 100, 101 and 102, 103, are secured to the base plates 98, 99 and extend upwardly therefrom. Suitable cross supports may be provided to divide each roller frame section into three roller compartments as shown in FIGURE 3. Support shafts 106, 107 are centrally located in each roller compartment and rotatably support the roller members 95, MP5. As shown in detail in FIGURE 13, the roller members have a V-shaped peripheral cross section which is configured to receive mating portions of each palletized plating fixture during movement of the palletized plating fixtures from station to station.
Referring again to FIGURE 2, at each station where a processing solution is applied to a workpiece on a palletized plating fixture, solution controlling and confining housings 110, 111, 112, 113, 114 are vertically movably supported for movement between a retracted upper position during transfer of palletized plating fixtures from. station to station and an extended lower position of sealing engagement with the palletized plating fixtures to form a processing cell during application of processing solution to the workpieces. Anode type housings 111,
1 1 114 are provided at electrical stations Nos. 3 and 6, and spray type housings 110, 112, 113 are provided at nonelectrical stations Nos. 2, 4 and 5.
Referring now to FIGURE 4, each of the spray housings comprises a rectangular casing 115 formed from sheet metal or the like and containing a plurality of spray nozzles 116. The lower portion of the casing is open and provided with a peripheral rim 117 which is adapted to be sealingly engaged with an upper surface of each of the palletized plating fixtures 118. The workpiece mounted on the palletized plating fixture is centrally positioned within the rectangular casing 115 adjacent the spray nozzles 116 when the spray housing is in the extended position. The spray housings are vertically movably supported on pipe members, 119, 120 which extend upwardly through support brackets 121, 122 fixed to the angle plat-es 81, 82 or other adjacent portions of the frame. A spray nozzle pipe 123 is connected to the lower ends of the pipe members. The pipe 123 is connected to a solution source through suitable piping 124 which is integrally connected to one of the support tubes 120.
ELECTROLYSIS CELL AND ASSOCIATED PARTS While the spray housing and pallet form a treatment cell, the cell thus formed differs from the electrolysis cell. The former has processing solution introduced through the housing, which does not involve the present invention. On the other hand, the latter type cell, the electrolysis cell, has processing solution introduced through the pallet. An anode housing forms the cover member in the electrolysis cell.
Eleclrolysis cell cover Referring now to FIGURES and 13 where the anode housing 114 at station No. 5 is illustrated, each of the anode housings comprises an outer rectangular casing 128 formed of welded sheet steel or the like and having a lower peripheral rim portion 129 which may be provided with a seal or gasket 130 for sealing engagement with an upper surface of each of the palletized plating fixtures 118. A coupling block 131 is secured to the top of the outer casing 128 and is adapted to be connected to a piston rod 132 which is reciprocably actuable by a hydraulic cylinder 133 or other suitable power driven motor means mounted on top of one of the cross support beams 77 as shown in FIGURES 2 and 4. Locating pin support brackets 134, 135 are suitably fastened to opposite sides of the outer casing 128 and support centrally located guide pins 136, 137 which serve to locate the anode housing 114 relative to the palletized plating fixture 118.
In order to stabilize movement of the anode housing 114 between the retracted position adjacent the upper cross support 77 and the extended position of cell forming engagement with the palletized plating fixture 118, sprocket wheel support brackets 140, 141 are suitably fastened to opposite sides of the outer casing 128. Each support bracket 140, 141 is provided with transversely extending horizontal shafts 142, 143 which are parallelly aligned and equally vertically spaced. Both ends of each shaft extend outwardly beyond the support brackets and rotatably support double sprocket wheel assemblies 144, 145. Only the apparatus on one side of the anode housing 114 is shown and hereinafter described in detail. It is to be understood that similar apparatus is provided on the other side of the anode housing. Thus, four sprocket wheels are mounted on each shaft in clusters 144, 145 of two sprocket wheels which are located at each of the corners of the casing 128. Two of four guide and sup port chains 146, 147 are provided on each side of the anode housing and each are connected at one end to one of four upper chain support brackets 148, 149 mounted on one of the upper cross supports. The other end of each chain is connected to one of four lower chain brackets 150, 151 mounted on the adjacent bracket plates 83, 84. Each chain is connected to the upper chain support bracket on one side of the anode housing and is connected to the lower chain support bracket on the opposite side of the anode housing. Each chain extends downwardly from the associated upper chain support bracket, winds around the lower surface of a first sprocket wheel located therebelow, extends across the anode housing to the opposite side thereof, winds around the upper surface of a second sprocket wheel aligned with the first sprocket wheel, and extends downwardly to the associated lower chain support bracket. Guide sleeve brackets 154, 155 are attached to the outer ends of the sprocket wheel brackets. A guide sleeve bracket is provided at each corner of the anode housing 114 for a purpose to be hereinafter described. In order to provide additional stabilization for the anode housing 114 adjustable guide bolts 156, 157 may be threadedly mounted on some of the guide sleeve brackets 155 and may be adjusted to position the ends thereof in close proximity to flanges of the adjacent upper vertical beam 70 to prevent lateral movement of the anode housing. A limit switch actuating arm support bracket 158 is mounted on the guide sleeve bracket 154 and carries actuating arms 159, 160 which are adapted to actuate limit switches 161, 162 mounted on the adjacent vertical frame 72.
The actuating mechanism previously described for the anode housings may be duplicated at all the stations. However, in order to reduce cost, a single housing actuating mechanism at a central station may be used to control movement of adjacent station housings. As shown in FIGURE 2, the spray housings 110, 112 at stations Nos. 2 and 4 may be rigidly connected to the anode housing 111 at station No. 3 by a frame 164 of welded plate steel so that movement of the anode housing 111 will cause similar movement of the adjacent spray housings 110, 112.
Referring now to FIGURE 13, the anode housing 114 further comprises an anode fixture which is mounted within the outer casing 128. The anode fixture comprises a casting 166 which has a lower inner peripheral surface 167 contoured and configured to match the configuration of a workpiece 168 to be plated and to provide a flow passage 169 along the outer surface of the workpiece.
The anode material varies according to the nature of the processing at a particular station For example, the alkali cleaning stations and the cyanide copper plating stations have cast iron anodes. The acid solution and nickel plating stations have cast iron anodes which are spray coated with a covering of .07 to 0.1 inch of lead. The chromium plating stations have cast aluminum anodes which are spray coated with a covering of .07 to 0.1 inch of lead. The thickness of the anodes are dependent on the amount of current applied, the amount of force which must be exerted thereon to obtain a satisfactory seal with the plating fixture, and other variables. A peripheral rim 170 surrounds the contoured surface 167 of the anode casting 166 and has a substantially flat botom surface 171 which is sealingly engageable with a portion of the palletized plating fixture 118 in the solution applying position. The upper portion of the anode casting is provided with spaced support posts 172, 173 which are rigidly secured to the anode casting 128 in any suitable manner. Slots 174, 175 are provided in the support posts to receive an electrical contact plate 176 which extends substantially the length of the anode casting and which is secured to a suitable connecting plate 177 at one end thereof. Insulating plates 178, 179 are provided between the contact plate 176 and the side surfaces of the slots to insulate the anode casing 128 from the anode casting 166. As seen from FIGURE 5, the connecting plate communicates with an electrical source via a flexible cable 180 and a bus bar 181.
Cell work carrier Referring now to FIGURES 13-17, the palletized plating fixture 118 is shown to comprise a cathode fixture formed about a hollow central casting 186 of any suitable