The invention relates to a barrel apparatus for barrel plating in which a non-open barrel is used, a workpiece is accommodated inside the barrel and immersed in a plating liquid, a negative electrode that is arranged inside the barrel and a positive electrode that is arranged in the plating liquid are electrically connected and electroplating is performed while the barrel is rotated about a center shaft, and is specifically effective as measures for the environmental protection.
In a plating apparatus for industry, constant voltage control in which power supply is supplied to a plurality of barrels from one rectifier is performed.
Plating is based on Faraday's law and the amount of material that is deposited according to the electrolysis of electrolytic solution is proportional to an amount of electricity that is passed. The amount of electricity that is required to deposit material equivalent to 1 gram is constant despite the kind of the materials. In zinc plating, if 1.0 A of the electric current flows to a unit of an area of 1 dm2 (10 cm×10 cm=100 cm2) for 1 hour, plating film 17.1 μm thick is deposited. The depositing speed is 0.285 μm/min, however in barrel plating, the plating film is deposited through the electric conduction by connecting an electricity conductor body (lead wiring) referred to as a conductor that is arranged inside a rotating barrel and a workpiece, so that there are many elements to hinder the calculation and there are many cases to depend on the skill of a worker.
In order to decrease the energy that is required to deposit the plating film, it is necessary to clarify the elements that are affected by the amount of electricity. The total amount of electricity that is used to deposit the plating film is decreased so that amount of CO2 discharged is capable of being decreased. Here, lists of the elements that relate to decreasing the amount of CO2 discharged and decreasing the running costs are described below.
The inventor of the invention has reviewed barrel plating with respect to the above-described perspectives and a certain outcome is obtained with respect to the open type barrel and an application is filed with respect to a portion thereof. However, the open type barrel has an opening section at an end surface of the barrel in the direction of the rotation shaft and the workpiece is accommodated in a portion that is defined by the diameter of the opening and an inner diameter of the barrel so that this is not appropriate because there is a problem that for example, long bolt or the like may be highly possible to run over from the opening. Traveling type barrels can be distinguished in carrier type (see
In the invention, according to the above-described knowledge, the barrel is non-open type and the knowledge that the length L thereof must be short rather than long is confirmed so that it is presupposed that the barrel apparatus is the elevator type. In the elevator type, the barrel is arranged so that the direction of the rotation shaft corresponds to the traveling direction of the barrel and the endless moving type that circulates a constant peripheral passage is taken. As a result, the length of the barrel is restricted to a constant pitch (distance between adjacent barrels) and this restriction means that the diameter D is large and the length L in the shaft direction is small regarding the barrel shape (
[Patent Document] JP-A-2008-95143
The invention is made in view of the above points, and an object is to provide a plating apparatus for a barrel plating in which the non-open barrel is used so that even a long bolt class is capable of being plated without problem, furthermore electric resistance is decreased in the barrel plating from a small workpiece to a large workpiece and the discharging amount of CO2 is capable of being decreased. Also, another object of the invention is to provide a plating apparatus for a barrel plating in which the barrel plating may be performed also using the plating apparatus of the related art that does not need to be basically changed. Also, decreasing of discharging amount of CO2 and decreasing of running cost are capable of being obtained.
To achieve above objects, the invention provides a barrel apparatus for barrel plating in which a non-open barrel is used. In the barrel plating process, a workpiece is accommodated in the barrel and immersed in plating liquid, a negative electrode that is arranged inside the barrel and a positive electrode that is arranged under plating liquid are electrically connected and electroplating is performed while the barrel is rotated about a center shaft. The barrel apparatus includes: a negative electrode arranged at a position that is in contact to the workpiece accommodated inside the barrel; and a positive electrode arranged at a position that is not in contact with the workpiece accommodated inside the barrel, wherein the barrel has a form that is substantially a cylindrical shape or substantially a polygonal cylindrical shape and a ratio of a diameter and a length thereof is in a range of 1:0.7 to 1:1.
As described above, according to the invention it is presupposed that the barrel apparatus is an elevator type barrel apparatus. As shown in
The apparatus of the invention includes a negative electrode 11 arranged inside the barrel 10 at a position that is in contact with the workpiece W accommodated inside the barrel and a positive electrode 12 arranged at a position that is not contacted to the workpiece W accommodated inside the barrel 10.
The barrel has substantially a cylindrical shape or substantially a polygonal cylindrical shape and a ratio of the diameter and the length of the cylinder is in a range of 1:0.7 to 1:1.
Also, the positive electrode inside the barrel may constitute an auxiliary positive electrode. In this case, a main positive electrode may be arranged inside a plating tank where plating liquid is filled (and outside of the barrel) so that the positive electrode is along substantially periphery of the barrel. In the related art, where the electrical connection is established only by a main positive electrode that is arranged at the outside of the barrel, the barrel main body hinders the electrical connection so that the voltage tends to be increased. In the invention, a space inside the barrel is widened in the diameter direction and the auxiliary positive electrode is capable of being arranged inside the barrel that is widened space so that an advantage can be anticipated in which the voltage is lowered. The barrel main body has a plurality of barrel holes at the peripheral side surface thereof. In the invention, the barrel hole preferably has a long hole shape so as to allow easy inflow and outflow of the chemicals. According to a preferred configuration, the direction of the long hole is inclined with respect to the rotation direction thereof. In other words, the long holes have an orientation which is differt from the rotation direction of the barrel.
The invention has the above-described configuration and function in which a non-open barrel is used so that, when the ratio of the diameter and the length is in the range of 1:0.7 to 1:1 even the long bolt class is capable of being plated without problems. A further advantage is that the electric resistance is capable of being decreased in the plating of a small workpieces and of large workpieces. Also, according to the invention, the barrel apparatus for barrel plating may be provided, in which the discharging amount of CO2 is capable of being decreased. Also, decreasing of discharging amount of CO2 and decreasing of running cost are capable of being obtained, although the plating apparatus of the related art need not to be basically changed.
Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
In the embodiment shown in
The barrel apparatus of the invention includes a pair of right and left negative electrodes 26 and 26 that are arranged inside the barrel main body 20 and at a position to allow contact to the workpiece W. An inside positive electrode 27 that is arranged at a position that does not contact the workpiece W inside of the barrel 10 (the inside positive electrode 27 corresponds an auxiliary positive electrode in one embodiment). The negative electrodes 26 and 26 inside the barrel are attached to the barrel main body 20 at the position of the bearing sections 19 and 21. Also, the inside positive electrode 27 is arranged at a position of the upper right portion that is away from the workpiece W inside the barrel and opposite to the workpiece W that is deposited at the lower left portion inside the barrel main body 20 when the barrel rotates to the right in the embodiment shown in
The inside positive electrode 27 has a laterally long rectangular shape and the longitudinal direction thereof is directed to be parallel with the center shaft direction of the barrel main body 20. A plate surface thereof is arranged inclined toward the workpiece in order to face to the workpiece that is in the left with respect to the rotation direction without contact the workpiece, at the time of inputting and at the time of rotation. Accordingly, a bracket 28 is screwed to the front and rear bearing sections 19 and 21 at both ends inside the barrel main body, and the inside positive electrode 27 is attached to the bracket 28 (see
A driving mechanism 30 is provided to rotate the barrel main body 20. The driving mechanism 30 has a motor 32 that is arranged at the base section of the hanger arm, a middle shaft 36 that is coupled to the motor 32 by pinions 33 and 34 and a chain 35, and reduction gears 37 and 38 that are at the other end of the middle shaft 36. The driving mechanism 30 drives a large gear 23a that is provided at the outer periphery of the end plate 23 and a reduction gear 38. Also, the other end 26b of the negative electrode lead wire 26a communicates to a sliding mechanism 39 and can receive the power supply while moving.
In the barrel apparatus shown in drawings, the inside positive electrode configures the auxiliary positive electrode and a main positive electrode 41 is configured and arranged so as to be along the entire periphery of the barrel inside the plating tank 40 in which plating liquid is filled. The main positive electrode 41 includes a portion 41a that is arranged to surround the workpiece W that is deposited to the left side of the barrel and a portion 41b that is arranged at the outside of the inside positive electrode 27. The portion 41a is provided to be easily and electrically connected to the workpiece W that is deposited to the left by the rotation of the barrel and the portion 41b is provided so as to increase the area of the positive electrode. Especially, three positive electrodes 27, 41a and 41b are arranged to surround the periphery of the workpiece W that is deposited to the left. Accordingly, an advantage in which the electric current is easily flowed is obtained. 42a and 42b in the drawing are lead members for the positive electrode and connected to a wiring from the conductive passage (not shown). 43 is a base table of the plating tank.
<Plating Test>
Using the barrel plating apparatus configured as described above, the plating test is performed by the zinc plating and contents and results are described below.
<The Contents of Plating Test>
Test process: acid cleaning (using 35% of concentration of hydrochloric acid, during 15 minutes in a room temperature)→alkali electrolyte (using a electrolyte agent that is generally used for the zinc plating, during 5 minutes in room temperature)→temporary rust prevention (using 1% of concentration of caustic soda, during 1 minute in room temperature)→plating (according to a condition shown in Table 1 below)→post processing (using chromating agent, pH 2.4, during 30 seconds at 25° C.).
The workpiece that is used in the plating is M4×12 tapping screw, an inputting amount in barrel is 40 kg, a surface area is 25.0 dm2/kg, total surface area is 1000 dm2, the plating liquid is Zn 13 g/l, NaOH 130 g/l, NaCO3 30 g/l, and as other luster, M3 agent 2 ml/l, B agent 0.3 ml/l are used.
<Results of Plating Test>
According to Table 2, 8.34 μm of average film thickness in a case where auxiliary positive electrode is present is increased in 11.6% with respect to 7.17 μm of average film thickness in a case where auxiliary positive electrode is not present and it is understood that large advantage is obtained. The result of the test is shown in a graph of
In barrel apparatus for the barrel plating of the invention, as described above, the plating is capable of being performed with the plating time to be decreased so that the amount of electricity is capable of being decreased. As a result, the discharging amount of CO2 is capable of being decreased.
In the embodiment, the barrel apparatus for the barrel plating of the invention is described applying to the zinc plating. However, the zinc plating is taken as a typical example thoroughly and the invention is not limited to the zinc plating.
Number | Date | Country | Kind |
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JP2011-081727 | Apr 2011 | JP | national |