Electro Plating Rectifier

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ahmedmansour15 Member Join Date: Dec 2008 Location: Cairo,Egypt Posts: 7	Electro Plating Rectifier 10/24/2010 2:08 AM
	we were connecting a plating rcetifier unit to a plating basin while the rectifier input is 380 volt three phase and the chemist required 1.2 DC volt for his process and we gave him the required voltage through the regulator installed in the unit but the plating was too bad and it becam very good and acceptable to the chemist when we switched off one phase of the input AC voltage ,need to have an explaination because the unit was working properly only with two phase input.
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#1 Re: electro plating rectifier 10/24/2010 2:58 AM
	It's years since I worked on a plating supply. But there's one thing I remember, too high a current gave poor deposition on the work piece (it builds up in a pattern that resembles tiling). The migration of the plating metal isn't voltage dependant, it's the current that determines the quality of finish. The lower the better. Obviously in a commercial situation time = money so a bit of juggling needs to be done to reach a happy medium. __________________ The reports of my death are greatly exaggerated.
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#2 In reply to #1 Re: electro plating rectifier 10/24/2010 3:40 AM
	The last plating plant I worked on was at a motorcycle museum so time didn't come in to the equation, just quality of finish. To see a 1929 Rudge in the workshop in concourse condition made me feel proud! I was sad when the last of the owners of the museum died and the collection was split up. http://www.telegraph.co.uk/motoring/6385674/99-year-old-is-safest-driver-no-speeding-tickets-in-84-years.html The article doesn't mention him and his brother racing in the IoM __________________ The reports of my death are greatly exaggerated.
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Anonymous Poster	#3 Re: Electro Plating Rectifier 10/25/2010 2:39 AM
	You do NOT control plating and its quality with voltage, . . . you do that with current. The plating you want to do will need a certain amount of current for every square meter of surface to be plated. So, if you measure the plating current and the plating does not meet your quality - reduce the current . . . this is best done by reducing the voltage not by elininlating one phase from your supply. Oleh
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aurizon Guru Join Date: Jun 2006 Location: Toronto Posts: 3968 Good Answers: 120	#4 In reply to #3 Re: Electro Plating Rectifier 10/25/2010 3:23 AM
	for plating you need to make sure the plating current is uniformly distributed over the workpiece. This often means large flat areas from which the plating metal goes into solution so that the path tothe plated area does not see large variances in distance that will cause the current per square cm to vary. Excess current cause the metal to make tiles and dendrites, if they happen, lower current and adjustments of the electrodes to get a uniform current are needed. In terms of rectification, FET based synchronous rectification are needed at low voltages, since the typical bridge rectifier will have a 1.4 volt forward voltage drop in a simple rectification situation and if you are plating at 1.4 volts, 40% of power is wasted. Tanks in series can alleviate this, but isolated design is needed. __________________ Per Ardua Ad Astra
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Haajee Guru Join Date: Feb 2006 Posts: 1758 Good Answers: 6	#5 In reply to #3 Re: Electro Plating Rectifier 10/25/2010 9:33 AM
	Regards. I think that it is the voltage that controls type of plating & current the speed. We have to keep voltage at critical Voltage well between limits in Electrolyzing processes like plating, Anodizing, collecting of different materials from solutions & like that.
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