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Technical Information >> (4) Equipment & Process for Electrophoretic lacquering
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PROCESS AT GLANCE
Basic equipment required are polypropylene tank which could be a large tank with overflow compartment to circulate lacquer. Once components are coated hold over tank for 10 to 15 seconds for excess lacquer to floow back in tank. Give it a shake and dip in Post Rinse tank.
Pre rinse tank and Post rinse tank.
Add rinse additive to pre and post rinse tank. Use deminralised water.
Depending on product coated eg. large surface area and higher quality of work would require 1 micron filter pump to be connected to post dip tank.
Post rinse tank could have additional compartment for deminralised water to circulate known as loop system . The advantage of loop system is that minute percentage of lacquer is recovered, however disadvantage of loop system is that it is exposed to contamination.
We recommend tank with overflow compartment. Permeate is dumped away so that you have clean system with no risk of contamination and solvents are added according to permeate dumped.
Attached to tank would be pump to circulate, filter, ultra-filtration system
Click here to see Equipment Pictures section
Rectifier to give DC power current 0-70 volts, 20 AMP Max. It is important that rectifiers give even current distribution. Typical coating thickness is achievable by variation of voltage over seconds. For example 30 volts @ 10 seconds will coat 3 microns, 30 volts @ 30 seconds will coat 6 microns and 40 volts @ 60 seconds will coat 12 microns. (various combinations of voltage and time)
Tank components such as saddles, heaters (running hot water inside metal tube), cooling coils.
Use a stainless steel anode to give an anode/cathode area ratio of approximately between 1:1 and 1:2.
Jigs to hang components to coat are made from copper or brass. Jigs have to be designed in accordance with the shape & size of component, tank size, production desired and current distribution.
pumps and filters. It is recommended that particle filtration down to 1 micron is maintained using normal filter
The agitation of lacquers is 2 to 3 times of bath turnover per hour. If black pigment is added to lacquer in tank it would requires good agitation of 4 to 6 times of tank turnover per hour and for white pigments Pigments which are heavier and may settle down in bottom of tank it requires good agitation of 8 to 10 times tank turnover per hour.
No ultra filtration is required on small installations of up to 20 litre baths.
Use ultra filtration system for larger baths. This would be tall Stainless steel tube with plastic top casing/housing to hold long membrane and would permeate 30 litre per hour. The pump pushes bath solution with 800 ĩS (microsiemens) to membrane, which will filter and feed the lacquer back in to tank and separate solvents etc as permeate. Depending on size of tank this could be fixed to tank or Porable ultra filtration system connected to tank as and when required.
For every 10 litre permeate removed add 350 ml of Shinex Primary Solvent and 5 ml Shinex MEQ Replenisher.
Information on portable & and small ultrafilteration membrane system which would permeate 10 litre per hour is available on request. This would be suitable for 30 to 40 litre bath.
Add Rinse Additives to pre and post demineralised water tanks as 1 to 2 ml per litre.
Using reflectrometer reading, a percentage of bath solids is established. Information on reflectrometer reading graph and oven test to measure solid content is available on request.
The conductivity of the solution needs to be maintained at recommended level to achieve good deposition. It changes on the usage/production carried and bath contamination. If conductivity reading is high ultra filtration is necessary.
The temperature of the solution in plating tank needs to be maintained at recommended level of 25-27 degree centigrade.
Oven to cure lacquer. Products are hanged in oven to cure for 20 minutes @ 160ēC (metal temperature), 25 minutes @ 145ēC and 30 minutes @140ēC. (various combinations of time and temperature)
Infra red light heat is used in continues conveyer ovens curing systems.
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PLATING WORKSHOP
Electrophoretic lacquering is a 'Continuous process after plating'. it could be continuation of electroplating line followed with lacquering tank, which is also described as 'wet on wet' plating process. It is not necessary for the components to be dried first.
Depending of base metal to coat the component would pass from various tanks of liquid filled with plating chemicals such as pre treatments, nickel plating, silverflash etc. This could be one continuous process or electrophoretic lacquering could be free standing process.
If components require colour the dye could be either added to tank or use option of post dye system where after clear coating components would be submersed in required colour post dye tank for few minutes and than cure lacquer in oven at described temperature. Some lacquers can be cured using infra red heat.
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For more information write to us on
info@shinextechnologies.co.uk
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