electrophoresis

EELLEECCTTRROOPPHHOORREESSII SS

ENVIRONMENTALLY CONSCIOUS METAL FINISHING

Sawyer and Smith Corporation

5412 Homegardner Road Castalia, Ohio 44824

Ph: 419.951.4818 Fax: 419.951.4822 www.electroplatingequipment.biz

[email protected]

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environmentally conscious metal finishing

TTTTTTTTEEEEEEEECCCCCCCCHHHHHHHHNNNNNNNNIIIIIIIICCCCCCCCLLLLLLLLAAAAAAAADDDDDDDD:::::::: BBBBBBBBAAAAAAAASSSSSSSSIIIIIIIICCCCCCCC IIIIIIIINNNNNNNNFFFFFFFFOOOOOOOORRRRRRRRMMMMMMMMAAAAAAAATTTTTTTTIIIIIIIIOOOOOOOONNNNNNNN The Buffoli group in the past five years has integrated its own production of

electroplating equipment, racks and accessories, with the design and construction of electrophoretic equipment as well as the marketing of the products.

The knowledge acquired by Buffoli in over thirty years of business is an unquestionable benefit for the manufacturing of the electrophoretic equipment. For this reason, the customer can consider Buffoli as an “exclusive” partner for the manufacturing of the equipment and for the make up and maintenance of the electrophoretic solutions.

Since the process is similar to the electroplating process (the coating is made by

an organic resin rather than metallic ions) a wide range of applications can be easily achieved.

TYPICAL APPLICATIONS …..

Bathroom fittings

Window and door furniture

Giftware and fancy goods

Electrical goods

Metal buttons

Metal parts for leather goods

Supermarket carts

Vehicle alloy wheels

Automotive components and accessories

Architectural aluminum extrusions

Toys

Medallions, coins and watches

Bicycle parts

Display stands

Decorative and functional parts

Lighting products

Hollowware

Eyeglass frames

Trophies

Household goods

Example of finishing with Techniclad electrophoretic products

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With Techniclad electrophoretic process is possible to coat every electroplated,

polished or only vibro-finished metallic surface. Obviously the brightness of the coating depends from the surface conditions of the metal before the electrophoretic process.

The Techniclad process starts with the pre-treatment phase according to the

conditions of the surface to be coated. However, in order to achieve a satisfactory coating the surface must be cleaned and degreased as much as possible in order to avoid the contamination of the electrophoretic solutions.

After the pre-treatments the pieces need a rinse phase with demineralized water

and special wetting agent. It reduces drag in by about 50% thus minimizing contamination.

The key-point of the process is the electrophoretic phase where, under

application of continuos current supplied by special-designed rectifiers, the pieces are coated with a uniform layer over their entire surface, even in deeply recessed areas. The coating thickness ranges from 5-30 µm depending on application.

The thickness can be easily controlled simply by modifying the current. It is important to understand that a surface coated with 20 µm thickness, variations are normally contained within ± 2 µm. The average coating time is normally between 60 and 90 seconds.

A key designed feature of the plant is a CLP (Closed Loop Purification) unit by means of an ultra filtration membrane, which can give over 95% recovery of resin solids. All materials coming from the CLP unit is recycled within the plant and purified, giving the process its “greenness”

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SOLID RESINS:CONCENTRATE

SMALL PARTICLES:PERMEATE

ULTRAFILTRATION

MEMBRANE

LARGE PARTICLES:- RESIN SOLIDSSMALL PARTICLES:- WATER, ELECTROLYTES ACID, SOLVENT etc.

The last phase is the hot rinse at 35 °C. The parts being coated will then be

placed in the oven for the curing at 140-160 °C for 20-30 minutes. Various parameters determine the thickness of coating: bath temperature,

dipping time, solvent percentage, and solid content percentage. In the following diagrams is indicated the relationship between various parameters and the thickness.

20 25

°C TemperatureSolid content

15 % 25 %

Tension 15 % 25 %

Solvent content

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GALVANISED METALS

POLISHED METALS

OTHERS TREATMENTS

Deg

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Deg

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Rin

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Rin

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Dra

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On

load

Rin

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Dem

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Pre

-dip

Ele

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Dra

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Hot

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Pas

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Off

load

U.F.

+ -+ -

Carb Anion Cation

Pre-treatment

Rinse

Techniclad

MATERIAL TO BE TREATED

OVEN CURING

FINISHED PRODUCT

PROCESS

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�� UNIFORM COATING: being an organic coating, the resins are deposited on

the work and become an electrical insulator. As the coating adheres on the work, the current is reduced until the electrolysis stops and deposition of resinous material is terminated. The coating process continues until all conductive areas on the work are insulated giving a uniform thickness over the part being coated.

�� HIGH RESISTANCE COATING: the electrophoretic process assures a long

lasting finish and is therefore suitable for external use, even in adverse environments.

�� HIGH EFFICIENCY: The production efficiency of eletrophoretic equipment is

normally much higher than electroplating equipment, thus obtaining an energy savings and less need of factory space.

�� LOW TEMPERATURE PROCESS: even the energy consumption during the

deposition is less than the consumption of the electroplating process. As a matter of point, the working temperature of the bath is contained between 20 and 25 °C.

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�� HIGH RECOVERY OF PRODUCTS: the use of a closed loop ultrafiltration

systems (standard features of the equipment supplied by Buffoli) gives over 95% recovery of resin solids.

�� SMALLER WATER TREATMENT: The electrophoresis tanks do not need

particular treatment of wastewaters; the only effluent is a periodic small amount of permeate. Therefore the water treatment is limited to simple ionic exchange resins plant for the treatment of the rinse waters.

�� AQUEOUS TECHNOLOGY: the water base of the electrophoresis radically

reduces the emission of V.O.C. (Volatile Organic Content). Beside the small quantity of solvent contained into the solution, electrophoresis is a non-toxic product. The water base assures no fire hazard.

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At the present time, the Techniclad process is available in three different groups:

�� TRANSPARENT FINISHING: the deposit is invisible but protects the underlying surface from corrosion and wear. The typical application is to protect precious metals without detriment to their appearance.

�� TRANSPARENT COLORED FINISHING: which modify the appearance of the metal by altering its color and without hiding its metallic nature. A typical application is the brass color finishing that modifies the aspect of zinc die cast or aluminum door handles matching the same aspect as solid brass. These finishes can make many different new colors.

�� OPAQUE FINISHING: where the coating material hides the underlying metal. These can also be produced in any desired color.

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The performances indicated below are the average results of laboratory trials. The results can be confirmed by specific trials using the customer’s material.

TEST CONDITIONS RESULT

Pencil hardness � 5 H

Adhesion (Cross cut) � 5 B

Corrosion resistance � On forged brass On cast brass Zinc die-cast On mild steel (Phosphate) On stainless steel On aluminum (extruded) On aluminum (cast)

600 – 1000 hours > 200 hours 500 hours 300 hours 300 – 2000 hours (depending on type)> 1000 hours > 1000 hours

Acid resistance 5% H2SO4 20 °C 1% H2SO4 20 °C

> 300 hours > 480 hours

Alkaline resistance 5% NaOH 20 °C 1% NaOH 20 °C

> 300 hours > 480 hours

Solvent resistance Acetone rub test 200 double rubs (on brass)

UVB test � No perceptible change after 500 hours.

Abrasion resistance � 30

� According to ASTM D3363-92a � According to ASTM D3359-97 � Neutral salt spray test according to UNI ISO 9227. � Using UVB 313. � According to ASTM D968 – 51. Expressed as liters of sand per Mil thickness.

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Laboratory in Buffoli’s premise

electrophoresis

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