Case study Nr. 16:
Plating on Plastics (PoP)

Initial situation

Although surface coatings in electroplating are usually combined with the treatment of metallic parts, metallic coating processes can also be applied with great success to non-electrical conductive surfaces. Especially for plastic surfaces, the application of a metallic coating can greatly improve functionality, appearance and feel. The metallic coating of plastics originates from the automotive industry, which in the 1960s and 70s required a reduction in fuel consumption due to lightweight construction. Today, metallic coated plastics can be found e.g. in bathroom fittings, controls, buttons in the clothing industry and a variety of household products and products for daily use. A variety of different plastics can be metal coated, but 90% of the coated plastic surfaces are made of ABS.

Task

Applying a durable and appealing metal coating to a plastic component is a very complex process and requires the highest degree of process precision. Before electroplating, the surface must be pre-treated by cleaning, pre-dipping, pickling, pre-treatment, neutralizing, pre-activating, activating, accelerating until it can then be chemically nickel-plated. This is followed by a series of electrochemical treatments to improve aesthetics and mechanical properties. In these processes alkaline and highly acidic chemical tanks are used which contain corrosive media from sodium hydroxyde (NaOH) to sulfuric acid (H2SO4) to hydrofluoric acid (HF). For the processes in the individual tanks to run efficiently,, these must be precisely tempered in a temperature range from 20°C to 80°C and here not only heaters, but also coolers are used to remove the electrical power dissipation. The immersion type heat exchangers used for this purpose must be resistant to the products used in the long term and have the greatest performance with a small footprint in the process tank.

Solution

The Calorplast immersion heat exchangers made of PP (polypropylene), PE-RT (polyethylene for raised temperatures), PVDF (polyvinylidene fluoride) and stainless steel (1.4571, 1.4301) are unique on the market due to their design and high area density.
Due to the very specific requirements of each individual process step, each heat exchanger is designed and constructed for the respective process tank.

Result

Calorplast heat exchangers have been convincing customers for over 35 years. The quality and supply of all heat exchangers from a single source ensures the correct temperature control of the entire process.

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