Kunststofftechnik Bernt GmbH

Tool construction • Plastic moulding • Electroplating

Dr. Herbert-Kittel-Str. 10 • D-87600 Kaufbeuren, Germany
Tel. +49 (0) 83 41 - 966 128 300 • Fax +49 (0) 83 41 - 966 128 360
www.ktbernt.de • info@ktbernt.de

DE | EN

Rack systems

We develop a personalised rack system for every part to be electroplated.

Flushing

After every chemical and electrolytic process, liquid residues remain on the workpieces. These must be removed or dislodged through thorough flushing.

Coating variants and technical specifications

Polished copper, double nickel, bright nickel, matt nickel/aluminium-look, polished chrome, 3Q7, etc.

Laboratory

To ensure a stable electroplating process, we examine the electrolytes in our cutting edge lab on a daily basis.

Environment

During the processes and procedures involved in plastic electroplating, the substances used need to be handled very carefully, taking human safety and the environment into account.
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Electroplating

In our cutting edge plastic electroplating process, we surface-finish the raw plastic components made from ABS or ABS-PC. KTB has many years of extensive experience in electroplating plastic parts with chrome finishes (polished or matt in various degrees of gloss) for indoor and outdoor applications. The metal layers give the surfaces a decorative appearance, make them highly scratch-resistant, and turn them into a more robust composite with improved heat resistance and protection against static charging, electrical disturbances (shielding) and UV rays. Due to the different dimensions, requirements, surfaces etc., for each item we use a specific processing program to control the electroplating machine.

Here are the basics of what you need to know about the plastic electroplating process.

Pre-treatment

Pickling
The butadiene stored in the ABS copolymer is extracted from the resin structure on the surface. The resulting caverns and cavities form the base for the galvanic coatings to adhere to.

Germinating
To be able to separate a conductive, thin metallic coating without current, we first need to germinate the roughened ABS surfaces with catalysing palladium. To keep the palladium in balance with the electrolytes, this is dipped in a protective tin colloid. At this stage of the process, the palladium germs are absorbed by the roughened ABS surface.

Catalysis
In the catalysis process, the protective tin colloid is removed with an acid mixture, as it would otherwise negatively affect the rest of the coating process. There is now active palladium on the surface.

Electroless nickel
The absorbed palladium on the plastic surface triggers the initial reaction in the electroless nickel electrolyte. An approx. 0.5µm thick, even layer of nickel grows on the ABS surface. The part's surface can now conduct electricity.

 

Electroplated coating

Pre-copper
The product is then immersed in a copper sulphate solution, where a few atomic layers of copper become separated through the charge exchange process, making the surface more conductive and preventing the electroless nickel coating from fusing.

Polished copper
The high-gloss copper layer is 20-30µm thick and ductile, which means it balances out the different expansion coefficients between metal and plastic.

Semi polished / polished nickel
A double layer of nickel is deposited for corrosion purposes and in order to compensate for tensions. The nickel layer is high-gloss and hard enough to be scratch-resistant.

Matt nickel / aluminium design
The nickel depositing process is briefly interrupted by the static distribution of finely dispersed organic substances in the cathode film. Through this surface disturbance, the directed light reflection of the initially shiny coating appears as a diffuse reflection. A thin chrome layer with a thickness of approx. 0.3µm is then deposited on the matt nickel.

Cracked nickel
To improve corrosion protection, an approx. 1-2µm thick, dynamic nickel layer is deposited on the polished nickel layer. As a result of the additional tensions, this cracked nickel layer breaks up during the subsequent polished chrome plating process together with the chrome layer, forming micro-cracked layers of chrome. Cracked nickel is used mainly in exterior automotive parts.

Polished chrome plating
Polished chrome plating takes place in very thin layers of 0.3-0.8µm.
The properties of the galvanic nickel base are key to the quality of the chrome plating.

After the chrome plating and drying process, the product is removed, checked and packaged. In addition to the usual visual inspection criteria, including degree of gloss, pores, scratches, stains, roughness, flowlines, welding seams and faulty coatings, we carry out the following tests:

- Layer thickness measurement using X-ray
- Thermal shock test compliant to DIN 53496
- CASS test compliant to DIN 50021
- Temperature resistance
- Adhesion tests (cross cut test, tape test)
- Dimensional stability
- STEP test (coulometric measurement)

 

Quality monitoring

After the chrome plating and drying process, the product is removed, checked and packaged. In addition to the 100% visual test which identifies and filters out deviating degrees of gloss, pores, scratches, stains, roughness, flowlines, welding seams and faulty coatings, we carry out the following tests during the process:

- Layer thickness measurement using X-ray
- Thermal shock test compliant to DIN 53496
- CASS test compliant to DIN 50021
- Temperature resistance
- Adhesion tests (cross cut test, tape test)
- Dimensional stability
- STEP test (coulometric measurement)

 

Flushing

Dreifach Kaskadenspüle mit Frischwasser – Spritzregister

After every chemical and electrolytic process, liquid residues remain on the workpieces. These must be removed or dislodged through thorough flushing. Flushing removes the film of electrolytes from the previous process that are sticking to the surface, preventing them from interfering in the subsequent stages of the process. If this is the final stage of the process, the parts are flushed to remove any corrosive or allergenic substances on the surface, so that the parts can be dried without staining.

 

Rack systems

Rack systems

We develop a personalised rack system for every electroplated part. The aim is to create optimal plating with optimised layers without distorting the plastic part. The rack frame is produced using brass due its good conductivity, while the actual contacts are made of stainless steel or titanium (resilience). The resilience of the contacts is adapted to the lower stability of the plastic. It is also important to insulate the rack. It should be fired at high temperatures so that the racks are not coated with metal.

 

Coating variants and technical specifications

Coating Electroplating

Coating variants

- Polished copper
- Double nickel
- Bright nickel
- Matt nickel / aluminium effect (various shades possible)
- Polished chrome
- 3Q7
- Rover ALU
- Pearlescent
- Silver Shadow
- Silver electroplating 09
- Micro-cracked matt chrome

Specifications

- Number of process tubs: 30
- Number of process tubs including flushing and storage stations: 108
- Tub volume 2,600 to 12,000 l
- Tub size 2,500 x 1,200 x 500
- Rack system - goods rack size 2,500 x 1,200
- Customised sizes also possible
- Lead time 2 to 3.5 hours (depending on the program)
- Max 248 racks in a unit
- Max. area 65m2/ hour or 1,400m2/day
- Electroplating machine with 10 transport trolleys and 2 transfer trolleys
- Departments: Assembly, QA, Laboratory (chemical/physical), Wastewater Treatment, Planning and Engineering, Production

 

Laboratory

Laboratory

In order to ensure a stable electroplating process, the electrolytes are examined in our cutting edge laboratory on a daily basis and new or used chemicals are added based on the analysis results.
We also carry out wet chemical analyses and apply cutting edge analytical methods (atomic absorption spectroscopy).
Here, we also monitor our compliance with wastewater limits.

 

Environment

Environment

During the processes and procedures involved in plastic electroplating, the substances used need to be handled very carefully, taking humans and the environment into account. It is therefore important to always act with the environment and human safety in mind. We follow this principle throughout our advanced safety management system as well as the technical safety mechanisms we have in place. As of 2015, we will be certified according to ISO 14001 (environmental management system) and ISO 18001 (occupational safety management system), which are incorporated into our integrated management system (IMS).

In our plant, all relevant processing tubs are fitted with an air extraction system, designed to the latest technical and chemical specifications. This extracted air is completely filtered. We take regular readings to monitor this process.

In our cutting edge water treatment process, the wastewater from the flushing and processing tubs is filtered to produce clean water. During this process, each batch of water is analysed as part of the final checks and only approved if it meets our high standards. All these analyses are subject to checks by external laboratories and relevant authorities.

 

REACH

We meet the requirements of the REACH scheme. Please note the following with regard to Article 33 of REACH:

The first candidate list, last modified on 28th October 2008, in accordance with Article 59 (1, 10) of Regulation (EC) No. 1907/2006 ("REACH") was published:

See the website of the European Chemicals Agency ECHA

The product and packaging contain no substances above 0.1 mass %, listed in the candidate list.

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Dr.-Herbert-Kittel-Straße 10, 87600 Kaufbeuren, Germany+49 (0) 8341 / 966 128 300+49 (0) 8341 / 966 128 300info(at)ktbernt.def
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