Why execute casting?

Electrical components and boards have to meet ever growing requirements such as e.g. humidity, extreme temperatures, mechanical loads and chemical impact. Casting technology provides highly effective protection for sensitive electrical units and electronics. Important decisive criteria in favor of the casting method include:


  • Protection against temperature fluctuations / air humidity
  • Protection against extreme mechanical load
  • Protection against unauthorized access
  • Protection against identification (know-how protection) 
  • Protection against chemical substances
  • Protection against agitation & vibration
  • Integration of electronics and cables
  • Sealing of housings / connectors 


However, during casting the process time and the weight (here approx. 0.2 kg) increase. In the illustrated assembly, normally 0.2 kg of cast material is applied. This often means that a high E-module or coefficient of thermal expansion (CTE) ‚works‘ on the printed circuits with respective long-term damage.


Is there any alternative?

An alternative could be a thick film layer, e.g. from the Bectron PT 4... series or Bectron PK 43.. series.

It is applied here on account of its excellent adhesive properties and high resistance to solvents, chemicals and weather conditions, especially as a protective lacquer.

These thick-film lacquers are being used more and more in the automotive industry, analog to protection by normal casting compounds. After the lacquer has been applied there is no evaporation of solvents! Drying after coating is made via two parallel potential mechanisms:

  1. Cross-linking under UV light with respective intensity within 1 minute.
  2. Cross-linking from humidity from ambient air.


Which benefits does this have?

  • Rapid tempering with UV light (optional).
  • Tempering via ambient air (similar to 2k PUR systems).
  • Flexible, soft films. No risk of tearing of components.
  • Temperature stability up to 155°C (short-time)
  • Film layers 200 - 900 µm.
  • Film layers up to 5000 µm possible in layer structure
  • Fluorescent


The following can be documented based on our internal tests;


Weight of assembly above

     Bectron PU 45xy cast

          200 Gramm

     Bectron PT 4600

              8 Gramm  

     Bectron PK 4340

            10 Gramm


Material prices

Material prices of the electronics protection are as follows:


Prices for the complete electronics protection (that which actually remains on one board) amounts to:

    • Electronics protection with Bectron PU 45xy costs min. 1 €/piece for the material
    • Electronics protection with Bectron PT 4600 costs 0.32 €/piece for the material
    • Electronics protection with Bectron PK 4340 costs 0.30 €/piece for the material


Using „Dam & Fill“ you can also partially protect applications, i.e. the cost is even lower.


The example of the 2k polyurethane cast vs. thick-film lacquer has shown that the durability of the customer module can be increased considerably and production costs reduced!

This means that a material price reduction of:

68% is achieved with Bectron PT 4600 and

70% is achieved with Bectron PK 4340.


The curing time has also been reduced significantly which means an increase in quantity is possible without extensive investment. And this feature is based on the reliable Bectron concept.