printed circuit boards

Ultrafiltration systems
for the regeneration of  photoresist solutions in printed circuit boards

A very important application that TECN.A. proposes to the P.W.B. industry is represented by the use of ultrafiltration membranes for the regeneration of spent concentrate solutions of the photoresist & soldermask developing and stripping processes.

Ultrafiltration is a physical filtration process done through the use of special membranes which allow the separation of the dissolved photoresist from the developing/stripping solutions.

The spent solution coming from the machine is concentrated in the ultrafiltration working tank until the maximum acceptable concentration is reached.

The clean solution permeates through the membranes and is sent again to the machine.


Compared to the traditional ways of operating the purification with chemical solutions, notwithstanding operational issues, ultrafiltration reduces or even zeroes the environmental impact of the developing and stripping processes, because IT DOESN’T GENERATE WASTE.


With ultrafiltration, the machine’s feed & bleed flowrate can be defined as high as you want, remembering that, once the initial investment has been redeemed, there are no more running expenses (product costs/purification costs).
A higher feed & bleed flowrate becomes a lower and constant concentration of dissolved film in the machine.

The expert professional in the P.W.B. field knows that this may bring the following advantages:

  • A constant break point.
  • A higher definition of the board paths during the development.
  • A considerable reduction of the  maintenance on the machine, because the fluid is always clean and filtered (ultrafiltered)
  • Important environmental advantages


The recycling of the spent solutions allows to reduce the consumption of fresh chemicals and to reduce purification costs.

Another important managerial advantage with ultrafiltration is the easiness in keeping constant the carbonate concentration in the developers with a simple process of neutralization that can be automatically carried on under instrumental control.

Tecna STRIP is the right method suitable for all processes of stripping carried out with ready to use solutions which contain ethanolamine.
Ultrafiltration in reality represents the only way of use for these products, because of:

  • High cost of the products themselves
  • High level of pollution

On these solutions the quote of reuse is nowadays around 70%

The very high ROI (Return On Investment) of this system (because of the recycling of very expensive chemical) allows the price of the whole system to be  recovered in just a few months.

TECN.A. has developed two lines of products to offer the best solution of treatment:

  • TECN.A UF-DEV for developing processes
  • TECN.A UF-STRIP for stripping processes 
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