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To achieve sufficiently strong cavitation, the interfacial tension of the water used
needs to be reduced for the foil test with the aid of agents containing surfactant.
We recommend the following ultrasound agents:
• TICKOPUR R 33
• TICKOPUR R 30
• TICKOPUR TR 7
• TICKOMED 1
• STAMMOPUR R
• STAMMOPUR DR 8
If none of these agents are available, a neutral or mild alkaline agent that does
not destroy aluminium should be used. The agent needs to be approved by the
manufacturer for use in ultrasonic baths.
Test result and documentation
Using consistent test conditions, the test result should be assessed according to
the perforated surface of the foils. The perforated surfaces of the foils should
always have roughly the same spread and distribution – they are never congru-
ent. A constant process check, e.g. when reprocessing medical devices, is only
possible with regular foil tests.
You can download a documentation template for documenting the
test results via this link:
https://bandelin.com/folientest/
You will also find a video showing the application.
Furthermore, the foil sheets can be archived in a suitable way (scan, photo, etc.).
Then you will be able to compare the foil sheets whenever necessary.
Performance of the foil test
1. Fill the ultrasonic oscillating tank with water and a suitable ultrasound agent
up to the filling level mark using the dosage specified by the manufacturer.
2. Degas the sonication fluid.
See chapter
5.7 Degassing sonication fluid
.
3. Tension the aluminium foil (household foil 10
μ
m to
25
μ
m thick) on the foil test frame. Depending on
the size of the bath, the frame may protrude. It is
sufficient to cover the part of the foil test frame
that is submerged in sonication fluid.
4. Place the covered foil test frame diagonally in the
centre of the ultrasonic oscillating tank. Secure it if neces-
sary.
5. Switch the ultrasound on. Sonicate the foil for at least
1 minute until visible perforation or formation of holes
occurs. The sonication time can be up to 3 minutes with
stronger foils (thicker or coated).
6. Switch off the ultrasound. Remove the foil test frame. Take the aluminium foil
off the foil test frame and allow it to dry.
