---
title: How can you produce PWIS-free surfaces?
description: Paint wetting impairment substances – PWIS for short – cause clearly visible defects in the end product, since they prevent an even wetting of the surfaces to be coated.
---

[Plasma Knowledge Base ](https://www.thierry-corp.com/plasma-knowledgebase)

# [How can you produce PWIS-free surfaces?](https://www.thierry-corp.com/plasma-knowledgebase/how-can-you-produce-pwis-free-surfaces)

 Written by [George Osenga](https://www.thierry-corp.com/plasma-knowledgebase/author/george-osenga) | Aug 17, 2021 7:08:47 PM

**Paint wetting impairment substances** – PWIS for short – cause clearly **visible** defects in the end product, since they **prevent an even** wetting of the surfaces to be coated. Funnel-shaped impurities and craters appear in the paint layer. Such substances can be **silicones, fluorinated (PTFE) substances, certain oils and greases**.

The **plasma process permanently dissolve**s all paint wetting impairment substances from the **surface** as well as from the elastomer itself.

Components made of a  **large variety** **of materials can be cleaned,** such as PVC-U, PVC-C, PP, PE, ABS and PVDF as well as **metal** components.

After cleaning, the components undergo plasma treatment for up to one hour, depending on their **degree of contamination**. To confirm the success of the treatment and ensure the components are **PWIS-free**, a **PWIS test** is carried out after the plasma treatment. The test we use is in compliance with the Volkswagen Test Regulation PV 3.10.7 and is a rapid test for the detection of **residual silicones**.

All you need is a clean **glass plate, acetone, a commercially available spray paint** which obviously must be **free of silicones**. The colour **white** has proven to be particularly well suited for this test. For the test, the material is placed on the glass plate and rinsed with acetone. After **venting** of the acetone, the glass plate is sprayed **crosswise** with the spray paint. After drying of the paint, it is clearly **visible** whether there are **silicone residues** on the surface. In these spots, the surface is not wetted by the paint, and so-called **crater** formation is observed.

Using **special processes**, however, plasma treatment is also suitable for treating **silicone materials**. Even **silicone rubber** can be made PWIS-free.

Removing **PWIS** substances from component surfaces meant to be **coated**, innovative and environmentally compatible **low-pressure plasma technology** can solve a problem which is becoming more and more pressing. **Plasma cleaning processes** integrated in the production chain have for example the following **benefits**:

- **Reduction** of the rework rate
- **Reduction** of the scrap rate
- **Prevention** of customer complaints
- **Increased** reliability of the production process

Diener electronic also offers this process as a **surface treatment service**. Several **plasma systems** as well as skilled and experienced staff are at your disposal. Thus, we can ensure **optimum **surface quality of your components and parts.

To learn more about etching, check out our eBook titled "[Plasma Etching and Cleaning Strategy for Better Product Quality](https://www.thierry-corp.com/plasma-etching-and-cleaning-strategy-for-better-product-quality?hsLang=en)."

<https://www.thierry-corp.com/plasma-etching-and-cleaning-strategy-for-better-product-quality?hsLang=en>

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