The perfect fit for automotive paint applications

June 22nd, 2024

Protective gloves can be a source of paint wetting impairment substances (PWIS) in assembly plants, causing defects to a car’s bodywork. Georg Rouette, Business Support Manager at Midas Safety, explains why the VDMA 24364 test provides an effective and reliable control measure for identifying PWIS and raises the standard of gloves used for paint applications.

One of the leading quality control issues that original equipment manufacturers (OEMs) in the automotive industry face is the prevalence of what are known as “paint wetting impairment substances” or PWIS. These substances are significant because they can cause costly defects on the bodywork of vehicles when cross-contamination occurs on the production line.

The sources of PWIS in assembly plants are wide-ranging. They can include substances such as the lubricants used for the moving parts of equipment through to less obvious culprits such as the materials found in instant coffee cups dispensed from canteen machines.

Unfortunately, protective gloves that contain silicone (or have come into contact with other PWIS) are also included on this list. Unwittingly, a worker donning gloves during the paint application process can prevent the paint from sticking well to a car’s bodywork, impairing the paint quality and leaving visible marks such as craters.

The automotive industry has been aware of the risks that PWIS pose for many years. In 2018, the German Association for Mechanical Engineering (Verband Deutscher Maschinen- und Anlagenbauer or VDMA for short) developed the first industry-approved test to improve the management of PWIS (known as Lackbenetzungsstörende Substanzen or LABS in German).

The VDMA 24364 test is effective in preventing the risk of PWIS cross-contamination because it applies stringent control measures on a zonal basis to reflect different risk levels in a plant.

To ensure that gloves conform to the VDMA 24364 standard, Butyl acetate is applied to the glove sample, which is rubbed on a glass test plate designed to simulate the substrate that will be painted in the assembly plant.

Glove manufacturers that have adopted the VDMA 24364 standard will have to produce a declaration of conformity to prove that the test has been completed successfully. This requires them to list certain information on the primary labelling so the end user can see the glove has passed VDMA 24364’s strict requirements.

One of the challenges glove manufacturers face is the insistence from some OEMs in the automotive industry that only silicone-free gloves are used. Although the intention may be to reduce the risk of silicone in gloves impairing paintwork, this approach is impractical.

First, silicone isn’t the only PWIS that can cause defects, so unless the OEM/coating plant has installed effective control measures to prevent exposure to other PWIS, then cross-contamination (and potential impairment) can still happen.

Second, silicone can be found in a wide range of products, and even gloves that are marketed as silicone-free can reveal traces of the material. It is worth noting, however, that small concentrations of silicone will not result in defects on a car’s bodywork.

To prove this, Midas Safety undertook a qualitative analysis on a small sample of gloves using a Fourier-Transform-Infrared Spectroscopy and found minuscule concentrations of silicone. More importantly, the gloves, which conform to VDMA 24364’s specifications, did not cause any paint-wetting impairment.

Although the harmonised VDMA 24364 standard is not a legal requirement, it remains the most comprehensive and practical test for detecting PWIS. Midas Safety has joined a growing body of more than 300 companies worldwide that have implemented the standard, helping customers in the automotive sector to safeguard their businesses from paint application impairments.

Having already tested selected gloves, the company plans to apply VDMA 24364 to other hand protection products over time, not only enhancing its testing capability, but also expanding its product range for automotive paint applications.

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