To measure is to know
Stop steering by gut feeling in wet paint application
In a modern manufacturing environment, precision is the norm. Yet the wet coating line, often one of the most expensive and energy-intensive steps in the process, is still regularly driven by intuition and experience.
A wet paint process is sensitive. To variation in paint, settings, environment and human behaviour. Those who do not measure do not see that variation and therefore have no idea what the process really costs. Time to trade in gut feeling for data-driven process insight.
Without metrics, optimisation remains guesswork
Without objective metrics, process improvement is akin to steering without visibility.
The products look good, customers are not complaining and the cabin is running. So it won't be too bad.
But the real profit or loss is in figures that are often not structurally monitored: too high layer thicknesses, low transfer efficiency, rework that “belongs to it” and booths that run without creating value. As long as these parameters are not visible, losses remain hidden. Practical context and examples can also be found at TechTalk.
Why steering by feel in wet paint is risky
In many wet paint environments, action is taken only when things go wrong. A bad day, a lot of rejection, a complaint. Then there is attention. Then the daily routine takes over again.
Without continuous data, you will not see:
- structurally too high layer thicknesses
- chronically low transfer efficiency
- recurrent rework
- cabin hours without application
These are not incidents, but quiet profit eaters. Individually small, on an annual basis often good for a hefty chunk of the margin.
The 4 indispensable KPIs (critical performance indicators) for a profitable wet-paint line
Those who really want to control wet paint application must look beyond “does it run”. These four key figures make the difference between feel and control.
1. First Pass Yield (FPY)
The percentage of products that pass the wet-paint line correctly in one pass. Each repainting means extra paint, extra labour, extra booth hours and extra risk. FPY is therefore a direct measure of process stability.
2. Layer thickness and transfer efficiency
In wet coating, material efficiency revolves around realised layer thickness and the ratio of applied to consumed paint. Structurally too thick layers or low transfer efficiency indicate wastage due to settings, atomisation, viscosity or feed problems. Without measurement, this remains completely under the radar. Causes around feed and mix ratios often connect to 2K and 3K dispensing technology for paint processes.
3. Effective spraying time versus cab rotation time
A wet-paint booth costs money as soon as it is running. Ventilation, air treatment and filtration continue even when not spraying. Setting effective spraying time against total running time reveals how much booth capacity really adds value and how much time is lost in colour changes, rinsing, waiting and adjustments. This also touches on basic issues such as availability and technical reliability, linked to maintenance and process security.
4. Rework analysis by cause
Knowing that there is rework is not enough. The cause is decisive. Categorising rework, e.g. dust inclusion, runners, orange peel or adhesion problems, reveals structural weaknesses in the process. Without that analysis, rework remains a symptom. With analysis, it becomes an improvement lever.
From data to targeted action
Measurement is not an end in itself. It is a tool to make targeted adjustments. When data shows that rework is rising in certain products, teams or institutions, you can take targeted action. Not based on suspicions, but on facts.
Data takes the discussion away from opinions and feelings. “I think it runs well” gives way to “this is what the process actually does”.
Conclusion
The wet paint line is often the final piece of production, but also one of the largest cost items. Those who continue to steer by gut feeling accept invisible losses. Those who measure, gain insight. Those who have insight, gain control. Optimisation does not start with working harder, but with knowing better. Whoever controls the numbers, controls the returns.
Those who want to translate this concretely to the workplace can also link it to paint application training. For questions: contact TLCA.
This text has been prepared based on content from TLCA Coating & Application.
FAQ
1) Why is steering by gut instinct in wet paint rarely profitable?
Because variation in paint, settings, environment and human behaviour remains invisible without measurement, masking costs and losses.
2) Which figures often remain under the radar without measurement?
Excessive layer thicknesses, low transfer efficiency, rework that “comes with it” and booth hours without application.
3) Which KPIs make the difference between feeling and control?
First Pass Yield (FPY), layer thickness and transfer efficiency, effective spray time versus cab turn time, and rework analysis on cause.
Without measuring points, losses in wet coating remain invisible. With KPIs such as FPY, layer thickness/transfer efficiency, effective spraying time and rework analysis, you steer towards process control in a targeted way.