Electroplating reel-to-reel production lines need to maintain minimum and maximum tolerance limits for the applied coatings. To save costs, layers are coated as thin as possible - especially when using precious materials. However, a certain margin between the minimum limit and the nominal applied layer thickness is necessary to ensure the adherence of the lower tolerance limit due to process variations.
Usually, strips at the beginning and at the end of a reel are cut out manually and measured offline. This is time consuming for the staff and the reaction time is too long: If a tolerance limit is violated, it is too late to interfere since the coating process is finished and the reel already left the production line.
Inline measurement equipment – based on the x-ray fluorescence (XRF) principle – provides continuous data about the applied coating thickness and allows immediate production process control. Feedback loops can be set up either with automatic communication between XRF instrument and coating line or manually by the operator. Therefore, the nominal applied thickness can be chosen to be closer to the minimum tolerance limit which significantly saves costs. Obviously, this is most effective for valuable metals but it also adds up for other coating materials. Additionally, products with rather tight tolerance limits can be manufactured only if there is a measurement system in the production line to determine the actual applied coating.
The following example where a gold (Au) coating of 2 – 4 µm needed to be applied shows the cost saving effects of such inline process control: Using offline instruments for quality control the nominal coating thickness was set to 2.8 µm Au to ensure not to violate the tolerance limit. After installing the inline measurement system FISCHERSCOPE® X-RAY 4000, the nominal coating thickness could be lowered to 2.3 µm Au.
Just by saving the 0.5 µm gold coating, the investment was amortized within half a year! Additionally, the production is now 100% documented. Every customer buying an electroplated reel gets a protocol with a statistical summary and a profile ensuring that the whole strip is coated properly within defined tolerance limits.
Using the FISCHERSCOPE® X-RAY 4000 production cost can be lowered significantly by reducing material consumption, especially effective for precious materials, and by eliminating scrap production. Additionally, 100% of the applied coatings on the product are recorded and therefore traceable to comply with ISO9000 standards. For further information, your local FISCHER partner will be glad to assist you.