The number of new and upgraded products that are to be produced by the web coating process is continuing to expand. One of the characteristics of these new products are that they will be specialty products with relatively low volumes. In addition, each product will have very different product requirements such as, coating weight, drying capacity, quality, coating weight uniformity Td & Md uniformity, substrate thickness and type and solvent needed.
As a result the coating machine has to be versatile and capable of meeting the new products. Typically, new products will start the product manufacturing cycle on an existing coater, which may have been designed, fabricated and installed many years ago and may not have the capability to meet the new products needs. Often new products are not a commercial success because the required product properties could not be economically achieved because of a fundamental limitation of the existing coater that could not be overcome.
Therefore; to avoid lack of commercial success with a new product because of coater limitations, it is very important that the current coater capability be know and readily available for all development personnel. The original coater design specifications should be analyzed to identify all of the important process parameters and the current coater characterized to insure it is still capable of meeting these specifications. Coater capabilities deteriorate with age and use. For example, if the range drive speed uniformity is +/- 5 %. It will be near impossible to obtain a +/- 1% Md coating weight uniformity. Airflow in the dryer could have decreased for several reasons and there will be a resulting loss in dryer capacity.
If limitations are detected early in the development process, they can be corrected. The best way to identify limitations is to develop manufacturing basic data early in the development process and compare with current capability. If limitations are detected then changes can be made in product composition the coater can be upgraded to meet the new product requirements.