Add details, background Aug 18 (Reuters) - Semiconductor equipment maker Applied Materials Inc AMAT.O forecast fourth-quarter revenue above market estimates on Thursday as chipmakers scale up output to plug a supply shortage that has hobbled sectors across the economy. Chipmakers have been flooding Applied Materials - the largest maker of semiconductor equipment - with orders to expand capacity as they try to ease an industry-wide supply crunch. While cracks have emerged in demand from chipmakers focused on smartphones and PCs as inflation hits consumer spending, the data center, industrial and automotive markets remain robust.