Double Layer Roll Forming Machine can roll form two different roofing profiles without changing anything because it has two layers. Upper and lower can rollform different profiles. Besides,the sea freight for import is saved by 50%.It is popular choice of both new entrepreneurs and established metal building manufacturers. The advantages of Quick Change type Purlin Roll Forming Machine when comparing with Traditional Channel Machines are as follows: 1.Produce different roof panel size in one machine 2.Save space 3.Easy operation, low maintenance cost