Great thanks - You are my hero of the day! Adjusting the printer settings should solve the problem. My ASA supplier has Nozzel temperatures of 215-240°C and the TPU at Shore 58D Nozzel temperatures of 230-260°C. Very likely reduce the printing speed and then everything should work at the usual 240°C… DuraPro ASA from Extrudr Fillament Austria Europ. However everthing at there own risks
Since i doing this for a while? Well i just do it on Cura. I like TPU aspechaly of its UV and Chemical resistance for outdoor use. ASA i just have in one case which leades to an incredibla benefite on a really spechale produkt for an industrial use. Welding is a process that joins materials, by using heat or force in a melting zone with or without welding filler. Yes, I have a bit of experience there. For 2 decades, however, only in subordinate consideration of the well-being of a whole machine and now more and more it`s only all about overarching systems… and for 8 years no company has brought me on a plane, that’s something for younger people 
But enjoy digging through material data sheets and dealing with layer construction… didn’t think there would be anything to read about it, interesting…