Hi, I have a Balco Lifestyle 3d Printer bough via Aldi, it has worked fine for about 20 months but now it has a problem with the filament not sticking to the bed, I am using PLA, bed temp 60c and Extruder setting at 200c , bed has been levelled, new nozzle, new bed, the filament just seems to stick to the nozzle. I have tried different pla fillaments. but no luck, how long is PLA usefull for? any help would be appreciated.