http://www.fyjs.cn/forum.php?mod=viewthread&tid=1849692&extra=page=1&_dsign=0ccab1bf
This report has indicated China now has two pulse production lines for J-20.
In August 19, two Chinese J-20 pulse production lines commenced operation, The production line has five stations, each station will take 8-9 days to finish its share of works. From start to finish, it will take 45 days to finish a plane, making it's annual capacity of 36 planes per year, or 72 planes for both production lines.
"8月19日,中航工业成飞总装厂举行“飞机总装站位式生产启动仪式”,标志着成飞总体装配进入了一个新模式。"
"每一个站位的装配节点8到9天,用45天左右的时间完成一架军机的装配,达到交付状态。'
Once the factory start production in full speed, every 4-5 days, there will be a new J-20 rolling off the production lines. In contrast, the F-35 factory could produce one plane per day.