The poor need compulsory and it has the following characteristics: 1, the needle bar sleeve with forced oil return device, the maximum limit reduces the pollution; 2, the main supply and improve the parts service life; 3, the movable needle guard board, just in the needle guard, eliminate the skipping, ensure the beautiful and ideal stitch; 4, bend needle mechanism adopts Yacha mechanism, eliminate the curved needle axial dynamic; 5, the silicone oil cooling device, the heat resistance of synthetic fiber line also can be used for high-speed sewing operations, while reducing machine needle temperature, to prevent the fault line, the stitch is more stable. It uses two straight needles, three bending needle respectively form package sewing, chain stitch, sewing and hemming simultaneously, exponentially increasing production efficiency, especially suitable for knitted underwear, shirts and so on commissure and straight operation.