A liquefier tube for an additive manufacturing system, including a body provided with a feed channel including a feeding portion having a first diameter, an outlet portion having a second diameter, the first diameter being larger than the second diameter, and a transitional portion interconnecting the feeding portion and the outlet portion. The transitional portion has a decreasing third diameter from the first diameter to the second diameter, and an inner surface of the transitional portion is provided with a plurality of ribs. Methods of manufacturing the liquefier tube.