The die holder interaction variable analysis of 1D2B screw heading machine and its adjustment algorithm design

Abstract

Die forming is a key process in a production line of metal screw manufacturing, the most commonly used industrial process equipment type is one-die two-blow (1D2B) heading machine. Current solutions for die holder adjustment among manufacturers rely mostly on inheritance of experience. The lack of systemized solutions for fundamental machine tuning causes a gap in technological and intelligent upgrade. This study analyzed the most difficult eccentric tuning of the 1D2B heading machine. The adjustment behaviour of die holder from first blow and second blow were systemized, and the relevant interaction was divided into the following procedures: first die eccentric component adjustment, second die eccentric component adjustment, decoupling of interactions, and precompensation process design. The dimensional differences corresponding to die holder adjustment mechanisms were used to allow operators to implement the adjustments sequentially to complete die holder tuning. This study developed a systemized tuning procedure based on designed algorithm. In the developed procedure, precompensation coupling design was conducted for effectively reducing tuning errors. Tuning based on the proposed procedure enabled the precise adjustment of the die holder positions relative to the eccentric errors of corresponding manufacturing dimensions. The developed procedure can solve the problems of manual trial-and-error operations and excessive abrasion of the die holder resulting from unstable tuning qualities. Key parameters proposed by one type of heading machine, such as equipment die holder’s adjusted pitch, die center distance, and position of the axis of rotation, were examined regarding the proposed adjustments to verify the feasibility of the systemized tuning method.