A reciprocating die roll forming machine for forming a pattern such as a thread form on the outer surface of a cylindrical blank includes at least one set of reciprocating dies operating upon the blank which rotates in place. The machine includes a slide and bearing combination to support the dies belt driven by a servo-motor controlled by a central processing unit. Mechanism is provided to deliver and position a blank for engagement by the dies. In one form, the machine includes multiple die sets to produce multiple parts during one die reciprocation cycle. In another form, the machine employs separate drive mechanisms to independently drive each die of a set.

A reciprocating die roll forming machine for forming a pattern such as a thread form on the outer surface of a cylindrical blank includes at least one set of reciprocating dies operating upon the blank which rotates in place. The machine includes a slide and bearing combination to support the dies belt driven by a servo-motor controlled by a central processing unit. Mechanism is provided to deliver and position a blank for engagement by the dies. In one form, the machine includes multiple die sets to produce multiple parts during one die reciprocation cycle. In another form, the machine employs separate drive mechanisms to independently drive each die of a set.

Cold-forming equipment configured as a high precision thread rolling assembly utilizing racks, guide rails, a bearing assembly including rolling element linear motion bearings and a gear reduction assembly.

A screw includes a shank portion, an outer thread portion and a laterally-extruded thread portion. The shank portion has an outer circumferential surface on which to form the outer thread portion having grooves. In a thread-rolling process, the laterally-extruded thread portions is formed by laterally extruding an inclined wall of one groove with respect to a longitudinal direction thereof such that a laterally-extruded portion is protruded in an adjacent groove and is tightly engaged with an inclined surface of a groove of inner threads of a screw hole

A screw includes a shank portion, an outer thread portion and a laterally-extruded thread portion. The shank portion has an outer circumferential surface on which to form the outer thread portion having grooves. In a thread-rolling process, the laterally-extruded thread portions is formed by laterally extruding an inclined wall of one groove with respect to a longitudinal direction thereof such that a laterally-extruded portion is protruded in an adjacent groove and is tightly engaged with an inclined surface of a groove of inner threads of a screw hole

A thread rolling die includes a thread rolling region comprising a working surface including a thread form. The thread rolling region of the thread rolling die comprises a sintered cemented carbide material having a hardness in the range of 78 HRA to 89 HRA. In certain embodiments, the thread rolling die may further include at least one non-cemented carbide piece metallurgically bonded to the thread rolling region in an area of the thread rolling region that does not prevent a workpiece from contacting the working surface, and wherein the non-cemented carbide piece comprises at least one of a metallic region and a metal matrix composite region. Methods of forming a thread rolling die as embodied herein are also disclosed.

A thread rolling die includes a thread rolling region comprising a working surface including a thread form. The thread rolling region of the thread rolling die comprises a sintered cemented carbide material having a hardness in the range of 78 HRA to 89 HRA. In certain embodiments, the thread rolling die may further include at least one non-cemented carbide piece metallurgically bonded to the thread rolling region in an area of the thread rolling region that does not prevent a workpiece from contacting the working surface, and wherein the non-cemented carbide piece comprises at least one of a metallic region and a metal matrix composite region. Methods of forming a thread rolling die as embodied herein are also disclosed.

The compound die includes a working surface with a coarse end for forming coarse threads and a fine end for forming fine threads. The coarse end has coarse crests and coarse roots thereon angled at a coarse thread pitch angle for the screw to be formed. The fine end has fine crests and fine roots formed into a working surface thereof at an angle matching a pitch angle for the fine threads of the screw to be formed. A transition is provided between the coarse end and fine end where each of the coarse roots is aligned with one of the fine roots. A screw such as a bolt is roll formed by first being rolled between a standard die parallel with the compound die and a course end of the compound die, followed by rolling between the standard die and the fine end of the compound die.

The compound die includes a working surface with a coarse end for forming coarse threads and a fine end for forming fine threads. The coarse end has coarse crests and coarse roots thereon angled at a coarse thread pitch angle for the screw to be formed. The fine end has fine crests and fine roots formed into a working surface thereof at an angle matching a pitch angle for the fine threads of the screw to be formed. A transition is provided between the coarse end and fine end where each of the coarse roots is aligned with one of the fine roots. A screw such as a bolt is roll formed by first being rolled between a standard die parallel with the compound die and a course end of the compound die, followed by rolling between the standard die and the fine end of the compound die.

A rolling die for forming a screw thread on a screw blank is disclosed. The rolling die has a plurality of grooves, where the grooves each have two flanks as seen in cross-section. At least a portion of each of the grooves has a forming area in which the size of a profile angle enclosed by the flanks decreases continuously along the grooves.