ALFING is a pioneer in the fracture splitting of connecting rods
Shortest cycle times/highest precision
Use of modern laser technology
High-speed cracking with process monitoring.
Highly efficient bolt assembly for complex and precise connections.
Location-oriented bush assembly
Recording of all important process parameters
In order to be able to assemble connecting rods and crankshafts, the “crank bore” of a connecting rod is separated during manufacturing. The separated components are then bolted together again. The separating of the “crank bore” is normally done with the inexpensive and extremely reliable procedure of “fracture splitting” or “cracking”.
During cracking, a stress riser is initially made with a laser at a defined position in the component. In the next step, a high amount of force is introduced into the work piece through a fracture mandrel. The break occurs exactly along the laser notch. The separated components do not have to be machined at the joint face, because the cracked surfaces guarantee a matching fit. The material must have sufficient brittleness in order to undergo cracking.
ALFING is a pioneer in the development of procedures and technologies for the fracture splitting of connecting rods. ALFING made this technology ready for large scale production in the beginning of the 90’s and it has been used throughout the world in ALFING machines. We are continually developing this process in close cooperation with our customers, because the demands for connecting rods are growing and thus, new shapes and new materials are being used. A particular challenge is the cracking of “tough” steel materials. When separating hardened or very tough substances, the pieces are cooled with nitrogen before cracking. The very tough substances become brittle through the cooling and are therefore able to be cracked.
Rotary transfer machines from ALFING are the optimal solution for cracking and assembling connecting rods. The shortest cycle times guarantee high productivity and the modular machine construction permits the execution of different process steps within a machine.
Optional test equipment:
The rotary table assembly machine can be loaded in different ways. Depending on the degree of automation, you can choose between simple manual loading, loading through conveyors and sliding beam transport or flexible loading with a robot.
The pre-requisite for a precise fracture is the quality of the previously made fracture notch. Predominantly lasers are used to create this notch. The newest generation of fiber lasers are used in ALFING machines.
For new materials, it may make sense to determine the optimal parameter settings for the process through testing. ALFING, with a state of the art testing laboratory, is also an ideal partner for this.
The cracking mandrel is the compound that decides the quality of every fracture machine. If there is a lack of experience, a lot of bad things may happen. The result could be unclean breaks, break outs, strong deformation or partial breaks.
This cannot happen with cracking mandrels from ALFING. Due to our decades of experience and our high-speed crack equipment, we have the perfect solution for every connecting rod size and every material. Process monitoring that informs the user of the quality of the crack process at any time is also available if desired.
Depending on the cycle time requirements, the bolt assembly of the connecting rods is distributed to one, two or three bolt stations. In the first step, the bolts are automatically inserted and pre-tightened. In the next step, the bolts are slightly loosened again and a vibrating unit can be activated to remove any loose particles from the joint faces. The final step is the tightening of the bolts with a defined torque.
The bushes are inserted automatically and - if necessary - aligned before insertion. The bushes are inserted with a servo pressing spindle with simultaneous monitoring of the insertion force and insertion depth.
The bush may also be calibrated.
Connecting rods are highly stressed components and subject to permanent technical development.
With our modernly equipped testing area, we support our customers during different phases of development: