Naslov
CAD template for individual stages of concrete screw production

Autori
Koraca, Filip

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, diplomski rad, diplomski

Fakultet
Fakultet strojarstva i brodogradnje

Mjesto
Zagreb

Datum
13.05

Godina
2022

Stranica
116

Mentor
Škec, Stanko

Ključne riječi
cold forming ; CAD template ; FEM ; fasteners ; concrete screws ; process improvement ; material flow ; tool parameters

Sažetak
Concrete screw anchors are well-known fasteners used in industries such as construction, automotive or nuclear. Among cold forming’s different methods, the ones mainly used for producing screw anchors are extrusion and upsetting. Screws must consistently meet the given requirements and perform the way they are meant to in different environments, and that's the task for which multi- stage cold forming is a suitable choice. Multi-stage cold forming is a widely used forming process for efficient and fast mass-production of simple and complex parts with great mechanical properties. Benefits to this forming process are negligible loss of material, good dimensional control, great surface finish, improved strength, and reproducibility. However, the forming sequence must be carefully designed by highly experienced die designers, and it requires both their experienced judgment and the implementation of established design rules. The development of such sequences is being improved through the years. Since one specific screw is designed in a couple of variations, to reduce the total design time, engineers have implemented CAD templates for automatically generating the forming stages for different screw lengths. The final product’s dimensions, tools, and machine parameters are given as an input, and the template outputs the forming part’s dimensions through the stages for different screw sizes and lengths. The template for hexagonal head screw anchors had issues with replicating the part’s dimensions from the machine, i.e., the actual formed stages were not following the computer-generated ones. The initially assumed root causes for the dimension differences were that the volume distribution between the screw’s head and body are not the same for all stages. Likewise, the effects of some machine parameters, such as different ejector positions, were previously not thoroughly examined. Therefore, the main objective of this thesis is to have a better understanding of the volume distribution between the screw’s head and body through the stages, and of the forming process itself. For these reasons, an analysis of the semi-finished screw billets through the stages using precise measurements and numerical analysis is necessary. The effects of different ejector positions were observed on the measurements, and further tested in a numerical analysis tool Deform2D. The necessary adjustments to the template are finally implemented, and the modified template is tested. The modified template had smaller differences to the real parts in comparison to the initial one.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

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