الفهرس 
Chapter(1) INTRODCTIONOnly 14 pages are availabe for public view
 |  | from | 145 |  |  |
| | | from | 145 | | |
Abstract
Vibration problems occur frequently in the manufacturing processes during metal cutting. The vibration level affects by many different parameters like the material type, the cutting parameters, the work piece geometry and the rigidity of tooling structure. As a result of vibration, the tool life decreases, the surface finishing becomes poor, and a disturbing sound appears. Tool holder structure is an affecting parameter in vibration so the focus was on it and studying its dynamic characteristics (Natural Frequencies, Damping Ratio and Mode Shapes). The aim of this thesis is
divided into two main parts: The First Part: is to estimate dynamic characteristics of a ”Milling Tool
Holder” of (MT4 ER32) type called holder (A) based on classical modal analysis systems (CMA) and finite element analysis (FEA) using ANSYS workbench. The analysis was carried out twice, once on the holder only and
the other on the tool-holder assembly. The data was collected by data
acquisition in CMA through an accelerometer fixed on holder (A) from one side and the holder was excited by an impact hammer from the other side. A
comparison between experimental techniques using CMA and theoretical
analysis using FEM by ANSYS software for dynamic characteristics estimation in two cases of holder only and tool-holder assembly. The results showed a good agreement between the two techniques.
The second part: is about the Operational Modal Analysis(OMA) that
was carried out on the milling tool holder(A) during cutting operation by
using falcon smart data collector. An Operational Modal Analysis was also
carried out on the origin holder of the used vertical machine of type (MT4/B16) called holder(B). A comparison was made between the holder A and the origin holder B. from Operational Modal Analysis, when comparing the holder (A) with the holder (B), it was found that the level of vibration decreases in the case of the holder (A), for more enhancing of machining operations a thin rubber layer was added to the holder A between the tool and the collet. The test was also made on the holder(A) after adding damping material (thin rubber layer) and the response of the holder(A) was obtained. A comparison was made between result data from OMA for the holder(A) before and after adding damping and it was concluded that the vibration level decreased in case of damping. The holder damping has a great influence in cutting processes which reduce the chatter and help in obtaining a high surface finish of products.