الفهرس 
arabic summaryOnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
Friction coefficient plays an important role in sheet forming processes. The formability of the sheet depends not only on the material properties but on the friction in tool-workpiece interface. Therefore, a careful design of lubrication system to achieve a suitable friction level is essential fopr producing high quality products in a timely and cost-effective way, accurate based simulation of forming processes to obtain optimum process, tooling dsign and in the implementation of intelligent or smart process control.
from previous studies, it was foud that, process variables including forming speed, temerature, lubricant composition and application method, tooling and sheet geometry and surface topography can all influence frictional behavior in sheet metal forming processes. Thus friction force is a complex function of many interacting variables which are constantly changing during the forming process. Therefore, it is important to study friction behavior and to estimate friction coefficient under conditions that represent real forming operations.
Because of enormous metal forming operations, no one test can cover the hole range of metal forming processes. So, many tests have appeared, such as;
1- Ironing friction test.
2- Plane-strain compression test.
3- Double cup extrusion test.
4- Ring compression test.
5- Bending under tension friction test (BUT).