Abstract   Knowing the amount of residual stresses and find technological solutions to minimize and control them during the production operation are an important task because great levels of deformation which occurs in single point incremental forming (SPIF), this induce highly non-uniform residual stresses. In this papera propose of a method for multilayer single point incremental forming with change in thickness of the top plate (0.5, 0.7, 0.9) mm and lubrication or material between two plates(polymer, grease, grease with graphite, mos2) to knowing an effect of this method  and parameters on residual stresses for the bottom plates. Also compare these results for the bottom plates with the single plate at same thickness 0.9 mm.The results showed that when increase thickness of the top plate the value of residual stresses will decrease for bottom plates and when used graphite with grease between two plates gives less residual stresses (R.S = 60.173 MPa.) reverse when used Mos2 which will gives a larger residual stresses (R.S = 146.617 MPa.) in the bottom plate. Keywords: Multilayer Single Point Incremental Forming (SPIF), Residual Stresses, Lubrication.

Incremental forming is a flexible sheet metal forming process which performed by utilizes simple tools to locally deform a sheet of metal along a predefined tool path without using of dies. One limitations of single point incremental forming (SPIF) process is the error occur between the CAD design and the product profile. This work presents the single point incremental forming process for produced pyramid geometry and studied the effect of tool geometry, tool diameter, wall angle, and spindle speed on the dimensional accuracy. Three geometries of forming tools were used in experimental work: ball end tool, hemispherical tool, and flat with round corner tool. The sheet material used was pure Aluminum (Al 1050) with thickness of (0.9 mm). The experimental tests in this work were done on the computer numerical control (CNC) vertical milling machine. The products dimensions were measured by utilized the dimensional sensor measuring instrument. The extracted results from the single point incremental forming process indicated the best acceptance between the CAD profile and product profile was found with the ball end tool and diameter of (10 mm), wall angle (50°) and the rotational speed of the tool was (800 rpm).

Extrusion is a process that used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section. The main advantage of this process with respect to other manufacturing processes is its ability to create very complex cross-sections, while the limitation of extrusion process is used to produced just a symmetric profile so this paper proposed an adopted algorithm that used to design and implementation the Asymmetric extrusion die that used to prevent the twisting that caused in metal when used to produce the Asymmetric product, and in other wise reduce the total extrusion power and die pressure distribution on metal during extrusion process. This adopted design was implemented in this work using Teflon material in both symmetric and asymmetric profile using CNC milling machine to demonstration the success of this algorithm.

Incremental forming is a flexible sheet metal forming process which is performed by utilizing simple tools to locally deform a sheet of metal along a predefined tool path without using of dies. This work presents the single point incremental forming process for producing pyramid geometry and studies the effect of tool geometry, tool diameter, and spindle speed on the residual stresses. The residual stresses were measured by ORIONRKS 6000 test measuring instrument. This instrument was used with four angles of (0º,15º,30º, and 45º) and the average value of residual stresses was determined, the value of the residual stress in the original blanks was (10.626 MPa). The X-ray diffraction technology was used to measure the residual stresses. The sheet material used was Aluminum alloy (AL1050) with thickness of (0.9 mm). The experimental tests in this work were done on the computer numerical control (CNC) vertical milling machine. The extracted results from the single point incremental forming process were analyzed using analysis of variance (ANOVA) to predict the effect of forming parameters on the residual stresses. The optimum value of the residual stresses (55.024 MPa) was found when using the flat end with round corner tool and radius of (3 mm), wall angle of (55°) and a rotational speed of the tool of (800 rpm). The minimum value of the residual stresses (24.389MPa) was found when using hemispherical tool with diameter of (12 mm), wall angle of (45°) and a rotational speed of the tool of (800 rpm).

The non-conventional spinning process for producing polygons cross-section.  Dimensional accuracy to check methodology of producing rectangular cross-section.  The measure opposite took place by offsetting the design points along normal vector.  The NC milling machine was used to obtain the Data (x, y, and z coordinate).  Forming ball diameter mainly increases the dimensional accuracy average error.The non-conventional spinning process was adopted for producing polygons, but one of the process limitations is the error between design and the final product especially with no-mandrel. Dimensional accuracy was adopted for this purpose which gives an indicator of the ability of the formed part to matches the design and checking validated of the adopted methodology for producing rectangular cross-section spun parts, by comparing the coordinating points of real part with the points of the design model. The point of a real part was measured by using a sphere probe fixed on the three-axis milling machine and capturing the data of machine axis movements for the center location of the probe, also, the measurements oppositely took place, by offsetting the points of design along the normal vector for comparison with the real part points. Three parameters were invested for study the effects on the dimensional accuracy, these parameters are spindle speed (48, 68, and 135 RPM), feed ratio (0.16, 0.22, and 0.32 mm/rev), and the ball diameter of the forming tool (16, 22 and 25 mm). The results show that tool ball diameter mainly affecting dimensional accuracy with a higher value of average error reach (6.47mm) when 16mm diameter of tool ball was used, on the other hand, the minimum average error was 1.705mm at low spindle speed.