Gandjar Kiswanto

An analytical method for obtaining cutter workpiece engagement during a semi-finish in five-axis milling

In five-axis milling, determining the continuously changing Cutter Workpiece Engagement (CWE) remains a challenge. Solid models and discrete models are the most common methods used to predict the engagement region. However, both methods suffer from long computation times. This paper presents an analytical method to define the CWE for toroidal and flat-end cutters during semi-finish milling of sculptured parts. The staircase workpiece model that resulted from rough milling was used to verify the method. The length of each cut at every engagement angle can be determined by finding two points: the lower engagement (LE) point and the upper engagement (UE) point. An extension of the method used to calculate the grazing point in swept envelope development was utilized to define the LE-point. The test showed that the existence of an inclination angle significantly affected the location of the LE-point. For the UE-point, it was first assumed that the workpiece surface was flat. A recalculation of the CWE was then performed to obtain a more accurate engagement profile with the actual surface. A technique called the Toroidal-boundary method was employed to obtain the UE-point when it was located on the toroidal side of the cutting tool. Alternatively, a method called the Cylindrical-boundary method was used to calculate the UE-point for a flat-end cutter on the cylindrical side of the toroidal cutter. The proposed model was successfully used to generate CWE data for two model parts with different surface profiles. The accuracy was verified twice: first, by comparing the coordinates of the UE-points with respect to the workpiece surface and second, by using Siemens-NX. The results proved that the proposed method was accurate. Moreover, because this method is analytical, it is more efficient in terms of computation time compared with discrete models.

Development of Closed Bounded Volume (CBV) grouping method of complex faceted model through CBV boundaries identification

For developing automatic tool-path planning in multi-axis roughing processes of complex faceted models, the so called Opened Bounded Volume (OBV) and Closed Bounded Volume (CBV) must be identified. The CBV feature in a complex faceted model can be detected through Paired Normal Vectors Bucketing method (PNVB). This paper describes further method to partition the CBV in a model that contains more than one CBV. Possibilities of CBV configuration are identified to define the boundaries between detected CBV. The faceted model is mapped on matrix, in order to analyze the existence of boundaries through matrices scanning procedure. An algorithm is developed and implemented to get the final CBV groups. At the end, each CBV group has its own data structure, to enable further analysis in planning the manufacturing processes. The developed method and algorithms can successfully identify and group all the CBV that exist in complex faceted models.

Inclination Angle Effect on Surface of Copper in Biomachining

Nowadays micro fabrication technology is very varied and being continuously developed. One of them uses bacteria as tools that known as biomachining. Acidithiobacillus ferooxidans is a one of bacteria which can do metal removal as a source of energy. The previous research has proven the ability of Acidithiobacillus ferooxidans for material removal process. In this research, biomachining process was added by angle of inclination parameter to know the effect on copper surface profile and roughness. This method was used to get profile shape result of multi-axis in biomachining. Workpieces were patterned by photolithography method and put in the bacterial culture medium, which was inclined 20° and 30° on inclinator. Profile shape and the surface roughness measurement data were taken by SURFCOM machine. The results of this research showed that by inclining 20° and 30° of biomachining sample produced different profile shapes and surface roughness.

Analytical Method for Obtaining Cut Geometry of Helical Toroidal Cutter during Semi-Finish in 5-Axis Milling

Cut geometry data is an essential information in current machining simulation and optimization. The tool orientation changed continuously during free-form machining become a challenge in predicting cut geometry in 5-axis milling. This paper present an extended analytical method to define cut geometry during semi-finish milling. The algorithm was developed by taken into account the existence of helical angle. The developed model was successfully implemented to generate the shape and the length of cut. From the test it was found that helical angle gives significant effect to the cut geometry.

Effects of High Speed Tool Rotation in Micro Friction Stir Spot Welding of Aluminum A1100

Technology of Friction Stir Welding (FSW) is a relatively new technique for joining metal. In some cases on Aluminum joining, FSW gives better results compared with the arc welding processes, including the quality of welds and less distortion. The purpose of this study is to analyze the parameters effect of high speed tool rotation on micro Friction Stir Spot Welding (μFSSW) to the shear strength of welds. In this case, Aluminum material A1100, with thickness of 0.4 mm was used. Tool material of HSS material was shaped with micro grinding process. The spindle speed was fixed at 30000 rpm. Tool shoulder diameter was 3 mm, and a length of pin was 0.7 mm. The parameter variations used in this study were the variable of pin diameter (1.5 mm, 2.0 mm, and 2.5 mm), a variable of plunge speed (2 mm/min, 4 mm/min, 6 mm/min), and the variable of dwell time (2 seconds, 4 seconds, 6 seconds). Where the variation of these parameters will affect to the mechanical properties of welds (as response) was the shear strength. Response Surface Methods (RSM) was used to analyze μFSSW parameters with the shear strength of welds. From the result of experiment and analysis, it is shown that the important welding parameters in high speed μFSSW process are pin diameter and plunge speed.

Analytical Method for Obtaining Cutter Workpiece Engagement in Five-Axis Milling. Part 3: Flat-End Cutter and Free-Form Workpiece Surface

In five-axis milling of 3D free form surface, determination of instantaneously changing cutter workpiece engagement for supporting force and surface quality prediction is still a challenge. In order to predict cutting force accurately, precise geometric information on cutter workpiece engagement is very important. Solid model and discrete model are the most common method used to predict the engagement region. Both methods give the result with the accuracy as the tolerance set in the beginning. However, the methods are suffering with the long computational time. This paper presents a new simple method to define Cutter Workpiece Engagement between flat-end cutter and free form workpiece surface. The engagement is calculated by using a combination of discretization and analytical method. Despite workpiece is discretized by normal vectors, but there is no calculation to check the intersection between cutter and normal vector. They are only used as the reference to define the shape of the surface at every Cl-point, mathematically. The engagement point is obtained based on predicted surface shape and tool orientation at instantaneous location. The formula were derived and implemented in a computer simulation. The program simulation can generate instantaneous cut shape and its size. To ensure the accuracy of the developed method, it was tested by compared the depth of cut generated by the program simulation with the depth of cut measured in Unigraphic. A test on sculptured part surface and workpiece surface was performed. The result indicates that the proposed method is very accurate.

Effects of Welding Parameters in Micro Friction Stir Lap Welding of Aluminum A1100

Technology of Friction Stir Welding (FSW) as a technique for joining metal is relatively new. In some cases on Aluminum joining, FSW gives better results compared with the Arc Welding processes, including the quality of welds and less distortion. FSW can even use milling machine or drilling machine, by replacing the tools and the appropriate accessories. The purpose of this study is to analyze the effect of process parameters on micro Friction Stir Lap Welding to the tensile load of welds. In this case, Aluminum material A1100, with thickness of 0.4 mm was used. Tool material of HSS material was shaped with micro grinding process. Tool shoulder diameter was 3 mm, while the diameter pin was 2 mm and a length of pin was 0.7 mm. The parameter variations used in this study were the variable of spindle speed (2300, 2600, and 2900 rpm), variable of tooltilt angle (0, 1, 2 degree) and a variable of Feed rate (50, 60, 70 mm/min). Where the variation of these parameters will affect to the mechanical properties of welds (as response) was the tensile load. Analysis and optimization parameters between the micro FSLW parameters with the tensile load of welds, is used a Response Surface Methods (RSM). From the result of experiment and analysis, it is shown that the important welding parameter in Micro Friction Stir Lap welding process is tilt angle.

Effect of interlayer in dissimilar metal of stainless steel SS 301 and aluminum alloy AA 1100 using micro resistance spot welding

Each material has advantages and disadvantages properties, and two different metals, which have advantages properties, were welded to apply its advantages in a construction. Different thermal and electrical properties will influence to a welded joining performance. Aluminum and steel joining by welding process lead to decreasing lap shear strength of welded joint, due to thermal properties. The problem is more complex when the welding process uses thin metal. The objective of this study analyze peak load, elongation, and fracture area (fractographic) from a welded joint between SS301 and AA 1100 with ferro interlayer which was welded by Micro Resistance Spot Welding (RSW). Ferro sheet was inserted between stainless steel and aluminum sheet, RSW machine was used to weld three different plates. Tensile test machine used to measure load and elongation value, and teared plates effected by tensile tested were measured by digital microscope. The highest load value could be achieved by 8 kVA of welding power. Elongation of the highest peak loads was shorter than the lowest peak load. Welding time more than 8 CT tend to produce the elongation become shorter. Welding time affected to decrease fracture area, however welding power has also significantly effect.Each material has advantages and disadvantages properties, and two different metals, which have advantages properties, were welded to apply its advantages in a construction. Different thermal and electrical properties will influence to a welded joining performance. Aluminum and steel joining by welding process lead to decreasing lap shear strength of welded joint, due to thermal properties. The problem is more complex when the welding process uses thin metal. The objective of this study analyze peak load, elongation, and fracture area (fractographic) from a welded joint between SS301 and AA 1100 with ferro interlayer which was welded by Micro Resistance Spot Welding (RSW). Ferro sheet was inserted between stainless steel and aluminum sheet, RSW machine was used to weld three different plates. Tensile test machine used to measure load and elongation value, and teared plates effected by tensile tested were measured by digital microscope. The highest load value could be achieved by 8 kVA of welding power. El...

Implementation of analytical boundary simulation method for cutting force prediction model in five-axis milling

ABSTRACT A simulation system was developed that deals with cut geometry and machining forces when a toroidal cutter is used during semifinishing in five-axis milling. The cut geometry was calculated using an analytical method called analytical boundary simulation (ABS). ABS was implemented to calculate the cut geometry when the machining used an inclination angle and a screw angle. The effect of tool orientation on the cut geometry was analyzed. The accuracy of the proposed method was verified by comparing the cut lengths calculated using ABS with cuts obtained experimentally. The result indicated that the method was accurate. ABS was subsequently applied to support a cutting force prediction model. A validation test showed that there was a good agreement with the cutting force generated experimentally.

Development of friction and wear full-scale testing for TKR prostheses with reliable low cost apparatus

Prostheses products must undergo simulation and physical testing, before clinical testing. Finite element method is a preliminary simulation for in vivo test. The method visualizes the magnitude of the compressive force and the critical location of the Total Knee Replacement (TKR) prostheses design. In vitro testing is classified as physical testing for prostheses product. The test is conducted to evaluate the potential failure of the product and the characteristics of the prostheses TKR material. Friction and wear testing are part of the in vivo test. Motion of knee joints, which results in the phenomena of extension and deflection in the femoral and tibia insert, is represented by friction and wear testing. Friction and wear tests aim to obtain an approximate lifetime in normal and extreme load patterns as characterized by the shape of the friction surface area. The lifetime estimation requires friction and wear full-scale testing equipments for TKR prostheses products. These are necessary in obtaining ...