Study of the Transcription Effects of Pressing Dies with Ultrasonic Polishing on Glass Molding

The micro lens array (MLA) has played an important role in optical systems for the past few years, and the precision of pressing dies has dominated the quality of MLAs in glass molding. Few studies have covered the transcription effects on surface roughness of pressing dies for this technology. Therefore, this research utilized pressing dies to produce a sine-wave lens array on glass molding, to transform the Gauss-distributed spotlight into a uniform straight one and then characterize the transcription effects of these lenses. Pressing dies with a sine-wave shape were firstly cut by wire electrical discharge machining (WEDM), and then ultrasonic polishing using diamond abrasives was applied to finish the sine-wave surface with an original roughness of 0.2 μm Ra. Next, the sine-wave lens arrays were pressed by glass molding at the appropriate pressure and temperature, before evaluating the transcription effects of transforming the Gauss-distributed spotlight into a uniform straight one. The result showed that the sine-wave lens array stuck easily to the pressing die and then ruptured during glass molding due to the poor surface roughness of pressing tool. However, the diamond abrasive with appropriate sizes could establish good surface roughness on pressing dies via ultrasonic polishing, and the pressing die with a low surface roughness of 0.08 μm Ra was able to successfully perform MLA in the glass molding. However, only pressing dies with a surface roughness smaller than 0.023 μm Ra could produce precision glass lenses to transform the Gauss-distributed spotlight into a uniform straight one.

PENENTUAN PARAMETER PROSES PEMBUBUTAN TERHADAP KEKASARAN PERMUKAAN MATERIAL ST 42 DENGAN METODE TAGUCHI

Penelitian ini bertujuan untuk mengetahui parameter apa saja yang berpengaruh terhadap kekasaran permukaan pada proses permesinan bubut konvensional dengan material ST 42 dan mengetahui parameter apa saja yang menghasilkan kekasaran permukaan yang baik dengan menggunakan metode Taguchi. Berdasarkan dari penelitian yang telah dilakukan maka diketahui tidak ada parameter yang berpengaruh terhadap kekasaran permukaan material baja ST 42. Parameter yang menghasilkan kekasaran permukaan material baja ST 42 yang paling baik adalah jenis mata pahat JCK dengan feeding 0,115 dan kehalusan 3,42 µm. This study aims to determine which parameters affect the surface roughness of the conventional lathe machining process with ST 42 material and to find out which parameters produce good surface roughness using the Taguchi method. Based on the research that has been done, it is known that there are no parameters that affect the surface roughness of the ST 42 steel material. The parameter that produces the best surface roughness of ST 42 steel material is the type of JCK tool blade with a feeding of 0.115 and a smoothness of 3.42 µm.

Cutting Features Between Surface Roughness in Feed Direction and Machining State of Radius End Mill Against Inclined Surfaces (In Case of Contour Machining and Five-Axis Machining with Constant Tilt Angle)

Optimum experimental conditions, that realize good surface roughness in feed direction, for a radius end mill against some inclined surfaces is obtained by the Taguchi method. Some cutting features due to the unique shape of the radius end mill are revealed via the degree of influence of various factors, which are calculated by the Taguchi method, and the geometric relationship of some contact states of the tool. The experimental conditions include cutting type, spindle speed, feed rate, depth of immersion, inclination angle, and corner radius. The results revealed that the contact states are highly significant, and can be categorized into three types. Furthermore, bottom and corner edges must be contacted simultaneously in order to obtain good surface roughness.

Optimization of Machining Parameters for MRR and Surface Roughness for 7024 AL-alloy in Pocket Milling Process

The objective of this work is the investigation of milling process variables which resulting in optimal values of the surface roughness and material removal rate during machining of 7024 Al-alloy. The machining operation implemented on C-TEK CNC milling machine. The effects of the selected parameters on the chosen characteristics have been accomplished using Taguchi’s parameter design approach; also ANOVA had been used to evaluate the contribution of each parameter on the process outputs. Different feed rates are used ranging from (60, 80 and 100) mm/min, found that high feed rates gives a high material removal rates and good surface roughness. On the other hand, using three levels of spindle speeds found that a higher spindle speeds gives better surface roughness with a little effect on MRR. The process results showed that maximum MRR achieved (2.40) mm3/min when machining feed rate (100) mm/min, spindle speed (1000) r.p.m, and depth of cut (0.6) mm while good surface roughness (0.41 µm) when machining feed rate (100) mm/min, spindle speed (1000) r.p.m, and depth of cut (0.2) mm. The level of importance of the machining parameters for material removal rate and surface roughness and is determined by using Taguchi designing experiments and the variance analysis (ANOVA).

Analysis of Surface Roughness Value When Drilling Magnesiumaz31 Using Taghuci Method

Magnesium alloy is one of super alloys material which wide used in manufacturing of automotive, biomedic, sport and electronic components. It was due to very light and resistent to corrosion. Surface roughness value has an important role to estabilish the quality of components. To produce a good surface roughness of machined surface, one of the important thing depends on the friction between the cutting tool and workpiece material when cutting process occurred. The aim of this paper is to analyse the surface roughness values of machined surface when drilling of magnesium alloy AZ31 using design of experiment of Taguchi Method. The experimental trials took place at cutting rotation of 635, 970 and 1420 rpm, feed rate of 0.10, 0.18 and 0.24 mm/rev, diameter tool of 10, 12 and 14 mm. The cutting of magnesium alloy was done by using a convensional drilling machine with TCA –35Erlo. Analysis of variance on the data of surface roughness value was done to get which factor is the most significant. The result shows that the feed rate is the most significant factor that contributed on the surface rougness value of machined surface. The minimum surface roughness value was attained at cutting rotation of 970 rpm, feed rate of 0.10 mm/rev and diameter of tool of 14 mm. Therefore, it can be stated that selecting the low feed rate factor produced low surface roughness value. Another hand, using high cutting rotation resulted low surface roughness value.Keywords—drilling, surface roughness, magnesiun AZ31,Taguchi Method

ANALYSIS TOOL OVERHANG IN THE MACHINE CNC ET-242 ON SURFACE ROUGHNESS WITH VARIATION OF FEEDING

Lathe is a process to get the shape of the cylindrical workpiece by rotating the workpiece on the spindle and moving the chisel towards the workpiece. To be able to screw the workpiece of the chisel should hang and extend from the turret. The length of the hanging chisel is called the tool overhang (Zelinski, 2005: 1). There is no definite hint of setting the tool overhang and only adjusted between the position of the turret and workpiece. In order to achieve a good surface roughness, usually the overhang tool is arranged to a minimum.In this study the independent variables used are the tool overhang 14 mm, 21 mm, 28 mm, 35mm and feeding 0.15 mm rotation-1, 0.25 mm rotation -1, 0.35 mm. rotation -1. The measured dependent variable is the surface roughness of the workpiece.From the results of testing and data analysis can be concluded that the tool overhang effect on the roughness of the workpiece surface results of the process of lathe in various variations of feeding (feeding). The longer the tool overhang and the greater the feeding motion will result in greater surface roughness. The lowest surface roughness was obtained from a 14 mm long overhang tool and feeding 0.15 mm rotation-1.Keywords : Machine CNC ET-242, Surface Roughness, Feeding Variation.

Surface Roughness Models and Their Experimental Validation in Micro Milling of 6061-T6 Al Alloy by Response Surface Methodology

Due to the widespread use of high-accuracy miniature and micro features or components, it is required to predict the machined surface performance of the micro milling processes. In this paper, a new predictive model of the surface roughness is established by response surface method (RSM) according to the micro milling experiment of 6061-T6 aluminum alloy which is carried out based on the central composite circumscribed (CCC) design. Then the model is used to analyze the effects of parameters on the surface roughness, and it can be concluded that the surface roughness increases with the increasing of the feed rate and the decreasing of the spindle speed. At last, based on the model the contour map of the surface roughness and material removal rate is established for optimizing the process parameters to improve the cutting efficiency with good surface roughness. The prediction results from the model have good agreement with the experimental results.

Surface Modifications and Their Effects on Titanium Dental Implants

This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effective surface for bone implant contact, cell proliferation, and removal torque, despite having good mechanical properties. Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness. Thus, a combination of a good surface roughness and mechanical properties of titanium could lead to successful dental implants.

Preparation of AlN Thin Film Deposited on SiO2 for Improving Temperature Frequency Coefficient of FBAR Used in CSACs

AlN films were deposited by RF magnetron sputtering on the SiO2films with different thickness. Preferred orientation, grain size, surface roughness and grain growth of the AlN films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM). It's found that when the thickness of SiO2films are 100 nm and 200 nm, the AlN films have characteristics of good C-axis preferred orientation, good surface roughness and vertical grain growth, which are suitable for application in thin film bulk acoustic wave resonators (FBARs). When the thickness of SiO2film is 300 nm, although the AlN film has characteristics of good C-axis preferred orientation and surface roughness, the grain growth is tilted, which is not suitable for application in the FBARs.

Polishing Experiment Study of the Elastic Coated Abrasives

A kind of elastic coated abrasives used for polishing large mould surface, such as automobile panel mould, is investigated in this research. Many polishing experiments were finished by using elastic coated abrasives in order to study the effects of grit and workpiece material on surface roughness and machining efficiency. It is concluded that surface roughness is minimum and polishing efficiency is the highest when using 120# abrasives at the same condition, surface roughness is the lowest and polishing efficiency is the highest for AISI 1045 steel in three materials. The difficulty of material removal is different if the textures prior to polishing are different in workpiece surface. Surface texture prior to polishing has effects on surface roughness and polishing efficiency. The research results provide foundation for process planning to achieve good surface roughness and high efficiency in the future research.