Burrs are source of dimensional errors, jamming and

misalignment in the assembly process. They may cause short

circuits in electrical components and may reduce the fatigue life of the part. Furthermore, burrs can be a safety hazard to personnel because they are usually sharp. This scientific research investigates the characterization of 8 mm diameter, 120° point angle of coated drill tool in burr formation. The exit burrs were investigated using two different types of popular coatings, namely TiN and TiAlN. The effect of cutting speed and feed rate of the tool in burr formation onto the workpiece are discussed. In this study, the exit burr height was measured using optical microscope. Moderately harder material, 304L series stainless steel was used in the evaluation of the super

coatings. The experiments were conducted using CNC HAAS

Milling Machine. These experiments can be classified as hard

drilling based on the experimental values and machining

conditions

Sivarao, Subramonian

Taufik, ,

English

Universiti Teknikal Malaysia Melaka (UTeM) Repository

COATING CHARACTERIZATION OF TiN & TiAIN ON BURR FORMATION IN DRILLING - PRAGMATIC INVESTIGATION SIVARAO TAUFIK Paper Presented at the International Conference on Engineering and JCT (ICE! 2007), 27 -28 Nov 2007, Hotel Equatorial Melaka. UNIVERSITI TEKNIKAL MALAYSIA MELAKA © Universiti Teknikal Malaysia Melaka coating Characterization of TiN & TiAIN on Burr Formation in Drilling - Pragmatic Investigation Sivarao, Rahim, Taufik, Ammar Manufacturing Engineering Faculty Universiti Teknikal Malaysia Melaka (UTeM) Hang Tuah Jaya, Ayer Keroh, Melaka Malaysia e-mail: sivarao@utem.cdu.my Abstract - Burrs are source of dimensional errors, jamming and misalignment in the assembly process. They may cause short circuits in electrical components and may reduce the fatigue life of the part. Furthermore, burrs can be a safety hazard to personnel because they are usually sharp. This scientific research investigates the characterization of 8 mm diameter, 120° point angle of coated drill tool in burr formation. The exit burrs were investigated using two different types of popular coatings, namely TiN and TiAlN. The effect of cutting speed and feed rate of the tool in burr formation onto the workpiece are discussed. In this study, the exit burr height was measured using optical microscope. Moderately harder material, 304L series stainless steel was used in the evaluation of the super coatings. The experiments were conducted using CNC HAAS Milling Machine. These experiments can be classified as hard drilling based on the experimental values and machining conditions. Keyword: TiN, TiAlN, drill tool, burr formation, coating characterization I. INTRODUCTION In every machining process, burr is formed as a result of plastic deformation. In drilling operation, usually burrs are produced on both the entrance and the exit surfaces of the work piece. The entrance burr forms on the entrance surface as material near the drill undergoes plastic flow. The exit burr is a part of the material extending off the exit surface of the work piece. Most burr-related problems in drilling are caused by the exit burr because the exit burr is much larger than the entrance burr [2]. Burrs are source of dimensional errors, jamming and misalignment in the assembly process. They may cause short circuits in electrical components and may reduce the fatigue life of the part. Furthermore, burrs can be a safety hazard to personnel because they are usually sharp. The existence of burrs on a work piece is source of the dimensional errors. The burr may reduce the fatigue life of the parts smce the hardened and brittle burr material can act as a crack ini~!ation point. or 67 taufik@utern.edu.rny Debris of the burrs can cause serious damage on the moving parts [8]. By reducing the burr formation, the cost of deburring can be minimized and on the other hand, it will improve the product quality and productivity. These are the main reasons of why the researchers are still keep trying to avoid the formation of a drilling burr or at least to minimize it, or sometimes, to control the type of the burr. The formation of the drilling burr depends on many parameters such as characteristics of work pieces (material properties, geometries, surface roughness, etc.), drills (material properties, geometries, tool wear, temperature, chip formations, etc.), and process parameters (cutting speed, feed rate, usage of coolant, rigidity of machine, temperature, etc.). Titanium nitride (TiN) is an extremely hard, ceramic material (-85 HRC or 24.5 GPa), often used as a coating on titanium alloy, steel, carbide, and aluminium components to improve the substrate's surface properties [l]. TiN has excellent infrared (IR) reflectivity properties, reflecting in a spectrum similar to elemental gold (Au). Depending on the substrate material and surface finish, TiN will have a coefficient of friction ranging from 0.4 to 0.9 versus itself (non-lubricated). Typical formation is a face-centered cubic crystalline structure with a roughly 1: l stoichiometry. TiN will oxidize at 600°C at normal atmosphere, and has a melting point of 2930°C. The most common use for TiN coating is for edge retention and corrosion resistance on machine tooling such as drill bits and milling cutters, often improving their lifetime by a factor of three or more. Because of TiN's metallic gold color, it is often used to coat costume jewellery and automotive trim for decorative purposes. TiN is also widely used as a top-layer coating, usually with nickel (Ni) or chromium (Cr) plated substrates, on consumer plumbing fixtures and door hardware. TiN is non-toxic, meets FDA guidelines and has seen use in medical devices and bio-implants, as well as aerospace and military applications. Figure 1 shows the sample of TiN drill tools used in this research. International Conference on Engineering and JCT (ICE/) Figure I: Laminated samples of TiN coated 8mm drill tools TiAlN is another coating frequently used for extreme conditions, where, it is considered superior to TiN, where the the characteristics were designed to run at even higher temperatures than the TiN coating. It produces to obtain good results in Stainless Steel, nickel based alloys, high temperature, and titanium alloys. These coatings permits the high speed semi-dry or dry machining operations and increases speed rate 50% over uncoated tool. Figure 2 shows the sample of TiAlN coated drill tools used in this empirical research. Figure 2: Laminated samples ofTiAlN coated 8mm drill tools II. LITERATURE REVIEW Many authors have investigated and still starving in their research in minimizing or eliminating the burr formation in metal cutting industries. The researchers often investigate the drill tool geometry and also properties of related material such as aluminium, stainless steel, mild steel, etc. In manufacturing process there are many key processes in reducing the burr formation. M. Abdel Mohsen Mahdy has studied in economic drilling conditions for a given de burring radius [I]. He describes about electrochemical deburring (ECD) to provide a simple and economical 68 approach to selectively remove burr from inaccessible areas with consistent result and absolute uniformity. Kihc Lee and David A. Dornfeld have studied in Micro-bun formation and minimization through process control [2 and the authors described about micro-burr formation ir machining. Tungsten-carbide micro-mills were used tc cut holes (in a drilling-like process) to investigate top bun formation. The researchers also investigated abow function of machining variables, e.g. feed rate, cuttini: speed and cutting edge radius, to help illuminate th< micro-burr formation mechanisms. Simon S.F. Chang and Gary M. Bone carried out studie~ in burr size reduction in drilling by ultrasonic assistanc< [3]. They have investigated about the effect of ultrasonic assistance on burr size, chip formation, thrust forces anc tool wear. A recent and promising method for reducini burr size in metal cutting is the use of ultrasonic assistance, where high-frequency and low-amplitudt vibrations are added in the feed direction during cutting Begon-a Pen-aa, Gorka Aramendia, Asuncio'n Riveroa and Luis N. Lo'pez de Lacalleb have studied i1 monitoring of drilling for burr detection using spindh torque [ 4]. The author has used high speed machinini centre (Agil-2) developed by Fatronik which is 3-axi: CNC machine of linear motors and Fidia control. Sung-Lim Ko, Jae-Eun Changa, and Gyun-Eui Yang hav1 studied in burr minimizing scheme in drilling [5] and the; describe about minimizing burr formation, it is propose1 that a step drill be used and the authors studied abou burrs formation by a step drill with step edges wen smaller in size comparing with those produced by : conventional drill with a point angle that was larger tha1 130°. Sung Lim Ko and jing Koo Lee have analyzed bur formation in drilling with a new concept drill [6]. Th authors studied about the drilling operations with a ne\ concept drill and were compared with a conventional HS: drill. Kiha Lee has investigated in optimization ani quality control in burr formation using design o experiment in drilling of intersecting holes [7]. Th drilling process of the crankshaft of automobile engine was elaborated by author. Berlin Shyu has studied about burr reduction by Toe Design [8]. The author studied about a compute simulation framework which helps user to easily produc the CAD of drills and other tools with finite elemer analysis verification for burr prevention. Karina Lei engineered burr formation in drilling intersecting hole [9] and the author developed a model for specific type c burr formation. The model was based on material properties and yield stress theory. The emphasis was o comparing two specific drill geometries. L. Ke Lauderbaugh Saunders studied in a finite element modi of exit burrs for drilling of metals [ 1 O]. The au the describes about the modeling work of Saunders an Mauch is extended using the Finite Element method. III. EXPERIMENTAL SETUP AND PROCEDURE In this experiment, CNC HAAS VF- I milling machine has been used for drilling. An image analyzer was used to measure the formed burr height. The burr formation by drill tool of Smm with 120° point angle coated with two different coatings namely TiN & TiAlN have been compared. They were investigated with the same machining conditions and experimental values. Drilling speed and feed have been considered as the prime parameters as they were amongst the significant in burr formation process. These experiments were conducted by the attempt of drilling 30 holes on a stainless steel plate using the same drill tool until the tool meets catastrophic failure in dry condition. The machining parameters and work material details are as shown in table I. Table 1: Machining parameters used for TiAlN & TiN Low High Low High 16 20 0.12 0.2 Material Stainless steel (304L series) Thickness lOmm Hardness 243BH Eight randomized experiments were conducted based on the 23 factorial design as per the DOE matrix shown in Table 2. Three replication has been conducted which totals up to 24 experiments. The experimental work by TiN coated drill tool is shown in figure 3. The results discussed here are the average of three replications carried out to av?id in reducing biasness. Table 2: DOE matrix: Run Speed Feed Coating l 1 I TiN 2 -1 I TiN 3 I -1 TiN 4 -1 -1 TiAlN 5 I -1 TiAlN 6 -1 I TiAlN 7 -1 -1 TiN 8 1 I TiAIN 69 Advanced Matcr;a/ Figure 3: TiN coated drilling on stainless steel workpiece IV. RESULTS AND DISCUSSION The burr formation after the drilling process with 8 mm TiAIN & TiN drill tools is discussed. The comparison of both the coating types was investigated at different levels of cutting speed and feed. From the analyzed data and the histograms shown in figure 4 and 5, TiAlN coating shows better characteristics than TiN at both machining levels of machining conditions by producing lower burr height. Burr height for TiN coating is greater that TiAIN coating. The results resides to TiAlN which presence lower burr heights and agrees well with most of the researchers on some common metallic work material. 350 oT!N 1111 TiAIN 300 c e 250 0 I 200: I ;: O> 150 ·c;; .s::. !::: 100 :J al 50 5 10 15 20 25 30 Hole number Figure 4: Burr formation (height) for low level machining (Experiment 4 vs. experiment 7) ofTiN & TiAlN coated drill tools. With reference to figure 5, The seriousness in the burr height is worst for high level maching experiments where at hole number 5, 15, 19 and 26, the burr height formed by TiAlN coating was greater than TiN. This could be to the non-homogenous material impurities, missing data in averaging the replication result, control of parameters, etc. It can also concluded that the parameters used such as cutting speed and feed rate have significant affect on burr formation within the range of experimental parameters. International Conference on Engineering and !CT (ICE!) 400 350 "2 18 TiN • TIAIN e 300 " 250 I I ~ 200 I .,, ·a; 150 ,r; ~ :J 100 Ill 50 0 5 10 15 20 25 30 Hole number Figure 5: Burr formation (height) for high level machining (Experiment I vs. experiment 8) ofTiN & TiAlN coated drill tools. Figure 6: Drill cap formation for TiAIN observed during the experiments. The final worked metal piece by TiAlN found to be producing more drill caps than TiN as shown in figure 6 as compared to TiN coating. Therefore, some simple rework is still required to remove the caps before finishing/final assembly stage. From this investigation, it is learned that the hardness of the coating has proportionally good result on burr formation, but the drill caps are still produced on this specified 304L series stainless steel material within the range of experimental values applied in this experiment. V. CONCLUSION As for this investigation, conclusion can be drawn saying that, in both low and high level machining conditions, the TiAlN coating performs better as compared to TiN. Anyhow, a slight draw back is that, too many drill caps are produce as compared to TiN for the same range of experimental values with Smm drill tool. Therefore, can be concluded that TiAlN coating gives better reduction of burr formation in drilling with Stainless steel (304L series) and can be strongly recommended if there is a mechanism of removing drill caps easily without much affecting on the production time, rate and cost. 70 VI. FUTURE WORK From the investigation, it is found that the profiles of drill caps formed are proportional with the number of drilled holes. Therefore, this investigation can be extended for tool wear and drill caps correlation statistical modeling or artificial intelligence modeling. Relatively, further investigations can be made to find out the influence of diameter, machining condition, material, etc. in burr formation with the same comparative coatings. VII. ACKNOWLEDGEMENT The authors would like to render their sincere thanks to the honorary Dean of the manufacturing engineering faculty, Prof. Dr. Mohd. Razali Muhamad for extending his guidance, help and support in completing this project. The authors wish to extend their sincere thanks to Mr.Khairul Affendy bin Mansor (Mancoi) and Mr. Nor Fauzi bin Tamin (Apau) the CNC lab technicians, Mr. Jaafar bin Lajis, the PIC of the metrology Jab, Mr. Jaafar bin Lajis for sincerely helped us in completing this research on time as scheduled. VIII. REFERENCES [I] M. Abdel Mohsen Mahdy, "Economic Drilling Conditions For A Given Deburring Radius", Journal of Materials Processing Technology. Vol. 110. pp. 197-205, 2001 [2] Kiha Lee, David A. Dornfeld, "Micro-Burr Formation And Minimization Through Process Controf', Journal of Precision Engineering. Vol. 29. pp.246-252, 2005. [3] Simon S.F. Chang, Gary M. Bone, Burr Size Reduction In Drilling By Ultrasonic Assistance, International Journal of Robotics and Computer-Integrated Manufacturing. Vol. 21. pp.442-450, 2005. [4] Begon-a Pen-aa, Gorka Aramendia, Asuncio'n Riveroa, Luis N. Lo'pez de Lacalleb, "Monitoring Of Drilling For Burr Detection Using Spindle Torque", International Journal Of Machine Tools & Manufacture. Vol. 45. pp.1614-1621, 2005. [5] Sung-Lim Ko, Jae-Eun Changa, Gyun-Eui Yang, "Burr Minimizing Scheme In Drilling", Journal Of Materials Processing Technology. 2003. [6] Sung Lim Ko and jing Koo Lee, "Analysis Of Burr Formation In Drilling With A New Concept Drill", Jurnal Of Material Processing Technology. Vol. 113. pp.392-398, 2001. [7] Kiha Lee, "Optimization and Quality Control in Burr Formation Using Design of Experiment(!/): Drilling Of Intersecting Holes", The Consortium on Deburring and Edge Finishing (CODEF). pp. 1-3, 2000. [8] Berlin Shyu, "Burr Reduction by Tool Design", The Consortium· on Deburring and Edge Finishing (CODEF). pp. 26-29, 2000. [9] Karina Leis, "Burr Formation in Drilling Intersecting Holes", The Consortium on Deburring and Edge Finishing (CODEF). pp. 35· 38, 2000. [ 10] L. Ken Lauderbaugh Saunders, "Finite Element Model of Exit Burrs For Drilling Of Metals", International Journal of Finite Elements in Analysis and Design. Vol. 40. pp.139-158, 2003. BIOGRAPHIES Mr. Sivarao is a research academia in manufacturing engineering faculty, Universiti Teknikal Malaysia Melaka (UTeM). He is currently active in his research area namely precision machining, cutting tools and artificial intelligence in the area of manufacturing. He also presented his research findings at many international events including , University of California (USA), University of Calgary, (Canada), Feng Chia University (Taiwan),_ etc. He has also published several numbers o_f resear_ch papers m nat10nal and international conference proceedmgs and Journals. Besides his research work, Mr. Sivarao is also a reviewer for; • Journal of Engineering Manufacture (JEM) - Proceedings of the Institution of Mechanical Engineers, Part B, UK • International Journal of Materials And Product Technology (IJMPT) _ Special Issue on: "Intelligent Machining-Computational Methods and Optimization" • International Conference on Manufacturing Science and Technology (ICOMAST2006), Multimedia University, Malaysia. • International Conference on Intelligent & Advanced Systems (ICIAS2007), Kuala Lumpur Convention Centre - UTP, Malaysia His research work on invention & innovation has also won him several medals in the national and international invention competitions including international exhibitions of inventions, Geneva year 2007. 71 Adranced Material Mr. Rahim is a deputy dean (academic) of the manufacturing engineering faculty, Universiti Teknikal Malaysia Melaka (UTeM). He specializes in design and development of manufacturability in the area of manufacturing engineering. His innovative and creativeness in design and development of newly invented products has enabled him to win a medal in the competition of Malaysia Technology Expo (MTE) year 2007. Mr. Taufik is an expatriate from Indonesia serving the manufacturing engineering faculty, University Teknikal Malaysia, Melaka. He has published a number of scientific research papers at international and national level. He specializes in the area of manufacturing design and development mainly involving concurrent and robust engineering; His invention capability has also made him to win a medal in the invention competition of Malaysia Technology Expo (MTE) year 2007. Mr. Ammar is a lecturer from the Department of Manufacturing Process, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka. He graduated from Technical University of Berlin, Germany, specializing in Production Technology and Manufacturing System. He is currently active in the research area comprising off production system and management. 

Coating characterization of TiN & TiAIN on burr formation in drilling pragmatic investigation

http://eprints.utem.edu.my/id/eprint/15106/1/Coating%20characterization%20of%20TiN%20%26%20TiAIN%20on%20burr%20formation%20in%20drilling%20pragmatic%20investigation212.pdf

Coating characterization of TiN & TiAIN on burr formation in drilling pragmatic investigation

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