Mechanics of Saw-Tooth Chip Formation in Metal Cutting

1999 ◽  
Vol 121 (2) ◽  
pp. 163-172 ◽  
Author(s):  
A. Vyas ◽  
M. C. Shaw
Keyword(s):  
Chip Formation ◽  
Hard Turning ◽  
Metal Cutting ◽  
Weight Ratio ◽  
Point Of View ◽  
Root Cause ◽  
Aerospace Applications ◽  
High Speeds ◽  
Thermal Origin ◽  
Extensive Experimental Data

The saw-tooth chip was the last of the major types to be identified. This occurred in 1954 during machining studies of titanium alloys which were then being considered for aerospace applications because of their large strength-to-weight ratio and corrosion resistance. This is a type of chip that forms when very hard brittle materials are machined at high speeds and feeds. Since this is an area of machining which will be of increasing interest in the future, particularly in hard turning, it is important that the mechanism and mechanics of this type of chip formation be better understood. At present, there are two theories concerning the basic origin of saw-tooth chips. The first to appear assumed they are of thermal origin while the second assumes they arise due to the periodic development of cracks in the original surface of the work. The thesis presented here is that the root cause for saw-tooth chip formations is cyclic cracking. This is followed by a discussion of extensive experimental data that supports this point of view.

Micro-Structural Analysis of Chip Formation During Orthogonal Machining of Al/SiCp Composites

2000 ◽  
Vol 123 (3) ◽  
pp. 315-321 ◽  
Author(s):  
S. S. Joshi ◽  
N. Ramakrishnan ◽  
P. Ramakrishnan
Keyword(s):  
Free Surface ◽  
Structural Analysis ◽  
Chip Formation ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Shear Plane ◽  
Point Of View ◽  
Unique Case ◽  
Orthogonal Machining ◽  
Cutting Point

Discontinuously Reinforced Aluminum (DRA) Composites form unique case from the research in metal cutting point of view. Reinforcement in these materials acts as “macroscopic” and “isolated” discontinuities in the path of the tool. The mechanism of chip formation for such materials is yet to be evolved completely. In this paper, the mechanism of chip formation during machining of Al/SiCp composites based on the micro-structural analysis of chips and chip roots is presented. It was evident that the mechanism involves initiation of a gross fracture on the chip free surface and its propagation toward the tool nose. The extent of propagation of gross fracture depends upon the cutting speed and volume of reinforcement in composites. A model of deformation of the material along the shear plane is presented in terms of a ratio of length of flow-type deformation on the shear plane to the total length of shear plane. Influence of volume of reinforcement in composites and cutting speed on the ratio was verified experimentally.

Analysis and Fabrication of a Mechanical Quick-Stop for Research on Chip Formation in Hard Turning Process

2019 ◽  
Vol 889 ◽  
pp. 87-94
Author(s):  
Nguyen Thi Quoc Dung
Keyword(s):  
Chip Formation ◽  
Hard Turning ◽  
Manufacturing Industry ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Cutting Process ◽  
Machining Process ◽  
Machining Parameters ◽  
Machining Processes ◽  
On Chip

Metal cutting is one of the most important machining processes in manufacturing industry. Thorough understanding of metal cutting process facilitates the optimization in selection of cutting tools and machining parameters. There are several methods used for studying phenomena in metal cutting process. Using a quick-top device is an efficient technique for investigation cutting process in which cutting action is stopped so suddenly that the “froze” specimen called the chip root honestly depicts what happened during cutting action. Design strategies of a quick-stop are accelerating cutting tool away from the workpiece or decelerating the workpiece remaining in engagement with the tool. Operation of a quick-stop device can be either mechanically or by explosive. Quick-stop devices can be utilized for various types of machining processes such as: turning, milling, drilling. This paper described the analysis, fabrication, and testing of a quick-stop device which is used for researching on chip formation in hard turning. This device has simple and safe operation which utilizes spring forces to retract the tool from workpiece during cutting. The results of performance at cutting speed of 283 m/min show that the separation distance is quite small, less than 0.2mm so that the deformations on the root chip are close to that while actual machining process. This indicates that the device has satisfied the requirements of an equipment for studying on chip formation.

SANDVIK Ti-3Al-2.5V GRADE 9

Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Endurance Limit ◽  
Weight Ratio ◽  
High Strength ◽  
Strain Ratio ◽  
Bend Strength ◽  
Aerospace Applications ◽  
Excellent Corrosion Resistance ◽  
Titanium Aluminum ◽  
Fatigue Endurance

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.

An overview on the concept of “Aam” and its significance as mentioned in Ayurvedic texts.

2020 ◽  
Vol 8 (01) ◽  
Author(s):  
Tejaswini Katare ◽  
Disha Sharma ◽  
Ganesh Puradkar ◽  
Arun Dudhamal
Keyword(s):  
Point Of View ◽  
The Body ◽  
Diagnosis And Treatment ◽  
Important Concept ◽  
Root Cause ◽  
Causative Factors ◽  
Undigested Food ◽  
Unhealthy Diet ◽  
Lack Of Exercise ◽  
All Diseases

Aam is an important concept described by Ayurvedic Acharyas which is responsible for many diseases. According to Ayurvedic point of view, all diseases are originated from aamdosh, vitiation of Agni i.e malfunction of Agni produces Aam. Aam is unripe, undigested food which is caused due to Agnimandya. Agnimandya produces aam and viceversa. We all know that all diseases are caused due to Agnimandya. Therefore as agnimandya and aam are the causative factors of each other, aam is the root cause of all diseases. Hence aam and agnimandya plays an important role in diagnosis and treatment of disease. Nowadays due to lack of exercise, unhygienic and unhealthy diet, incapability to obey the rules of sound body maintenance and increasing pollution results in agnimandya and aam production in the body and decrease in immunity resulting into various diseases. The concept of aam is the most important fundamental principal of Ayurveda in understanding the physio- pathology of the disease.

On the Effect of Electrodischarge Drilling on the Fatigue Life of Inconel 718

2014 ◽  
Vol 891-892 ◽  
pp. 1451-1456
Author(s):  
Elena Bassoli ◽  
Andrea Baldini ◽  
Andrea Gatto ◽  
Antonio Strozzi ◽  
Lucia Denti
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
Metal Cutting ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Aerospace Applications ◽  
Rotating Bending Fatigue ◽  
Cutting Operation ◽  
Rotating Bending ◽  
Superposition Effect

Difficult-to cut-materials are associated with premature tool failure, most likely in the case of complex geometries and this shapes. However, Nickel-based alloys are commonly used in high-temperature and aerospace applications, where thin deep holes are often required. Then, the only viable manufacturing solution relies on non-contact processes, like electrodischarge (ED) drilling. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. Aim of the paper is to study the effect of holes (0.8 mm diameter, aspect ratio 10) produced by ED drilling on the fatigue life of Inconel 718. Rotating bending fatigue tests are carried out on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Based on previous studies, extremal ED parameters are selected, giving best surface finish versus highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis.

scholarly journals Simulation of plastic deformation and destruction in the process of chip formation

2018 ◽  
Vol 211 ◽  
pp. 17007
Author(s):  
Tanel Tärgla ◽  
Jüri Olt ◽  
Olga Liivapuu
Keyword(s):  
Plastic Deformation ◽  
Formation Process ◽  
Chip Formation ◽  
Rheological Model ◽  
Metal Cutting ◽  
Depth Of Cut ◽  
Key Factors ◽  
Local Zone ◽  
Complex Process ◽  
Relaxing Medium

Metal cutting is a complex process in which several mechanisms are at work simultaneously. The mathematical modelling allows carrying out research into the optimization of machining conditions. This work examines the simulation of chip formation during the process of cutting. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elasticductile- plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for the chip formation process. The key factors that govern the chip formation have been taken into account, such as tool vibration frequency and amplitude, depth of cut, feed rate.

Sandwich Structures for Naval Ships: Design and Experience

2000 ◽  
Author(s):  
Karl-Axel Olsson
Keyword(s):  
Lightweight Design ◽  
Weight Ratio ◽  
Point Of View ◽  
Economic Point ◽  
Plastic Foams ◽  
Reinforced Plastics ◽  
Sandwich Construction ◽  
Glass Fibre Reinforced Plastic ◽  
Glass Fibre Reinforced ◽  
Common Face

Abstract In Sweden we have a long experience with different types of vehicles and ships in sandwich construction, especially Navy ships such as minesweepers, mine-counter-measure-vessels and corvettes. GRP (Glass fibre Reinforced Plastic) and FRP (Fibre Reinforced Plastics) have been the most common face materials, but metallic materials such as Al-alloys, coated carbon steel and stainless steel have also been used. Core materials have usually been cellular plastic foams of cross-linked PVC (Polyvinyl-chloride), but also extruded PS (Poly-styrene), PUR (Poly-urethane), PEI (Poly-ether-imide) and PMI (Poly-methacryl-imide). Different continuous and discontinuous manufacturing processes have been used. Vacuum assisted infusion has been introduced recently, because it is a closed process, gives high fibre content and a good quality of the laminates. Sandwich design has mainly been used in the transportation area, where lightweight design is needed to give higher performance and load bearing capacity. The use of sandwich construction will give high stiffness- and strength-to weight ratio. This is usually not enough from an economic point of view to justify the introduction of sandwich construction, but other integrated functions must be considered, i.e. insulation, energy consumption, damping, fewer components, lower manufacturing costs, low maintenance, signature effects (military) etc.

scholarly journals Tribological Investigations of PVD Coated Multi-Layer Constructions

2015 ◽  
Vol 5 (1) ◽  
pp. 97 ◽  
Author(s):  
Marcus Schulze ◽  
Holger Seidlitz ◽  
Franziska Konig ◽  
Sabine WeiB
Keyword(s):  
Carbon Fibre ◽  
Physical Vapor Deposition ◽  
Large Scale ◽  
Metal Cutting ◽  
Wear Behavior ◽  
Cutting Tools ◽  
Weight Ratio ◽  
High Strength ◽  
Coating System ◽  
Wear Rates

<p class="1Body">Multi-layer constructions become more and more relevant in lightweight applications due to their high strength to weight ratio. They offer excellent crash, damping and recycling properties. Also, the morphology of thermoplastic carbon fibre reinforced plastics (CFRP) render them interesting for large scale manufacturing processes. Nevertheless, a major disadvantage results in a poor resistance against wear and tear, e.g. erosion, which is attributed to weak hardness properties. Hence, this work deals with tribological investigations on orthotropic carbon fibre reinforced polymers (PA 6) either with protective ceramic coating or without. The chosen coating system is a well-known protective covering of metal components, e.g. metal cutting tools, produced by physical vapor deposition (PVD). To characterize the coating system on thermoplastic CFRP, standard analyzing methods are utilized, like optical and scanning electron microscopy (SEM). The tribological investigations are conducted by the tribological ball on disk method to generate wear tracks on the sample surfaces and hence to calculate the wear rates. These results are compared to literature findings with respect to a certain protective coating system (TiN) and a second nano-structured gel coating system, where both systems are deposited on a thermosetting material, i.e. carbon fibre reinforced epoxy resin, respectively. For this purpose the feasibility of depositing a protective ceramic layer on thermoplastic CFRP is demonstrated. First results on suitable surface pre-treatments have shown a significant influence on the coating quality. The improved performance regarding the wear behavior with respect to tribology compared to the poor substrate and existing technologies is shown additionally.</p>

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