SEM views of auxiliary flange wear of the worn insert after 74 minutes of machining under dry and high-pressure coolant conditions by SNMG insert. SEM views of auxiliary flange wear of the worn insert after 45 minutes of machining under dry and high-pressure coolant conditions by SNMM insert.
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Chapter-2
Literature Review
Introduction
LiteratureReview
Such a high rake surface temperature can also raise the temperature at the tool flank. The heat generated during machining also raises the temperature of the cutting tool tips and the work surface near the cutting zone [6].
Summary of Review
High pressure coolant also provides lubrication by blowing lubricating fluid between the chip and the cutting edge at hundreds of kilometers per hour [15]. It has the advantage of a power full current that calls reach to the cutting area. However, high production machining, milling and drilling with high cutting speed, feed rate and depth of cut are inherently associated with the generation of large amount of heat and high cutting temperature.
Such high cutting temperature not only reduces dimensional accuracy and shelf life, it also damages surface integrity and product quality. Longer cutting under high cutting temperature causes thermal expansion and distortion of the work, especially if it is of small <:r, small size, which leads to dimensional and shape inaccuracies. The surface quality of products also deteriorates with increasing cutting temperature due to the formation of built-up edges, oxidation, rapid corrosion and the induction of residual tensile stress and surface microcracks.
A flood of fluid directed over the back of the slide is the most corrunon method of applying the cutting fluid.
Chapter-3
Objectives of the presentwork
Chapter-4
Introduction
Design And Fabrication Of The HPC Jet Delivery System
4.3 _ Experimental Procedure
Excessive chipping (flaking) or catastrophic fracture ofthc cutting edge
- ExperimentalInvestigation
- Cutting Temperature
- Dimensional Deviation and Surfllee Roughness
The roughness of the machined surface after each cut was measured with Talysurf(Sutronic]<, Rank Tylor Hobson limited). A wear SEM view of the main and secondary flanks of the worn plate after approximately 74 minutes of stainless steel treatment for SNMG plates and 45 minutes of stainless steel treatment for SNMM plates under dry and HPC conditions are shown in Fig. A and. Figure 4.10 Wear SEM view of the main flank of the worn SNMG insert after processing under dry and HPC conditions.
Fig.4.12 SEM views of the main flank wear of the worn SNMM insert after machining under dry and HPC conditions. Fig.4.13 SEM views of auxiliary flange wear of the worn SNMM insert after machining under dry and HPC conditions by insert. During straight turning in a center lathe, the diameter of the machined part is found to gradually (I) increase along the length of cut due to gradual wear of the tool tip (2) decrease due to thermal expansion and subsequent cooling of the job as The working temperature increases significantly during machining and (3) increases due to the system compliance of the machine-fixturc-tool working system under the action of the cutting forces.
The order of dimensional deviations possible due to thermal expansion of the work even in dry machining and due to compliance with the machine-fixture-tool-workpiece system was calculated for the steel samples being machined. Under current conditions and values, these appear to be extreme. small compared to what is possible due to tool tip wear. Therefore, in this study, it is assumed that the dimensional deviations are mainly due to tool tip wear. Irregular deformation of the auxiliary cutting edge at the tool tip due to chipping, breaking and wear.
Irregular deformation of the auxiliary cutting edge at the tool-tip due to chipping, fracturing and wear,
The performance and service life of any machined part is primarily governed by the quality of that product, which for a given material is generally evaluated by the quality of that product, in terms of surface roughness, oxidation, corrosion, residual stresses, and the surface of dry underground. micro cracks. Therefore, surface finish is an important index of machining, because the performance and service life of the machined component are often affected by its surface finish, the nature and extent of residual stresses, and the presence of surface or subsurface microcracks, if any. especially when that component is to be used under d}1larnic loading or in conjugation with some other mating part. Generally, good surface finish, if essential, is achieved by finishing processes such as turning, but is sometimes left to machining.
Even if the final turning is to be done, the machining must be done beforehand with as low a surface roughness as possible to facilitate and save turning and to minimize the initial surface defects. On the other hand, the main causes of surface roughness development in continuous machining operations such as turning, especially of nodular metals, are: Figure 4.15 Variation of average surface roughness, Ra with machining time in dry and HPC conditions.
The variation in surface roughness observed in the progress of machining of stainless steel by the SNMG and SNMM insert at a given cutting speed, V".
Chapter-5
Result & Discussion
CuttingTemperature
However, during machining at lower Vo, when the chip-tool contact is partially elastic, where the chip leaves the tool, the HPC is drawn into this elastic contact area in a small amount due to capillary effect and is likely to allow more efficient cooling. As Vo increases, the swarf makes full plastic or solid contact with the angled surface of the tool and prevents fluid from entering the hot swarf-tool interface. As shown in Figure 4.5 (a) and Figure 4.5 (b), the effect of HPC cooling improved to some extent by reducing the feed, especially at lower cutting speed.
It is possible that the thinner chips, especially at lower chip speeds, are pushed up slightly by the HPC beam coming from the opposite direction, allowing it to move closer to the contact zone of the hot chip tool to remove heat more effectively. Furthermore, at high cutting speeds, the coolant may not have enough time to remove the heat accumulated in the cutting zone, resulting in less temperature drop under HPC conditions. With de-increa=in_feed_rate, S",.~.in-Fig.4-.--Ha) ami-4.-5 (b), -- the contact length of the chip tool generally increases, but the close curvature of the grooves parallel and close to the cutting edges of the insert have reduced the contact length of the chip tool and thus possibly helped in further reducing the chip tool temperature.
However, it was observed that the HPC jet in its current mode of application enabled the reduction of the average cutting temperature by almost 5% to 10% depending on the levels of the process parameters, V0 and Pra. temperature is expected to have a favorable influence on other processing indices.
Tool Wear
When using the SNMG tile, the average wear of the auxiliary flank is greater than when using the SNMM tile in dry and !-IPC conditions. Although the wear of the auxiliary flank (V.) occurs less intensively, it also plays an important role in machining by worsening the dimensional inaccuracy and roughness of the finished surface. The significant reduction in dimensional deviation observed in this investigation can be reasonably attributed primarily to the reduction in wear on the auxiliary flank of the HPC pads.
It can be observed that in Figures 4.14 (a) and 4.14 (b) the dimensional deviation increases with increasing job length for both dry cooling and HPC. 4.14 (a) and 4.14 (b) also show that in dry and high pressure cooling the dimensional deviation increases with increasing part length. Dimensional deviation is less in high-pressure cooling compared to dry machining using both inserts due to much less wear interruption or initial wear and the absence of a notch on the auxiliary insert flank.
Careful observation of the figures showing dimensional deviations under different processing conditions and those showing average arm wear visualizes that the observed dimensional deviation is closely related to the corresponding auxiliary arm wear.
Surface Roughness
It has previously been mentioned that the diameter in straight turning of long bars can deviate from the theoretically expected value due to progressive wear of the tool tip, variation in the compliance of the M-F-T-W system along the axis of the lathe, and thermal expansion or distortion of the tool tip. job if very heated. Since HPC reduced the average auxiliary flank wear and produced no wear on the additional cutting edge, the surface roughness also grew very slowly under HPC conditions. However, it is clear that HPC improves the surface finish depending on the work tool mattTiais-llIld mainly by controlling the deterioration of the auxiliary insert by wear, chipping and built-up edge shape.
Since HPC reduced the average auxiliary flank wear and produced no auxiliary insert wear, the surface roughness also grew very slowly under HPC conditions. However, it is obvious that HPC improves the surface finish depending on the work tool materials and mainly by controlling the deterioration of the additional cutting edge by wear, chipping and built-up edge shape. Careful observation of the figures showing surface roughness under different machining conditions and those showing average flank wear visualize that surface roughness observed is closely related to corresponding auxiliary flank wear.
This result may also occur due to rapid gradual wear of the SNMM tool tip due to system compliance of the machine-holding-tool-working system under the action of cutting forces.
Chapter-6
Conclusion
G., "Study of the Role of Cutting Fluid in Machining Performance", Lubrication Engineering, Vol.10, p. 34; Use of Minimum Quantity of Lubricant (MQL) and Diamond Coated Tools in Aluminum-Silicon Alloy Drilling", Journal of Materials Processing Technology. Rice, "Some Effects of Cutting Fluids on Chip Generation in Metal Cutting", ASME Transactions, Vol.
0., "High speed machining of aero-engine alloys", Journal of the Brazil Society of Mechanical Science & Engineering. Haddad, "Ultra-high pressure machining of titanium through shear lubrication/cooling", Transaction of NAMRIISME, pp. Haddad, "Ultra-high pressure machining of titanium through shear lubrication/cooling", Transaction of NAMRlISME, p.
Ber, "Influence of high pressure flushing through the rake face of the CUllingtool", Annals ofCIRP, Vol.
