Optimizing CNC Turning With Atomization-Based Cutting Fluid And Nozzle Materials

1)Do a short literature review on the nozzle design for CNC machine and research on atomization nozzles for CNC machines
2)identify a research gap that I can work in my experiment
3)Suggest a nozzle design (atomization nozzles or other potential designs) that is available in the market for high pressure coolant CNC machine.
4)Design an experiment to evaluate surface finish and cutting force using nozzle available in marke For mild steels . 

Importance of Quality Control in CNC Turning Operations

During manufacturing operations such as cutting, Turning and other, quality control of the operations is vital. This is because they affect the overall product quality hence the life and serviceability of an item. When performing a CNC turning operation the surface finish of the operation is very important. A number of parameters can affect the turning quality e.g. the nozzle diameter, cooling fluids used and the pressure of operation.  Recent studies have demo stated that ACF i.e. Atomization based cutting fluid is very promising in terms of cooling rate and elimination of unwanted turning at a low-level scale. As a result, the inspected surface finish has low deforms

Different scientists utilized distinctive nozzle materials for different applications and process. Tungsten carbide, sapphire, HCHCr steel, aluminum nozzles for blending stage, metal and steel nozzles at the leave arrange, Stainless steel, Tool Steel, profound responsive particle scratching (DRIE), Alloy steel (EN38) warm treated of hardness 50 HRC was utilized for nozzles are utilized as nozzle materials for investigate reason [2].

Tian et al., (2009) had worked with the nozzle material and outline. Fluid jets of the CNC are in condonation with the nozzles in the relation to the workpiece surface. This produces a perfect turning or wearing of the metal surface being shaped. The nozzle is subjected to high wear when there is the incorporation of abrasive material to assist in metal cutting and shaping. These are made of hard materials, for example, tungsten carbide or manufactured sapphire. Tungsten carbide nozzles are utilized for round cross?sections in the scope of 0.12?0.8mm breadth. Sapphire nozzles are made just for roundabout cross?sections. The size changes from 0.2 to 0.7 mm distance across. Nozzles are designed with a circular cross-section. this minimizes the fiction and abrasive effect caused by the jet to the nozzle material. In most instances, Nozzles made of tungsten carbide have a normal existence of 12 to 30 hours while nozzles of sapphire keep going for around 300 hours of the task [4].

Nath, Kapoor, and Srivastava, (2017), clarifies the nozzle is the most basic part in CNC fluid jet cutting machining. Earthenware production is subject to wear, have wide potential as grating fluidized nozzle materials. In his research paper, Jian used W, Ti, and SiC in the design and building of the composite material nozzle.  The disintegration wear conduct of the (W, Ti)C/SiC slope nozzle was explored and contrasted and a customary artistic nozzle. Results demonstrated that the inclination fired nozzles displayed an evident increment in disintegration wear obstruction over the regular earthenware nozzles. The instrument mindful was observed to be that the tractable worries at the passage area of the nozzle were incredibly decreased when contrasted and the traditional nozzle. This impact may prompt an expansion in protection from crack, and consequently, increment the disintegration wear obstruction of the angled nozzle. It is demonstrated that inclination structures in earthenware nozzles are viable to enhance the disintegration wear opposition of ordinary clay nozzles in fluid jet machining [5].

Atomization-Based Cutting Fluid and Nozzle Materials for Better Surface Finish and Tool Life

For operation of a 7MPa CNC machine high pressure coolant, VBSCO high pressure coolant nozzle can be used. in this case the model WX is the most suitable. it is designed for operating pressures of up to 100 bars hence is within range. The nozzle is made of steel and has an adjustability of 35⁰. The specifications for this nozzle are 1/8''PT-Ø4*10L[9].

The atomization– based cutting liquid (ACF) splash framework highlights two coaxially– gathered spouts of various measurements, consistently estimated beads delivered through the ultrasonic atomizer move through the bead spout at a low speed, and 3 at that point are enclosed by the high velocity of the fluid streaming, however, the nozzle is centered to create an axisymmetric splash jet . The jet is encroached onto the instrument rake face to deliver a quick moving slight liquid film (arranged by many μm) for machining interface spreading of the workpiece and the chips. With a specific end goal to affirm delivering a thin film that is suitable for machining operation, the bead impingement must happen under the 'spreading' administration this is taken care of by the splash parameters of the jet, for example, gas speed, impingement point, stream rate, spout plan, and so forth. In this framework, as a high– speed gas, a blend of air– CO2 is utilized with a specific end goal to lessen the temperature of the impinging beads from 18– 20 C to around two to three ^oC. CO2 additionally helps to stifle the smoke from the cutting amid titanium machining [6].

Numerous investigations tended to the titanium machining issues for harsh cutting activity; in any case, there are not very many examinations on getting is done with a surface finish on turning to the machine. Amid the unpleasant turning of titanium compounds, cutting rate past 65 m/min extend prompts a quickened device wear, and that in turns influences surface harshness. It was found that there is an increase in the surface hardness of the workpiece/ material turned. this was mainly as a result of the high temperatures at the cutting edge of the fluid jet.

This can be sum up as the major machining parameters like., viz., feed rate, and profundity of cut declines by a few times when contrasted with that in harsh cutting. Subsequently, the extent of the apparatus chip interface that firmly rules the machining yields can act distinctively amid titanium machining, for example, cutting and turning.

Experimental Setup for Evaluating ACF Spray Performance

As a result, there is a research opportunity in the evaluation of ACF spray performance on the surface finish of mild steel and comparison with flood coolant and a compressed air system. In this case, other parameters that can be evaluated will be the life of the tool, the highest cutting temperatures, and the performance of the ACF CNC machine [1].

In addition, at a low profundity of cut, titanium has a low modulus of elasticity hence its more brittle than and can cause prattle and prompts poor surface complete, roundness and apparatus life. Amid get done with the cutting of numerous materials like or mild steel or aluminum, a sharpened or turned edge is prescribed for accomplishing enhanced surface complete and lessening device wear; nonetheless, this marvel may not be valid as a sharp front line performs better amides full-scale machining of titanium. Besides, Veldhuis and Zareena watched side-stream and material haul out of Ti-6Al-4V during a scale machining, however, the reason for this was not clarified, as a result, more can be done to this effect  [2].

Finish turning experimental setup can be conducted by using a mild steel bar of a diameter of 105mm x 324 mm. this can be done on the Mori Seiki frontier -I lathe.  All tooling actions can be done using the triangular microcrystalline Iso grade carbide insert, K313. the tooling setup was arranged at 5⁰ perpendicularly to the angle of the rake. A 11⁰ is left a nose extension of 0.8 radii was allowed at 60⁰ major cutting [3].

A work positioner will be used to hold the ACF spray unit, this will be flexible to allow for angle tuning and workability. the optimum diameter of the spayed gas will be designed at 18.8 mm and 1,6mm for the lower velocity. The nozzles will have a slope of 4⁰ maximum and a minimum of 0.75⁰.  

In this experimental setup we shall place the internal nozzle at 5mm, as a result, the chips will be ejected at the opposite direction., the end goal for this is to ensure that the chips are dispersed and do not remain or fall back on the turned surface. The current atomizers ensure that chips formed are about 11.8 μm which are at a speed of 0.9 m/s at a fluid conveyance rate of 20ml/min [4]. At this rate the beads velocity is at the prescribed best rate of about 5m/s as recommend by Arifin et al. In this case the low-speed design and configuration are not required in the current designs of ACF slash system.  

The unit will be set at around 350 in relation to the rake surface and the splash separated by 35mm between the nose of the instrument and the outer nozzle spout. the splash will be set against the chip stream head.  When a volumetric mixture of air and carbon (iv) oxide is utilized at high speed than the atomization increases while the temperatures rise by 2 or 3⁰ [8]

In the experimental set up there are five test parameters that will be considered when dealing with the nozzle and high-pressure coolant. this factor includes cutting pace, producibility of the cut and the ACF jet parameters which include, stream rate and gas speed. 

[1]S. Zhu, "The Design and Application of a New Type of CNC Tool Nozzle", Key Engineering Materials, vol. 693, pp. 286-291, 2016.

[2]L. Tian, W. Wang, X. Liu, Y. Zhang and S. Ji, "Fabrication and Performance Analysis of PMMA Substrate Diffuser/Nozzle Micro-Pump by CNC Milling Machine", Advanced Materials Research, vol. 60-61, pp. 198-201, 2009.

[3]C. Nath, S. Kapoor, and A. Srivastava, "Finish turning of Ti-6Al-4V with the atomization-based cutting fluid (ACF) spray system", Journal of Manufacturing Processes, vol. 28, pp. 464-471, 2017.

[4]S. Gariani, I. Shyha, F. Inam, and D. Huo, "Experimental analysis of system parameters for minimum cutting fluid consumption when machining Ti-6Al-4V using a novel supply system", The International Journal of Advanced Manufacturing Technology, vol. 95, no. 5-8, pp. 2795-2809, 2017.

[5]M. Vinod Kumar, "ANFIS for Predicting Surface Roughness in Turning Operation Performed on CNC Lathe", Applied Mechanics and Materials, vol. 110-116, pp. 1793-1798, 2011.

[6]S. Mukherjee, A. Kamal, and K. Kumar, "Optimization of Material Removal Rate During Turning of SAE 1020 Material in CNC Lathe using Taguchi Technique", Procedia Engineering, vol. 97, pp. 29-35, 2014.

[7]A. Sarchami, N. Ashgriz, and H. Tran, "An atomization model for splash plate nozzles", AIChE Journal, p. NA-NA, 2009.

[8]Z. Ariffin Selamat, N. Bahiyah Baba, M. Alias, N. Mohamad, A. Razlan Yusof, and M. Mustafizur Rahman, "Effect of CNC Lathe Machining Performance by Varying Coolant Nozzle Diameter", Indian Journal of Science and Technology, vol. 9, no. 9, 2016.

[9]Dongguan Yuebosi Electronics Technology Co., Ltd. Trade Assurance China (Mainland)|Manufacturer, Trading Company, "High Pressure Coolant Nozzles For Cnc Machine Tool - Buy High Pressure Coolant Nozzles,High Pressure Nozzle,High Pressure Coolant Nozzle Product on Alibaba.com", www.alibaba.com, 2018. [Online]. Available: https://www.alibaba.com/product-detail/high-pressure-coolant-nozzles-for-CNC_728145059.html. [Accessed: 21- Sep- 2018].