The Effect of Harmonic Helix Angle Variation on Milling Stability

2011 ◽  
Author(s):  
Zoltan Dombovari ◽  
Gabor Stepan
Keyword(s):  
Mechanical Model ◽  
Manufacturing Industry ◽  
Distributed Delay ◽  
Cutting Speed ◽  
Helix Angle ◽  
Angle Variation ◽  
Delay Differential ◽  
Distributed Delay Differential Equations ◽  
Milling Tools ◽  
Time Periodic

The linearly varied helix tool is widely used in manufacturing industry and milling tools are available in the market with these special cutting edges. There were several attempts to introduce complex harmonically varied helix tools, but the manufacturing of sinusoid edges is extremely difficult and its effect on cutting dynamics is not clear yet. In this study a mechanical model is introduced to predict the linear stability of these special cutters. It is shown that these milling tools cause distribution in regeneration and the corresponding time periodic distributed delay differential equations are investigated by semi-discretization. This work points out how the harmonically varied helix cutters behave in case of high and low cutting speed applications.

The Effect of Helix Angle Variation on Milling Stability

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Zoltan Dombovari ◽  
Gabor Stepan
Keyword(s):  
Manufacturing Industry ◽  
Distributed Delay ◽  
Cutting Speed ◽  
Helix Angle ◽  
Helical Milling ◽  
Angle Variation ◽  
Delay Differential ◽  
Distributed Delay Differential Equations ◽  
Milling Tools ◽  
Time Periodic

Helical milling tools of nonuniform helix angles are widely used in manufacturing industry. While the milling tools with these special cutting edges are already available in the market, their cutting dynamics has not been fully explored. Also, there have been several attempts to introduce complex harmonically varied helix tools, but the manufacturing of harmonic edges is extremely difficult, and their effect on cutting dynamics is not clear either. In this study, a general mechanical model is introduced to predict the linear stability of these special cutters with optional continuous variation of the helix angle. It is shown that these milling tools cause distribution in regeneration. The corresponding time-periodic distributed delay differential equations are investigated by semi-discretization. This work points out how the nonuniform and harmonically varied helix cutters behave in case of high and low cutting speed applications.

scholarly journals On Periodic Solutions of Delay Differential Equations with Impulses

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 523 ◽  
Author(s):  
Mostafa Bachar
Keyword(s):  
Periodic Solution ◽  
Fixed Point ◽  
Fixed Point Theorem ◽  
Differential Equations ◽  
Delay Differential Equations ◽  
Distributed Delay ◽  
Impulsive Delay Differential Equations ◽  
Impulsive Delay ◽  
Delay Differential ◽  
Distributed Delay Differential Equations

The purpose of this paper is to study the nonlinear distributed delay differential equations with impulses effects in the vectorial regulated Banach spaces R ( [ − r , 0 ] , R n ) . The existence of the periodic solution of impulsive delay differential equations is obtained by using the Schäffer fixed point theorem in regulated space R ( [ − r , 0 ] , R n ) .

Optimization of Edge Geometry of Cylindrical Milling Tools to Enhance Dynamic Stability

2019 ◽  
Author(s):  
Zoltan Dombovari ◽  
Daniel Bachrathy ◽  
Gabor Stepan
Keyword(s):  
Dynamic Performance ◽  
Distributed Delay ◽  
Tool Geometry ◽  
Analytical Methodology ◽  
Minimization Principle ◽  
Milling Operations ◽  
Regeneration Effect ◽  
Delay Differential ◽  
Milling Tools

Abstract Tool geometry directly influences the dynamic performance of milling operations. Both surface properties and stability behavior are significantly influenced by the regeneration effect. The regeneration phenomenon is modelled by delay differential equations with delays originated from the time passed between consecutive flute passes. This work presents the implementation study of a constrained general optimization scheme for cutting edges of cylindrical milling cutters based on functional minimization principle. Mathematically, this leads to the determination of the corresponding weight function of a distributed delay differential equation. The presented semi-analytical methodology is based on the general milling model implemented in the semidiscretization framework.

scholarly journals Roughing Milling with Ceramic Tools in Comparison with Sintered Carbide on Nickel-Based Alloys

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 734
Author(s):  
Pablo Fernández-Lucio ◽  
Octavio Pereira Neto ◽  
Gaizka Gómez-Escudero ◽  
Francisco Javier Amigo Fuertes ◽  
Asier Fernández Valdivielso ◽  
...  
Keyword(s):  
Cutting Speed ◽  
High Volume ◽  
Cemented Carbide ◽  
Performance Ratio ◽  
Cost Performance ◽  
Ceramic Tools ◽  
The Cost ◽  
Engine Components ◽  
Coated Carbide ◽  
Milling Tools

Productivity in the manufacture of aircrafts components, especially engine components, must increase along with more sustainable conditions. Regarding machining, a solution is proposed to increase the cutting speed, but engines are made with very difficult-to-cut alloys. In this work, a comparison between two cutting tool materials, namely (a) cemented carbide and (b) SiAlON ceramics, for milling rough operations in Inconel® 718 in aged condition was carried out. Furthermore, both the influence of coatings in cemented carbide milling tools and the cutting speed in the ceramic tools were analysed. All tools were tested until the end of their useful life. The cost performance ratio was used to compare the productivity of the tested tools. Despite the results showing higher durability of the coated carbide tool, the ceramic tools presented a better behavior in terms of productivity at higher speed. Therefore, ceramic tools should be used for higher productivity demands, while coated carbide tools for low speed-high volume material removal.

scholarly journals Investigation on the Surface Quality Obtained during Trochoidal Milling of 6082 Aluminum Alloy

Machines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 75
Author(s):  
Nikolaos E. Karkalos ◽  
Panagiotis Karmiris-Obratański ◽  
Szymon Kurpiel ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Manufacturing Industry ◽  
High Surface ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
High Surface Quality ◽  
Trochoidal Milling

Surface quality has always been an important goal in the manufacturing industry, as it is not only related to the achievement of appropriate geometrical tolerances but also plays an important role in the tribological behavior of the surface as well as its resistance to fatigue and corrosion. Usually, in order to achieve sufficiently high surface quality, process parameters, such as cutting speed and feed, are regulated or special types of cutting tools are used. In the present work, an alternative strategy for slot milling is adopted, namely, trochoidal milling, which employs a more complex trajectory for the cutting tool. Two series of experiments were initially conducted with traditional and trochoidal milling under various feed and cutting speed values in order to evaluate the capabilities of trochoidal milling. The findings showed a clear difference between the two milling strategies, and it was shown that the trochoidal milling strategy is able to provide superior surface quality when the appropriate process parameters are also chosen. Finally, the effect of the depth of cut, coolant and trochoidal stepover on surface roughness during trochoidal milling was also investigated, and it was found that lower depths of cut, the use of coolant and low values of trochoidal stepover can lead to a considerable decrease in surface roughness.

EXPERIMENTAL STUDY ON THE CO2 LASER CUTTING OF NOVEL POLYAMIDE 6/FLUOROELASTOMER THERMOPLASTIC ELASTOMERIC BLENDS

2015 ◽  
Vol 88 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Shib Shankar Banerjee ◽  
Anil K. Bhowmick
Keyword(s):  
Low Power ◽  
Co2 Laser ◽  
Process Parameters ◽  
Laser Power ◽  
Laser Cutting ◽  
Manufacturing Industry ◽  
Cutting Speed ◽  
Polyamide 6 ◽  
Thermoplastic Elastomers ◽  
Dynamic Vulcanization

ABSTRACT The application of the low-power CO2 laser-cutting process to fluoroelastomer (FKM), polyamide 6 (PA6), PA6/FKM thermoplastic elastomers (TPEs), and their thermoplastic vulcanizate (TPV) is reported. The main laser process parameters studied were laser power, cutting speed, and material thickness. The value of the top and bottom widths of the slit that were formed during laser cutting (kerf width), melted transverse area, and melted volume per unit time were measured and analyzed. Interestingly, TPE showed a smaller melted area and melted volume per unit time when compared with those values with PA6. Dynamic vulcanization further decreased these values. For example, the melted areas of PA6 and TPE were 510 × 10−3 mm2 and 305 × 10−3 mm2, respectively, which reduced to 238 × 10−3 mm2 for TPV at 40 W laser power. FKM showed the lowest value (melted area of 180 × 10−3 mm2). In addition, the output quality of the cut surface was examined by measuring the root mean square (RMS) roughness of the cut edges and heat-affected zone (HAZ). The obtained results indicated that the dimension of the HAZ and RMS roughness largely decreased in TPE when compared with PA6. For example, the HAZ of PA6 was 700 μm, which decreased to 230 μm for TPE at 40 W laser power. On the other hand, HAZ was nonexistent for FKM. Infrared spectroscopic analysis showed that there was no structural change of TPE or pristine polymers after applying the low-power CO2 laser on the surface of materials. CO2 laser cutting will be a new technique in this industry, and this analysis will assist the manufacturing industry to choose a suitable laser system with exhaustive information of process parameters for cutting or machining of rubber, TPEs, and TPVs.

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