Improving in surface quality of precision thin-walled pipes

2021 ◽  
pp. 557-559
Author(s):  
A.A. Filatov ◽  
O.V. Sokolova ◽  
E.V. Lagoshina
Keyword(s):  
Surface Quality ◽  
Deformation Zone ◽  
Original Method ◽  
Axial Forces ◽  
Thin Walled ◽  
Periodic Rolling

The causes for the occurrence of axial forces during the cold periodic rolling in the deformation zone are considered. Original method for solving of the axial forces minimization to increase the productivity of mills and the quality of the finished product is presented.

scholarly journals Improvement of Surface Quality based on Magnetorheological Fluids Flexible Fixture During Milling Thin-walled Parts

2021 ◽  
Author(s):  
Yong Zhang ◽  
Shan Gao ◽  
Ning Yang ◽  
Xiaohui Jiang ◽  
Guokuan Zhao ◽  
...  
Keyword(s):  
Surface Quality ◽  
Rotational Speed ◽  
Complex Structure ◽  
Point Contact ◽  
Feed Speed ◽  
Cutting Depth ◽  
Maximum Decrease ◽  
Speed Change ◽  
Thin Walled

Abstract Aerospace thin-walled parts have the characteristics of low stiffness and complex structure, which are easily deformed by machine tool vibration, cutting force and heat during machining. The traditional fixture is in point contact with the workpiece, and the workpiece bears uneven force, which results in poor surface quality and low precision of the part. Therefore, it is urgent to improve the machining efficiency and surface quality of workpiece. According to the performance of magnetorheological fluid, a magnetorheological flexible fixture is designed to completely wrap the parts so as to make them bear uniform force, improve the stiffness of the system and inhibit flutter. Firstly, the stiffness distribution of thin-walled parts, flexible fixtures and fixture-workpiece system is studied in this paper. It can be seen that the symmetrical center stiffness of magnetorheological flexible fixtures is relatively low. Through milling experiments with single process parameters, it is found that when the rotational speed, cutting depth and feed speed change, the composite clamping effect is better than the traditional clamping effect, in which with the increase of rotational speed, the vibration acceleration in Ax, Ay and Az directions decreases by 25.16%, 26.87% and 10.78% respectively; When the cutting depth increases, Ay decreases by 23.12% at the maximum. When the feed speed changes, it decreases by 15.78%. Finally, based on the case of milling thin-walled parts with magnetorheological flexible fixture, it is obtained that the coaxiality of composite clamped thin-walled parts decreases by 13.85%, and the maximum decrease of cylindricity is 36.73%. Roughness value Rz decreases by 80.47% at the maximum. In summary, the above results have verified that the machining quality of the magnetorheological flexible fixture is better.

In-Process Laser Re-Melting of Thin Walled Parts to Improve Surface Quality after Laser Metal Deposition

2019 ◽  
Vol 813 ◽  
pp. 191-196
Author(s):  
Francesco Bruzzo ◽  
Guendalina Catalano ◽  
Ali Gökhan Demir ◽  
Barbara Previtali
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Surface Quality ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Average Roughness ◽  
Thin Walls ◽  
Energy Inputs ◽  
Thin Walled

Laser metal deposition (LMD) is an additive manufacturing process highly adaptable to medium to large sized components with bulky structures as well as thin walls. Low surface quality of as-deposited LMD manufactured components with average roughness values (Ra) around 15-20μm is one of the main drawbacks that prevent the use of the part without the implementation of costly and time-consuming post-processes. In this work laser re-melting is applied right after LMD process with the use of the same equipment used for the deposition to treat AISI 316L thin walled parts. The surface quality improvement is assessed through the measurement of both areal surface roughness Sa(0.8mm) QUOTE and waviness Wa QUOTE (0.8mm) parameters. Moreover, roughness power spectrum is used to point out the presence of principal periodical components both in the as-deposited and in the re-melted surfaces. Then, the transfer function is calculated to better understand the effects of laser re-melting on the topography evolution, measuring the changes of individual components contributing to the surface roughness such as the layering technique and the presence of sintered particles. Experiments showed that while low energy density inputs are not capable to properly modify the additive surface topography, excessive energy inputs impose a strong periodical component with wavelength equal to the laser scan spacing and directionality determined by the used strategy. When a proper amount of energy density input is used, laser re-melting is capable to generate smooth isotropic topographies without visible periodical surface structures.

Study and Build-Up of Deformation Zone at Cutting of Thin-Walled Tube by Torsion

2017 ◽  
Vol 746 ◽  
pp. 16-21
Author(s):  
S.G. Simagina
Keyword(s):  
Deformation Zone ◽  
Heating Temperature ◽  
Compression Force ◽  
Angular Deflection ◽  
Thin Walled Tube ◽  
Temperature Impact ◽  
Thin Walled ◽  
Force Range ◽  
Intensive Development

Intensive development of Russian aviation and aerospace industries put an emphasis to the problem of quality of using materials and workpieces and to the value of technical and economical indexes in the context of planned production level [1, 2]. Waste-free technologies are preferred. Cutting by torsion or cutting by shear are preferable technologies if thin-walled tube cutting is the main blanking operation. Build-up of workpiece deformation zone plays an important role in the cutting process. Deformation zone determines stability of details during further processing and exploitation. An extended research was conducted about tube separation process using torsion with an active counterpressure. Some parameters was defined in the result of research, in particular: distribution of deformation zone along length and thickness of workpiece, angular deflection and compression force and workpiece heating temperature impact on build-up of whisker disposition in the cut zone. It allows identifying optimum compression force range and temperature conditions. Compliance with recommended practices allows conducting thin-walled tube separation simultaneously with build-up on the workpieces whisker structure that is fortunate for further pressure treatment and exploitation.

A study on surface quality of thin-walled machined parts

2018 ◽  
Vol 5 (9) ◽  
pp. 18730-18738 ◽  
Author(s):  
Manikandan Hareendran ◽  
S. Sreejith
Keyword(s):  
Surface Quality ◽  
Machined Parts ◽  
Thin Walled

scholarly journals Influence of End Mill Helix Angle on Surface Quality of Aluminium Thin-Walled Parts

2018 ◽  
Vol 26 (42) ◽  
pp. 177-188
Author(s):  
Ivan Buranský ◽  
Matej Bračík ◽  
Vladimír Šimna
Keyword(s):  
Surface Quality ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Helix Angle ◽  
End Mill ◽  
Cnc Machine ◽  
End Mills ◽  
Thin Walled ◽  
Cutting Speeds

Abstract This paper deals with the influence of the end mill helix angle on the flatness and surface quality of aluminium (EN AW 6082) thin-walled parts. The three teeth solid end mills of 12 mm diameter with same and different helix angle of third tooth were designed. The tests were performed using the HSC 105 linear CNC machine and following cutting parameters: cutting speeds (800, 100 and 1200 m.min−1), feed per tooth (0.12 mm), cutting depth (for roughing 10 mm and for finishing 5 mm). Evaluation of surface quality of the processed thin-walled parts shows that the helix angle of the end mills has a significant influence on the surface quality of the thin-walled parts. The best results were obtained in the case of end mill with different 35° helix angle of third tooth and cutting speed 1000 m.min−1.

scholarly journals INFLUENCE OF END MILL VARIABLE PITCH ON SURFACE QUALITY OF ALUMINIUM THIN-WALLED PARTS

2018 ◽  
Vol 2018 (04) ◽  
pp. 2552-2557
Author(s):  
Ivan Buransky ◽  
Matej Bracik ◽  
Vladimir Simna ◽  
Tomas Vopat
Keyword(s):  
Surface Quality ◽  
End Mill ◽  
Variable Pitch ◽  
Thin Walled

Modeling of surface roughness for manufactured thin-walled structure

2018 ◽  
Vol 233 (4) ◽  
pp. 1216-1223 ◽  
Author(s):  
Jixiong Fei ◽  
Bin Lin ◽  
Shuai Yan ◽  
Mei Ding ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Dynamic Deformation ◽  
Low Frequency ◽  
Experimental Results ◽  
Superposition Method ◽  
Milling Force ◽  
Machined Surface ◽  
Thin Walled

Deformation of thin-walled structure during machining will influence the surface quality of the final part. Present article investigates this problem and develops a method to predict the surface roughness of the machined surface. To achieve this, the prerequisite is to obtain the dynamic deformation along the milling path. To calculate it accurately, the workpiece is simplified as thin-walled shell and the milling force is simplified as moving input. An expression of the dynamic deformation of the whole structure, which under the excitation of moving milling force, is derived by solving the vibration equation using modal superposition method. Then, the deformation along the milling path is computed by substituting the path coordinates into the expression. The deformation along the milling path is filtered to remove its low-frequency and mid-frequency signals before it is used to evaluate the surface roughness of the machined surface. At last, several machining cases are implemented to demonstrate the proposed method. The experimental results match well with the predicted results. From the predicted and experimental results, it is founded that the deformation during processing is the main reason leading to the poor surface quality of the flexible machined workpiece.

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

Sign in / Sign up

Export Citation Format

Share Document