An Investigation Into Fixture Error Compensation in Micromilling Using Tool-Based Conductive Touch-Off

2010 ◽  
Author(s):  
Jacob A. Kunz ◽  
Angela Sodemann ◽  
J. Rhett Mayor
Keyword(s):  
Tool Path ◽  
Micro Milling ◽  
Machining Accuracy ◽  
Positional Error ◽  
Curved Surfaces ◽  
Milling Tool ◽  
Micro Features ◽  
Tool Stresses ◽  
Compensation Approach ◽  
Forward Kinematic

In micro-milling, decreased tool size leads to a need for tighter tolerances for fixture error in order to avoid excessive tool load and maintain machining accuracy. In 4-axis machining on a curved surface, fixture errors propagate cumulatively leading to a significant error at the tool tip. As a result a compensation approach is essential to successful microfeature production on curved surfaces. Tool stresses are shown to be highly dependent on the amount of fixture error. The scaling down of tool sizes is shown to result in an exponential increase in tool stresses. This paper proposes the use of a conductive touch-off method that utilizes the milling tool in its spindle to perform an in-situ registration mapping of positional errors. The fixturing errors are characterized using the Denavit-Hartenberg robotic linkage convention. A forward kinematic solution uses homogeneous transformation matrices to investigate the effects of fixturing errors on milling tool path errors in 4-axis micro-milling on curved surfaces. The touch-off registration measures the positional error in the tool axis direction allowing for axial tool position compensation. This results in decreased tool stresses and increased channel depth accuracy which is necessary for successful milling. A preliminary implementation of the conductive touch-off registration approach has demonstrated the efficacy of the technique when applied to production of micro-features on concave surfaces.

scholarly journals Vibration-based tool life monitoring for ceramics micro-cutting under various toolpath strategies

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 125
Author(s):  
Zsolt János Viharos ◽  
László Móricz ◽  
Máté István Büki
Keyword(s):  
Tool Path ◽  
High Efficiency ◽  
Vibration Signal ◽  
Ceramic Materials ◽  
Micro Milling ◽  
The Novel ◽  
Feature Selection Technique ◽  
Tool Condition ◽  
Signal Features ◽  
Milling Tool

The 21st century manufacturing technology is unimagined without the various CAM (Computer Aided Manufacturing) toolpath generation programs. The aims of developing the toolpath strategies which are offered by the cutting control software is to ensure the longest possible tool lifetime and high efficiency of the cutting method. In this paper, the goal is to compare the efficiency of the 3 types of tool path strategies in the very special field of micro-milling of ceramic materials. The dimensional distortion of the manufactured geometries served to draw the Taylor curve for describing the wearing progress of the cutting tool helping to determine the worn-in, normal and wear out stages. These isolations allow to separate the connected high-frequency vibration measurements as well. Applying the novel feature selection technique of the authors, the basis for the vibration based micro-milling tool condition monitoring for ceramics cutting is presented for different toolpath strategies. It resulted in the identification of the most relevant vibration signal features and the presentation of the identified and automatically separated tool wearing stages as well.

Milling of Micro Grooves on Glass Cylinder Surfaces

2011 ◽  
Vol 5 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Takashi Matsumura ◽  
◽  
Yoshihito Ueki
Keyword(s):  
Longitudinal Direction ◽  
Fused Silica ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Cylinder Surface ◽  
Machining Accuracy ◽  
Machining Processes ◽  
Glass Cylinder ◽  
Simultaneous Control ◽  
Milling Tool

Micro milling is presented to machine micro grooves on a glass cylinder surface in a depth of cut of more than 10 µm. The milling tool is inclined in the cutter feed direction to finish fine surfaces in the operation. The effect of tool inclination on the cutting process during a rotation of the cutter is discussed in an analytical model. A 4-axis machine tool is developed to machine the micro grooves using the rotational and the linear motions. The cutting position on the cylinder surface is controlled to incline the milling tool in the cutting direction. Machining processes with a linear control in the longitudinal direction, with a rotational control of the workpiece, and with a simultaneous control of those motions are verified on the machine developed. Adjustment of workpiece alignment and pre-finishing are required for a high machining accuracy in the cutting operation. A feed rate of less than 0.24 mm/min is required to finish crack-free surfaces in cutting of fused silica.

Experimental Investigation of Micro-Milling Accuracy Using On-Machine Measurement System

2010 ◽  
Author(s):  
Xinyu Liu
Keyword(s):  
Measurement System ◽  
Tool Path ◽  
Geometric Error ◽  
Micro Milling ◽  
Dominant Factor ◽  
Contour Error ◽  
Confocal Laser ◽  
Machining Accuracy ◽  
Laser Sensor ◽  
Tool Diameter

In this paper, we proposed an error decomposition method, in which some major error components can be experimentally estimated using an on-machine measurement (OMM) system. Unlike the conventional machining, the geometric error of a micro-tool, i.e., the deviation of the effective tool diameter from a nominal value, becomes a dominant factor affecting the machining accuracy. The error stems from both the tool fabrication error and the dynamic runout of the spindle system under high rpm. An on-machine measurement system based on a non-contact confocal laser sensor was developed that can accurately and efficiently acquire the effective tool diameter. To compensate the error due to the tool geometric error, the effective tool diameter was used to replace the nominal tool diameter to generate the tool path. The experimental results showed that the tool geometric error contributes over 50% to the total machining error. After compensation, the machining accuracy was significantly improved. The machine contour error has negligible influence on the dimension error of the machined feature, but it affects the form error, such as circularity of a machined hole. The process induced surface location errors were estimated from both experiments and model simulations, and good match was achieved.

Error correction technique for numerical control machine tools based on the simplex method

2021 ◽  
pp. 095440542110281
Author(s):  
Hongwei Liu ◽  
Rui Yang ◽  
Pingjiang Wang ◽  
Jihong Chen ◽  
Hua Xiang
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Simplex Method ◽  
Tool Path ◽  
Repeated Measurements ◽  
Numerical Control ◽  
Machining Accuracy ◽  
Correction Technique ◽  
Fluctuation Range ◽  
Nc Machine

The objective of this research is to develop a novel correction mechanism to reduce the fluctuation range of tools in numerical control (NC) machining. Error compensation is an effective method to improve the machining accuracy of a machine tool. If the difference between two adjacent compensation data is too large, the fluctuation range of the tool will increase, which will seriously affect the surface quality of the machined parts in mechanical machining. The methodology used in compensation data processing is a simplex method of linear programming. This method reduces the fluctuation range of the tool and optimizes the tool path. The important aspect of software error compensation is to modify the initial compensation data by using an iterative method, and then the corrected tool path data are converted into actual compensated NC codes by using a postprocessor, which is implemented on the compensation module to ensure a smooth running path of the tool. The generated, calibrated, and amended NC codes were immediately fed to the machine tool controller. This technique was verified by using repeated measurements. The results of the experiments demonstrate efficient compensation and significant improvement in the machining accuracy of the NC machine tool.

scholarly journals Towards Efficient Milling of Multi-Cavity Aeronautical Structural Parts Considering ACO-Based Optimal Tool Feed Position and Path

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 88
Author(s):  
Yupeng Xin ◽  
Yuanheng Li ◽  
Wenhui Li ◽  
Gangfeng Wang
Keyword(s):  
High Speed ◽  
Tool Path ◽  
Milling Process ◽  
Ant Colony ◽  
Machining Accuracy ◽  
Ant Colony Optimization Algorithm ◽  
Peripheral Milling ◽  
Structural Part ◽  
Milling Method ◽  
Structural Parts

Cavities are typical features in aeronautical structural parts and molds. For high-speed milling of multi-cavity parts, a reasonable processing sequence planning can significantly affect the machining accuracy and efficiency. This paper proposes an improved continuous peripheral milling method for multi-cavity based on ant colony optimization algorithm (ACO). Firstly, by analyzing the mathematical model of cavity corner milling process, the geometric center of the corner is selected as the initial tool feed position. Subsequently, the tool path is globally optimized through ant colony dissemination and pheromone perception for path solution of multi-cavity milling. With the advantages of ant colony parallel search and pheromone positive feedback, the searching efficiency of the global shortest processing path is effectively improved. Finally, the milling programming of an aeronautical structural part is taken as a sample to verify the effectiveness of the proposed methodology. Compared with zigzag milling and genetic algorithm (GA)-based peripheral milling modes in the computer aided manufacturing (CAM) software, the results show that the ACO-based methodology can shorten the milling time of a sample part by more than 13%.

Aero-Engine Blade Deformation Control of Milling Process

2011 ◽  
Vol 308-310 ◽  
pp. 1198-1204
Author(s):  
Hui Xian Chen ◽  
Hao Li ◽  
Hai Tao Feng ◽  
Min Juan Du
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Error Compensation ◽  
Leaf Blade ◽  
Tool Path ◽  
Iterative Solution ◽  
Helical Milling ◽  
Machining Accuracy ◽  
Element Simulation ◽  
Compensation Plan

The leaf blade manufacture precision's influencing factors are numerous, and they have coupling relationship each other. So it is difficult to peel out a single factor on the influencing regularity of the blade's machining accuracy. By researching the engine blades of helical milling state under the existing fixture, the leaf blade deformable model based on the instantaneous milling strength was established. Meanwhile, the off-line multi-level error compensation plan was proposed based on the processing surface static error forecasts and compensation. In order to revise the primitive NC tool path code and eliminate the processing distortion inaccuracy, the elastic deformity on each knife position spot is solved on the basis of iterative solution, using the finite element simulation and milling strength model. By using ANSYS finite element simulation, it receives the real-time error compensation of the tool path. And then The experiment has proven the accuracy and the usability of the compensation plan.

A New Method for the Prediction of Micro-Milling Tool Breakage

2017 ◽  
Author(s):  
Xiaohong Lu ◽  
Haixing Zhang ◽  
Zhenyuan Jia ◽  
Yixuan Feng ◽  
Steven Y. Liang
Keyword(s):  
Cutting Parameters ◽  
Ultimate Stress ◽  
New Method ◽  
Micro Milling ◽  
Force Model ◽  
Bending Stress ◽  
Tool Breakage ◽  
Parameters Selection ◽  
Milling Tool ◽  
Milling Force Model

Micro-milling tool breakage has become a bottleneck for the development of micro-milling technology. A new method to predict micro-milling tool breakage based on theoretical model is presented in this paper. Based on the previously built micro-milling force model, the bending stress of the micro-milling cutter caused by the distributed load along the spiral cutting edge is calculated; Then, the ultimate stress of carbide micro-milling tool is obtained by experiments; Finally, the bending stress at the dangerous part of the micro-milling tool is compared with the ultimate stress. Tool breakage curves are drawn with feed per tooth and axial cutting depth as horizontal and vertical axes respectively. The area above the curve is the tool breakage zone, and the area below the curve is the safety zone. The research provides a new method for the prediction of micro-milling tool breakage, and therefore guides the cutting parameters selection in micro-milling.

scholarly journals 5-Axis Flank Milling Tool Path Smoothing Based on Kinematical Behaviour Analysis

2011 ◽  
Vol 223 ◽  
pp. 691-700 ◽  
Author(s):  
Xavier Beudaert ◽  
Pierre Yves Pechard ◽  
Christophe Tournier
Keyword(s):  
Tool Path ◽  
Maximum Velocity ◽  
Flank Milling ◽  
Machining Time ◽  
Machined Surface ◽  
Tool Paths ◽  
Area Of Interest ◽  
Milling Tool ◽  
Joint Coordinates ◽  
Kinematical Behaviour

In the context of 5-axis flank milling, the machining of non-developable ruled surfaces may lead to complex tool paths to minimize undercut and overcut. The curvature characteristics of these tool paths generate slowdowns affecting the machining time and the quality of the machined surface. The tool path has to be as smooth as possible while respecting the maximum allowed tolerance. In this paper, an iterative approach is proposed to smooth an initial tool path. An indicator of the maximum feedrate is computed using the kinematical constraints of the considered machine tool, especially the maximum velocity, acceleration and jerk. Then, joint coordinates of the tool path are locally smoothed in order to raise the effective feedrate in the area of interest. Machining simulation based on a N-buffer algorithm is used to control undercut and overcut. This method has been tested in flank milling of an impeller and can be applied in 3 to 5-axis machining.

A Small-Line Segment Dynamic Transition Algorithm Based on Axial Error Tolerance

2016 ◽  
Vol 851 ◽  
pp. 433-438
Author(s):  
Shu Jie Sun ◽  
Hu Lin ◽  
Liao Mo Zheng ◽  
Jin Gang Yu ◽  
Bei Bei Li ◽  
...  
Keyword(s):  
Tool Path ◽  
Maximum Velocity ◽  
Error Tolerance ◽  
Contour Error ◽  
Work Piece ◽  
Machining Accuracy ◽  
Machining Efficiency ◽  
Processing Efficiency ◽  
Dynamic Transition ◽  
Machining Quality

To ensure the machining precision of work piece and improve the machining quality and machining efficiency, a dynamic transition method based on axial machining accuracy is given. Firstly, the maximum machining contour error is computed based on the axial machining accuracy, and the tool path is processed based on the machining contour error to reduce the amount of command points. Secondly, the circle transition method is used to make the tool path smoother and the machining efficiency higher. Finally, the radius of the transition circle is adjusted based on the maximum velocity of each transition circle. The experimental results shows that the method proposed could effectively satisfy the needs of the machining accuracy and improve the processing efficiency, while reduce the amount of path data.

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