scholarly journals Experimental Determination of Dominant Multipliers in Milling Process by Means of Homogeneous Coordinate Transformation

2017 ◽  
Author(s):  
Adam K. Kiss ◽  
Daniel Bachrathy ◽  
Gabor Stepan
Keyword(s):  
Detection Method ◽  
Monodromy Matrix ◽  
Quantitative Measure ◽  
Milling Process ◽  
Chatter Detection ◽  
External Excitation ◽  
Transient Vibration ◽  
Milling Operations ◽  
Dominant Characteristic

In this contribution, a chatter detection method is investigated for milling operations. The proposed approach can give not only qualitative condition (stable or unstable), but a quantitative measure of stability. For this purpose, it requires an external excitation of stable machining condition. Transient vibration of the perturbation is captured by means of stroboscopic section, and the corresponding monodromy operator is approximated by its projection to the subspace of the dominant modes. The monodromy matrix is determined with the application of homogeneous coordinate representation. Then, the periodic solution and the dominant characteristic multipliers are calculated and their modulus determines the quantitative measure of stability condition.

scholarly journals Surface Integrity Investigation to Determine Rough Milling Effects for Assessment of Machining Allowance for Subsequent Finish Milling of Alloy 718

2021 ◽  
Vol 5 (2) ◽  
pp. 48
Author(s):  
Jonas Holmberg ◽  
Anders Wretland ◽  
Johan Berglund ◽  
Tomas Beno ◽  
Anton Milesic Karlsson
Keyword(s):  
Surface Integrity ◽  
Milling Process ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Milling Operations ◽  
Milling Operation ◽  
Machining Allowance ◽  
Rough Milling

The planned material volume to be removed from a blank to create the final shape of a part is commonly referred to as allowance. Determination of machining allowance is essential and has a great impact on productivity. The objective of the present work is to use a case study to investigate how a prior rough milling operation affects the finish machined surface and, after that, to use this knowledge to design a methodology for how to assess the machining allowance for subsequent milling operations based on residual stresses. Subsequent milling operations were performed to study the final surface integrity across a milled slot. This was done by rough ceramic milling followed by finish milling in seven subsequent steps. The results show that the up-, centre and down-milling induce different stresses and impact depths. Employing the developed methodology, the depth where the directional influence of the milling process diminishes has been shown to be a suitable minimum limit for the allowance. At this depth, the plastic flow causing severe deformation is not present anymore. It was shown that the centre of the milled slot has the deepest impact depth of 500 µm, up-milling caused an intermediate impact depth of 400 µm followed by down milling with an impact depth of 300 µm. With merged envelope profiles, it was shown that the effects from rough ceramic milling are gone after 3 finish milling passes, with a total depth of cut of 150 µm.

A novel online chatter detection method in milling process based on multiscale entropy and gradient tree boosting

2020 ◽  
Vol 135 ◽  
pp. 106385 ◽  
Author(s):  
Kai Li ◽  
Songping He ◽  
Bin Li ◽  
Hongqi Liu ◽  
Xinyong Mao ◽  
...  
Keyword(s):  
Detection Method ◽  
Milling Process ◽  
Multiscale Entropy ◽  
Chatter Detection

scholarly journals Mathematical model for determination of the most advantageous conditions for formation of parts of aerospace engineering on the operations of the end milling

2018 ◽  
Vol 224 ◽  
pp. 01111
Author(s):  
Dmitriy L. Skuratov ◽  
Dmitriy V. Evdokimov ◽  
Dmitriy G. Fedorov
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
End Milling ◽  
Inequality Constraints ◽  
Milling Process ◽  
Linear Inequality Constraints ◽  
Milling Operations ◽  
Constraint Inequalities ◽  
Cutting Zone

A mathematical model has been introduced for determining the most advantageous conditions for parts formation when end milling operations. This model consists of a linear objective function and linear inequality constraints and takes into account the kinetics of thermal processes in the cutting zone. The equation determines the processing time was used as the objective function and constraint inequalities are related with the functional parameters and the parameters of the milling process and determines the quality of the machining.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

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