An Accurate Method for Determining Cutter-Workpiece Engagements in Five-Axis Milling With a General Tool Considering Cutter Runout

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Zhou-Long Li ◽  
Li-Min Zhu
Keyword(s):  
Axial Compressor ◽  
Accurate Method ◽  
Milling Process ◽  
Cutter Runout ◽  
Common Intersection ◽  
The Common ◽  
Five Axis ◽  
Contact Arc ◽  
2D Space ◽  
General Tool

Cutter runout is universal and inevitable in milling process and has a direct impact on the shape of the in-process geometry. However, most of the works on the cutter-workpiece engagement (CWE) extraction neglect the cutter runout impact, which will result in a loss of precision. In this paper, an accurate method is presented to obtain CWE boundaries in five-axis milling with a general tool integrating the cutter runout impact. First, each flute's rotary surface is analytically derived. Then, by intersecting the section circle corresponding to the current flute with each of the rotary surface formed by previous flutes, a set of candidate feasible contact arcs (CFCAs) are obtained, and the valid feasible contact arc (VFCA) is defined as the common intersection of these CFCAs. Next, by intersecting the VFCA with the workpiece surfaces, the partial arc which locates inside the workpiece volume is extracted as the engagement arc. Finally, the CWE map is plotted by mapping a set of engagement arcs to a 2D space. To validate the proposed method, the CWE maps with/without integrating the cutter runout impact in five-axis milling of an axial compressor blisk are extracted and compared. The results reveal that the shape of CWE boundaries is changed a lot owing to the cutter runout impact. A cutting force comparison experiment has been carried out to show that the proposed method will lead to higher prediction accuracy especially in the finish milling process with low immersion angle.

Experimental investigation of the influence of cutting parameters on surface quality and on the special characteristics of micro-milled surfaces of hardened steels

2021 ◽  
pp. 095440622110130
Author(s):  
Barnabás Zoltán Balázs ◽  
Márton Takács
Keyword(s):  
Surface Quality ◽  
Surface Profile ◽  
Cutting Parameters ◽  
Relevant Information ◽  
Milling Process ◽  
Micro Milling ◽  
Machined Surface ◽  
Analysis Of Dynamics ◽  
Five Axis ◽  
Coated Carbide

Micro-milling is one of the most essential technologies to produce micro components, but due to the size effect, it has many special characteristics and challenges. The process can be characterised by strong vibrations, relatively large run-out and tool deformation, which directly affects the quality of the machined surface. This paper deals with a detailed investigation of the influence of cutting parameters on surface roughness and on the special characteristics of micro-milled surfaces. Several systematic series of experiments were carried out and analysed in detail. A five-axis micromachining centre and a two fluted, coated carbide micro-milling tool with a diameter of 500 µm were used for the tests. The experiments were conducted on AISI H13 hot-work tool steel and Böhler M303 martensitic corrosion resistance steel with a hardness of 50 HRC in order to gain relevant information of machining characteristics of potential materials of micro-injection moulding tools. The effect of the cutting parameters on the surface quality and on the ratio of Rz/ Ra was investigated in a comprehensive cutting parameter range. ANOVA was used for the statistical evaluation. A novel method is presented, which allows a detailed analysis of the surface profile and repetitions, and identify the frequencies that create the characteristic profile of the surface. The procedure establishes a connection between the frequencies obtained during the analysis of dynamics (forces, vibrations) of the micro-milling process and the characterising repetitions and frequencies of the surface.

An accurate instantaneous uncut chip thickness model combining runout effect in micro-milling using cutters with the non-uniform helix and pitch angles

2019 ◽  
Vol 234 (5) ◽  
pp. 859-870 ◽  
Author(s):  
Qiang Guo ◽  
Yan Jiang ◽  
Zhibo Yang ◽  
Fei Yan
Keyword(s):  
Tool Path ◽  
Chip Thickness ◽  
Milling Process ◽  
Machining Process ◽  
Micro Milling ◽  
Cutter Runout ◽  
Model Combining ◽  
Key Factor ◽  
Cutting Point ◽  
Instantaneous Uncut Chip Thickness

As a key factor, the accuracy of the instantaneous undeformed thickness model determines the force-predicting precision and further affects workpiece machining precision in the micro-milling process. The runout with five parameters affects the machining process more significantly compared with macro-milling. Furthermore, modern industry uses cutters with non-uniform pitch and helix angles more and more common for their excellent properties. In this article, an instantaneous undeformed thickness model is presented regarding cutter runout, variable pitch, and helix angles in the micro-milling process. The cutter edge with the cutter runout effect is modeled. Then, the intersecting ellipse between the plane vertical to the spindle axis and the cutter surface which is a cylinder can be gained. Based on this, the points, which are used to remove the material, on the ellipse as well as cutter edges are calculated. The true trochoid trajectory for each cutting point along the tool path is built. Finally, the instantaneous undeformed thickness values are computed using a numerical algorithm. In addition, this article analyzes runout parameters’ effects on the instantaneous undeformed thickness values. After that, helix and pitch angles’ effects on the instantaneous undeformed thickness are studied. Ultimately, the last section verifies the correctness and validity of the instantaneous undeformed thickness model based on the experiment conducted in the literature.

Triangulating Topological Spaces

1997 ◽  
Vol 07 (04) ◽  
pp. 365-378 ◽  
Author(s):  
Herbert Edelsbrunner ◽  
Nimish R. Shah
Keyword(s):  
Homotopy Equivalent ◽  
Topological Spaces ◽  
Sufficient Condition ◽  
Voronoi Cells ◽  
Delaunay Complex ◽  
Common Intersection ◽  
Finite Set ◽  
The Common ◽  
Nerve Theorem

Given a subspace [Formula: see text] and a finite set S⊆ℝd, we introduce the Delaunay complex, [Formula: see text], restricted by [Formula: see text]. Its simplices are spanned by subsets T⊆S for which the common intersection of Voronoi cells meets [Formula: see text] in a non-empty set. By the nerve theorem, [Formula: see text] and [Formula: see text] are homotopy equivalent if all such sets are contractible. This paper proves a sufficient condition for [Formula: see text] and [Formula: see text] be homeomorphic.

Performance of Tools Design when Helical Milling on Carbon Fiber Reinforced Plastics (CFRP) Aluminum (Al) Stack

2013 ◽  
Vol 465-466 ◽  
pp. 1075-1079 ◽  
Author(s):  
Erween Abdul Rahim ◽  
Z. Mohid ◽  
M.R. Hamzah ◽  
A.F. Yusuf ◽  
N.A. Rahman
Keyword(s):  
Milling Process ◽  
Helical Milling ◽  
Machining Parameters ◽  
Reinforced Plastics ◽  
Comparable Performance ◽  
Hole Making ◽  
Milling Characteristics ◽  
The Common ◽  
Fiber Reinforced Plastics

Hole making process is not strictly to the drilling technique where others machining could also influence to the quality in CFRP hole.Therefore, helical milling process becomes as an alternative method to produces bore on CFRP plate thus minimizing the defects. The common defects on CFRP are delamination, splintering and cracking. Meanwhile, if the CFRP stacking together with aluminum plate, burr at exit hole of aluminium plate is produced. Therefore, it is essential to control the critical machining parameters to assure a good quality of the hole. The main objective of this project is to improve the hole quality of CFRP/AL stack in terms of surface roughness using helical milling technique. In addition the cutting force and temperature will be measured as well. There are three levels of cutting speeds; two levels of feed rate and depth per helical path are made accordingly to helical milling characteristics. It was found that all tool design exhibit comparable performance for helical milling process on CFRP/Al stack.

On the Use of Problem-Specific Candidate Generators for the Hybrid Optimization of Multi-Objective Production Engineering Problems

2009 ◽  
Vol 17 (4) ◽  
pp. 527-544 ◽  
Author(s):  
K. Weinert ◽  
A. Zabel ◽  
P. Kersting ◽  
T. Michelitsch ◽  
T. Wagner
Keyword(s):  
Pareto Front ◽  
Mold Temperature ◽  
Milling Process ◽  
Production Engineering ◽  
General Applicability ◽  
Multi Objective ◽  
Conflicting Objectives ◽  
Objective Space ◽  
Engineering Problems ◽  
Five Axis

In the field of production engineering, various complex multi-objective problems are known. In this paper we focus on the design of mold temperature control systems, the reconstruction of digitized surfaces, and the optimization of NC paths for the five-axis milling process. For all these applications, efficient problem-specific algorithms exist that only consider a subset of the desirable objectives. In contrast, modern multi-objective evolutionary algorithms are able to cope with many conflicting objectives, but they require a long runtime due to their general applicability. Therefore, we propose hybrid algorithms for the three applications mentioned. In each case, the problem-specific algorithms are used to determine promising initial solutions for the multi-objective evolutionary approach, whose variation concepts are used to generate diversity in the objective space. We show that the combination of these techniques provides great benefits. Since the final solution is chosen by a decision maker based on this Pareto front approximation, appropriate visualizations of the high-dimensional solutions are presented.

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