Non-cutting Tool Research Articles

A parameter-variant trochoidal-like tool path planning method for chatter-free and high-efficiency milling

Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling. However, the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths. To address these issues, this paper introduces a parameter-variant trochoidal-like (PVTR) tool path planning method for chatter-free and high-efficiency milling. This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step. Initially, the nonlinear equation for the PVTR toolpath is established. Then, a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle. The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process. Finally, several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.

A Novel Modification to the Incremental Forming Process, Part 1: Multi-directional Tooling

Incremental forming (IF) is a novel sheet material forming technique, which has the ability to eliminate the need for die sets. The IF method forms sheet material by use of a non-cutting tool, which gradually deforms the sheet material into the desired shape. In the following works, this research proposes a range of novel tool geometries that allows forming of the sheet material in multiple directions at a rapid rate, allowing for greater formability, improved surface finish, and reduced springback. Additionally, several tool features are proposed which achieve this forming motion. Part 1 of this research describes the design of the tooling, as well as variations that are possible with the tool's geometry. In part 2 of this research, the proposed forming method is validated.

A Novel Modification to the Incremental Forming Process, Part 2: Validation of the Multi-directional Tooling Method

Incremental forming (IF), a novel sheet material forming technique which has the ability to eliminate the need for die sets, forms sheet material through the use of a non-cutting tool that gradually deforms the sheet material into the desired shape. Generally, the shape of the tool tip is a hemisphere.In the following works, the authors validate a novel tool shape, presented in Part 1 of this research, that allows forming of the sheet material in multiple directions at a rapid rate. The works described herein demonstrate that a more complex tool tip can result in greater formability, improved surface finish, and reduced springback. The tested tool tip shape described herein is that of two hemispherical tips, revolved about a common radius from a single axis, vertically offset to half of the tool path's step size.

Rule and branch-and-bound algorithm based sequencing of machining features for process planning of complex parts

The machining sequence of machining features is vital to achieve efficient and high quality manufacturing of complex NC machining parts. In most feature-based process planning system, the machining features are sequenced as the lowest level unit. However, a single machining feature of complex parts such as aircraft structural parts is usually machined by multiple machining operations. The one-to-many mappings between the machining features and the machining operations cause the increase of the non-cutting tool path. In order to solve this problem, some types of machining features of complex parts are decomposed into several sub-machining features that are associated with a single machining operation individually according to the rules which are abstracted from the machining process of complex parts. Benefitting from the decomposition, the sub-machining features from different machining feature can be assembled into a sub-machining feature in order to avoid the cutting tool marks. The different types of sub-machining features are sequenced in the light of some rules which are also extracted from the machining process of complex parts. And the branch-and-bound algorithm are employed to sequence the same type sub-machining features to minimum the non-cutting tool path. A pilot feature-based process planning system has been developed based on this research, and has been used in some aircraft manufacturers in China.

Features of ensuring the accuracy of coordinated dimensions when using typical flow sheets

When developing any design it is mandatory to carry out dimensional analysis of all design solutions. The main aspect in this case is primarily calculating output parameters coordinated dimensions of the hole. Two typical flow sheets: cutting tool guiding and noncutting tool guiding are investigated. Analytical dependences for calculating the accuracy of coordinated dimensions for typical flow sheets are presented in the paper. Dependences for determining the interaxle dimension, dimension from the base, positional variation are proposed. The specific weight of the components of the geometric error in the non-cutting tool-guiding and cutting tool-guiding flow sheets is determined. Calculated values of total processing error using modular machine tooling are defined. Studies have shown that the accuracy of coordinating dimensions and positional variations depends on the total geometric accuracy of machine flow sheet elements and total elastic deformations. This will allow to set the optimum accuracy of processing major parts, defining the output geometric parameters of modular machines and select the desired assembly method.

Modeling and controlling of surface micro-topography feature in micro-ball-end milling

The machined surface micro-topography has a great influence on the surface quality and the surface function. A simulation algorithm of machined surface topography is present in this paper, in which the influence of the tool vibration is considered. From the overall surface texture formation, surface texture interval, surface texture height, and surface texture direction, the geometric characteristics of surface micro-topography in micro-milling was defined and investigated. The influence of process parameters, especially the initial phase angle of cutter and the tool vibration, on the geometric characteristics of surface micro-topography is investigated, and the method to control the process parameter is proposed. Especially, this paper presents a novel method, through the planning of noncutting tool path, to control the initial phase angle of cutter which has significant effect on surface topography. The experiments shows that the control deviation of the surface texture direction is less than 2°, and the machined surface topography consistent with the simulation result, which means that the modeling and controlling of surface topography is feasible and effective.

Process definition of preformed part machining for taking benefit of parallel kinematic machine tool kinematic performances

In the automotive or aeronautical industries, few parallel kinematic machine tools (PKM) are used in high-speed machining (HSM). However, the dynamics of these machine tool structures could be relevant for HSM since their acceleration potential is much higher than serial kinematic machine tools. However, a particularity of PKM is to have kinematic performances depending on the tool pose in the machine workspace. Thus, this paper proposes a method to increase the productivity of performed part machining with PKM by taking advantage of their kinematic performances, with the aim of decreasing the time of the non-cutting tool movements. Process parameters defined by this method are the machined part setup, the planning of the machining operations, the control of potential redundant axis and the definition of the tool paths between cutting operations. The developed method is achieved in four successive steps based on a modelling of the kinematic behaviour of a given PKM. Each step leads to define one of the process parameters with regard to the decrease of non-cutting time. Thus, this method only requires common optimization algorithms that increase it robustness and its adaptability to different structures of PKM. It is illustrated with drilling operations on preformed parts with the Tripteor X7 machine tool developed by the PCI-SCEMM Company.

Optimization of Non-Cutting Tool Paths

The focus of CAM systems is on effectively creating cutting tool paths. However, collision risk is very high on multi axes machines when performing non-cutting traverse moves. If available, CAM systems offer limited setting options for non-cutting tool moves. In this paper an approach is presented that allows to automatically generating non-cutting tool paths. Process planners will not only be released from developing and simulating time-consuming multi axes traverse moves. The automatically calculated traverse moves will also machine-specifically optimized with respect to various optimization criteria.

Analysis on multiple sets of feature-based tool paths for prismatic machining parts

In a typical feature-based model, a set of features is used in both part description and tool path generation for the purpose of linking CAD and CAM. However, in a part with feature interactions, there may exist multiple sets of features to represent the same part. The multiple sets of features represent multiple ways to interpret the part geometry. From the machining point of view, the multiple sets of features represent different ways for machining the same part. Since the part can be produced by machining various sets of features, additional analysis and evaluation are required to find a 'good' set of features for representation and machining. This research develops a systematic method to analyse the multiple sets of features from the machining point of view. First, the cutting tool path inside a feature and the non-cutting tool path between features are identified. Tool path generation methods are developed for different types of predefined features. As a result, a set of tool paths for machining a set of features can be determined. Finally, the multiple sets of tool paths associated with the multiple sets of features can be obtained. The multiple sets of tool paths are evaluated based on the difference in length and time. In summary, a set of features that can be machined with a shorter tool path is considered better. The parts considered in this research are three-dimensional prismatic machining parts to be machined on a three-axis NC milling or machining centre. The prismatic machining features include steps, slots, blind steps, blind slots and pockets. The boundary representation data of the part are input to an implemented software system for analysis. The result can be used to evaluate the alternate process plans from the machining point of view for the purpose of better integration of CAD and CAM.

Feature-based noncutting tool path selection : Jong-Yun Jung and Rashpal S. Ahluwalia, pp. 165–176

Feature-based noncutting tool path selection : Jong-Yun Jung and Rashpal S. Ahluwalia, pp. 165–176

Feature-based noncutting tool path selection

Abstract This paper describes feature-based noncutting tool path selection using integer programming (IP). The IP approach provides an optimum tool travel sequence while avoiding multidispatch of tools. The paper also describes the tool dispatching sequence, tool visiting sequence, and IP constraints for manufacturing features. The noncutting tool path is compared with the cutting tool path to select the shortest possible total tool path.

Stylus type touch probe system

A non-cutting tool or stylus (32), mounted in a position where a tool normally resides on a turret (26) of a numerically controlled machining system, rubs against the workpiece (41) as it rotates. The rubbing vibrations emanating from the workpiece (41) are picked up as a touch signal by an accelerometer (62) whose output signal is conditioned and fed to the numerical control (46). Diameter measurements, for example, are made directly by touching two opposing points on the workpiece (41) on opposite sides of the machine centerline (14) whereupon a difference calculation is made to provide the required diameter measurement.