Modelling concave globoidal cam with indexing turret follower: A case study

Belokar

et al. 2019

Purpose This paper aims to propose an elementary approach towards the measurement of a globoidal cam profile used in an automatic tool changer (ATC) of computer numerical control (CNC) machines. Design/methodology/approach A simple and unique online method has been designed for the profile metrology of the cam. This simple methodology will replace the traditional methodology of profile metrology of cam by coordinate measuring machine (CMM). A globoidal cam with an indexable turret and roller follower (rotating in an enclosed track) has been evaluated in our analysis. This analysis plays a significant role in the performance determination of the cam as well as the ATC of CNC machines. Findings A novel model has been designed and implemented to investigate the profile of a globoidal cam. The proposed methodology becomes an enhancement over the old methodology, i.e. measurement through CMM. Theoretical analysis and practical implementation prove the significance of the method. Originality/value An enhanced methodology to effectively measure the globoidal cam profile has been proposed. The practical implication of the proposed methodology remains for the CNC machine tool and ATC manufacturers. Finally, analytical explorations have been carried out to prove the validity of the proposal.

Section: Introductionmentioning

confidence: 99%

Track-based analysis for profile generation on globoidal cam in automatic tool changer of CNC machining center

Belokar

et al. 2019

“…Domestic and international scholars have carried out many researches for the dividing error of globoidal cam, such as the reverse researches [1][2] [3] ; For the globoidal cam which is processed using equal channel manufacturing method, the effect of machining error has on dividing error is studied [4] . And the effect of profile tolerance have on dividing error of globoidal cam is also investigated [5][6] .…”

Section: Introductionmentioning

confidence: 99%

Evaluation Method Research on the Dividing Error of Globoidal Cam Based on Entropy Weights

Zhao¹,

Li²,

Dou³

et al. 2017

dtmse

The globoidal cam mechanism is the core of the tool changer in CNC machines. Its dividing error will directly affect the precision of the tool changer and the machining accuracy of CNC machines. To reduce the dividing error of globoidal cam, the key problem is establishing an evaluation method for its dividing error. Considering the unsound problems of the existing evaluation methods, this paper adopts the fuzzy comprehensive evaluation method based on entropy, and establish the evaluation indexes from lateral error indicators, longitudinal error indicators and the dynamic indicators this three aspects respectively. Then the dividing error of globoidal cam could be evaluated. Through the case analysis, the proposed evaluation method and indexes for the dividing error of globoidal cam in this paper are proved to be effective.

“…The research on Globoid indexing cam mechanism is mainly on structure-design, modeling and simulation, and manufacturing technique [1][2][3][4][5][6]. However, these studies did not involve the working width of globoid indexing cam.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Overlap Coefficient on Contact Behavior of Globoidal Indexing Cam Mechanism

Liu

Luo

Chang

et al. 2014

AMR

An method was proposed to derive the formula of the overlap coefficient and the influence of main parameters on overlap coefficient were also discussed; The load distribution is deduced and the rule of contact load varying with overlap coefficient was revealed; The results indicate that the increasing overlap coefficient can extend the time of rollers engaging, reducing the contact load of globoidal indexing cam mechanism and altering the load distribution.