Influence of Elastomer Layers in the Quality of Aluminum Parts on Finishing Operations
Open Access
- 21 February 2020
- Vol. 10 (2), 289
- https://doi.org/10.3390/met10020289
Abstract
In finishing processes, the quality of aluminum parts is mostly influenced by static and dynamic phenomena. Different solutions have been studied toward a stable milling process attainment. However, the improvements obtained with the tuning of process parameters are limited by the system stiffness and external dampers devices interfere with the machining process. To deal with this challenge, this work analyzes the suitability of elastomer layers as passive damping elements directly located under the part to be machined. Thus, exploiting the sealing properties of nitrile butadiene rubber (NBR), a suitable flexible vacuum fixture is developed, enabling a proper implementation in the manufacturing process. Two different compounds are characterized under axial compression and under finishing operations. The compression tests present the effect of the feed rate and the strain accumulative effect in the fixture compressive behavior. Despite the higher strain variability of the softer rubber, different milling process parameters, such as the tool feed rate, can lead to a similar compressive behavior of the fixture regardless the elastomer hardness. On the other hand, the characterization of these flexible fixtures is completed over AA2024 floor milling of rigid parts and compared with the use of a rigid part clamping. These results show that, as the cutting speed and the feed rate increases, due to the strain evolution of the rubber, the part quality obtained tend to equalize between the flexible and the rigid clamping of the workpiece. Due to the versatility of the NBR for clamping different part geometries without new fixture redesigns, this leads to a competitive advantage of these flexible solutions against the classic rigid vacuum fixtures. Finally, a model to predict the grooving forces with a bull-nose end mill regardless of the stiffness of the part support is proposed and validated for the working range.Funding Information
- Eusko Jaurlaritza (KK-2019/00051)
This publication has 44 references indexed in Scilit:
- Thin-Wall Machining of Light Alloys: A Review of Models and Industrial ApproachesMaterials, 2019
- A review of chatter vibration research in millingChinese Journal of Aeronautics, 2019
- Effect of cutting speed on the surface integrity of face milled 7050-T7451 aluminium workpiecesProcedia CIRP, 2018
- Analysis of Process Damping in MillingProcedia CIRP, 2016
- Vibration frequencies in stable and unstable millingInternational Journal of Machine Tools and Manufacture, 2015
- Chatter avoidance in the milling of thin floors with bull-nose end mills: Model and stability diagramsInternational Journal of Machine Tools and Manufacture, 2011
- A pole/zero cancellation approach to reducing forced vibration in end millingInternational Journal of Machine Tools and Manufacture, 2010
- Deformation prediction and error compensation in multilayer milling processes for thin-walled partsInternational Journal of Machine Tools and Manufacture, 2009
- The milling of airframe components with low rigidity: A general approach to avoid static and dynamic problemsProceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2005
- Analytical Prediction of Stability Lobes in MillingCIRP Annals, 1995