Nowadays, in different industries, especially in the automotive industry, the use of lightweight materials such as aluminum alloys has been increased in order to reduce the weight of parts and fuel consumption. These alloys have low formability at room temperature. To overcome this problem, forming at elevated temperatures is proposed. In this paper, formability of 5052 aluminum alloy sheet under hydrodynamic deep drawing assisted by radial pressure process has been studied at the warm condition. Initially, after analyzing the effect of geometric parameters on thickness distribution and punch force, the effects of temperature, fluid pressure and punch speed on thickness distribution, punch force and limiting drawing ratio have been investigated. Also, the effects of forming temperature and punch speed on the minimum thickness of the workpiece have been studied using the Taguchi method. Based on the obtained results, higher temperature in warm isothermal and non-isothermal states leads to a decrease and increase in the part thickness, respectively, while higher punch speed helps in thickness improvement. It was found that the limiting drawing ratio increases with increasing temperature in nonisothermal state and with decreasing temperature in an isothermal condition. In addition, an increase in fluid pressure leads to a higher limiting drawing ratio. Review History: Received: 2017/06/23 Revised: 2017/10/13 Accepted: 2017/10/30 Available Online: 2017/11/05

Nowadays, due to the demand for lightweight construction and fuel consumption reduction, especially in automotive and aerospace industries, the use of aluminum alloys has drawn much attention. Nevertheless, poor formability at room temperature is the main drawback of using these alloys. To overcome the problem, the work material is formed at elevated temperatures. In the present paper, Hydrodynamic Deep Drawing assisted by Radial Pressure (HDDRP) process has been selected over other forming methods. The aim of the study is to investigate the applicability of this process in conjunction with warm forming. For this purpose, experimental and numerical attempts have been made on warm forming of flat-bottom cylindrical cups in isothermal condition. At first, a series of warm hydroforming experiments were performed to determine the effect of tool temperature and forming speed on the thickness distribution of the final part and on the required forming load. Then, a set of finite element analyses (FEA) were performed using ABAQUS explicit to extend the findings. The Response Surface Method (RSM) was then used to build the relationship between the input parameters such as temperature and forming speed, and output responses including minimum part thickness and maximum punch force. It is demonstrated that the required forming force was decreased with increase in punch speed and tool temperature. Additionally, minimum thickness of the part is increased with increasing temperature and decreasing punch speed. Studying the Limiting Drawing Ratio (LDR) revealed that elevating the forming temperature causes reduction in LDR, while rising the punch speed leads to a slight enhancement in it. For the evaluation of part dimensional changes after forming, springback analysis was done via studying the through-thickness hoop stress distribution. It is found that using warm isothermal HDDRP in high forming rate results in more uniform stress distribution and lower level of stress and so a better springback behavior.

Lubrication plays an important role in increasing efficiency of a machining operation when high temperature and friction are two major issues. In the current study, two various types of lubricant SAE10 oil and vegetable oil were tested in end milling of a steel St60 block and the results were compared with dry condition. To have a clear understanding of the lubrication effects, three different concentrations for each lubricant using proper solvent were made and surface roughness (Ra), machining power and tool wear were compared in three distinct machining conditions. These conditions differ in depth of cut and machining speed (in a constant feed rate) according to real application. Among the lubrication environments, SAE10 assisted machining in low spindle speed showed better results. Moreover, it was observed that dry machining and machining in presence of vegetable oil especially in the cases of cutting fluids with lower oil content in fairly high tool velocity lead to process productivity improvement. Finally, dry machining resulted in more wear on cutting tool.

Turning is deemed as one of the most fundamental processes of metal cutting in industry. The heat generated in the cutting zones during turning plays an essential role in the final workpiece quality and power consumption. The present work tried to elaborate the performance of a new cooling technique i.e. pre-cooling the workpiece integrated with a developed cutting fluid applied with minimum quantity cooling lubrication method. To do so, to produce the desirable eco-friendly and user-friendly cutting fluid, water mixed vegetable oil was combined with a little amount of anti-bacterial agent and a scented essence. To assess the machining parameters in question i.e. surface roughness, consumed machining power and chip formation as well as machining hazards, some tests were conducted on the hardened and tempered AISI 1045 steel. Based on the findings of the study, a great improvement was observed in terms of machining parameters as well as health and ecological-related issues. The better machining performance of the new method probably is mainly due to efficient penetration of the oil into the tool–workpiece interface and colder cutting zone when compared with the conventional machining. Also, compared to the straight oil, the new vegetable oil showed positive results in terms of controlling the growth of bacterial colony. It seems that the proposed combined cooling method may potentially enhance the productivity of cutting operations in terms of machining quality, costs, operator health and environmental protection.