Machinability of Rolled Aluminum using Advanced Coated Cutting Tools and its Characterization

Because of multiple properties like higher values of corrosion resistance, formability, weldability along with greater structural utility aluminum alloys are generally gaining more and more demand in industries and household. With this the requirement for searching of higher quality cutting tool to machine aluminum is also growing. Here different cutting tools like MTCVD+TiCN+Al2O3 , MTCVD+TiCN+Al2O3+TiOCN, MTCVD+TiN+TiCN+Al2O3+TiN, PVD AlTiN, cemented carbide (k-10) insert brazed with Polycrystalline Diamond and Polycrystalline Diamond Inserts are being used to machine rolled aluminum in dry condition and then comparative analysis are made. The cutting is of orthogonal type and capstan lathe is used for the same. Under different conditions of cutting the surface roughness along with morphology of chip are analyzed. Under constant depth of cut (doc) along with variable velocities and feed, the turning operation is performed. With SEM and XRD the identification including characterization of cutting tool were also performed. The polycrystalline diamond tool is found to give optimum surface finish, thin type of chip along with mirror like finish during machining operation.

Effect of lead on the machinability of brass alloys using polycrystalline diamond cutting tools

The international safety regulations are pushing the manufacturers of water systems and equipment to remove lead from material compositions due to the potential human hazard of lead absorption. The usage of green lead-free brass alloys is becoming mandatory in many important markets, demanding the manufacturers to quickly adapt their production techniques both casting and machining to this new reality. Regarding machining, lead has been used to facilitate the chip control, working as a natural chip breaker and reducing the tool wear. Therefore, the reduction of lead composition in brass alloys contributes to a machinability decrease of the materials leading to higher cutting forces, long chips and higher tool wear. This work focuses on the machinability characterization of three different brass alloys (leaded, medium-leaded and minimally leaded) by means of cylindrical external turning process with polycrystalline diamond inserts. A parametric study covering three different depths of cuts, three feed rates and four cutting speeds was conducted for three brass alloys with two repetitions. Cutting forces, chip morphology and surface roughness were analysed and compared between alloys. Complementary microstructural and mechanical characterization of the alloys were performed. Analysis of variance was performed to analyse the results. Cutting forces, power consumption, specific cutting pressure, roughness and chip morphology identification were used as comparison criteria among the tested materials. Results have demonstrated the decrease of machinability with the lead reduction, with higher cutting forces and longer chips. Polycrystalline diamond tools used in this work could be a good option to overcome the machinability challenges of the lead-free brass alloys.

Feature extraction on an intelligent polycrystalline diamond insert clock testing method and prediction of product performance

Increasing applications of polycrystalline diamond inserts in rock drilling is visibly seen as the discovery of new oil wells and tunnelling projects for metro lines are on a continuous rise around the world. As a result, the market consumption of polycrystalline diamond inserts is increasing severely. However, the sudden increased requirement of polycrystalline diamond inserts has also triggered a global competition as new players are increasing each day. The prevailing situation offers a dynamic challenge to the manufacturers to successfully stay in the business, and hence, enhancing product quality has become an essential requirement. In other words, to stay competitive and to remain ahead of the pack, it is critical to build up innovative testing capabilities of the polycrystalline diamond insert so as to pre-empty the undesirable functional characteristics of the polycrystalline diamond insert as well as to proactively engage the production floor for ensuring high product quality. This manuscript unveils a developed intelligent polycrystalline diamond insert testing platform that would link the failure characteristics of the polycrystalline diamond insert to the fracture mechanics through the study of process digitisation of the tool–work interface. An experimental set-up was developed, which incorporates a dynamometer, acoustic emission and accelerometer, for the digitisation of data signals in a feature extraction engine. The feature extraction engine in turn is used to monitor the failure of polycrystalline diamond cutting inserts during machining. The raw data fed through the feature extraction engine were used to identify the progression of failure in terms of flank wear or tool life for the polycrystalline diamond cutting inserts. The system comprises three key elements, which are (a) sensing and conditioning, (b) information extraction and (c) performance and failure analysis. The results of this experiment build the feature extraction engine that tracks the progression of flank wear in the polycrystalline diamond cutting inserts with reasonable accuracy. Furthermore, the break-in testing of a randomly selected insert from the production floor was applied to the feature extraction engine platform to predict the produce performance. This method also alerts the in-process manufacturing stages and enabled to considerably reduce the production scrap of polycrystalline diamond inserts.

Machining Characteristics of High Speed Dry Milling of Biodegradable Magnesium-Calcium Alloy

Metallic degradable biomaterials have attracted a huge attention lately for orthopedic fixation applications. Binary magnesium and calcium (Mg-Ca) alloys have emerged as a promising choice in terms of biocompatibility to avoid stress shielding and provide sufficient mechanical strength. In this paper, efficient and ecologic machining of a lab-made Mg-Ca alloy with 0.8 wt% calcium, cutting speeds of up to 47 m/s, and without coolant are investigated. Polycrystalline diamond inserts are applied and the possibilities of flank built-up formation, chip ignition, and tool wear are sought during the cutting experiments with the aid of a developed on-line, optical monitoring system. Chip morphology characteristics produced by different combinations of cutting parameters, i.e. cutting speed, feed, and depth of cut are studied.