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Machine Tools
Published in David A. Stephenson, John S. Agapiou, Metal Cutting Theory and Practice, 2018
David A. Stephenson, John S. Agapiou
A flexible transfer line (FTL) is a production system designed for high-volume production, which is capable of producing a family of similar parts with unplanned changes or additional machined content. The life cycle of individual parts can vary from a few to several years as long as there is sufficient flexibility to fully utilize the system for 10–15 years. Such systems allow new products of the same family to be introduced quickly without major retooling. The changeover time between different products is usually a few hours, depending on the number of workstations involved and the available flexibility. Flexible transfer machines are well suited to applications in which a few similar parts are required in high volumes (e.g., >50,000/year), as is often the case in automotive powertrain and component production. Flexible transfer lines require a significant initial investment premium compared to conventional transfer machines and still require accurate part planning and market forecasts to operate economically. Currently, flexibility is commonly accomplished by using machining stations with indexable heads (turrets) or shuttle heads, each fitted with a number of different tools. CNC machines have also been used in FTLs, making them similar to the agile production systems described in the next section, although machine layout (serial vs. parallel) is generally different from that in an agile cell. In addition to requiring a significant premium in initial investment, flexible systems increase machine structural and fixture complexity and often required tooling and gaging inventories.
On the machinability of selective laser melted duplex stainless steels
Published in Materials and Manufacturing Processes, 2022
Karl Peter Davidson, Guy Littlefair, Sarat Singamneni
Drilling experiments were conducted on a Fanuc Tape drill mate Model T compact CNC machining center with the samples held in a two-piece jig. For the torque measurements, the sample holding jig was fixed on a Kistler 9272 four component dynamometer. Glass insulated E-Type thermocouples 0.25 mm in diameter are inserted into the aforementioned holes and are connected to a Measurement Computing USB-2416 data logger for recording the temperature variation with time at different locations along the length of the drilled hole. Two drill designs with 10 mm in diameter were used in this study, 1) indexable insert head and 2) solid carbide drills. An Iscar Sumocham DCN 100–050-16A-5D indexable head body and the TiAlN PVD coated Sumocham ICM 100 IC908 insert were used for the stage 1 machining trials depicted in Fig. 1. The same tools are also used in the evaluation of the machinability of SLM samples processed with varying laser energy densities. For all the machining trials involving comparative assessments between the wrought bar stock and the SLM samples, the insert-type drill bits used repeatedly, with each insert employed for two or more successive machining trials, due to the high costs involved in the tooling. This may have induced some uncertainty in these results, as the responses from all the trials are not from fresh tools with sharp cutting edges. Also, one of the drill bodies failed with one of the elevated speed case and so, a replacement body was procured and used for the remaining trials in this set.
A review on cryogenic treatment of tungsten carbide (WC-Co) tool material
Published in Materials and Manufacturing Processes, 2021
Ramji et al.[85] investigated the effectiveness of cryo-treatment on indexable drilling tools in machining cast iron. They have observed that cryogenically treated (CT) and cryogenically treated with dual tempered (CTT2) tools displayed lesser forces, higher life, and lower surface roughness. They have ascribed the performance improvement to the formation and precipitation of fine eta-carbides. Cryo-processed carbide drills exhibited lesser tool wear than the as-sintered tools in machining 304SS and CFRP material under identical machining conditions.[80,106]
Judging of machining feasibility and calculation of midsection for the five-axis milling of shrouded centrifugal impeller
Published in Journal of Industrial and Production Engineering, 2020
Hong-Zhou Fan, Yan-Long Cao, Guang Xi
As a kind of trough type part, the unshrouded centrifugal impeller was the most widely used centrifugal impeller in recent years, and a series of achievements about numerically controlled machining of unshrouded impeller was made [6–8]. Chu et al. [9,10] focused on the five-axis machining of an unshrouded centrifugal impeller with split blades, and proposed a novel tool-path generation method. The entire process was divided into the following four steps: rough milling, blade semi-finish milling, blade finish milling, and hub finish milling. Furthermore, the machining zone was split, recombined, and parameterized; and the high-efficiency tool paths were calculated and the novel five-axis machining of unshrouded centrifugal impeller with split blades was achieved. Zhu et al. [11,12] proposed a simultaneous optimization method for tool path and shape for the five-axis flank milling of unshrouded centrifugal impeller. New algorithm was presented; new cutters such as conical cutter and barrel cutter were used; tool path and shape were optimized; and the optimized five-axis flank milling method of unshrouded centrifugal impeller was successfully achieved. Wu et al. [13,14] focused on the high-efficiency machining with the non-orthogonal four-axis machine tool. The collision and interference correction for impeller machining were obtained, the tilt angle of indexable table was optimized, and the high-efficiency machining of unshrouded centrifugal impeller with non-orthogonal four-axis machine tool was completed. Sun et al. [15,16] focused on the thin-walled parts, and a predictive modeling of chatter stability considering force-induced deformation effect in milling was proposed and the chatter was well predicted. Furthermore, a kinematics performance-oriented smoothing method was proposed to plan tool orientations and the geometrically interference-free and kinematically smoother tool orientations were effectively generated.