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What Is This Thing Called Lean Manufacturing?
Published in Bob Sproull, Theory of Constraints, Lean, and Six Sigma Improvement Methodology, 2019
The next step in the process is referred to as interior turning and, again, there are two interior turning machines labeled B1 and B2, one on each side. In the third step, there were two possible choices for drilling, C1 and C2. After the pinion was automatically inspected for cracks (with one, common automated gage), it then progressed to one of two hobbing machines, D1 and D2. The parts were then collected in storage bins and sent as large batches to an outside vendor for heat treatment. Upon return from heat treatment, the pinions then proceeded to hard hobbing, E1 and E2, and then on through the remainder of the process as indicated in Figure 2.5. Hobbing is a machining process used for gear cutting, cutting splines, and cutting sprockets on a hobbing machine, which is a special type of milling machine. The teeth or splines are progressively cut into the workpiece by a series of cuts made by a cutting tool called a hob. Compared with other gear forming processes, it is relatively inexpensive but still quite accurate, thus it is used for a broad range of products.
Gear Cutting/Manufacturing
Published in Zainul Huda, Machining Processes and Machines, 2020
A hobbing machine has two non-parallel spindles: one spindle is mounted on a workpiece (e.g. gear blank) and the other spindle is mounted on the hob. Hobbing machines are characterized by the largest “module” or pitch diameter it can generate. There are mainly two types of gear hobbing machines: (a) horizontal hobbing machines and (b) vertical hobbing machines. Horizontal hobbing machines have the gear-blank spindle mounted horizontally; they are usually used for cutting longer workpieces i.e. cutting splines at the end of a shaft. In vertical hobbing machine, the gear blank spindle is mounted vertically (see Figure 10.10). Most hobbing machines are vertical hobbers; the vertical hobbing machines can produce all types of pinions and gears/gear wheels.
Gear-Cutting Machines and Operations
Published in Helmi Youssef, Hassan El-Hofy, Traditional Machining Technology, 2020
Hobbing is a gear-generation method most widely used for cutting teeth in spur gears, helical gears, worms, worm wheels, and many special forms (Figure 6.8). Hobbing machines are not applicable to cutting bevel and internal gears. The tooling cost for hobbing is lower than for broaching and multiple-tool shaping heads. For this reason, hobbing is used in low-quantity production or even for a few pieces. Compared with milling, hobbing is fast, accurate, and therefore suitable for medium- and high-quantity productions. The hob is a fluted worm of helix angle α with form-relieved teeth that cut into the gear blank in succession. A simplified gear train of a hobbing machine is shown in Figure 6.9.
Analysis method for factors influencing gear hobbing quality based on density peak clustering and improved multi-objective differential evolution algorithm
Published in International Journal of Computer Integrated Manufacturing, 2021
You Guo, Ping Yan, Dayuan Wu, Han Zhou, Yancheng Shi, Runzhong Yi
To verify the validity of the characteristic process parameters that affect the quality of hobbing, through the actual processing of 92 gears, the actual machined gears are quality inspected under the guidance of the relatively independent hobbing quality inspection parameters Dk obtained from section 3.2, and record the process parameters and Dk. Members of the laboratory research team conducted research on the quality prediction of hobbing based on the characteristic process parameters obtained in this paper. Based on the adaptive and variational inference algorithms, an adaptive Gaussian mixture regression model (AVIGMR) for hobbing machining error prediction that considers random perturbations is presented. AVIGMR can predict machining errors (quality inspection parameters) based on a given process parameter. This prediction model takes the hobbing characteristic process parameters obtained by the algorithm in this paper as input, and outputs the machining error of hobbing.
Capabilities evaluation of WSEM, milling and hobbing for meso-gear manufacturing
Published in Materials and Manufacturing Processes, 2018
Sujeet Kumar Chaubey, Neelesh Kumar Jain
Three MSBG were manufactured by milling and WSEM each and three MHG were manufactured by hobbing and WSEM each to evaluate their manufacturing capabilities. Austenitic stainless steel (SS 304) was selected as material for MSBG and MHG due to its non-magnetic nature, higher strength and very good resistance to corrosive environment which is commonly encountered in biomedical, food processing, pharmaceutical, chemical plants and domestic applications. Examination of its chemical composition revealed to have 18.04% Cr; 8.32% Ni; 1.08% Mn; 0.053% C; 0.48% Si; 0.017% S; 0.038% P; and balance Fe by weight. Table 2 presents specifications of MSBG and MHG along with details of machine tool, cutting tool and machining medium used in milling, hobbing and WSEM processes. Figure 1(a) depicts concept of manufacturing of MHG and MSBG on the computer numerical controlled (CNC) WSEM machine (model: Sprintcut Win from Electronica Machines Tools Ltd. Pune, India) on which deionized water was used as dielectric and 250 micron diameter brass wire as the cutting tool. It has capability to manufacture gears of maximum face width of 50 mm and inclination angle up to ±30° whose given value is achieved by moving the upper wire guide and keeping fixed the lower wire guide i.e., helical gears having helix angle up to 30° and bevel gears having cone angle up to 60° can be manufactured on it.
State space modelling carbon emission dynamics of machining workshop based on carbon efficiency
Published in International Journal of Computer Integrated Manufacturing, 2018
Hongcheng Li, Haidong Yang, Huajun Cao, Chengjiu Zhu
Taking a gear production workshop for example, an experimental study is carried out for modelling its carbon emission dynamics based on the proposed approach. The workshop has two production lines (A1 and A2) which are used to produce two types of gears. Gears with material 20CrMnTiH steel, teeth number 30, modulus 3.75 mm, spline modulus 2.5 mm, and weight 2.29 kg (blank weight 3.027 kg) are produced in production line A1. A1 includes seven processes, broaching spline, fine turning, hobbing, carburzing and quenching, grinding plane, gear grinding, and cleaning. Furthermore, each batch of 200 gears is heated for 450 min in a 160kW box type furnace in carburising process, and 20 min are required in cleaning process with 54kW equipment. Operation time and resource input information of individual process in line A1 are listed in Tables 2 and 4, respectively. Gears with material 45# steel, teeth number 35, modulus 3 mm, and weight 2.16 kg (blank weight 3.382 kg) are produced in production line A2. A2 also includes seven processes, rough turning, finish turning, hobbing, carburising heat treatment, grinding plane, grinding, and cleaning. Operation time and resource input information of individual process in line A2 are listed in Tables 3 and 5, respectively. In heat treatment process, the semi-finished gears are processed in the equipment with 160 kW rated power for 12 s, and the water-oil quenching is used for high frequency induction hardening.