Computer aided process planning (CAPP) is an important bridge between computer aided design (CAD) and computer aided manufacturing (CAM) in computer integrated manufacturing environment. Operation sequence generation is one of the most difficult tasks in CAPP. The aim of operation sequencing in CAPP is to determine the best order of machining operations with minimal manufacturing cost while satisfying all the precedence constraints. This paper presents a proposed method for optimizing operation sequence using modified clustering algorithm. The key concept of method is that the precedence constraints are firstly checked for selecting all possible next operations of the last operation in the sequence and their traveling costs are compared to choose the optimal feasible operation which has the minimum traveling cost in the sequence. Then, all operation sequences are calculated the total traveling cost for obtaining the optimal sequence result. Because of removing all unfeasible sequences at the beginning of procedure and selecting the optimal operation into sequence in each step, the time can be significantly reduced. The capability and performance of the proposed method are demonstrated in three specific case studies. The comparisons show that the proposed method can solve the problem in much lesser computational time while generating more alternate optimal feasible sequences than previous algorithms.

This paper proposed two imaginary planar rack-cutters to create a spherical gear pair with ring-involute teeth. The spherical gear pair can be used to a knee joint mechanism. The imaginary planar rack cutter consists of two kinds of conical tooth. One is convex conical teeth to create a spherical gear with concave ring-involute teeth; the other is concave conical teeth to create a spherical gear with convex ring-involute teeth. Based on two-parameter envelope theory and coordinate transformation matrix, the planar rack cutter with concave teeth or convex teeth can derive the mathematical model of the spherical gears with convex teeth or concave teeth, respectively. Through the obtained mathematical model, a computer-aided software package and a 5-axis CNC machine, the real prototype of the spherical gear is manufactured. The real prototype of the spherical gear is used to replace knee joint mechanism of a skeleton.

In this paper, a lexicographic bi-criteria food packing problem arising in actual packaging equipments is considered. Given a set I = {i | i = 1,2,...,n} of current n items (for example, n green peppers) with their weights w_i and priorities p_i, the problem asks to find a subset I′ (⊆ I) so that the total weight ∑_i∈I′ w_i is no less than a given positive t which denotes a target weight for each package, and it is minimized as the primary objective, and further the total priority ∑_i∈I′ p_i is maximized as the second objective. The problem has been known to be NP-hard, while it can be solved exactly in O(nt) time if all the input data are integral. In this paper, for a given real ε > 0, an O(n²/ε) time heuristic algorithm with rounded weights is proposed such that the heuristic total weight is at most (1 + ε) times the optimal total weight. Numerical experiments are also conducted to compare the proposed and known heuristic algorithms with rounded weights, and the results are reported.

The problem of developing a product acceptance determination procedure for multiple characteristics has attracted the quality assurance practitioners. Due to sufficient demands of consumers, it may not be possible to deliver the quantity ordered on time using the process based on one manufacturing line. So, in factories, product is manufactured using multiple manufacturing lines and combine it. In this manuscript, we present the designing of an acceptance sampling plan for products from multiple independent manufacturing lines using exponentially weighted moving average (EWMA) statistic of the process capability index. The plan parameters such as the sample size and the acceptance number will be determined by satisfying both the producer's and the consumer's risks. The efficiency of the proposed plan will be discussed over the existing sampling plan. The tables are given for industrial use and explained with the help of industrial examples. We conclude that the use of the proposed plan in these industries minimizes the cost and time of inspection. Smaller the sample size means low inspection cost. The proposed plan for some non-normal distributions can be extended as a future research. The determination of sampling plan using cost model is also interested area for the future research.

Transverse-flux motors are suitable for getting high torque density by increasing their number of poles owing to the independent coil design from the number of poles. However, these kinds of motors typically have a large amount of permanent magnets with increasing the number of poles. We have designed a transverse-flux motor with a consequent-pole rotor having almost half amount of magnets compared with conventional surface-mounted magnet rotors. Although this motor can generate comparably large average torque to the conventional motors, it has larger cogging torque. And, conventional skew structures, often applied to axially uniform motors, are generally effective for reducing the cogging torque by offsetting dominant harmonic components but cannot be applied to transverse-flux motors including our motor due to their axially non-uniform structure. This paper describes radially skewed armature cores, compatible to basic configuration of general transverse-flux motors, for the cogging torque reduction of our motor. Results of FEM magnetic analysis and its spectral analysis indicate that the most dominant harmonic component of the cogging torque reduces by 96%, and consequently, peak-to-peak value of the three-phase cogging torque reduces by 87%. These analysis results are almost agreed with experimental result, in which the most dominant harmonic component reduces by 86% and peak-to-peak value of the cogging torque can be approximately estimated to decrease by 82%. Therefore, the radial skew structure could be verified to effectively suppress the cogging torque of the transverse-flux motor.

On the tracing measurement system, which based on the double position sensitive detectors (PSDs), the position of the same moving point can be detected synchronously through two PSD sensors that have a certain distance. The point will be imaged on both PSDs, and two groups of plane coordinates will be obtained, then the spatial coordinates of the moving point will be obtained through coordinate transformation. To different measuring range, the double PSDs mounting plate on the tracing measurement system can adjust the space relative position of the PSDs, including relative swing angle, pitch angle and light heart relative distance, besides, it can hold its relative position, thus the mounting plate has five degrees of freedoms (DOFs) that can be adjusted. The design of many DOFs adjustable mounting plate is the key technology of the tracing measurement system which based on the double PSDs. The design of double PSDs mounting plate on the tracing measurement system (mainly includes four DOFs platform support and the support to adjust the positions of the PSD and the lens) was completed in this paper, and the designed plate met the design requirements.

During the tapping process, chip snarling at high cutting speeds is a major obstacle in the improvement of machining efficiency. A cut tap tool coated with nickel-phosphorus (Ni-P)/abrasive particle composite film reduced the chip curl diameter and prevented chip snarling under high cutting speed conditions (50 m/min). In this study, the local coefficient of friction at the sliding zone of the chip-tool interface was estimated on the basis of the sticking-sliding friction model and using the cutting torque and thrust force measured during the tapping process. In addition, the effects of the local coefficient of friction at the sliding zone on chip curl diameter and secondary shear zone thickness were analyzed to investigate the mechanism of preventing chip snarling when using tapping tools coated with composite film. Tapping tests were conducted using four tapping tools that were steam treated, TiCN film coated, Ni-P/cBN film coated, or Ni-P/SiC film coated. The workpiece material was a rolled structure steel. The cutting speeds were 10, 30, and 50 m/min. The results demonstrated that chip curl diameter decreased with an increase in the local coefficient of friction at the sliding zone. The local coefficients of friction for tapping tools coated with composite films (1.51-1.91) were higher than those for tapping tools with conventional surface treatments (1.35-1.58). The secondary shear zone thickness also increased with an increase in the local coefficient of friction at the sliding zone. These results indicated that the tapping tool coated with Ni-P/abrasive particle composite film provided a high local coefficient of friction at the sliding zone, which increased the secondary shear zone thickness and reduced the chip curl diameter.

Recently, the viewpoint of service has become widespread. In learning domains, service providers have been required to adopt the viewpoint and to provide values co-created by teachers and learners. However, production by a service provider means the generation of potential value, whereas usage by a service receiver implies the generation of real value. That is, a receiver creates value independent of the value generated by a provider. Indeed, value co-creation takes place in a joint sphere where providers and customers interact with each other. Thus, service providers must attempt to generate the potential value through service design and play a role of co-producer of the real value in the interactions between the providers and the receivers. In the current study, we developed an ontology to share the knowledge on value co-creation and the information related to the interactions between the providers and the receivers. In concrete terms, we proposed ontological descriptions of receiver states for sharing knowledge in learning service design, and conceptualized elements of consensus building and value co-creation, according to the conceptual model of value co-creation proposed in a previous study. In addition, concepts pertaining to academic emotions are also described to represent contents of consensus building. Then, we demonstrated instances of a consensus building, which is extracted from conversations during counseling by a teacher (mentor) and a learner. As a result, we obtained a metamodel for co-design processes in the learning service design, and a conceptual framework of the knowledge sharing on learning states including academic emotions by the ontological descriptions.

This paper describes a new method of molding micro parts using a mold which was manufactured by layering metallic foils and plates. Coolant channels are circulated uniformly under the mold surface, at a depth sufficiently close to the surface. Hence, the mold temperature can be kept uniform over the large area of inserts of both the movable and fixed die plates. Two stainless steel foils in which micro-gates and cavities are machined by electrical discharge machining, respectively, are layered on the insert of fixed die plate. The space between the insert of movable die plate and the stainless foils, called sheet runner, is first filled with resin due to injection. Thereafter, the micro-cavities are filled with resin through the micro-gates due to the pressure rise in the sheet runner. The air vent effect due to the layered structure helps the resin to fill the cavity smoothly. The process conditions under which polypropylene micro disk of 200μm in diameter and 60μm in thickness can be formed uniformly over the sheet runner area of 40mm by 50mm were obtained changing the injected resin volume, resin temperature, and gate size. Besides, micro lens 200μm in diameter and 50μm in thickness were formed using molds manufactured by electrical discharge machining and electrolyte jet machining.

The precision of mechanical equipment closely associated with parts manufacturing precision. This article mainly to realize the machine precision on the basis of low manufacturing accuracy of parts through the homogeneous coordinate transformation and the Taguchi theory. Firstly, using the homogeneous coordinate transformation to establish the transfer accumulation model of machine precision. Secondly, the mathematical model of three dimensional tolerance based on the new generation Geometrical Product Specification (GPS) is built. Thirdly, this paper establishes the tolerance matching model based on Taguchi method and Taguchi orthogonal table model to improve the machine assembly precision without increasing manufacturing cost. Finally, with the example of horizontal machining center to discuss the 3D deviation transmission accumulation model, through the comparison analysis between the random combination method and the Taguchi orthogonal table on controlling the accumulated deviation show that the control effect of the first group’s experimental scheme for Taguchi orthogonal table is worst, while the third group is best. In a word, building the best deviation combination scheme of statistical significance not only reduce the cost, but also improve the overall assembly quality and has a certain guiding significance for the actual production.

A composite motion eccentric helical curve-face gear pair consisting of a helical non-circular gear and an eccentric helical curve-face gear is put forward based on the combination of eccentric gear and curve-face gear. This new gear pair can implement the rotation of intersected axes as well as the movement of output axe. Based on the spatial coordinate transformation theory, the coordinate system of eccentric helical curve-face gear pair is obtained and the pitch curve of eccentric helical curve-face gear is designed. The meshing equation and the tooth surface equation of eccentric helical curve-face gear are derived based on the spatial gear engagement theory and the conjugate surface theory. By changing the different parameters of eccentric helical curve-face gear pair, the influencing factors and variation of transmission ratio, pressure angle and kinematics are analyzed. According to the motion relationship of the gears and the method of generation, the establishment of solid model for the eccentric helical curve-face gear is presented with the application of SolidWorks. Furthermore, the correctness of the design theory of eccentric helical curve-face gear pair is verified by using the motion simulation and the experimental verification.