Abstract: Forging and casting are the commonly used manufacturing methods for the blank part of complex parts, such as the compressor blade and engine casing. Their geometric shapes are usually complex and difficult to measure or model. Besides, blank parts of different batches usually show slight difference in terms of shape and material consistency. Therefore, the axial cutting depth for the first sequence of rough machining is not fully decided. As a consequence, the rough milling process can only be planned with conservative feed rate, which leads to long machining time. Aiming at improving machining efficiency for roughing process, a feed rate optimization method by combining the monitored cutting force in the whole milling process with off-line optimization is developed in this paper. Firstly, the paper presents an analytical force model to calculate the instantaneous milling force and recognize the actual axial cutting depth, and a cutting force analysis method to recognize optimizable cutting segments of a trajectory. Secondly, a linear interpolation algorithm is applied to divide the optimizable cutting segments by interpolating a number of monitoring points. After that, the maximum feed rate of each monitoring point is calculated according to actual machining condition. The optimal feed rate is achieved after restraining with the constraints and smoothing with the least squares algorithm. To validate the effectiveness of the developed optimization method, a machining experiment with milling a designed blank part was conducted. Compared with the constant feed rate method, the developed method saved machining time by 19.83%.

Abstract: Two- (2PTs) and three-part tariffs (3PTs) are widely used for selling goods, to compensate workers, and in procurement contracts. They are practical alternatives to complex nonlinear tariffs in on-demand services and technology industries and are more profitable than the restrictive per-unit and unlimited-use pricing. A 2PT imposes both a fixed (access) fee and a per-unit (usage) fee, and a 3PT generalizes it by bundling some free units (an allowance) into the fixed fee. Intuitively, bundling free allowance provides an additional lever to the firm, enabling it to charge differential marginal rates to improve profitability. However, designing a 3PT is a challenging problem, and the optimal solution is known only when the market has homogeneous consumers or two discrete segments. We advance theory about optimal 3PT design by developing a reformulation that simplifies the solution procedure for the general case and generates new theoretical and practical insights. Our analysis reveals, surprisingly, that when the market demand follows an increasing price elasticity (or, approximately, when consumer distribution follows an increasing hazard rate), the optimal 3PT outcomes are identical to optimal 2PT outcomes. This result generalizes to a menu of tariffs. By contrast, the free allowance in a 3PT may be truly impactful when market demand is multimodal or corresponds to distinct segments with sharp across-segment differences, or when consumers have certain tariff biases. Our results help explain how and when 3PT matters, and they can help managers make informed decisions about how to design and employ nonlinear pricing.

Abstract: In the numerical control machining of thin-walled parts, the quality and stiffness of the thin-walled structure will change continuously, due to the removal of the material. The cutting characteristics will also change significantly. One of the chatters in cutting process is a serious problem. Presently, the main solutions are to achieve steady cutting from the process route, the external process stiffness, the clamping scheme, the optimization of the dynamic parameters, and the adoption of new processes. In light of the chatter problem of thin-walled parts, it is based on the structural stiffness and modal finite element analysis of thin-walled workpiece. The allowance distribution state of thin-walled workpiece is determined and optimized in semi-finishing machining, based on eigenvalue sensitivity analysis method. The goal is to minimize the structural allowance, and the non-uniform allowance design method is achieved by optimizing the thickness of the grid allowance in the premise of ensuring its thin-walled stiffness and other modal characteristics. The goal of improving the process its own rigidity of the thin-walled parts is realized. Finally, the comparison of the experimental results between the uniform allowance process distribution and the non-uniform allowance process scheme is made. The results indicate that the non-uniform allowance of optimization program based on eigenvalue sensitivity can improve both the stiffness and the main modal frequency of the thin-walled structure, which can guarantee the stability of the cutting process.

Abstract: Currently, worn blade repair work, obtaining the target surfaces manually wastes too much time. To improve repair ability, an innovative adaptive repair strategy is proposed which covers pre-inspection, welding, and machining process. Different from finding repairing surface manually, the welded surface and machining surface are restructured with less manual intervention. The welded surface ensured enough material for subsequent machining is captured by extracting upper profile boundary surface of its design one. Furthermore, a target machining surface satisfied design requirements, machining allowance, and geometric continuity is restructured using an effective optimization method. To prove the availability of the proposed method in this paper, a compressor blade repair instance, including welded surface and machining surface optimization and simulation is demonstrated at last.

Abstract: Aerospace blade is the most important part for pneumatic performance with expensive material and cost. Precise NC machining after near-net forming is a trend for aerospace blade machining. If the billet cannot cover the machining surface, the localization is necessary before machining. Because of little machining allowance and various tolerance requirements, free-form surface localization of aerospace blade becomes a puzzle. Traditional free-form surface localization researches focused on finding an appropriate position for design surface to guarantee the enough machining allowance. Different from traditional free-form surface localization research, the form tolerance is considered in the localization optimization. The localization result needs to satisfy the machining allowance and tolerance requirements. To achieve this target, the characteristics of blade modeling and inspection are analyzed. And then, a tolerance constraint is introduced into localization to ensure that the machining surface could satisfy the tolerance requirements. The traditional localization method and the new method considering design tolerance are applied on a compressor blade localization, respectively. From a comparison, the necessity of form tolerance constraint is verified.

Abstract: The invention discloses a machining method of an special-shaped antenna housing with a deep blind hole. The machining method comprises the steps that 1, best fit is conducted on mechanical machining allowance of the antenna housing; 2, a supporting tool is mounted; 2, alignment is conducted on the antenna housing; 4, the exterior surface of the antenna housing is machined; and 5, the deep blind hole of the antenna housing is machined. According to the machining method, the machining precision of the special-shaped antenna housing with the deep blind hole is improved by adopting the supportingtool and standard reconstruction and an alignment method based on three-dimensional scanning.

Abstract: The invention discloses a machining method of a large-size wind tunnel compressor case. The machining method comprises the steps of scribing lines on pre-machined positions on the case; conducting rough machining on the case with the scribed lines as the reference, wherein rough machining of the case comprises rough milling of central parting faces of an upper case body and a lower case body; conducting semi-finish machining on the case with the scribed lines as the reference; conducting finish machining on the case with the scribed lines as the reference; roughly drilling gripping-fit holes of the central parting faces of the upper case body and the lower case body; roughly milling a bottom plane of a lower case body mounting support; roughly turning two end faces of the upper case body and two end faces of the lower case body; and conducting stress relief treatment on the upper case body and the lower case body. According to the method, rough machining, semi-finish machining and finish machining are conducted, the workpiece allowance is removed step by step; the problem that deformation is caused by the machining stress generated in the massive and continuous machining process isavoided; and the large-size wind tunnel compressor case which meets design and technological requirements is finally machined and formed.

Abstract: The invention provides a multi-tool zoning rough machining technological method for an opening type overall leaf disc. By means the method, the maximum applicable tool size is calculated firstly, multiple different sizes of tools are selected, a leaf disc channel is divided into multiple machining zones, the tool as large as possible is used for conducting rough machining on each zone, materials are removed as many as possible, and the rough machining efficiency of the opening type overall leaf disc channel can be effectively improved. By means of the multi-tool zoning rough machining technological method, the large-size tools are used for machining as much as possible in different machining areas, due to the fact that the large-size tools are superior than the small-size tools whether inthe aspects of machining efficiency or rigidity in channel rough machining, and more than 80% of the rough machining allowance can be removed; and in addition, the other 20% of the machining allowanceof the overall leaf disc is completed through layered side milling of the small tools, all numerical control milling machining processes can be completed on a workpiece through one-time clamping, andthe rough machining efficiency of the opening type overall leaf disc channel is improved.

Abstract: The invention provides a method for machining a stepped shaft. The method comprises the following steps of a, material preparation, wherein bar steel is selected according to the diameter size; b, material forging, wherein bars are forged into steel sections; c, milling, wherein the two end faces are milled, and center holes are formed; d, turning rough machining, wherein large diameters are subjected to turning rough machining, the allowance of 0.2 mm to 0.4 mm is reserved, small diameters are subjected to turning rough machining, and the allowance of 0.15 mm to 0.35 mm is reserved; e, milling machine machining, wherein the periphery and bottom of a key groove are subjected to milling machine machining, and the allowance of 0.15 mm to 0.35 mm is reserved; f, thermal treatment, wherein thermal treatment is carried out, and it is guaranteed that the hardness ranges from 52 HRC to 56 HRC; g, grinding machine finish machining, wherein the large diameters, the small diameters and the two end faces are subjected to grinding machine finish machining to reach the dimensional requirement; h, milling machine finish machining, wherein the key groove is subjected to milling machine finish machining to reach the dimensional requirement; i, chamfering, wherein two sections are subjected to first chamfering and second chamfering respectively; j, mirror polishing, wherein the machined steppedshaft is subjected to mirror polishing. According to the method for machining the stepped shaft, manufacturing is easy, the manufacturing cost is low, the machining precision is high, and volume production is convenient.

Abstract: In the Conventional Theory (CT) of the electron broadening of hydrogenlike spectral lines in plasmas, the perturbing electrons are considered moving along hyperbolic trajectories in the Coulomb field of the effective charge Z − 1 (in atomic units), where Z is the nuclear charge of the radiating ion. Thus, the CT assumed that the motion of the perturbing electron can be described in frames of a two-body problem, one particle being the perturbing electron and the other ‘particle’ being the charge Z − 1. However, in reality it is a three-body problem, involving the perturbing electron, the nucleus, and the bound electron, so that trajectories of the perturbing electrons should be more complicated. In the present paper we take this into account via the standard analytical method of separating rapid and slow subsystems by using the fact that the characteristic frequency of the motion of the bound electron around the nucleus is much higher than the characteristic frequency of the motion of the perturbing electron around the radiating ion. By applying this method we obtain more accurate analytical results for the electron broadening operator than in the CT. We show by examples of the electron broadening of the Lyman lines of He II that the allowance for this effect increases with the electron density Ne, becomes significant already at Ne ∼ 1017 cm−3 and very significant at higher densities. We also briefly discuss a paper by Baryshnikov and Lisitsa (Sov. Phys. JETP 53 (1981) 471) where the fundamental symmetry of the effective potential for this problem was used in a different way.

Abstract: The invention provides a machining method of an inclined hole. The machining method comprises the following steps of a1, measuring and drawing, wherein the size of the intersection point of the centerline of the inclined hole and the side wall of a workpiece is calculated according to a drawing, the position point of the intersection point is drawn, and an oval is drawn; a2, tool manufacturing, wherein an angle clamping tool is manufactured, and the workpiece is clamped in the tool; a3, locating, wherein a milling cutter is pre-arranged on a bench drill, cutter alignment is carried out with the intersection point, and a shallow hole in the oval is milled; a4, machining, wherein a spindle of the bench drill keeps fixed, the bench drill is replaced with a center drill, a center hole is firstly drilled, a drill bit is further replaced for chambering, finally the reaming allowance ranging from 0.1 mm to 0.2 mm is reserved, and rough and refined secondary reaming is carried out through a reamer to achieve the specified size; a5, detection equipment is used for detecting the inclined hole, and chamfering is carried out; and a6, the workpiece is cleared. According to the machining methodof the inclined hole, the machining steps are clear, the machining efficiency is high, the effect is good, and the machining method has the beneficial effect that angel control is simple.

Abstract: The invention discloses an automatic tested piece centering correction and machining allowance determination method of a large machine tool The automatic tested piece centering correction and machining allowance determination method of the large machine tool at least comprises the following steps that S1, a photoelectric measuring device is arranged, and the photoelectric measuring device comprises a telescopic photoelectric detector which is arranged around the machine tool and corresponds to a tested piece and a receiving device; S2, the zero point coordinate of the current machine tool ismeasured, a probe of the telescopic photoelectric detector extends or retracts towards the machine tool, at the moment when the foremost end of the probe touches the tested piece, the machine tool suspends running for at least 1 second, the receiving device receives the position information of all axes of the machine tool, the position information of the axes of the machine tool at present is recorded, points given in a program are correspondingly and circularly recorded, then, the zero point of the tested piece is calculated, and meanwhile the allowance value is given; and S3, the machining allowance is automatically corrected, the zero point position coordinate worked out in the S2 is automatically input to a workpiece coordinate system set by the machining program of a machine tool controller, and automatic correction centering is completed By means of the automatic tested piece centering correction and machining allowance determination method of the large machine tool, the machining time is saved, and the accuracy of the zero point is guaranteed every time

Abstract: The invention provides a bearing gasket machining technology. The machining technology comprises the following steps of material preparation, wherein corresponding bar materials are selected; turningrough machining, wherein the allowance of 0.3-0.6 mm is retained for the outer diameter of the bar materials for turning rough machining; scribing and wire penetration hole punching by a bench worker;line cutting, wherein line cutting is carried out on inner diameter of a bearing gasket, line cutting is carried out on the bar materials so that the bar materials can be cut and shaped, and the allowance of 0.4-0.6 mm is retained for the thickness of the gasket; thermal treatment, wherein it is guaranteed that the rigidity of the gasket is 58-62 HRC; grinding machine finish machining, wherein the bearing gasket is machined to the size requirement through grinding machine finish machining; flaw-detection test, wherein the machined bearing gasket is subjected to flaw-detection test. The bearing gasket machining technology is simple in process, convenient and rapid and low in machining cost, and facilitates batch machining.

Abstract: The invention relates to the field of mold machining and discloses a standard mold machining technological process. The standard mold machining technological process comprises the following steps of preparing an integral board; plain milling; grinding the board; pressing the board, straighten a reference edge, repositioning by a machining center to align a reference origin point, and dotting by acenter drill to examine coordinates; machining a bottom hole; removing allowance of the machined hole; machining the machined hole in place; machining a countersunk head; machining a threaded hole; sawing a material; performing finish milling with an angle square; chamfering; and putting into storage. By machining the machined hole and the countersunk head of the integral board at one time and cutting the sawed material into single mold boards, the standard mold machining technological process solves the problem of replacing rough boring cutter, a finish boring cutter and a countersunk tool and pressing the board as a single board is machined in the prior art.

Abstract: The invention provides a high-melting-point polymer machining method and machining system. The method comprises the steps that a part digital model with complete characteristics is obtained; specifiedcharacteristics except a hollow structure or a curved thin wall in the part digital model are removed, and furthermore, allowance is added to form a blank digital model; the blank digital model is imported into specified layering software so as to form driving data corresponding to the blank digital model; the driving data are imported into additive manufacturing equipment, and a three-dimensional solid blank is manufactured based on the blank digital model; and the three-dimensional solid blank is machined so as to add the removed specified characteristics into the three-dimensional solid blank to form a part with the complete characteristics. According to the technical scheme of the high-melting-point polymer machining method and machining system, the manufacturing problems of high machining cost and a long production period in the prior art can be solved.

Abstract: The invention belongs to the technology of precision casting, and particularly relates to a zero-allowance precision casting turbine guide vane size precision control method. The zero-allowance precision casting turbine guide vane size precision control method is characterized by comprising the following steps: performing precision control on a vane profile size of a guide vane; and performing precision control on an exhaust side size of the guide vane. The invention provides the zero-allowance precision casting turbine guide vane size precision control method, which makes the size precision of the guide vane meet a design requirement with consideration of an influence of subsequent treatment on the vane size, shortens the shaping period of a guide vane mould, and ensures the consistency of guide vane quality.

Abstract: The invention relates to the technical field of machining and provides a numerical-control machining method of a large-sized aluminum alloy integrated frame part. The numerical-control machining method of the large-sized aluminum alloy integrated frame part comprises the following steps that the part is fixed, and datum holes and false bosses are machined; the false bosses are fixed to a tool at intervals, rough machining is conducted on the part through an equal-height layered machining method; after rough machining is completed, the part is released, the false bosses are fixed to the tool, and fine machining is conducted on the part. According to the numerical-control machining method of the large-sized aluminum alloy integrated frame part, in the rough machining stage, since the false bosses are fixed at intervals, the residual stress in the part is fully released in the machining process; when the first face is roughly machined and fine machined, the machining allowance is removedthrough a stepwise method, the residual stress in the part is gradually released, and the deformation amount of the part in the machining process is reduced.

Abstract: The invention discloses a milling method of a high-precision suspended web. The milling method is used for efficient and stable milling of a large-size suspended web structure and comprises the stepsthat the glossy face of a part is subjected to rough milling, and the technical allowance is reserved; a frame face is subjected to rough milling, the technical allowance is reserved, and a pluralityof false bosses are reserved according to the structural characteristics, so that the structural rigidity of the part is improved; the frame face is pressed in an unstressed mode, a positioning datumface is corrected, and thus the situation that the machining error is caused by part deformation is prevented; a glossy face web is subjected to semi-fine milling, and the small allowance is reserved;and the glossy face web is subjected to finish machining in place in modes of a small-diameter tool in small cutting quantity and back-and-forth feed, and thus the situations that cutter back-off deformation is caused by the large cutting quantity, and the surface quality of a part becomes poor due to trajectory change and acceleration and deceleration of a machine tool are prevented. The millingstability of the large-size suspended web structure is effectively improved, the part machining efficiency and the surface quality integrity are improved, and reworking polishing of a bench worker isreduced.

Abstract: We employ a rational expectations framework similar to that proposed by Fleming et al. (1998) to examine the source, and nature of, information linkages between the emission allowance and energy markets as gauged by the correlation of return volatilities. Estimating the model for bivariate pairings of securities suggests that market linkages arise from sensitivities to common information rather than from indirect spillovers, with emission allowances most strongly linked to the crude oil market.

Abstract: This work derives its motivations from the increasing interest towards Additive Manufacturing and the lack of studies, mainly in the field of fatigue. The effect of build orientation and of allowance for machining on DMLS produced Maraging Steel MS1 has been assessed. The experimental results, properly set up by tools of Design of Experiment, have been statistically processed and compared. The outcomes were that, probably due to effect of the thermal treatment, machining and material properties, the aforementioned factors do not have a significant impact on the fatigue response. This made it possible to work out a global curve that accounts for all the results, consisting in a high amount of data points. This can be regarded as one of the most generable and reliable fatigue models being currently available in the literature. Fracture surfaces have been carefully studied as well, individuating the initiation points being usually located at sub-surface porosities. Micrographies along the stacking direction and the build plane have been performed as well.

Abstract: The invention discloses a complex special-shaped casting measurement checking method based on laser tracking measurement, wherein the method belongs to the field of machining manufacture and settles problems such as thin wall, cutting-through and insufficient thickness caused by a blank casting error after product machining. According to the method, a measurement laser tracker or a scanner is utilized for measuring a complex special-shaped casting, and high-precision dimension scanning and measurement to the profile and inner chamber of the casting are realized, thereby obtaining cloud data ofthe profile and the inner chamber point of the complex special-shaped casting. Then through software, a solid model is generated from coordinate points, thereby realizing three-dimensional model acquisition of a blank object. Finally position registering and inclusive analysis are used as basic comparison principles, thereby obtaining a product machining allowance distribution rule, and supplyingdata supporting for subsequent numerical control machining and qualified product manufacturing.