Abstract: The structural distortion problem of large thin-walled aerospace components has roused much concern on more agile, digitized and cost-efficient precision manufacturing techniques, in particular, designing suitable machining plans according to the real shape of workpieces. To improve the machining accuracy of large thin-walled aerospace components, a methodology of three-dimensional machining allowance modeling and analysis is proposed in this paper. Firstly, the fundamental principles of 3D models matching and alignment between the casting blank and the design part are presented. And by datum transformation from virtual design references to real-world references on casting blanks which are accessible more easily, measuring, positioning and machining the casting blank will be more convenient to realize. Furthermore, the technical character of a large thin-walled aerospace component is considered and a technical framework for 3D machining allowance analysis is given. Finally, the proposed methodology is validated by an experimental study using a typical large thin-walled aerospace component of a hypersonic vehicle. Improvements in accuracy and efficiency performance are realized in comparison with traditional methods.

Abstract: This study investigated the determination of the allowance that must be added to the cycle time estimate, which is a critical concern when assigning internal due dates. Because no method for estimating cycle times is completely accurate, producing such estimates remains problematic but has rarely been addressed in the literature. A large allowance postpones the internal due date, diminishing company appeal when a factory manager negotiates with a customer. Therefore, in this study, a nonlinear approach was proposed to normalize the cycle times. After estimating the cycle time of a job by using a back propagation network, the allowance added to the cycle time can be effectively reduced through the collaboration of several computing clouds. Theoretical properties of the proposed method were validated, and a case from a wafer fabrication factory was used to evaluate the effectiveness of the proposed method in comparison with various existing methods. According to the experimental results, the proposed method facilitated establishing tight upper bounds on the cycle times. The proposed method was proven to be very effective. A nonlinearly normalized BPN and cloud computing approach was proposed to establish tight upper bounds on the cycle time estimation.A case from a wafer fab was used to evaluate the effectiveness of the proposed method which was compared with various existing methods.The proposed methodology was improved by increasing the number of collaborating computing clouds.The proposed methodology was much more efficient under a cloud-computing environment than under other environments.

Abstract: The invention relates to the field of industrial manufacturing, in particular to an intelligent CNC (computer numerical control) processing method on the basis of industrial robots. The intelligent CNC processing method includes steps of building models by the aid of three-dimensional drawing software according to manufacturing requirements, carrying out layering processing on machining allowance according to milling depths, acquiring machining paths of each layer, generating simulation paths of rough machining, producing paths of fine machining, acquiring the shortest paths by the aid of Floyd algorithms and carrying out simulation machining by the aid of CAM (computer-aided manufacturing) data; simulating robot machining procedures and acquiring point sets of intersection portions by the aid of AND algorithms; acquiring mechanical collision locations in the machining procedures and optimizing postures of the robots by the aid of posture interpolation algorithms to obtain optimized algorithms so as to correct the machining paths, convert G codes and carry out CNC client interpretation and robot machining. Compared with the prior art, the intelligent CNC processing method has the advantages that automatic machining and intelligent production can be carried out by the aid of the robots, and accurate machining effects can be realized; the production efficiency can be improved, and the labor cost can be reduced.

Abstract: The invention discloses a thin-wall ring part machining method and an automatic auxiliary supporting device thereof According to the allowance of a workpiece bearing surface, the corresponding machining method can be adopted In the manufacturing procedure that the workpiece bearing surface has allowance, according to the change of contact force between the workpiece bearing surface and the automatic auxiliary supporting device after a certain number of materials of workpieces are removed, the automatic auxiliary supporting device can automatically adjust radial auxiliary supporting space positions, and workpiece deformation in the machining process can be released In the manufacturing procedure that the workpiece bearing surface does not have allowance, the automatic auxiliary supporting device is controlled to support the workpiece bearing surface to be of an ideal shape, and then machining is performed In order to implement the machining method, the automatic auxiliary supporting device is invented, and the device can adjust the radial auxiliary supporting space positions automatically By means of the thin-wall ring part machining method and the automatic auxiliary supporting device thereof, the effect that part deformation is small after unloading is guaranteed, wall thickness precision can meet the requirements, and meanwhile automation of the auxiliary supporting device is realized

Abstract: The use and advantages of simulation of cold rolling with allowance for the nonstationary and stochastic nature of its parameters are shown. The results of simulation of the parameters of rolling and electric drives are compared to experimental data obtained by oscillography on the Severstal 1700 five-stand cold-rolling mill. A method of finding the most effective technology from the characteristics of the rolling process and the rolled strip are developed based on a dynamic model. It is concluded that it is reasonable to use the dynamic model of cold-rolling process in developing new and improving existing technologies for the production of cold-rolled wide thin strips.

Abstract: A vibroplatform model has been presented, which is used in industry for the separation and transportation of granular materials. An analysis of the results of theoretical and experimental studies of the coefficient of friction between the screen and sand granules has been carried out in real operating conditions of the vibroplatform.

Abstract: The invention belongs to the aviation aluminum alloy plate cutting machining technology and particularly relates to a numerical control machining method for a large wing integral panel. According to the numerical control machining method for the large wing integral panel, combined stress release grooves are formed in the two sides and the middle of a large wing integral panel workblank to release internal stress of the workblank during machining, in a layered machining mode, the inner profile of the large wing integral panel is machined first, then the outer panel is machined, deformation control during numerical control machining of the large wing integral panel is achieved by reserving allowance for finish machining, the purpose of control over numerical control machining deformation of the large wing integral panel is achieved, and large practical application value is achieved.

Abstract: The problem of performing adaptive machining to program the milling of the detail contours on the CNC machine in case of virtual-location procurement is solved. The correction of the CNC-program by measuring the actual position of the workpiece on the machine table is proposed, and the correction of the control program can be implemented in the result of solving the task of minimax, when looking for such state of its position in space to the maximum allowance on the machined contour was minimal. A mathematical model is developed that unambiguously identifies the position of the workpiece on the machine table according to the measured coordinates of the three points. The developed algorithms automatically search for the correction of the CNC-program for implementing the principle of adaptive machining solution of the problem of minimax. The soft program is created and the method of designing the CNC-program for a virtual basing of the workpiece on the CNC machine is developed. Experimental testing has confirmed efficiency of the developed technique.

Abstract: Many new assistive input systems developed to meet the needs of users with functional impairments fail to make it out of the research laboratory and into regular use by the intended end users. This paper examines some of the reasons for this failure and focuses particularly on whether the developers of such systems are using the correct metrics and approaches for evaluating the functional and social attributes of the input systems they are designing. This paper further focuses on the importance of benchmarking new assistive input systems against baseline measures of useful interaction rates that take allowance of factors such as input success/recognition rate, error rate, correction effort and input time. By addressing each of these measures, a more complete understanding of whether an input system is practically and functionally acceptable can be obtained, and design guidance for developers is provided.

Abstract: The invention relates to a thin-walled cage square pocket machining process, and belongs to the technical field of cage machining processes. The problems that broaching deformation can happen easily when a broaching mode is used for machining and cost is high when a wire-electrode cutting mode is used for machining in an existing machining process of thin-walled cage square pockets are solved, drilling-milling holes are used for replacing drilling holes in the prior art, square hole broaching is used for replacing wire-electrode cutting in the prior art, and thus machining cost is greatly reduced. The working procedures of 'final turning of two planes' and 'finish turning of the outer diameter' are added, and therefore the cage outer diameter and end face allowance can be removed ultimately, and the cage dimension can meet the product dimension requirements; in a cage obtained through the forming process in the first step, by adding the machining allowance of the outer diameter and the machining allowance of the end face, the radial wall thicknesses of the pockets before machining can be guaranteed, the axial wall thicknesses of the pockets after forming can meet the broaching conditions, and the thin-walled cage pockets can be broached. The thin-walled cage square pocket machining process is used for machining the thin-walled cage square pockets.

Abstract: The invention provides a heat treatment method for machining deformation prevention of a 7055 aluminium alloy thin-walled structure. The heat treatment method comprises the following steps: performing rough machining on a member blank till the thickness allowance is 5-8 mm; performing first-level aging treatment; re-performing rough machining on the blank subjected to first-level aging treatment till the thickness allowance is 1-3 mm; performing second-level aging treatment; re-performing rough machining on the blank subjected to second-level aging treatment till the thickness allowance is 0.5-1 mm; performing third-level aging treatment; and finally, performing finish machining on the blank subjected to third-level aging treatment into an end product, wherein the temperatures of the first-level, second-level and third-level aging treatment are 150-250 DEG C and maintained for 25-35 h. The three-level of aging treatment can reduce the residual stress of the 7055 aluminium alloy thin-walled structure after each time of machining, further can prevent the 7055 aluminium alloy thin-walled structure from machining deformation in the machining process, improves the product dimensional accuracy and ensures that a product can maintain the original strength level.

Abstract: The invention discloses a precision machining method for a deep and narrow groove of a flame tube thin-walled part. The precision machining method comprises the following steps that a, a matched rough machining grooving cutter, a matched finish machining grooving cutter and matched machining parameters are selected according to materials of the part and design dimensions of the length, the width and the depth of the to-be-machined deep and narrow groove in the part; b, an initial position of the to-be-machined deep and narrow groove is cut by a first depth, continuous feeding is conducted at an allowable maximum feeding speed, and an allowance is reserved; c, downward machining is continued without retracting, a second depth is reached through cutting, continuous feeding is continuously conducted at a medium feeding speed, and an allowance is reserved; d, downward machining is continued without retracting, a third depth is reached through cutting, machining is continuously conducted at a minimum feeding speed, and an allowance is reserved; and e, the finish machining grooving cutter is a profiling arc groove cutter and is used for completing finish machining to meet the final dimensional requirements.

Abstract: Comparative analysis of three kinds of boundary condition for solution of the diffusion equation in a mathematical model of vacuum carburizing (low-pressure one) is performed for plotting the carbon concentration curves in carbon and alloy steels. With allowance for the special features of mass transfer in formation of the diffusion layer and for the effect of control factors of the carburizing process, the mass transfer coefficient in the equation of the boundary condition of the third kind is evaluated with the help of parametric equations.

Abstract: The invention relates to the field of machining, in particular to a machining method of thin-wall bearing sleeve parts. The method includes the steps of blanking and work-piece blank forging; rough turning, stabilizing and finish turning; and rough grinding of two times. In the rough turning process, technology construction chucks are reserved in forging blanks, rough turning is carried out on work-pieces, and a step circle is added for axially clamping a construction table; the stabilization treatment is added to remove internal stress of the work-pieces further, and sizes of the work-pieces keep stable; and in the finish turning process, 0.9 mm allowance is reserved for diameters of outer circles and holes, and the allowance keeps stable after finish turning. A surface grinding machine is adopted during rough grinding of the first time, two end faces are ground to keep the parallelism degree of 0.05, a center is aligned according to the outer circles, rough grinding is carried out on the outer circles, the holes and the end faces, and the finish grinding diameter allowance is 0.4 mm. The method has the advantages that operation is simple, the accuracy of the work-pieces can be guaranteed, the manufacturing cost is low, parts are easy to disassemble, the use effect is good, the machining quality of the work-pieces can be effectively guaranteed and the efficiency of the work-pieces can be improved, thereby being suitable for volume production of large-diameter thin-wall parts.

Abstract: Macroeconomic data are subject to revision over time as later vintages are released, yet the usual way of generating real-time out-of-sample forecasts from models effectively makes no allowance for this form of data uncertainty. We analyse a simple method which has been used in the context of point forecasting, and does make an allowance for data uncertainty. This method is applied to density forecasting in the presence of time-varying heteroscedasticity, and is shown in principle to improve real-time density forecasts. We show that the magnitude of the improvements that might be achieved from this method depend on the nature of the data revisions.

Abstract: Impeller is widely used in modern industry and plunge milling is considered as the most effective way for rough machining of impeller channel. However, for extremely twisted blade, single layer milling may easily cause large machining allowance, which will influence cutting efficiency seriously. Therefore, a new approach to tool path planning for layered plunge milling of free-form surface impeller channel is presented. Firstly, a feasible method of machinability analysis of channel is given. Secondly, the layered model of plunge milling which relative to the maximum tool and tool length is constructed. And then according to the model, tool path of layered plunge milling could be planned. Finally, the generated tool path of single layer and layered plunge milling are simulated. Simulation result shows that the approach is appropriate and feasible to reduce the machining allowance and reduce the working load for the following semi-finishing and finishing milling. [Received 30 September 2016; Revised 15 November 2016; Accepted 18 January 2017]

Abstract: The invention relates to the field of machining, in particular to a fan wheel disc arc mortise machining method. The fan wheel disc arc mortise machining method includes the steps of part clamping, namely selecting and remaking an aluminum plate about 200 mm in thickness and about 450 mm in diameter, turning to level two ends of the aluminum plate, machining a positioning face according to the dimension of a seam allowance of a part, clamping the aluminum plate in a machining center, drilling a blind hole 60 mm in diameter and 8 mm in depth according to a position of a datum hole, screwing a double-thread screw into the blind hole to press the part tightly, aligning the datum hole with a pin, mounting the part on a fixture, aligning to ensure that part datum runout is not more than 0.01 mm, pressing a press plate tightly and making sure that the circumferential center and the rotating center of a machine tool coincide after part mounting. The fan wheel disc arc mortise machining method has the advantages that machining precision is high, dimensional precision and technological requirements are controlled effectively, machining steps are reasonable, machined part dimensions and technical conditions can meet the requirements of technological drawings, requirements on the part surface quality are guaranteed and production efficiency is improved.

Abstract: Macroeconomic data are subject to revision over time as later vintages are released, yet the usual way of generating real-time out-of-sample forecasts from models effectively makes no allowance for this form of data uncertainty. We analyze a simple method which has been used in the context of point forecasting, and does make an allowance for data uncertainty. This method is applied to density forecasting in the presence of time-varying heteroscedasticity, and is shown in principle to improve real-time density forecasts. We show that the magnitude of the expected improvements depends on the nature of the data revisions.

Abstract: The invention discloses a production technology of a shock absorber supporting seat. The production technology comprises the following steps: a, selecting materials; b, preheating; c, carrying out pressure casting; d, trimming; e, carrying out aging treatment; and f, machining. According to the production technology, AlSi10MNMg aluminium alloy material is adopted, pressure and time of pressure maintaining during the pressure casting process are strictly controlled, certain machining allowance is reserved at the end face of spin rivet, aging treatment is carried out after die-cast formation to enhance hardness, and the reserved machining allowance is removed through machining to ensure machining precision and remove the section without being formed compactly on the end face of spin rivet, so that the anti-fatigue performance of the supporting seat is greatly improved, and the anti-fatigue performance tests can reach 2800-3000 times; and in addition, the spin rivet crack phenomenon of a product is effectively reduced, the spin rivet crack proportion is reduced to 1%, and the product yield is greatly increased.

Abstract: The invention relates to a control method of a five-axis double-end-surface grinding machine. The method comprises steps as follows: step 1, the size of a workpiece and a grinding technology are set, the workpiece is mounted, a grinding procedure is started, and the workpiece is ground roughly by grinding wheels and then is subjected to semi-finishing grinding; step 2, a measuring procedure is started, and the allowance for machining is worked out; step 3, a finishing machining procedure is started, and the workpiece is subjected to finishing machining grinding; step 4, after grinding is completed, a final measuring procedure is started, and whether the size of the workpiece is qualified is judged; if the size is qualified, the next step is implemented; and if size is not qualified, the step 3 is implemented; step 5, whether end surfaces are ground completely is judged; if the end surfaces are ground completely, the workpiece is dismounted; and if the end surfaces are not ground completely, the angle is rotated by the aid of a magnetic reciprocating workbench, and the step 1 is implemented. With the control method, automatic grinding, automatic compensation and automatic measurement of the double end surfaces are realized, rough machining, finishing machining and automatic measurement of the periphery of a ceramic mold core can be completed efficiently in one-time clamping, the production efficiency and precision can be improved, and the cost can be reduced.

Abstract: The invention provides a machining method of an indexing cam, and belongs to the field of machining. The machining method comprises the following steps: 1, performing rough machining, and retaining a machining allowance 1 to 2 mm after the rough machining is completed; 2, performing semi finish machining, and retaining a machining allowance 0.3 to 0.6 mm after the semi finish machining is completed; 3, determining a cylindrical arc surface according to the shape of the indexing cam, performing finish machining of the cylindrical arc surface, and performing machining through a machining tool from outside to inside or from top to bottom by taking an isoparametric curve as a driving curve; 4, performing finish machining on the side surface of a cam slot: performing finish machining on the side surface of a lower corner, performing machining through a T-shaped tool, and performing finish machining on the side surface of the cam slot except the lower corner; 5, performing precision machining on the curved surfaces of two end surfaces of the indexing cam; 6, performing finish machining on the side surface of the upper section of the cam slot except the curved surface of the side surface; and 7, performing finish machining on the curved surface of the side surface. The machining method is high in machining precision, and the machined curved surface can operate smoothly.

Abstract: The invention discloses a processing system of mobile equipment shells. The processing system comprises a forging mould and a numerically-controlled machine tool, wherein the forging mould is used for roughly machining a preprocessed plate to obtain a rough base with the size being larger than the preset allowance of a product, the forging mould comprises an upper mould component and a lower mould component, a mould core for forging the plate is mounted on the upper mould component, and the lower mould component is provided with a cavity allowing the plate to be placed in; the numerically-controlled machine tool used for finely machining the rough base to remove the preset allowance to obtain the product. The processing system has the advantages that the plate can be roughly machined by the forging mould before the numerically-controlled machining to form the rough base, the machining quantity of the numerically-controlled machining is reduced, only the preset allowance needs to be removed, about half of CNC machining time can be reduced, the product structure and product size cannot be changed, product machining efficiency can be increased effectively, product machining cost and company resource cost are lowered evidently, and product appearance, size and performance requirements are satisfied.

Abstract: The invention discloses a casting method of a middle pressure valve casing of a steam turbine. The casting method comprises the following steps: 1) reserving a reasonable rough machining allowance according to the drawing of a middle pressure valve casing part; 2) arranging reasonable pads in the upper inner cavity and at the outer part of the middle pressure valve casing casting by adopting the rolling-hot-spot-circle method; 3) arranging a centralized riser and an outer wall pad which are in reasonable proportion; 4) calculating the size of the hot spot circle of an isolated hot spot at the location of the valve seat, performing whole-circle amplified allowance shrinkage compensation on the calculated increased machining allowance by adopting the rolling-hot-spot-circle method, and arranging chilling blocks on the outer wall of the casting in a matched manner; 5) after casting shakeout, preliminarily removing part of surplus machining allowance at the location of the valve seat; 6) performing mechanical machining so as to remove the rest of machining allowance at the location of the valve seat. According to the casting method of the middle pressure valve casing of the steam turbine, shrinkage compensation is carried out by adopting special whole-circle amplified allowance at the location of the valve seat, and the chilling blocks are arranged on the outer wall of the casting to change the thermal field of the casting, so that the shrinkage porosity moves inwards in the occurring position and is eliminated finally, and the shrinkage compensation problem of the valve seat is solved; besides, a big riser is arranged at the top for overall shrinkage compensation, and the surface defect problems of the casting are also solved.

Abstract: The invention relates to the field of machining, in particular to a double drive ring machining method which includes the steps: first, rough machining inner and outer contours, uniformly reserving finish allowance, performing heat treatment for a part to improve the overall mechanical property of the part, particularly performing end face leveling, cylindrical turning and inner hole turning after drilling, and turning an inner hole with the depth larger than the thickness of the part; turning, clamping and aligning the part after cutting off the part, leveling the other end face and ensuring overall length; performing heat treatment; precisely flat grinding two large end faces, taking one precisely grinded large end face as a datum for precisely turning the inner and outer contours, precisely machining internal and external circles, clamping the external circles by a copper soft jaw, aligning the other precisely grinded end face, controlling end face moving amount to be within 0.01mm and precisely turning the inner hole and an inner hole step hole. The double drive ring machining method is simple to operate and suitable for popularization, workpiece machining quality can be ensured, production efficiency is improved, and production cost is reduced.

Abstract: The invention discloses methods for machining thin-walled components, relates to the field of machining, and particularly relates to a method for machining thin-walled components. The method includes steps that thin-walled portions and other portions are roughly machined together, machining allowance of 1 mm needs to be reserved at wide locations of the thin-walled portions to prevent the thin-walled portions from deforming due to high speeds and engagement of cutting edges during rough machining, rough machining modes should be surrounding cutter feeding modes, and cutters are spirally extended to the side walls of the thin-walled components from the peripheries to the middles of the thin-walled components in each cutter feeding procedure; the cutters are selectively end milling cutters with tungsten steel cutters, so that deformation of the thin-walled portions due to impact force generated when the cutters approach the thin-walled portions can be effectively reduced, and requirements on sufficient strength of the cutters can be met; top curved surfaces are subjected to semi-finish machining, 6mm spherical cutters are selected for carrying out semi-finish machining on the top curved surfaces, excessive defective materials are removed, and accordingly uniform finish machining allowance can be reserved. The method has the advantages that the method is easy and convenient to implement, the machining quality and the machining precision of workpieces can be guaranteed, the production efficiency can be improved, and the production cost can be reduced.

Abstract: The invention discloses an NFV (Network Functions Virtualization) system reliability evaluation method based on a performance allowance, and belongs to the technical field of network communication and a reliability. The method comprises the steps of: determining a system key performance parameter; defining a system testing profile; in a prepared testing scene, acquiring key performance parameter data in real time; giving a threshold of the system key performance parameter; and calculating a system performance allowance reliability under the testing profile. The performance allowance means a deviation degree between the key performance parameter value and the regulated threshold thereof, is relatively easy to acquire, is changed along with time, and can extract effective reliability data of statistical distribution characteristics. The NFV system reliability evaluation method disclosed by the invention solves a problem that when a product works normally and sufficient fault data cannot be obtained, new fault criterions are defined by the performance allowance, and according to different selected key performance parameters, different performance allowance reliabilities are obtained so as to complete reliability evaluation on a high-reliability complex communication system.

Abstract: PROBLEM TO BE SOLVED: To enlarge a presentation range of information to a driver during travel without threatening the safety of a driver.SOLUTION: A driving support device 2 comprises: an acknowledgment required time calculation part 19c for calculating an acknowledgment required time required for a driver to acknowledge information to be presented when it is assumed that the information is presented; a risk calculation part 19d for calculating a risk that the safety of the driver is threatened; a driving time allowance calculation part 19e for calculating a driving time allowance given to the driver; a safety driving required time calculation part 19f for calculating a safety driving required time required for the driver to perform safety driving; and a presentation control part 19b for, when it is determined that the driving time allowance is larger than a sum of the safety driving required time and the acknowledgment required time during non-presentation of the information to be presented, presenting the information to be presented.SELECTED DRAWING: Figure 1