Papers by Keyword: Precision

Abstract: The article deals with diagnostics of machine tool precision and necessity to train basic routines of measurement and its preparation. Such training is essential for efficiency of diagnostic processes as preparation is usually the most time-consuming and skill-demanding part of overall measurement. The article roughly describes simulation of machine tool errors on proposed experimental device and its implementation into the training process in order to gain experiences with measurement on machine tools in wide scale of conditions. Described device is designed to simulate several geometrical errors, inaccuracies and environmental impacts on precision of positioning which affects not only machine precision but also effectivity of measurement itself.

Abstract: In this paper authors conducted analysis of management features on machine-tools with numerical control using neural network for achieving exactness. Applications of Hopfield networks are discussed in the paper along with application of neuron computers that offer decision making of tasks ticker-coil.

Abstract: Incremental Sheet Forming is a flexible process characterized by low costs and higher process times with respect to traditional forming technologies. It is therefore suitable for prototypes, small series or custom mass productions. Its flexibility derives from the use of a hemispherical punch that is moved by a CNC machine and gradually deforms the sheet in presence, or not, of a counter die. As a consequence, the sheet clamping is reduced and the part accuracy is lower than traditional sheet forming process as stamping. Therefore, the improvement of the part accuracy in Incremental Sheet Forming is a relevant research topic and solutions for error reduction are required for improving the process quality.The present paper describes the use of an Iterative Learning Control (ILC) algorithm for compensating the ISF part geometrical error. In particular, it iteratively corrects the part geometry on the basis of the error map obtained as the difference between formed and target part geometries. The ILC uses the target geometry to form a first trial part, it measures the obtained geometry and estimates the geometrical error map. Then the error map is used to modify the target geometry and another part is formed. This procedure gets iterated until the desired geometrical tolerance is achieved.The correction algorithm was experimentally tested in forming both axisymmetric and not axisymmetric parts using aluminum sheets. Results showed that in few iteration steps it was possible to significantly improve the part accuracy and to achieve geometrical tolerances comparable with the traditional sheet forming processes.

Abstract: In this study, the influence of workrest positions on the deflection of a crankshaft is investigated, in order to enhance the machining precision in orbital grinding. Crankshafts of 3m, 5m and 8m are selected, and three types of states (no machining, journal machining and pin machining) are studied. The model is simplified with stiffnesses applied to the stock instead of real contact between workrest and stock. As the workrests are positioned to the machining region, the deflection of the machined stock is reduced. Pin machining shows more stable result than journal machining.

Abstract: Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationships between outputs and inputs have greatly influence about the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper one presents the general aspects of a railbound forging manipulator, like geometry, structure, general kinematics and forces of the main mechanism from such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed.

Abstract: Influence of screen distance on precision of screen-printing circuit is discussed in detail. This paper presents solution methods which improve precision of screen-printing for circuit board by derivation relationships of screen distance and precision of screen-printing

Abstract: Basing on the Image-Pro plus (IPP) technique, a kind of groove filter rod characteristic parameters (such as groove depth, channel ventilation area, number of grooves) measurement system was build. Method: put 5 groups of standard channel ventilation area-known groove rods and 10 pre-cut self-made groove filters under the microscope with the groove sides up, adjust the intensity of the light and the focal length, take the pictures of all. Use IPP to measure all the parameters, and MINTAB to analyze the accuracy and precision of the IPP system. Results: (1) the IPP system is convenient to operate, easy to use and fast to measure the characteristic parameters such as channel ventilation areas, groove depth as well as groove numbers of the groove filters. (2) the measurements for the channel ventilation area, groove depth doesn't exist linear bias. The channel ventilation area precision index GageR&R = 24.66 < 30, and groove depth precision index GageR&R = 26.40 < 30, which means measurement precision is good.( 3)The manual measurement mode and automatic measurement mode of IPP system in regard to the measurement results bear no significant difference (P > 0.05), and can be chosen for different needs. The measuring method provides help in the research of groove filters rod’ tar-reducing mechanism as well as in the increase of production process control capacity.

Abstract: This text introduces one non-standard new clamping mechanism which is used to clamp the nuclear fuel rods in welding process. For hard working conditions in hot cell, it requires that the equipment should be anti-radiation, also with good stability and certain precision.

Abstract: The new generation of the tractors with the front and rear linking systems makes more perfect combined aggregates, when some of them are mounted on the front of the tractor and others on the rear of the tractor. Thus the soils can be significantly compacted by the wheels of the tractors.Gantry agriculture has great influence on the soil structure. The possibilities to minimize the interaction between the chassis and the soil compression of different types circular and shuttle gantry modules were theoretically investigated. The influence of the unevenness fields on curvature of chassis ways and to selection of the chassis types were investigated.

Abstract: Environmental function matrix computing can provide aircraft data support for guidance instrument systematic error compensation to promote the precision. There were two ways to calculate the environmental function matrix, telemetry data direct computing method and telemetry data iterative computing method. A new iterative computing method with tracing data was put forward. The three methods were compared by using simulated data to do the experiment .It could be concluded that the precision of the tracing data iterative computing method was the best of three methods.