Abstract:
A system and method for supporting a workpiece includes a plurality of support assemblies (19,200) with movable heads (22, 202). Positional errors are ascertained for the heads (22, 202) based on different positions thereof and used to properly position the heads (22, 202) to support the workpiece. Other inventive aspects are directed to features of the support assemblies (19,200) and heads (22, 202) thereof.
Abstract:
A machine tool has a carriage (28), has a workpiece carriage (28) for carrying a workpiece (32) from which material is removed by a tool (54) carried by a tool carriage (48). A two-axis scale (86, 88) is attached to one of the carriages, and cooperates with a reading head (96, 98) attached to the other carriage. The output from the reading head is processed by signalling processing means to provide an indication of the position and/or movement of the carriages relative to each other and for generating positional data about one or both of the carriages to assist in controlling their movement in order to perform a machine operation. By directly measuring the relative positions of the two carriages, problems arising from, for example, distortions of the machine frame on which the carriages are mounted are at least mitigated. A preferred embodiment of the machine incorporates a second reading head attached to one carriage and incorporating the scale on another carriage so that the outputs from the two reading heads can be used to determine whether there has been any relative angular displacement of the paths followed by the carriages. There is also provided a method of determining the linear movement of one of the carriages relative to the other, and the machining process achieved using the machine tool.
Abstract:
A system and method for supporting a workpiece includes a plurality of support assemblies (19,200) with movable heads (22, 202). Positional errors are ascertained for the heads (22, 202) based on different positions thereof and used to properly position the heads (22, 202) to support the workpiece. Other inventive aspects are directed to features of the support assemblies (19,200) and heads (22, 202) thereof.
Abstract:
In an electric discharge apparatus of the type wherein an electrode (1) such as a wire electrode or a diesinking electrode and a workpiece (6) are disposed in such a manner as to face each other with a very small gap between them, a working solution (7) is put into the very small gap, discharge is caused between the electrode (1) and the workpiece (6), and the electrode (1) and the workpiece (6) are moved relatively by driving shafts (37), (67) such as ball screws in order to electrically discharge the workpiece (6) into a desired shape, the present invention determines correction data for correcting the driving quantity of the driving shafts (37), (67) under a plurality of different load and temperature conditions, stores in advance these correction data in a memory (41), selects a correction data suitable for the actual working condition from among the correction data thus stored in the memory and corrects the driving quantity to be given to the driving shafts (37), (67) in accordance with the selected correction data. Even if the driving shafts (37), (67) undergo expansion or contraction due to heat from surroundings, or deformation or expansion/contraction due to load by the weight of the workpiece (6) and the working solution (7), the driving quantity of the driving shafts (37), (67) can be corrected correctly. Accordingly, the relative position between the workpiece (6) and the electrode (1) can be controlled accurately, and high precision working can be performed.
Abstract:
A machine tool is controlled through a process incorporating the steps of measuring geometric and thermal errors (102) with accurate instruments, creating a global differential wet model of machine tool position (104) and using this model to control real time compensation of machine tool operation. A controller modifies (112) encoder-type position feedback signals used by the machine to compensate for geometric and thermal errors in the manner dictated by the global differential wet model.