1. Technical Field
The embodiments of the present disclosure relate to measuring manufactured objects, and particularly to a computing device and method for generating engineering tolerances of a manufactured object.
2. Description of Related Art
Measurement machines are widely used in industry to measure manufactured objects (e.g., metal castings). Measured dimensions of the manufactured objects determine if the manufactured objects meet design specifications and provide information for improvement in process control. Each measured dimension corresponds to a nominal dimension and a pair of engineering tolerances, which define a permissible range of the measured dimension. The engineering tolerances may vary for different measured dimensions. Determining engineering tolerances for plenty of measured dimensions may be time consuming and error-prone.
The present disclosure, including the accompanying drawings, is illustrated by way of examples and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
In the present disclosure, the word “module,” as used herein, refers to logic embodied in hardware or firmware, or to a collection of software instructions, written in a program language. In one embodiment, the program language may be Java, C, or assembly. One or more software instructions in the modules may be embedded in firmware, such as in an EPROM. The modules described herein may be implemented as either software and/or hardware modules and may be stored in any type of non-transitory computer-readable medium or other storage device. Some non-limiting examples of a non-transitory computer-readable medium include CDs, DVDs, flash memory, and hard disk drives.
In step S301, the setup module 210 sets engineering tolerances to a determined number of decimal places and stores the engineering tolerances into the storage system 12. Decimal place is the number of digits to the right of a decimal point. For example, 0.8 is one decimal place. 0.08 is two decimal places. 0.008 is three decimal places. In one embodiment, the setup module 210 sets a pair of engineering tolerances including an upper tolerance and a lower tolerance for each number of decimal places. For a specific number of decimal places (e.g., two decimal places), the lower tolerance may be an opposite number of the upper tolerance. That is, an absolute value of the lower tolerance is equal to an absolute value of the upper tolerance, and a sign of the lower tolerance is opposite to a sign of the upper tolerance. For example, for two decimal places, the upper tolerance can be 0.08 and the lower tolerance can be −0.08. Depending on the embodiment, the upper tolerance and the lower tolerance of a specific number of decimal places may be different. For example, for two decimal places, the upper tolerance can be 0.04, and the lower tolerance can be −0.03.
In one embodiment, the setup module 210 sets engineering tolerances for one decimal place through five decimal places. For one decimal place, the engineering tolerances can be ±0.1 (an upper tolerance 0.1 and a lower tolerance −0.1). For two decimal places, the engineering tolerances can be ±0.08 (an upper tolerance 0.08 and a lower tolerance −0.08). For three decimal places, the engineering tolerances can be ±0.06 (an upper tolerance 0.06 and a lower tolerance −0.06). For four decimal places, the engineering tolerances can be ±0.04 (an upper tolerance 0.04 and a lower tolerance −0.04). For five decimal places, the engineering tolerances can be ±0.02 (an upper tolerance 0.02 and a lower tolerance −0.02). The setup module 210 may set a pair of default tolerances of the manufactured object. For example, the setup module 210 sets a pair of default tolerances ±0.05 including a default upper tolerance 0.05 and a default lower tolerance −0.05.
In step S302, the receipt module 220 receives a measured dimension of the manufactured object (e.g., a measured diameter of a shaft of the manufactured object) and a nominal dimension corresponding to the measured dimension. In one embodiment, the measured dimension of the manufactured object is obtained by a coordinate measuring machine (CMM) and stored in the storage system 12. The nominal dimension is a theoretical dimension of the manufactured object. The nominal dimension may be entered by a user (e.g., entered by the user via a keyboard connected to the computing device 10) or pre-stored in the storage system 12. In one example, the measured dimension is 8.7915 and the nominal dimension is 8.7900. The unit of the measured dimension and the nominal dimension may be in millimeters.
In step S303, the retrieval module 230 determines a number of decimal places of the nominal dimension. According to the number of decimal places of the nominal dimension, the retrieval module 230 retrieves a pair of engineering tolerances of the manufactured object corresponding to the measured dimension from the storage system 12. In one example, the number of decimal places of the nominal dimension is 1 and the engineering tolerances for one decimal place are set as ±0.1. Accordingly, the retrieval module 230 retrieves the engineering tolerances ±0.1 as the engineering tolerances of the manufactured object corresponding to the measured dimension. In one embodiment, the retrieval module 230 may retrieve the pair of default tolerances if no engineering tolerances for the number of decimal places of the nominal dimension are stored in the storage system 12.
In step S304, the determination module 240 determines whether the measured dimension of the manufactured object is within a permissible range defined by the nominal dimension and the retrieved pair of engineering tolerances (e.g., 8.7900±0.04 mm) In one example, the measured dimension is 8.7915, the nominal dimension is 8.7900, and the retrieved pair of engineering tolerances of the measured dimension is ±0.04. The permissible range defined by the nominal dimension and the retrieved pair of engineering tolerances is between 8.7500 and 8.8300. Therefore, the measured dimension is within the permissible range.
In step S305, the display module 250 displays the measured dimension, the nominal dimension, and the retrieved pair of engineering tolerances on the display device 14. The display module 250 may further display a result that indicates whether the measured dimension is within the permissible range defined by the nominal dimension and the retrieved pair of engineering tolerances on the display device 14.
Although certain disclosed embodiments of the present disclosure have been specifically described, the present disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the present disclosure without departing from the scope and spirit of the present disclosure.
Number | Date | Country | Kind |
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201110309825.8 | Oct 2011 | CN | national |