COORDINATE MEASURING MACHINE By C.SOMU Asst.prof SNS tech 6/9/2018 CMM CAD/CAM/CIM SNSCT COORDINATE MEASURING MACHINE By C.SOMU Asst.prof SNS tech

SOURCE http://www.coord3-cmm.com/mct-sl-gantry-cmm/ 6/9/2018 SOURCE http://www.coord3-cmm.com/mct-sl-gantry-cmm/ CAD/CAM/CIM SNSCT

COORDINATE MEASURING MACHINE The coordinate measuring machine (CMM) is the most prominent example of the equipment used for contact inspection of parts. When used for CIM these machines are controlled by CNC. A typical three-dimensional measuring machine consists of a table, which holds the part in a fixed, position, and movable head, which holds a sensing, probe. The probe can be moved in three directions corresponding to the X, Y and Z Coordinates. 6/9/2018 CAD/CAM/CIM SNSCT

For manual operation, the control unit is provided with joysticks, or other devices which drive X, Y and Z servo motors (AC/DC). During operation, the probe is brought into contact with the part surface to be measured and the three co-ordinate positions are indicated to a high level of accuracy. 6/9/2018 CAD/CAM/CIM SNSCT

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integrated into the material flow system of CIM. The major features of a CMM are: (i) Stationary granite measuring table: Granite table provides a stable reference plane for locating parts to be measured. It is provided with a grid of threaded holes defining clamping locations and facilitating part mounting. As the table has a high load carrying capacity and is accessible from three sides, it can be easily integrated into the material flow system of CIM. (ii) Length measuring system: A 3-axis CMM is provided with digital incremental length measuring system for each axis. (iii) Air bearings: The bridge, cross beam and spindle of the CMM are supported on air bearings with high rigidity. They are designed insensitive to vibrations. . 6/9/2018 CAD/CAM/CIM SNSCT

6/9/2018 (iv) Control unit: The control unit allows manual measurement and self teach programming in addition to CNC operation. The control unit is microprocessor controlled. Usually a joystick is provided to activate the drive for manual measurement. CNC Measuring Centers are provided with dynamic probe heads and a probe changing system, which can be operated manually or automatically. (v) Software: The CMM, the computer and the software together represent one system whose efficiency and cost effectiveness depend to a large extent on the software CAD/CAM/CIM SNSCT

The features of CMM software will include: Measurement of diameter, centre distances, lengths, geometrical and form errors in prismatic components etc. On-line statistics for statistical information in a batch. Parameter programming to minimize CNC programming time of similar parts. Measurement of plane and spatial curves. Data communications. Digital input and output commands for process integration. Programs for the measurement of spur, helical, bevel and hypoid gears. Interface to CAD software. 6/9/2018 CAD/CAM/CIM SNSCT

TYPES OF CMM (i) Column type (ii) Bridge type {iii) Cantilever type 6/9/2018 TYPES OF CMM (i) Column type (ii) Bridge type {iii) Cantilever type (iv) Gantry type CAD/CAM/CIM SNSCT

ADVANTAGES OF CNC OPERATION OF CMM CNC operation increases cost effectiveness through the following advantages: i. Shorter measuring times ii. Higher throughput rates iii. Better repeatability iv. Economical even for small batches v. Simple operation vi. Unmanned second and third shift inspection of parts if parts are loaded automatically. 6/9/2018 CAD/CAM/CIM SNSCT

SPECIFICATION OF CMM STUDENT PART( SELF STUDY) STUDENT DISCUSSION 6/9/2018 STUDENT PART( SELF STUDY) STUDENT DISCUSSION CAD/CAM/CIM SNSCT