Accelerator Magnet Technology Division

Measurement facility

Coordinate Measuring Machine (CMM)

Coordinate measuring machine (CMM) is a 3-D measurement system designed and developed for magnetic field mapping and fiducialisation of large size dipole magnets of Indus-2. The system incorporates three orthogonal granite slides, floating on air bearings, driven by DC servomotors and data acquisition system. Hall probe is used for field mapping where as an electronic switch (touch probe) is used for physical axis transfer. The 3-cordinate system named “3-D Magnaflux” has granite slides with strokes (x,y,z) of 3m x 0.8m x 0.6m in three orthogonal planes. The slides float on air-bearings and are driven by independent servomotors coupled to linear friction drives. Incremental non-contact optical encoders with position feedback, controls the machine. The complete system is PC controlled with provision to operate it in manual mode through joystick pendant and in auto-mode as programmed. The position and corresponding field values are acquired simultaneously for analysis. Omni directional sensitive electronic switch provided a touch trigger for the position. Y-slide of the system carries a non-metallic adopter where the Hall probe and trigger probe are connected. Dedicated PC-programs are used for both probe scanning and data (field and position) analysis to give field-strength, effective magnetic length, mid-plane and field quality. Table 1 gives the specifications of CMM. Schematic layout of CMM machine is shown in figure 1. Figure 2 shows the photo of CMM.

Table 1: Basic specifications of coordinate measuring machine (CMM)



X-Table stroke

3000 mm

Y-Table stroke

800 mm

Z-Table stroke

600 mm

Table feed

0-1500 mm/min.

Resolution of feed back mechanism

0.0005 mm

Positional accuracy for XY and Z
(Non cumulative with electronic compensation)

± 0.01 mm/1000 mm

Height of the probe arm from the ground when fixed to the system (from the lowest position)

1150 mm

Figure 1: Schematic layout of CMM

Figure 2: Photo of CMM

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