CMM probe heads: complexity simplified
Essentially there are two types of probe heads available for a coordinate measuring machine: fixed or articulating.
As the name implies the fixed probe head points vertically downwards in the minus Z direction. It offers the most economical approach to probing especially if you are measuring flat parts that only require approach normal to the XY plane. Geometrically complex shapes can also be measured with the fixed probe head. One way is to build a probing cluster comprising of up to 5 individual styli that allow measurement in all five planes. Another way is to utilize a change rack where different configurations may be placed in the rack and can be picked up and dropped off by the coordinate measuring machine as required. The most important thing to remember when utilizing the fixed probe head is that a measurement plan must be prepared prior to the commencement of measurement.
Manual articulating and indexing probe heads: Manual articulating probe heads provide movement in the B axis and rotation in the A axis however, they are non-repeatable in that the direction selected cannot be recorded or returned to easily. This works fine on a manual coordinate measuring machine but does present difficulties on a DCC machine. Manual indexing probe heads allow the probe head to rotate to repeatable positions. Some sophisticated manual probe heads allow the CMM to move the head to a preordained position. This is usually accomplished in unison with a stylus change rack. Other 2 axis adjustable indexing probe heads offer up to 168 repeatable positions (15°) reorientation is facilitated by the easy to read scales. The beauty of this is that there is no requirement to requalify the probe therefore measurement throughput is greatly enhanced.
Motorized indexing probe heads offer the ultimate in performance for the modern coordinate measuring machine. The CMM knows where the stylus tip is at all times due to the feedback loop from the probe head control system. The major benefit of a motorized system is the ability to program and measure on-the-fly, no complex pre-preparation is required simply index to position and measure!
We can help you in choosing the correct probe head for your job. If you’re faced with budget constraints we can develop strategies that will allow you to utilize fixed head and indexing heads to successfully measure your parts.