The infeed centerless gage shown here measures two shafts simultaneously. On each shaft, the outside diameter is measured in two places and part taper is calculated. The gage provides automatic closed-loop control of an infeed centerless grinder based on these part diameter and taper readings.

The gage system employs a DGM3000n controller. This microprocessor based unit displays gage readings on a 6"X8" Color LCD screen. On this particular application, windows are used to display diameter readings, taper readings and statistical process control data.

The gage fixture shown was designed to handle two .5” (12,7mm) diameter parts approx. 3.5” (90mm) long with a diameter tolerance of .0005” (,0127mm).

 

The gage fixture consists of a dovetail base that supports brackets holding four V-blocks for locating the parts, four QS200 gage heads with fingers, and two end locator blocks. Integrated into the brackets is a rotating hold-down mechanism comprised of two nylon arms clamped to a shaft that is rotated by a pneumatic ram. The fixture can be reconfigured for different length parts by adjusting the brackets laterally along the dovetail and for different diameters by adjusting the V-blocks vertically.

Sequence of Operation

The general sequence of operation for the gaging system is as follows:

1. Aafter grinding, the loader places the parts into the gage fixture adjacent to the machine
2. Proximity switch on the fixture provides an input to the machine/loader controller when it senses "part present”
3. Tthe machine control energizes a pneumatic valve to activate two "hold down" arms. The arms swing over the parts to pull them down firmly into the locating "V" blocks in the fixture. At the same time the gage fingers, which are initially retracted for loading, close into contact with the part diameters
4. Part size data is taken from each of the four gages and is stored in the DGM3000n
5. The part sizes are compared to pre-set tolerance limits, and relay outputs "Good", "Over" or "Under" are provided to the machine control depending on part size condition
6. A running average (user settable) of part sizes is compared to pre-set compensation limits, and relay outputs for "Comp In" or "Comp Out" are provided when the limits are exceeded
7. When the machine control receives the outputs, it knows that the gage cycle is complete and de-energizes the pneumatic valve, retracting the hold-down arms and the gage fingers
8. The parts are removed from the fixture and new parts are loaded to begin again at step 1

Infeed Centerless Dual Shaft Gage (PDF)