FVTC - Machine Shop 5 - Blanchard Surface Grinder Construction

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Blanchard Surface Grinder Construction

Figure 1. Blanchard Grinder Construction

Chuck Rotation, Wheel and Coolant Pump Controls

Figure 2. Chuck Rotation, Wheel and Coolant Pump Controls

These electrical controls consist of an upper and lower set of buttons that when depressed control the chuck rotation, wheel start and stop, as wheel as the coolant pump (Figure 2).

Figure 3. Spindle Head Controls

Spindle Head Rapid Traverse Buttons - The head rapid traverse buttons are used for rapid positioning the wheel head. The rapid traverse buttons must be use with extreme caution.

Feedrate Variation Dial - The feed variation dial is used to set the feedrate.

Feed Travel Distance Dial - A predetermined feed distance can be set on the feed travel distance dial. Once the dial has been set to the down feed distance and the feed is actuated, the head will feed down at the feed rate setting. The down feed will then trip out when the zero on the dial comes around to the zero setting. The feed travel distance dial is graduated in 0.001 inches.

Wheel Feed Handwheel - The wheel feed handwheel is used to manually position the wheelhead.

Power Feed Activation Lever - The power feed activation lever, when pulled down, engages the downfeed.

Horsepower Ammeter - The horsepower ammeter indicates the amount of current draw at the wheel spindle motor. Check the amount of current draw before beginning the cut, if the draw on the motor starts to jump up significantly, reduce the feedrate or dress the wheel.

Chuck Speed Selector - The chuck speed selector is used set the chuck rotation speed (Figure 4). The chuck speed settings are in revolutions per minute. When setting the chuck speed, stop the chuck rotation before shifting gears.

Figure 4. Chuck Speed Selector

Magnetic Chuck Holding Controls - The magnetic chuck controls use a rectifier and circuits to control the magnetizing and demagnetizing of the electromagnetic chuck. The control contains two switches marked ON, OFF, POWER and RESIDUAL. Two pilot lights are included on the control (Figure 5). A red light illuminates when the switch is in the ON position. This magnetizes the chuck. OFF demagnetizes the chuck. Residual removes magnetizing current from the chuck but does not completely demagnetize the chuck. Residual magnetism LIGHTLY holds the work on the chuck. A white light illuminates when the switch is in the residual current position.

Figure 5. Magnetic Chuck Holding Controls

Wheel Dressing

To dress a wheel is to remove dull abrasive grains from the cutting face of the wheel. The Blanchard grinder is equipped with a manual star type wheel dresser (Figure 6).

Figure 6. Wheel Dresser

The wheel dresser is actuated by the wheel dresser handle on the front of the machine(Figure 7). When the finish on the work appears glazed or when the spindle motor begins to draw too much current, it is time to dress the wheel.

Figure 7. Wheel Dresser Handle