Working of Surface Grinding Machine

Working of Surface Grinding Machine Points : Working of Surface Grinding Machine To achieve good result, the operator must know how to set up a job, using the most suitable work holding devices. The size and shape of the work-piece naturally determine the kind of holding device to use and the set up required. The table of a horizontal surface grinder is usually provided with T-slots. The work c be bolted directly to the table top, or can be mounted in a vise or in v-blocks. Where possible, the work is held on a magnetic chuck, which is built into or attached to the machine table. In clamping work to the table directly, the, piece must be firmly held in place. Great care should be taken to avoid springing, warping, or other distortion of the work-piece. Ground work is expected to the true and accurate.

In surface grinding, the work speed is determined by the rate of movement of the machine table which supports the work and moves it back and forth past the grinding face of the wheel. Work speed or table speed is also called the rate of table traverse. It is expressed in surface feet per minute (sfpm) or surface meter per minute (smpm). The cross-feed speed in the in or out movement of the wheel on the work a movement at right angles to the table as it reciprocates. The cross-feed should be in proportion to the width of the wheel and the finish desired. Cross-feed should not exceed, even in rough grinding, one half the width of the wheel’s face per table stroke. The lower the cross-feed for any given width of wheel face, the greater the depth of cut that can be taken.

For actual wheel speeds for safe operation, the recommendation of the wheel manufacturers should be followed at all times.

The in feed, or depth of cut, is governed by the amount of metal to be removed and finish desired. The hand wheel at the top of the grinder, for use in setting the in feed, has a dial graduated in tenths of thousandths, thus making it possible to grind flat surfaces to an accuracy of 0.0025 mm or 0.0001 inch.

Depth of cut determines to a great extent the pressure built up between the wheel and work during the grinding operation. High working pressure may create heat which will distort or burn the work. Thin stock requires reduced in feeds and light cuts. Dry grinding operations require lighter cuts than wet operations. If a coolant is used, it must regulate the direction and flow of it. Volume of coolant is more important than pressure. The nozzle of the coolant pipe should direct the coolant to the contact area between the wheel and the work.