How centreless grinding works

Many people look upon centreless grinding as some sort of magical and impossible. Of the grinding processes, centreless is certainly among the least understood from a fundamental perspective. On the surface, it indeed does tend to defy much of what we think we know about cutting metal. Learning to put parts into a centreless grinder is easy, but the hard part is getting the part ground properly. It can take many years for an operator to learn how to master centreless grinding to where parts can be ground to very high tolerances. In centreless grinding, there are no centres used to hold the parts being worked on. The parts being machined are held in place by the grinding wheel, regulating wheel and work blade. Advantages Using the centreless grinding process as opposed to traditional grinding offers many advantages. One huge advantage of centreless grinding compared to traditional grinding is the time that is saved. The way centreless grinding saves you time is that loading parts into a centreless grinder is quick, easy and extremely hassle free, compared to traditional OD grinding machines. Another advantage and a real profit generator is that centreless grinding machines can be fed parts automatically. This alone can save a significant amount of labour hours and dollars because a lot more work can be produced in a more efficient manner. Obviously' if the labour costs can be diminished that means more money to the bottom line. What really make centreless grinders worth their weight are the tight tolerances that can be held on parts. Traditional OD grinding machines and methods can't even get close. When the fact that parts can be automatically fed into the centreless grinder is added to the equation, you can see how profitable and accurate centreless is. Centreless grinding, if set up properly, will achieve roundness, surface finish and dimensional tolerances that are among the best available in metalworking. Moreover, the process is able to improve the roundness of out-of-round workpiece blanks. Centreless grinding parts to roundness When looking at the process of grinding between centres, it is easy see how a part can be ground into roundness when starting with a part that isn't perfectly straight. On an OD grinder, the part is chucked between centres and the operator moves the grinding wheel into the part. As the wheel moves in, the high points of the bent part are ground away until the part is eventually rounded. But when you look at centreless grinding, making a part round when it is bent can look impossible. However, if you are familiar with the process you know it is done quite easily if you know the secrets to setting up the job. The part is supported by an angled work blade as it floats in between the regulating wheel and the grinding wheel. How high the part floats above the centreline of the wheels is what will determine the roundness of the part. Here are three tips to creating round parts with a centreless grinder: (1) When setting up the job, place the centreline of the work piece as high as possible on the blade. The angle of the blade lets the part ride up high allowing the centreline of the part to be higher than the centreline of the wheels. Usually, the higher part rides on the blade, the better for roundness. (2) Next, the speed that the part rotates at helps in making a part round. Using higher speeds typically works best, It will become round faster also. Too fast and you might have to deal with the part chattering. Monitor the wheel speed to find the optimum rotation. (3) When thru-feed grinding, you will also have to calculate the speed of traverse across the wheels. This speed must be adjusted to keep the part grinding round. Typically, adjust the feed slower to grind a bar that iMen's Sneaker Hub Online