When manufacturing parts, it is often necessary to drill two or more holes in identical locations. This is known as machining holes in parallel. In such a machining process, the holes must be of the same size and distance apart. There are three ways to accurately position two parallel holes for economic precision: the polar coordinate method, the CAD/CAM method, and the coordinate measuring machine (CMM) method.
The polar coordinate method is the oldest and simplest way to measure the position of two parallel holes. This method uses a ruler, a protractor, and a pair of calipers (or other measuring tools). After measuring the initial hole’s position, the absolute polar coordinates (distance from the origin and angle from the x-axis) of the other hole is calculated. The absolute polar coordinates can then be used to precisely place the second hole.
The CAD/CAM method is the most automated way of machining two parallel holes. A CAD/CAM software designates a two-dimensional centerline for the two holes. The software then calculates the distances between the two holes and automatically creates a program for the CNC machine. The CNC machine will then machine the exact positions of the two holes.
The third method is the coordinate measuring machine (CMM) method. A CMM is a sophisticated measuring tool that is used to measure the exact size, location and orientation of components. This method is usually used in cases where very high accuracy is required. The machine will measure the exact position of each hole with a 3D coordinate system.
In conclusion, there are three ways to accurately position two parallel holes for economic precision: the polar coordinate method, the CAD/CAM method, and the coordinate measuring machine method. Each has its own advantages and disadvantages and should be evaluated to select the best approach for the application. Ultimately, the choice of method will depend on the specific requirements of the application and the design of the part being machined.
