Alignment of a machine is broken down by steps, with the first step to establish references from which all measurements are compared.
- For the level attribute of components this reference is always level relative to earth.
- For the horizontal attribute, it is not quite as simple. The reference used must be accessible throughout the length of the machine. This reference is generally a representation of the theoretical machine centerline, typically installed in the tending (operator) aisle floor. It is commonly referred to as an offset machine centerline or machine baseline and its purpose is to provide an accurate reference from which all other machine components can be measured for perpendicularity or parallelism.
In the event a machine does not have a baseline, or the existing line is in question, one can be determined. The method used to determine the machine centerline is fairly straightforward. A temporary reference must be used to initiate the inspection, which is somewhat parallel to the machine centerline. Using this reference, individual machine components are inspected for their centerline location. From this information, a line is then established which is the best possible representation of the overall machine centerline.
Baselines are typically found in the tending side aisle floor of most machines and are represented by either a brass plug with a prick punch mark, or a stainless steel bushing which accepts an optical target. The baselines installed by ASNA are generally of the stainless steel bushing variety, as the ability to make use of the commercially available optical target allows the baseline to be more accurate, repeatable and efficient.
The next step in aligning a machine is to determine the overall alignment condition of said machine which can be accomplished by performing an initial survey using the common references as described above. Resultant data can be assimilated and the more crucial elements of alignment pinpointed. Using this information a plan can be developed for each specific machine which allows for alignment to be performed over a period of several shutdowns. If time allows, alignment plans can be developed for major shutdowns.