Turning Long Shafts Common Deficiencies and Their Causes
Turning long shafts, such as those used in the automotive industry and other heavy manufacturing, is a complex and highly specialized process. As with any machining process, there are potential inconsistencies that can lead to defects. This article discuss some of the common deficiencies experienced with long shaft turning and the potential causes.
Threading
Misalignments in the threading of a long shaft cause several problems. Poorly formed threads can cause significant stress concentrations in the shaft leading to breakage or excessive wear. Poor alignment of the thread, or angular misalignment, can lead to accelerated material removal or to problems with assembly.
Taper
With most long shafts, there is a potential requirement for reduced diameter over some or all of the length. With the length of the workpiece and the high possibility of consistent material removal, a misalignment of the taper can cause crowding of the tool on the workpiece, which can lead to loss of quality in the taper profile, or a material build up on the cutting tool. This can reduce the life of the tool and lead to poor surface finish and excessive tool wear.
Bends and Cracks
Long shafts may be prone to bending in one or multiple axes. This is usually the result of incorrect machining techniques, and the use of inadequate cutting forces. When a long shaft bends too much, it can not only lead to quality problems, but can also cause cracking or failure.
Vibrations
Vibrations in long shaft turning can lead to multiple issues. Vibrations can cause excessive wear of the cutting tools and damage to the cutting edge. This can decrease tool life, and can also lead to poor surface finish.
In addition, vibrations induced in long shaft turning can cause inaccuracies. This can happen if the tool holder is not properly mounted and stabilized, or if the positioning of the long shaft is not accurate. If the vibrations are severe enough, they can cause misalignments in the short and long axes of the workpiece.
Kerf Loss
Kerf loss is the amount of material removed by the cutting process which is not accounted for in the final product specification. A common cause of kerf loss is the use of inadequate cutting forces and improper machine settings. This can lead to material being removed from the workpiece which is not accounted for or designed for when cutting. This can lead to deterioration of surface finish, and can also lead to inaccurate measurements.
Inspection
One of the main causes of long shaft deficiencies is not performing proper inspections. Long shafts require frequent inspections to ensure that any inconsistencies that have developed have been addressed in a timely manner. It is also important to pay particular attention to the taper, threading, and straightness of the long shaft, in order to detect any irregularities as soon as possible.
Conclusion
Long shaft turning is a very complex process, and is prone to many potential inconsistencies. In order to ensure consistency in the machining process, frequent inspections need to be performed and the machine needs to be set up correctly. In addition, a correctly maintained cutting tool should always be used, and any irregularities that may arise should be addressed in a timely manner. By following these steps, manufacturers will be better able to detect any potential long shaft deficiencies, before they become a significant issue.
