As Published by Maintenance Technology Magazine September 2017 issue
If greater reliability and uptime are of any concern to you, then precision maintenance is a key component in achieving it. This means having clear and simple, yet meaningful, procedures in place for the different tasks involved. Two such tasks are precision alignment and balancing. LUDECA’s 5-Step Procedures will help guide your facility and maintenance staff to achieving precision maintenance.
The alignment and balancing procedures lay out the basic steps required to align and balance machines safely, reducing risk of injury and increasing likelihood of a quality outcome. Checklists simplify the workflow and serve to remind employees of the processes required to consistently and safely perform the precision maintenance task.
Well-aligned and balanced machines run more reliably, with a greatly reduced probability of failure. This allows for better maintenance planning, greatly reduced repair and maintenance expenses, increased uptime and more profits.
A good alignment procedure ensure that machines are aligned to the proper tolerances for the running condition of the machines, taking into account such things as thermal growth and anticipated positional changes. This ensures that the greatest efficiency is achieved in your running machinery, prolonging their health and reducing power consumption. Studies have shown that well-aligned machines result in a 3% to 10% reduction in power consumption. Noise and heat generation is reduced, producing a safer work environment.
- Production Quality
Good alignment and balancing result in better product quality since vibration is minimized, resulting in a more uniform and higher product quality. Unexpected breakdowns in production machinery may lead to costly waste from scrappage and high restart costs for the production line.
- Training & Procedural Consistency
Once implemented, a procedure ensures all employees involved in the activity face clear and consistent expectations and processes, leading to a better understanding between all staff in the facility. Training expense can be reduced since often only refresher training is required to update understanding of the technology utilized as updates are rolled out. Records should be kept that document employee training.
The next step in precision maintenance and reliability is the Implementation of formal specifications that detail every step in a task from safety to activity process to documentation, to ensure that anyone involved can follow the procedures and guidelines without confusion, and reach the desired outcome for all machinery types in the plant. Such specifications typically take from two to three months to develop and a further two to three months to roll out and fully implement. LUDECA has written a number of these specifications for customers worldwide. Let us help you as well.
by Alan Luedeking CRL CMRP
Soft Foot has often been noted as the most inexact science portion of Shaft Alignment. Historically, when people think of Soft Foot, they often want to neglect, ignore, or otherwise do everything possible to not deal with it. This is one of the traps that leads down the path of bad habits, bad alignments, and more problems down the line.
Shaft alignment can be thought of as two things: 1) Aligning the couplings and 2) Checking for and correcting Soft Foot. Soft Foot, in fact, plays so much of a role in shaft alignment, that if one were to analyze the 6-Step Alignment Procedure below, one can see that Soft Foot actually appears in 3 out of the 6 steps. Therefore, Soft Foot can be thought of as half the alignment job.
Overall Alignment Procedure
1. Pre-alignment checks
2. Rough alignment to “eyeball clean” (with bolts loose).
3. Rough soft foot: Loosen all bolts and “fill any obvious gaps”.
4. Initial alignment. Get to within 5 to 15 mils at coupling or less than 20 mils at feet.
5. Final soft foot. All feet less than 2.0
6. Final alignment within tolerances.
Note: Step # 1 includes shim inspection and cleaning of machine supports
What is Soft Foot?
Soft Foot is Machine Frame Distortion.
How does it happen?
Soft Foot can happen from a number of things, including:
• Bent Feet
• Bad Bases (warped, uneven, flimsy)
• Dirt, rust, corrosion under feet
• Excessive number of shims
• And many more…
What should be done about it?
A full and extensive diagnosis should be done on every machine foot to determine whether or not the tightening of that particular bolt is causing machine frame distortion, and thereby adding coupling misalignment or machine frame strain. A few helpful tips to remember are:
• Minimize total number of shims under each machine foot to no more than 4 shims per foot.
• Make sure the area is clean, including machine feet, bases, shim packs, etc.
• Any jacking bolts that may be causing force against the machine frame should be backed off, so as to not interfere with the soft foot check.
• When checking for soft foot, only one machine foot should be loosened at a time, and the deflection or movement at the shaft noted.
With advancements in technology, PRUEFTECHNIK laser alignment tools can help diagnose whether a machine has a soft foot. The newest addition to the PRUEFTECHNIK line of tools, the Rotalign ULTRA, not only diagnoses the soft foot condition of the entire machine, but tells the user exactly how much to shim each foot, in order to correct the soft foot condition.
So the next time someone tries to pass off a bad Soft Foot problem as not being “that bad”, be aware that it is 50% of the alignment. Your machine’s Soft Foot condition should be taken care of, because if it has not, neither has your Shaft Alignment.
by Ana Maria Delgado, CRL
When craftsmen are given the task of laser alignment, quite a few assumptions are made. One very common assumption is that now that a laser system is being used, anyone can do alignment. Another is that since a laser is being used, everything is alignable. Put a laser system on an unalignable machine and you will still have an unalignable machine, only with an expensive laser alignment system attached to it. A laser alignment system does NOT guarantee that a machine is alignable!!! (Actually, all machines are ultimately alignable, if only you throw enough time and resources at them- perhaps an entirely new base or foundation is needed, and/or redoing the entire piping. The questions is, is it worth it in some cases? The point is, that just because you put a laser on a machine, that does not make it instantly alignable, vanishing all other problems.)
However, a laser alignment system, combined with a skilled and trained craftsman and a good alignment procedure, will greatly expedite alignments and help determine if a piece of equipment is alignable at all. The following is a tried and true procedure that will greatly expedite alignments.
Pre-alignment checks are critical in ensuring successful alignment. All surfaces should be clean and burr-free with metal to metal contact between the feet and shims, and the shims and base. Shim packs should be consolidated to three or four shims per foot. Jackscrews should be installed. A concentricity and runout check should also be done on the coupling and shaft. It is also a good practice to check the base for flatness.
The next step is to accomplish a rough alignment. Use whatever method that you prefer to get the machines reasonably close, or “eyeball” clean. A straightedge will work on some couplings in short-coupled machines. On machines with spacer couplings, the laser and a tape measure can be used very effectively. The purpose of this step is to remove gross misalignment and ensure that the laser and detector are in line enough to take readings. (Note that the best laser systems offer range extension so even rough alignment can easily be done with the laser.)
After your rough alignment has been accomplished, a rough soft foot check is in order. Eliminate any obvious rocking and fill any obvious gaps. This should be done with all hold-down bolts loose. Now it is time to use your laser alignment system. Make sure that all required dimensions are entered accurately and that initial alignment measurements are repeatable. Assuming you still have a rough alignment, a final soft foot check is in order. Follow your laser system’s recommendations for this. The ROTALIGN ULTRA even features a comprehensive soft foot wizard that guides you through the entire process, diagnoses the condition and suggests a solution. After any corrections are made, retighten all hold-down bolts, then recheck each foot individually with all the others tight. We recommend a tolerance of 2.0 mils or less. Now for the final alignment: The first correction that should be made is getting the vertical plane in tolerance. When making shim corrections, monitor the horizontal plane to make sure your machine does not move laterally too much. Once you are satisfied the vertical alignment is in tolerance, proceed to final horizontal corrections. Leave the hold-down bolts snug (not tight). They do not need to be all the way loose to make effective horizontal moves. This is where good jackscrews become invaluable, Try to avoid hitting machines with hammers. When machine is within tolerance alignment is complete. Save the alignment file for documentation and future reference.
Many years of involvement with machinery alignment reveal that this is the best and fastest procedure for precision alignment. Each step is necessary and important in accomplishing the next step. Take your time and be diligent and you will succeed in your alignment.
by Ana Maria Delgado, CRL
Laser alignment is an essential component of a proactive maintenance strategy for rotating machines. This practical guide provides information and guidelines for the implementation of good shaft alignment of directly coupled rotating equipment including terminology, alignment methods, troubleshooting soft foot, causes of machine breakdown and related case studies.
Download your complimentary copy now!
by Ana Maria Delgado, CRL