Precision Alignment Implementation
Kathy | October 1, 2005
Arizona Chemical (Arizona) operates 14 manufacturing locations worldwide. In the “good old days,” each plant was relatively well assured of a production basis each year. As markets matured, distribution improved and customer requirements tightened, however, Arizona had to change to remain competitive. The sites now compete with sister plants for production capacity, as well as for capital funding. Production is assigned (scheduled) based on many factors. One of these is equipment reliability.
The site referenced in this article is in Savannah, GA. It was once part of a paper mill operation. Chemicals produced at the time of this writing were actually a side benefit of the paper-making process in that they extracted valuable products from the pine oils released in processing wood for paper making. Most of the mechanics had come from the paper side of the plant, as had their maintenance practices.
The paper industry is notable for its early adoption of precision alignment techniques. Starting with dial indicators, this segment was among the first to employ the rim-and-face technique. Later on, the reverse-rim method gained acceptance. When laser alignment systems were developed almost 20 years ago, the paper industry was among the first to embrace the new technology.
Regardless of how good they are, though, technology and tools alone are not enough. There is a need for a cultural change. People have to believe that there is a better way. They have to believe that “doing things differently” actually will make a difference in their plant’s operation, its competitiveness and their own livelihoods. This cultural change is what made the difference at the Savannah plant.
Getting an edge
Project Advantage is a corporate-wide initiative that International Paper (IP) has made available to its operating units. The key to its success is local “buy in.” Without the commitment of a plant’s management, the program is not started. But, it also is not a top-down type of mandate. Rather it offers a “better way” that plant management can embrace. In return for their commitment and support, IP provides training and guidance to make the initiative work. Further, Project Advantage doesn’t just cover maintenance. Instead, it touches all aspects of a unit’s operation (e.g., production, engineering, shipping and receiving, customer support, etc.).
The management of Arizona’s Savannah plant decided in 1999 to adopt key elements of Project Advantage to improve their operations. Besides the maintenance function, efforts also were undertaken in production and administrative areas.
Several years later, the plant’s maintenance superintendent began identifying key failures, pump work and other failures. Uptime was good, but significant resources still were being dedicated to repairs and equipment rebuilds. Almost all pumping capacity was backed up with spares, so the impact of failures could be minimized. In February of 2003, an introductory meeting was held at the plant. This meeting was conducted by IP corporate personnel who were champions of Project Advantage.
Based on the initial presentation, plant management elected to participate in the program. This meant committing resources to improving several key areas of the plant. Project Advantage encompassed about 30 different operational areas. The four on which the plant chose to focus were precision maintenance, operator-based reliability (ODR), work systems and root cause failure analysis (RCFA). In the maintenance arena, this meant adopting a precision process. Methods and tools would have to change in order that maintenance could be performed in a precision fashion.
The chemical plant cooperated with the paper mill on precision training as a way of leveraging scarce resources. At the time, there were approximately 35 mechanics, instrumentation technicians, pipe fitters, electricians and millwrights. All of these people were trained. They learned that installing precision would prevent rework and enhance the reliability of their operations. Management approached this as a solid investment that would yield returns, and backed it up with budgets for tools and training. A recap of the type of training provided is described below.
Keeping in mind that precision alignment is a subset of precision maintenance, several related topics were addressed in the training. It was natural at a chemical plant for mechanical seal and pump training to be provided. This training improved the knowledge and skill level regarding seal installation, maintenance and performance during operation, which, in turn, increased availability and reliability.
Among the leading causes of machinery failures are installation/assembly errors. Within the scope of Project Advantage, significant time was devoted to teaching how to avoid those types of errors. Personnel were taught how to determine the proper shaft fit for common applications (e.g., bearings, sheaves, impellers, etc.). They also learned how to reduce and prevent fit errors with precision measurement tools, such as depth, inside and outside micrometers, telescoping gauges, dial indicators, radius gauges, torque wrenches and digital “Vernier” style calipers.
Precision alignment was approached from the basics. First of all, a clear understanding of the objective of precision alignment was taught and demonstratedÐto measure and position two or more machines such that their rotational centerlines are within tolerance when the machines are at operating temperatures and conditions. It was found that there had been several different definitions “floating around” the plant. Thus, by obtaining buy-in to one common definition, it was easier to work to a common goalÐsomething that seemed quite obvious, but was not always achievable!
Part of the basics training included learning how to graphically plot alignment conditions and results. Before the acquisition of any (laser) alignment systems, however, dial indicator methods were taught. This reinforced the fundamentals of alignment and ensured that the plant did not rely on the availability of laser technology to secure the benefits of precision alignment. Some fundamental concepts clearly had to be learned and understood before an effective precision alignment program could be implemented. The plant determined that those responsible for the alignment of machinery would, at a minimum, need to understand:
- Basic math functions (addition, subtraction, adding & subtracting positive/negative numbers, multiplication and division)
- How a dial indicator works
- Rotational centerlines
- Pre-alignment checks
- Offset misalignment
- Power planes
- Correction planes
A process was taught, starting with a prescribed set of pre-alignment steps and stages to better secure a precise alignment. Participants were taught how to understand and be able to prove relative shaft centerline-to-centerline position. The focus on coupling condition was de-emphasized.
A key to the precision alignment process is addressing the critical pre-alignment checks, such as runout, correcting pipe strain, soft foot, rough alignment and establishing a torquing sequence. Skipping any of these steps can lead to a frustrating and unsuccessful alignment. By emphasizing these preparatory steps, and demonstrating their importance, mechanics would learn to take the time to prepare before aligning. This means that at times it takes longer to perform an alignment, but overall many more alignments are accomplished successfully.
Dial indicator methods
The rim-face and reverse-rim dial indicator methods were practiced. Technicians were taught to choose the right method for the job, as well as to how to check for bar sagÐand how to correct it. Gaining an understanding of what to do when machinery becomes base-bound or bolt-bound was especially useful. The graphical solution method has proven very useful for solving base-bound situations. By learning the “old way,” alignment fundamentals were reinforced and this paved the way for successful adoption of laser alignment tools.
Alignment tolerances were also explored during the Project Advantage training initiative. When the program began, there was some confusion about how to interpret an alignment tolerance chart and then how to properly apply these tolerances. An effective aligner must know how to use alignment tolerances. Simply relying on an instrument’s “idiot light” to tell one when machinery is aligned is not a substitute for understanding the application of alignment tolerances. For the novice, it can lead to costly errors. The aligners needed to understand why tolerances are important. They were also taught how to take a set of tolerances from an OEM and convert them into useable parameters for the particular alignment instrumentation being used.
Realizing that all machinery moves as it goes from a state of rest to its operating temperature and conditions, time was spent discussing dynamic movements. Although most of the machinery that is routinely aligned only moves slightly, there are many machines that require offsets to account for dynamic movements. Unfortunately this concept had previously been neglected as part of the alignment process. The usual excuses included:
- Because it doesn?t matter…
- We always leave the motor 5 mils low…
- We can calculate the growth…
- We don’t have targets from the OEM…
- It is too difficult and expensive to measure…
Dynamic movement does indeed matter. It can cause machinery to significantly deviate from an aligned condition as it goes from off-line to running. One can make an effort at calculating the thermal growth, but this is only part of the total dynamic movement. Keep in mind that there are reaction forces (such as dowels, piping, etc) that cannot be accounted for with thermal growth measurements. In addition, the horizontal movement (and machines don’t grow symmetrically!) cannot be calculated.
OEM-provided targets (if available) should be taken with a grain of salt. It has been found that they almost always provide for equal growth at the front and rear of machinery. Moreover, they almost never provide any guidance about horizontal movement. The only answer is to measure the true dynamic movement of the specific critical machinery. To meet this goal, the plant acquired special fixturing (OL2R Fixtures) and a laser system for measuring the dynamic movement on the specific machinery.
Finally, the value of documentation was emphasized to the participant. Documentation plays an important part in improving reliability. Forms have been created for the physical inspection, as well as for the installation and alignment process. Now, at the Savannah plant, all maintenance procedures are recorded on equipment-specific sheets and kept with the respective equipment’s file. This allows a mechanic to evaluate the history of a piece of equipment while preparing to perform a replacement or alignment. Documentation has been a key part of the process, as it also helps in communicating “wins” to other plant personnel and serves to maintain focus and momentum.
Selecting a laser alignment tool
From the precision maintenance training, the mechanics at this Arizona plant realized that most of the precision alignments could be accomplished with dial indicators. But. they also knew that a properly selected laser system offered too many compelling advantages to not be the standard for all precision alignments. The mechanics did not want an overly complicated (and feature-laden) laser alignment system, although they did tend to be somewhat gadget-oriented, to the point of always wanting more power, more options.
Next, the millwrights were involved in the evaluation and selection of a laser alignment tool. They knew that while many features from the various vendors were nice, when it came time to do a precision alignment, they probably only needed a small fraction of those features. They did not want to become bogged down and confused by all the bells and whistles that had seemed so necessary when they first looked at the laser systems. Such features can waste time and effectiveness if people operate the system with a trial-and-error approach, don’t ever become proficient or abandon the tool altogether. This ends up costing time and money with each and every alignment they perform. After the millwrights had their say as to which system they wanted, an easy-to-use laser alignment tool was selected.
A culture change
At Arizona Chemical in Savannah, there has been a marked change in people’s attitudes about precision alignment. They now see it as part of an overall effort that is improving the reliability of the site’s equipment. With management backing, there has been a consistent effort to move forward. There has been no back sliding; people have stopped taking short cuts with machinery alignments. Precision is now standard—and expected. Personal job satisfaction runs high at this plant, with the millwrights feeling as though they’re working in a professional manner. The following list outlines some of the benefits to date:
- Prior to precision maintenance, the mode of operation was to simply replace parts; many pieces of equipment were spared, with quick change-outs allowing for continuous processes to remain operational. Now, however, failures have been reduced and the spared equipment is scheduled for regular operation, rather than being held for emergencies.
- The plant initially started out having root cause meetings every week. Because of improvements, though, these meetings were rescheduled on a monthly basis.
- Training on structured problem-solving was provided to some of the mechanics. This allowed them to take charge in resolving most equipment issues.
- Additional training was planned, including precision alignment follow-up training. Even welders have gone through the precision maintenance class, gaining better appreciation of what millwrights do/need.
- Plans were put in place for a pump shop designed specifically for rebuilds; providing a clean environment with all the necessary tools and fixturing for proper pump overhauls.
The mechanics at this plant have identified and outlined key factors they believe can make a precision alignment program more effective. There are many resources available (especially online) that anyone beginning a precision alignment program can tap into to explore how to leverage these key areas:
- Securing management commitment
- Gaining essential stakeholder “buy-in”
- Developing training strategies (it needs to be thorough and on-going)
- Obtaining agreement for a precision alignment objective
- Teaching the basics of alignmentÐover and over again!
- Always working to some agreed-upon alignment tolerances
- Using documentation to build a complete machine history and to communicate “wins”
- Taking dynamic movement into account—it will make a difference!
- Fostering a culture change to one of “precision”
- Carefully selecting laser alignment systemÐget what you need (forget about what you “want”)
EDITOR’S NOTE: This article is based on a presentation in Norfolk, VA, at the 12th Annual SMRP Conference, in October 2004.
Mark Garza is a reliability engineer at Arizona Chemical. His responsibilities include managing the predictive and preventive maintenance of plant equipment, managing a mechanical integrity program and providing technical support for the maintenance department.
Ron Sullivan has served as president of VibrAlign, Inc. since 1996. He joined this organization in 1989 as field service manager, responsible for supporting industrial customers with predictive maintenance consulting services, including: vibration analysis, training, field balancing, and laser alignment services; telephone: (800) 379-2250 ext. 103; e-mail: firstname.lastname@example.org