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A wHolistic Approach to Paper Machine Alignment
By Bill Wick

(Editor's Note: The following is a summary of an article that appeared in the March/April issue of Paper360)

As the paper industry infrastructure ages, proper machine and roll alignment becomes even more critical. Alignment can save money and allow the equipment to run longer and more efficiently. It can also prevent poor product quality (broken edges, holes), paper breaks, felt wear, and worn dryer can bearings, gearboxes and roller bearings.

In terms of alignment, think of the paper machine as a single unit rather than just various sections. As each section feeds the following section, alignment can be critical. The alignment problem you assume is in the dryer section, may possibly have originated in the press. This is true of rolls as well; each has an effect--good or bad--on the roll that precedes or follows it. It is important to understand how making an adjustment will affect the rest of the paper machine.

WET END AND PRESS
In the wet end, emphasis should be on the Fourdrinier and press. Poor alignment here can result in broken edges, breaks, holes and excessive wear of wires and clothing. Other critical components include the breast roll, couch roll and vacuum roll.

Damage from poor wet end alignment can result in repair and rebuild costs of between $60,000- $120,000 per roll. But an annual program to address these issues that costs about $10,000-$20,000 per roll change for PM's with alignments (based on normal bearing wear, size and speed of machine), can save $40,000-$150,000 per roll.

The cost of a Fourdrinier wire change averages from $60,000-$100,000 per change (assuming 1-2 expected wire changes). Unexpected wire changes due to alignment issues will also affect cost per ton and profitability. An alignment program can save and average of $250,000 on large machines, including the cost of downtime.

DRYER SECTION
As the press feeds the dryer section, proper alignment allows the paper to pass smoothly between sections.

Concerns in the dryer section include felt wear, line shafts, gearboxes, dryer can bearings and frame wear. A dryer can bearing replacement can cost $10,000-$60,000 and cause 1-2 days of downtime. Dryer can replacement can cost $100,000, not including downtime. The cost savings benefit of a preventing dryer can failure with a good alignment program can be enormous.

REEL AND WINDER
Efficient operation of the reel is critical to end product quality. Good alignment prevents product loss due to broken or baggy product and/or bad roll ends. Good spools for the winder mean more profit.

The Winder is the final operation before the product is wrapped and sent to the customer. This is where a mill makes its reputation, by providing a quality product that exceeds your customer's expectations. Misalignment in the winder section can mean missed deliveries, poor product quality and waste.

A wHolistic approach means including alignment in your planned maintenance and not treating it as an afterthought. Planned alignment checks will identify where problems originate so that root cause(s) can be addressed. The cost of planned alignment checks is minimal compared to unscheduled repairs, rebuilds, product losses and downtime. When budgeting maintenance for the year, it is better to include an alignment program than to experience unexpected down time and repair cost for issues that could have been prevented.

Bill Wick has is owner and founder of American Industrial Metrology. He will also be a presenter during the OpEx Forum at PaperCon2013 in Atlanta, April 28-May1, 2013.

LEARN MORE
Learn more about "why" things happen on a paper machine, at TAPPI's three-day Paper Machine Operations course, May 21-23, 2013 in Atlanta, GA.

This course will provide you with an improved understanding of the overall paper machine operation, a fundamental understanding of fiber properties, and the way mechanical components function.

After successfully completing this course, you will be able to:

  • Describe how the mechanical components and operations of the paper machine affect the structure of paper and thus the quality.
  • Identify design and operating features of the paper machine that affect machine performance.
  • Identify ways to improve paper machine efficiency and product quality based on a new understanding of the overall operation.

You'll also receive a binder with copies of the PowerPoint presentations from the course.

This course is intended for paper machine operators, technicians, process engineers, product development engineers from paper manufacturers, and service technicians and engineers from clothing, chemical and other suppliers.

More information is available online.

 

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