PFFC - September 2007 - (Page 12)

WEB LINES ost of us like to feel we are wellsupported, i.e., secure and stable. A roller isn’t that different. How should a roller be supported or attached to your equipment? To answer this question, let’s review your roller support needs and your options to meet these needs. M Support Your Rollers By Timothy J. Walker Contributing Editor Shaft-holding options include: 1) bearings, 2) shoulder bolts, or 3) engineered plugs that function as large shoulder bolts. In inexpensive equipment or wrinkle-insensitive products, this method is good enough. The engineered plug approach can work quite well, especially if it includes split caps and some minor alignability. When you don’t have bored side frames, there uAligned | Rollers should be parallel to each are two other options to connect rollers to any other. Each roller must be installed and horizontal or vertical surface: flange mounts measured to be level (perpendicular to gravity) (where the shaft holder bolts to the side frames and trammed (perpendicular to a machine’s parallel to the roller shaft) and pillow block centerline), usually to less than 2 mils/ft error. mounts (where the shaft holder is bolted down (Stretchier, thicker, and narrower webs are in a direction perpendicular to the roller shaft). less sensitive to misalignment than this.) Even Flange and pillow block mounts can be well or rollers that will be intentionally misaligned poorly executed, depending on the details of should begin with a known parallel reference their execution. position. Flange and pillow uRigid | Rollers should block mounts may be hold their position and an all-in-one design alignment through with an integrated To keep your alignment tension and process standard bearing changes and over the life and a Zerk fitting. rely over time, of the equipment. Though these are uServiceable | Rollers great for many shaft to on the should be designed so applications, overly they can be removed greased bearings often hold things in place. for maintenance and have higher rotational reinstalled back into drag than I’d like to their alignment position see in my idler rollers. with reasonable ease. If the live shaft roller has an exceptionally long shaft or journal (something that should be Machine builders attempt to meet these three avoided), having spherical bushings to capture the needs through two general approaches. Which bearing can avoid detrimental torsional bearing approach is used often depends on whether the loads from shaft bending. equipment’s structure will include two thick steel I’m a fan of split cap pillow block mounts. The plates, usually called side frames, on either side of pillow block mount is the easiest to level and tram the web path. in independent steps. The split cap feature is the To mount a series of rollers between two side best for easy removal and reinstallation of a roller frames, the builder will clamp the two plates to- without losing alignment. gether and bore all the roller positioning holes as And one last point on alignment of these shaft a set. When the side frames are separated holders: If you’d like to keep your alignment and spanned by rollers, in theory, the over time, don’t rely on the bolt friction rollers should automatically be paralto hold things in place; take the time lel since the holes are spaced identito drill and pin the roller mounts cally in each frame. securely in place. The bored holes may be quite If you are a person who enjoys livaccurate, but in all bored side ing on the edge, you may find roller WHAT IS YOUR frame cases, something must be support options a boring topic. For WEB TENSION? press fit into the holes that then you thrill seekers, I have two words: Part 1 of a 2-Part holds the shaft. This is what will cantilevered rollers. But that will have Series make or break this approach. to wait for a future column. don’t bolt friction COMING NEXT MONTH Web handling expert Tim Walker, president of TJWalker+Assoc., has 20+ years of experience in web processes, education, development, and production problem solving. Contact him at 651/686-5400; tjwalker@tjwa.com; www.webhandling.com. 12 | SEPTEMBER 2007 WWW.PFFC-ONLINE.COM http://www.webhandling.com http://WWW.PFFC-ONLINE.COM

Table of Contents Feed for the Digital Edition of PFFC - September 2007

Table of Contents First Glance From the Editor Calendar of Events Web Lines Process Management News Clips Narrow Web & Label Reporter Narrow Web & Label What’s New Products Narrow Web Sustainability: Going Green? What's the Score with Wal-Mart's Scorecard? Straight Talk From Your Trade Associations Learn 5 Key Elements to Creating Cost-Effective and Eco-Conscious Packaging Install Energy-Efficient Light Fixtures and Reap the Environmental Benefits People, Profit, Planet: How to Balance the Impact of a Triple-bottom-line Philosophy Show Preview What’s New Products Services Directory Classified Marketplace Equipment Buyers & Sellers Advertisers Index Experience Speaks

PFFC - September 2007

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