Music City plays host to converters attending the Flexographic Technical Assn.'s annual conference and exhibition.Read more
Folding carton and corrugated converters will find equipment displays and educational opportunities in die-cutting, foil stamping, embossing, and more.Read more
How well do you understand the relationship between your films and your corona treater?Read more
EVOH allows conversion from foil and metallized film laminations to co-extruded barrier films.Read more
News | New Products
VpCI-126 EM UV film provides high-tech corrosion protection from aggressive environments and UV exposure
With a number of co-located events and educational features, the show promises many offerings for those involved in processing and packaging
All operating units of the company are now branded under the Constantia Flexibles in an effort to present a consistent, clear image to the customer
Labels from around the world are honored in a competition the head judge calls “the Oscars of the global label industry”
The new survey points to confidence in?the foodservice packaging industry for 2015, and there is optimism despite economic and environmental challenges
The event, coming in September, will co-locate with Pharma EXPO, and organizers expect an improving economy will bolster both shows
OpenColor 2.0 multichannel profiling software comes with extensive color correction tools and a test chart generator, plus many other new features
Directories | Reports
PFFC brings you exclusive White Papers from our online sponsors.
Visit Kelly on Static from Static control expert Dr. Kelly Robinson, president of Electrostatic Answers; Kelly has 27+ years of experience in problem-solving and consulting.
Visit Tim's Web Lines to handle and wind your paper, film, foil, and similar products. Take advantage of Tim’s 25+ years just like over 100 converters have.
Visit Mark's Coating Matters from fluid coating expert Mark D. Miller; Process improvement and project management for precision roll-to-roll coating applications.
Visit Marketing Mojo for dynamic marketing insights from Stephanie Millman that inspire new ideas on how to stay on top of your customer’s mind.
Visit Yo’s Yarns to share the thoughts, impressions, experiences, and news that impact the converting industry. . . or anything else that happens to be on her mind!
Visit Tom's Poly Ploys, where Tom will be writing on various topics that the typical polymer processor would encounter on the job.
- November 16, 2012, Timothy J. Walker
Bigger cores avoid many winding defects. I like to joke that the ideal wound roll is a gigantic core with one wrap on it. Think about it.
Bigger cores have fewer layers for a given length of web on the core. Fewer layers of build up mean less magnifying of long-term thickness variations, less significant hardbands, and less winding-induced bagginess. Fewer layers mean less near core pressure buildup and high-pressure defects, such as coining, core impressions, blocking, starring/spoking, and core crushing.
A smaller change from core diameter to final roll diameter means a smaller torque range requirement for a given roll and a winder with a wider tension range able to handle a great variety of products.
The greatest benefit of bigger cores is in torque transmission and associated telescoping. Near core layers have two strikes against them in the challenge of transmitting center winding torque into outer layer winding tension. First, they are at a mechanical disadvantage to the tension at the outside of the roll. Second, they have less area per layer to develop the friction needed to transmit torque. Bigger cores eliminate the near core layers and their low torque transmission capacity.
Diameter will increase, but the diameter increase in moving from a 3-in. (75-mm) to 6-in. (150-mm) inner diameter core is not much. For a 20-in. (0.5-m) diameter roller, moving from a 4-in. outer diameter to a 7-in. outer diameter (assumes a 0.5-in. core wall thickness) only increases the final diameter by 0.85 in.
Yes, I know your customer wants everything on a 3-in. core. Yes, I know that 6-in. cores cost more than 3-in. cores. Yes, I know that 6-in. shafts and core chucks cost more than 3-in. shafts and chucks. This just means the change has to be justified.
Count up your waste from hardbands, core impressions, bagginess, blocking, spoking, and telescoping and see if the move to larger cores is justified. If you are winding rolls that simply move from your coater to your slitter, calculate the costs and savings of winding on reusable metal drum cores.
Web handling expert Tim Walker, president of TJWalker+Assoc., has 25 years of experience in web processes, education, development, and production problem solving. Contact him at 651-686-5400; email@example.com; www.webhandling.com.