EVOH allows conversion from foil and metallized film laminations to co-extruded barrier films.Read more
Mark Miller helps you identify the right material selection for tooling that will carry fluid to your substrate.Read more
Product and Technology of the Year Awards praise Hazen for Titleist golf ball sleeves and cartons and SAM N.A. for slot die with internal …Read more
Web handling expert Tim Walker offers three options for this machine direction folding process.Read more
News | New Products
Recognized for FleXtreme printing technology used to create Bofrost bag
MOR-FREE LPlus1 high-efficiency, solventless laminating adhesive is said to aid compliance with food legislation and improved machinability
Off-the-shelf products, available in a broad range of sizes, configurations, and materials, are suited for many types of converting machinery
Now offering smaller, 250mL recyclable, BPA-free cartons for easy storage in backpacks and lunchboxes
Multilayer films lend insulation to NASA Magnetospheric Multiscale components and vehicles in space
The event will chart pathways to growth success with a number of presentations covering industry research
The NW210-E Inkjet UV digital narrow web press makes it first home at the p-s label converter
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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; firstname.lastname@example.org; www.webhandling.com.