Michael Pappas, president of Catbridge, answers slitting and rewinding questions in the Jan/Feb 2013 issue of Flexible Packaging magazine. He addresses issues ranging from integrating new functions in a slitter rewinder to troubleshooting tips.
Q: Where does slitting and rewinding fit in the flexible packaging process?
A: Slitting and rewinding is almost always the last step in the process of preparing materials for customers. As such, it is critical on a number of levels. First, materials that reach the slitter rewinder have great value added. They have started as base films or other substrates and been through any number of value added processes including coating, laminating and printing. Second, waste costs most at the slitter and must be kept to a minimum; each square foot of material holds great value. Third, slitting and rewinding is the last step in quality control. And finally, finished rolls off the slitter are the final result that customers will receive, and as such, appearance and roll quality are critical.
Q: Explain ways a converter can troubleshoot slitting and rewinding when a problem arises before needing to call a specialist to check on machinery.
A: Problems in slitting and rewinding will most often be evident visually at the rewind. Telescoping rolls, soft rolls, edge weave and “off core” are common problems. A number of things can be looked at before calling in help, including:
- Are the job settings such as tension correct for the specific material being run?
- Is the material good? Are there pronounced quality issues such as extreme gauge bands?
- Are knives sharpened properly and set correctly for the material being run?
- Are rewind shafts operating correctly?
- Has there been any build-up of inks or coatings on rolls that is causing loss of proper traction and tension?
Q: Are you seeing any new developments or new techniques for slitting and rewinding? If so, what are you noticing?
A: There have been a number of developments in slitting and rewinding in the last few years. Slitters have become more than just an unwind, knives and a rewind. Many applications have called for integration of other functions between unwind and rewind. Inline lamination, adding or removing a liner, camera systems to detect defects and lasers for inline perforation are just a few.
Additionally, full automation of turret rewinders has become a reality. Yesterday's turrets simply rotated a disc and maybe cut off finished webs. Today’s machines do this and much more, including auto taping of strands to new cores, auto tail taping, labeling and vacuum hold-down of finished tails prior to tail tie to maintain tension to the last wrap for better alignment and finished roll appearance.
Perhaps the most revolutionary advance in slitter technology is the advent of single shaft winding for the vast majority of flexible packaging work. For jobs traditionally done on a duplex winder, winding on a single shaft machine (like our model 324FP) allows dramatic increases in throughput. Very simple to operate, a single shaft winder will typically outproduce a duplex machine two to three to one.
Q: What’s new with Catbridge?
A: Catbridge has taken the lead in single shaft winding for flexible packaging and other materials. Patented technology and state-of-the-art designs and features allow us to offer extremely productive, precise, and ergonomically-friendly machines. Also, our new slitting and rewinding lab will be fully functional in early February. Our lab will consist of two models, a 900 duplex and 324FP single shaft turret. The 900 duplex operates up to 2,800 fpm and can rewind to 32” maximum diameter, giving it a wide range of application possibilities including large diameter bottle labels. These machines will allow our customers to visit and run trials on different materials with shear, score or razor slitting. We are excited at the opportunity to work with our customers to help them streamline their converting operations, getting more finished rolls out with less.
To read the original article in Flexible Packaging's digital magazine, click on the link below:
For even more flexpack questions and answers, click on the link below to view our earlier Q&A.
2011 Slitter Rewinder Q&A for Flexible Packaging