Turning Defects into Perfection
- Published: September 01, 2002, By Nsenga Byrd Thompson, Staff Editor
Gravure, while under attack by flexo, still is considered as the print process capable of producing the best quality. However, claims from customers of print defects still arise and can be a major cause for concern. One company in the South African market that is aware of these factors and is working to ensure that quality remains a standard is Rotoflex-Quix, a member of the Nampak group of companies.
Based in Pietermaritzburg, South Africa, Rotoflex-Quix is the Nampak Group's flexible packaging division, specializing in a wide range of packaging products for a diverse group of companies in the snack, confectionery, general food, and soup industries. The company performs surface printing as well as reverse printing on the full range of packaging films.
At the 2001 Gold Pack Awards, the premier award ceremony for the South African packaging industry, Rotoflex-Quix won the coveted overall Gold Pack Trophy for the Twistall twist-wrap concept as introduced to the confectionery industry.
To support this on-going commitment to quality, Rotoflex-Quix recently installed the PrintVision/9000NT Automatic Defect Detection System from Advanced Vision Technology (AVT).
Detection Perfection
The PrintVision/9000NT system is designed to detect and indicate a wide range of print defects such as color variations, mis-register, streaks, misprints, scumming, or blade lines. The system is able to detect print defects as small as 0.1 sq mm, but can be customized on a per job or global basis to ensure that jobs are produced within a specific tolerance.
“We bought our first AVT system three years ago,” explains Graham Braby, managing director at Rotoflex-Quix. “At that stage the technology was fairly new, and to our knowledge, AVT was the only company that was active in this field at the time. We installed the first system on one of our gravure presses, partly as an experiment and partly to get operator acceptance.”
The company explored several other solutions, but decided — based on the excellent performance of the system and the great customer service it received — to purchase AVT detection systems for all of its main gravure presses.
Rotoflex-Quix currently operates seven printing presses, with the four newest presses being installed with PrintVision systems. The latest machine to have the system added is an eight-color Cerutti 940 press.
Before the installation of the first PrintVision system, Rotoflex-Quix relied on historical and statistical information based on the roll retention samples that were taken from each parent roll.
“It is no longer sufficient to statistically analyze all the retention samples to try and determine whether the work going out the door is fine or not. Customer demands have changed dramatically and proper quality assurance systems are now the order of the day,” says Graham Braby, managing director at Rotoflex-Quix.
“The AVT system is an assurance device, which has allowed us to catch print problems at the source — as they happen. As a result, we have dramatically reduced our print-related customer returns. Our company image has benefited, but more importantly, we have been able to save the significant costs related to this waste,” explains Braby.
It was this reduction in waste, in its various forms, that allowed Rotoflex-Quix to justify the expenditure on the second, third, and fourth PrintVision systems.
“In the beginning, there was a lot of skepticism from the operators that this new system was a policeman that was going to check how good they were. However, once the first machine was accepted, we had 100% support from the journeymen, to the point that the press journeymen on the other presses actually requested more installations on more machines. Therefore, the subsequent installations were welcomed,” says Braby.
“The AVT system also increased the confidence of the journeymen and has resulted in faster press running speeds,” he adds.
Getting Results
Peter Klute, deputy-managing director at Rotoflex-Quix, also has witnessed the benefits associated with the company's use of the defect detection system.
“The system has given us the ability to detect faults of a semi-permanent nature, as well as faults that remain unseen by the traditional press controls. The system's roaming camera alerts the operator to defects that are impossible to detect at high running speeds,” notes Klute.
Klute continues: “While waste in our factory is a key parameter that has to be controlled, the potential risk of delivering poor quality to a key customer is even more important. Failure to eliminate that risk will result in a job having to be re-run, often at short notice. Costs in the form of damage to our company's quality image are also important. All facts considered, we believe we recovered the cost of our first installation in the first year.”
In addition, the AVT PrintFlow reporting module generates a report indicating the type of defect that has been detected, as well as the position in the roll where it occurred, making the decision regarding removal of faulty material during subsequent operations both easier and more effective.
The Waiting Game
Looking to the future, Braby is eagerly awaiting AVT's pRegister automatic register pre-setting and control system.
“I have seen the automatic register control in operation on a CI flexo press.” he says. “With that system you don't have to rely on the journeyman to correct register variances; within two revolutions of the CI drum the system automatically brings the press back into register. It is quite phenomenal.”
Braby adds, “AVT doesn't have this for gravure presses yet, but I know they are working on this, and when they are ready to market it, I am first in the queue. AVT knows how crucial this would be in our industry.”
CONVERTER INFO
Rotoflex-Quix
240 Ohrtman Rd., Willowton
Pietermaritzburg 3200, South Africa;
+27 033 845 5200; fax: +27 0331 78397
SUPPLIER INFO
Advanced Vision Technology, Hasharon, Israel; +972 9 7614444; avtinc.com
Cerutti Giovanni Officine Meccaniche, Monferrato, Italy; +39 0142 459300; cerutti.it
