Log level raised

Italy's FEBA Converting Machinery claims to have “successfully produced the world's first fully automatic non intervention slitting operation on a lathe slitter”.

Usually, operators need to set at least the traversing stops for the slitting head, either mechanically or electrically, and the limit stops to take in to account the diameters of the roll and the slitting blade. This operation, when changing blades and log sizes, can increase downtime and overall cycle times to a stage where the conversion costs are no longer in tune with the base price of most lathe slit commodity products, says FEBA. At the same time, in order to cut the overall cost in lathe slitting conversion, increasing profitability, machine users are looking toward Lean Manufacturing Techniques that allow one machine to be extremely flexible, handling all blade sizes, log sizes and slit width changes, quickly and efficiently.

“Having to set any machine manually totally ruins the inherent basis for lean manufacturing,” says Mike Attard, director of Eurograv, FEBA's UK agent, “and this will only have a detrimental effect on production and profitability. In the ideal world, the operator would load the log, choose the product number from the machine's PLC (in order to set the slitting parameters), and the machine should then do the rest,” he adds. “But, unfortunately, most so called automatic lathe slitting machines rely on the operator to set the amount of slitting head traverse and the distance of the blade from the material, and also the distance that the blade itself travels in to the shaft.”

With FEBA's new Level 5 specification, it is claimed this is no longer an issue. The company's F400, F500 and F600 CNC controlled lathe slitters can all be equipped with the Level 5: it removes the need for the operator to manually set the movements and distances which, if incorrectly set, can quadruple cycle time.

According to FEBA, this new specification is automatically able to position the blade in relation to the external diameter of the log being slit (by means of sonar); and automatically self centre the blade (by laser), irrespective of its diameter, or how much has been removed during the grinding/polishing process - all of which is essential for the correct operation of an automatic blade axis angle and CNC system. It is claimed that this system will not only slash cycle times when loading different diameters of material, but also when the operator has to change blades diameters.

Level 5 machines can now incorporate fully programmable blade axis angles and automatic roll edge acquisition. With this, the operator leaves the machine to automatically find the edge of the log and it can then be programmed to traverse to the pre-determined trim width and adjust the blade axis angle for these trim widths.

Mike Attard adds: “Once the operator has fitted a new blade and fed a new log on to the machine, he only needs to press a zero point search button on the Omron PLC, and the machine will find the positions automatically, and check them during the course of the run”

FEBA has also developed an electromagnetic displacement system for the Level 5 Specification - another 'claimed world's first' - which eliminates the need for lead screws and pistons for both head traverse and penetration movements. The lack of inertia employed by this new EMDS carriage displacement system is said to “remove any servicing and lubrication issues, and ensure operation long after conventional lead screws and bearings have worn away”.

It is said that users of these new systems are reporting increased yields of as much as 35 per cent in some cases, when compared with existing automatic machines.

“FEBA looks at the preventative maintenance and tries to remove the burden of reactive maintenance for customers, “asserts Mike Attard. “That's why it has introduced not only EMDS, but also automatic lead screw and bearing lubrication on the more conventional Levels 1, 2 and 4.”

Level 5 machines can store 400 different slitting recipes and include PC connection for production supervision and set-up, while a standard modem link ensures immediate factory intervention should the need arise. Flash cards can increase data storage to thousands of recipes.

Mike Attard adds “We are seeing more and more converters produce rolls “Just in Time,” and having to change blades and accommodate different log sizes can take up to half an hour on some machines. With the Level 5 specification, new blades and diameter changes can be accomplished very quickly and without the usual operator errors.”