Nov 17, 2015
A typical core supply system is illustrated in Figure 1. In this example, cores are stacked onto a core table where an indexer indexes the cores into a trough outside the tend side of the winder. The cores are then pushed past a measuring assembly and glue gun into a core lifter assembly inside the winder (or sometimes directly into a core trough inside the winder).
The cores are then picked up by suction cups mounted on a core loader assembly (Figure 2). The core loader assembly is typically mounted to the roll ejector assembly. The core loader receives the cores from the core lifter assembly or core trough, then transfers them into the drum pocket.
Every core loader eventually runs into the same problem at some point - the cores fall during the set change process. The following list of probable causes and their corresponding corrective actions are some troubleshooting steps to follow in order to diagnose and resolve cores falling from the core loader. But first, some safety considerations...
DANGER: Crushing hazard. If your core loader is equipped with safety latches, verify they are in place, securing the core loader in a maintenance position before performing maintenance on the core loader. If there are no core loader safety latches, make sure you secure the core loader so that it cannot move while being worked on.
DANGER: De-energize all equipment that may move and injure maintenance personnel, such as the roll ejector, rider roll, front drum and rear drums. Follow all mill lockout/tagout procedures.
CAUTION: Glue can cause irritation of the skin or eyes. Make sure to wear protective gloves and an eye shield during any maintenance.
CAUTION: Burn hazard. Follow the hot melt adhesive equipment manufacturer's instructions. Touching the hot-melt or the hot parts of the device can cause serious skin burns. Be sure to have enough time for letting the hot melt adhesive equipment and its components cool down before maintenance. The hot melt adhesive equipment cools in room temperature from 160°C (320°F) to the touch temperature, i.e. below 50°C (120°F), in about one to two hours.
Core trough is dirty, core trough alignment is incorrect or core trough is twisted.
Suction cup contact to the core is insufficient.
Suction cups are dirty, holes are blocked or suction cups are broken.
Vacuum blower is dirty or filter is clogged.
Vacuum blower is not working.
Leak at the suction connection.
For more information on core loader maintenance and core supply system improvement recommendations, contact your Valmet representative.