February 2021 Volume 3

AUTOMATION

Loading/Unloading Automation To supply the induction heater with sufficient material, a wide array of automated feeding systems are utilized. Traditional solutions such as bin tippers, step feeders, vibratory conveyors, rotary feeders, billet/bar descramblers, and gantry de-stackers were the first to be used to accept a large amount of material and pass it on to the next operation in an organized orientation. Step Feeder This feeding mechanism uses a reciprocating stepper plate design to bring the billets out of the hopper onto a takeaway conveyor. The conveyor drives the billets towards the Induction heaters and at the same time creates the accumulated string of billets (log effect) required to feed through the heating systems, using pinch-roll drives or tractor drives.

Infeed Conveyors Infeed conveyors come in various sizes and configurations based on the billet size and shapes and can be commercially purchased or custom-designed for a specific application. Typically, these conveyors utilize variable speed drive (VFD) systems and are used to transfer billets or parts into a drive mechanism that will feed billets through the induction heating system. Pinch-Roll Drives Pinch-roll drives are one of the more popular drive systems on the market. These systems are designed to pinch” billets between two rollers and drive the billets through the induction heating system at a controlled feed rate. A typical pinch roll drive system uses two opposing rollers, typically one over the other, synchronized (electronically or geared) to match rotation speed between the two. The rollers are either polyurethane coated or knurled to enhance the gripping force on the billet diameters. The pinch roll drive system is designed with a range of adjustment to accommodate different billet diameters to be run. The pinch roll feed rate is controlled by a variable frequency drive (VFD) to accommodate a range of billet feed rates for the modern-day forge company.

Figure 2. Bin-tipper and step feeder

Rotary Feeders Rotary feeders are another alternative feeding mechanism and are typically used for selected applications using long billet lengths relative to diameter. These systems are designed with a specially configured hardened rotary track and an extended track width to accommodate a range of diameters and various longer length billet sizes. The rotary track is designed to pick up longer billets out of a hopper section in a horizontal attitude and index them to an elevated height where they are metered onto an infeed conveyor, and fed to the induction heating system. Infeed Automation Infeed automation systems such as conveyors, pinch roll drives, tractor drives, pusher systems, and robotics are used to transfer billets into; and through the heating systems. These will typically include mechanisms that can drive a series of billets through the induction coils with controlled feed rates and consistency. This automation is usually an integrated function of the heating system but can also be retrofitted into older forging systems.

Figure 3. Pinch roll drive

Tractor Drives Tractor drives are another form of a driving mechanism used to drive a string of billets through an Induction Heating System. As opposed to pinch-roll drives, tractor drives utilize opposing “chain” cat-tracks to pinch billets and drive them thru an induction coil line. The “cat-track” design allows for a longer length of contact area across the billet(s) surface, creating more driving force than a single tangent point typical of pinch-roll units. Along with the longer surface contact, the tractor drive is designed with a heavy duty upper cylinder that provides downward pressure to allow the assembly to drive billet thru a longer heating coil line length. One key advantage of a tractor drive system is its ability to handle billets with “tong” holds. A “tong” hold is a small diameter inexpensive

FIA MAGAZINE | FEBRUARY 2021 33