February 2021 Volume 3

EQUIPMENT & TECHNOLOGY

Conveyor Maintenance Issues and Planning for Forging Operations By Mathew Frank

As a general rule, conveyors in forging shops see very heavy-duty use in normal operations and are often a critical element in maintaining production. Keeping conveyors in robust working order in a forge shop requires a conveyor whose capacity is matched to the operation, an understanding of the underlying of the conveyor’s engineering, attention to wear patterns, and a strategic maintenance plan. Some customers, with highly customized conveyors integrated into high volume forging lines maintain spare conveyors, sending well used conveyors back to Transcon Conveyor for refurbishment. This level of preventive maintenance is driven by the economic risks of unplanned downtime and ensures that high-volume forging lines are not slowed or shut down by a conveyor failure. All too often, conveyors reach a point of no return due to misunderstanding how conveyors wear. It is easy enough to replace broken components, and tend to shaft and roller bearings by cleaning and lubrication, but it is harder to recognize and address items which lead to misalignment of the drive train, belting, and rails, or to abnormal use-wear which will lead to premature wear and failure. Standard repair and replacement of components are usually straight forward and only create issues if non-standard repairs or inappropriate replacements reduce the resiliency of the original conveyor or introduce imbalances which increase use-wear. A common example of reducing the resiliency of a conveyor is disabling or inadequately replacing shear pins, clutches, pneumatic or electronic overload sensors designed to protect the belt, chains, and drive train from normal use shocks. Even if this does not result in catastrophic failure, the inability of the conveyor to absorb normal shocks can create relatively minor misalignments which lead to abnormal wear patterns which shorten the life of the conveyor.

Before

After

Ignoring the longer-term issues of misalignment caused by operating practices will shorten the useful life of a conveyor. For all conveyor designs in which the drive, sprockets, drive chains and belt surfaces are not aligned with each other will suffer abnormal use-wear patterns which are likely to result in excessive wear and a shortened life. Conveyors which are moved in and out of position, often with tow motors, but which are not specifically designed and strengthened to withstand this sort of flexing, can be knocked out of alignment. Often the conveyor will run easily, and the misalignment will not be obvious, but the little misalignments will add up over time. Misalignment can also occur with normal adjustments of the belt tension, often a common operational issue as heat and load vary during a production cycle. If belt tension adjustments do not keep the sprocket shafts square to the belt and frame, the forces on the sprockets, drive chain and belt pan assemblies will be skewed and will result in accelerated and uneven wear. Once this sort of unbalanced wear is introduced to a conveyor, it only tends to get worse, often leading to further mis-adjustments and skewing. Since conveyors are often repurposed into new operating circumstances in which heavy loading and high temperatures can permanently set deflection bends into hinge pins. In and of itself, this is not necessarily an issue for the belt pans themselves, but the hinge pins are also the axles running through the rollers in the drive chains. The slight angle created in these hinge pins in the roller can often lead to uneven wear in the roller block assembly. Even normal use will wear the belt pins and the roller bearings, which sets off a string of knock-on effects. This normal wear rate will accumulate in each roller axle, and the belt will lengthen. It is standard practice to tighten the take-ups. As most operators have

Shaft Parts

Roller Blocks

FIA MAGAZINE | FEBRUARY 2021 11