Automating the Chip Removal Process with PRAB Conveyors

“Keeping up with high Q rates” sounds like the title of a reality TV show. It’s definitely an important aspect of any industrial manufacturing operation that puts a priority on optimizing output. If the goal is to machine as many parts as possible in the shortest amount of time to maximize profitability, a high material removal rate (Q) is critical to achieving that objective.

Aerospace, for example, is an industry that regularly machines 3000-lb. pieces of metal down to parts that are approximately 10-20 percent of the original piece’s size and weight. That process naturally generates high volumes of metal chips, shavings, grindings and turnings. Gantry mills and other high-speed machining centers need to quickly move these massive amounts of material from the cutting machines to ensure effective machining, a clean work area for surface finish, and minimal lag time before the next block is set in place and the process begins again. The coolant used by the cutting machines has to be dealt with as well.

High-rate applications require a multi-faceted conveying solution capable of handling large volumes of scrap and fluid in an efficient, automated fashion. PRAB offers several conveyor options, each having advantages and disadvantages depending on the specifics of the application.

1. Steel Belt Conveyors

The simplest and most versatile solution for high Q rates, PRAB steel belt conveyors can handle most types of wet or dry metal scrap – from bushy material to chips and turnings – in any volume, and in a wide variety of conveyor paths.

Steel belt conveyors can move a high volume of material consistently, even in piles and high surges, but they aren’t the best solution for dealing with large amounts of liquid flow. They also have a lot of moving parts that wear quickly and require maintenance when chips and fine particulate enter the mechanism.

2. Drag Conveyors

Designed for conveying and elevating the most difficult, most abrasive, wet or dry materials in severe-duty situations, PRAB drag conveyors can be installed at floor level for easy transfer of material from the machine table to the conveyor. They also feature multiple infeed and discharge points to fit specific applications, and they can be customized with coolant pumps for integration with a PRAB chip and fluid filtration system.

Compared to steel belt conveyors, drag conveyors can handle a higher volume of coolant, and they have fewer moving parts to deliver more consistent material flow as opposed to surge loading. They are not ideal for processes that send solid materials or parts through the conveyor, and they are not conducive to moving longer, stringier drill chips or turnings that can twist up and bundle.

3. Trough Conveyors

These workhorse conveyors transfer all types of metal chips, fines and turnings, wet or dry bushy wads, and tramp metal solids with time- and energy-saving efficiency. Their liquid-tight trough construction makes them ideal for high-volume coolant flow applications, and their flush-with-the-floor orientation allows both material and coolant to run directly into the conveyor with minimal manual interaction or slowdown of the process.

PRAB offers these conveyors in two types:

• A Harpoon® trough conveyor has a ram assembly that floats in the trough and reciprocates back and forth. These troughs can collect high volumes of turnings, chips, stringies and as much fluid as is required. They can even pass small chunks of solid material that end up in the trough. While this conveyance method is a little slower than others, a Harpoon trough can move a higher volume of material, so it can accomplish the same results as a faster-moving conveyor. Component wear can be a concern with these conveyors, however, due to metal-on-metal contact on the bottom of the trough as the ram assembly reciprocates.
• The Push-Bar™ trough conveyor was developed to combat this issue. In this type of conveyor, the ram assembly is mounted on a bushing and rail system that lifts it off the bottom of the trough. This allows fluid and fine particulate to flow through the conveyor along the bottom of the trough without the excess wear. In applications where there is a lot of fine particulate moving through the conveyor, the Harpoon system may be preferable because it scrapes along the bottom of the trough and will do a more thorough job of cleaning out the particulate. In a Push-Bar system, because the ram assembly is suspended slightly above the bottom of the trough, there will always be some amount of material there.

Conclusion

Automating the chip removal process is essential for keeping up with high Q rates in metalworking operations. By using PRAB conveyors, machine shops can produce more parts with less downtime between jobs (as well as create more value for their scrap and increase revenue by recycling coolant with additional PRAB equipment). Our engineers will help you understand and asses the pros and cons of each system as it applies to your operation so you can implement the best solution for your specific needs.