by Mary Scianna
Cost effective ways to remove chips
If you’re machining metal, you’re generating chips. And if you’re generating chips, you want the most cost effective way to eliminate them.
There are several ways to improve chip handling efficiency and create more value for your chips, but the type of products and system you select will depend on a number of factors. One is the size of your shop. If you generate large chip volumes from multiple machines, automation may be an option. Another factor is whether your chips are ferrous or non-ferrous. Ferrous chips allow a shop to consider magnetic conveyors or magnetic filtration systems. The third factor is budget; chip handling systems can range from a few thousand dollars to $100,000+ for large scale automation.
If your shop uses a chip conveyor, “with a conventional belt style one, chips and coolants run through the conveyor via holes in the steel belt,” explains John Mackowski, product manager for metalworking, Eriez Magnetics, Erie, PA. “The chips tend to remain inside the housing of the conveyor where the bearings and other moving parts are located. The chips grind away at various items causing the conveyor to fail.”
One solution is a magnetic conveyor. Eriez offers a model with sealed units to prevent chips or coolant from getting to the mechanical moving parts, reducing the chance of failure.
Magnetic filtration systems are another option. Eclipse Magnetics has a system for sub-micron filtration of industrial fluids that it claims cuts filter costs by up to 100 per cent and extends fluid life by a factor of ten.
But these systems can only handle ferrous materials. And conveyors are also typically more expensive than standard hinged-belt type conveyors, “but if one takes into account machine downtime when a conveyor is not functioning properly, along with the repair costs incurred, the magnetic conveyor may be a better choice in the long run,” says Mackowski.
Waste coolants and chips represent a signficant cost. Coolants are expensive and when chips are mixed with them, they can’t be recycled to extend coolant life. Also, chips with coolants are wet and heavy, and will cost more to dispose of because of the weight.
Products such as chip vacuums and filtration systems can help. Exair, for example, offers a “Chip Trapper” and a “Chip Vac.” The Chip Trapper extends coolant life, says Kirk Edwards, applications engineer with Exair Corp., Cincinnati, OH, by sucking “the coolant out of your sump and cleans it by trapping shavings, swarf and chips in a reuseable filter bag. Fewer chips in your coolant means fewer surfaces for bacteria to grow. It also delivers cleaned coolant back into your coolant sump and provides aeration, which is important to keep bacteria at bay.”
Vacuum systems are a good option for shops with multiple materials, adds Edwards. The company’s Chip Vac mounts on to standard 30, 55 and 110 gal drums. “By using different drums for different materials, it aids in sorting chips for recycling, and recovrs some cost of material while keeping your shop clean.”
Long stringy chips are problematic when they accumulate. “On mechanical conveyors, these chips get stuck in the moving parts and eventually jam the conveyor and stop it from running,” says Mackowski. “On magnetic conveyors’ these ‘birds’ nests’ are so light and physically big they do not have much steel in them and don’t allow the magazine sufficient material to ‘grab on to’. They just sit on the slider surface of the conveyor and conglomerate until they fill the entire conveyor.”
They won’t “jam” the conveyor as they would on mechanical conveyors, but they also won’t convey well on the magnetic conveyors, adds Mackowksi.
“A common remedy for magnetic conveyors is to use a rare earth magnetic or two in place of the standard ceramic magnetic elements. The rare earth materials is many times stronger (and many times more expensive) than the ceramic magnets. They may capture and convey the birds’ nests, but there are no guarantees this will work either.”
Ways To Reduce Chip Handling Costs
Reduce transportation and disposal costs.
Condense, crush and compact your chips and eliminate fluid content to reduce volume and reduce disposal costs.
Extend coolant life and cut coolant consumption costs.
Chips in coolants will create bacteria and shorten coolant life. Removing the build-up of chips via conveyors or other handling methods will help extend coolant life and allow manufacturers to recycle the fluid.
Increase worker safety.
Sharp chips lying around a machine floor are a potential health hazard to machinists and other workers in the shop. Eliminating them will reduce the risk of worker injury and eliminate potential lost labour that could result from an injury.
Reduce maintenance costs.
Workers spend less time cleaning up chips on the floor and more time focused on machining. Automated systems reduce maintenance costs even further. SMT