“Waterjet Abrasive Recycling Can Slash Operating Costs”
Modern Application New, May 200 3
The WARD abrasive recycling and drying unit takes water slurry, serparates the abrasive material, dries it, sizes it and returns it for re-use in the process.
The total cost of abrasives in an abrasive waterjetting operation can reach 50% of the total operating cost. An Ohio-based company offers the opportunity of slashing that portion of the cost by as much as 85% with on-site abrasive recycling.
Richard Ward, owner of WARDJet, Inc. (Kent, OH) a full-service waterjet shop, realized the costs of acquiring and disposing of the abrasives for his shop’s equipment was a major cost to his business.
Abrasives in the waterjet process are typically treated as a single-use, once through cutting medium, which have to be disposed of once used and mixed with kerf materials as a slurry. Ward knew that if the abrasive material could be recycled and re-used, huge operating cost savings could be realized. However, recycling of the abrasive was not considered viable for several reasons.
First, the slurry of used abrasive and kerf material usually packs into almost a solid mass in the receptacle tank of a typical water machine. This makes separation of the abrasive a challenge.
Next, because of the precision nozzles and cut expectations from these machines, re-use of the abrasive material was usually not considered an option because of quality concerns.
Driven by the desire to reduce the cost of waterjetting, Ward developed an abrasive recycling system capable of separating the abrasive material from the cutting waste, and returning high quality abrasive material.
“Proving recycling works has certainly not been easy,” says Ward. “To be able to remove the abrasive and recycle it, producing in many cases a cleaner product than was supplied new, on a continuous basis and in some situations running 24 hours per day, for the most part running unattended, was a real challenge,” says Ward.
The system he has developed is called the WARD (Waterjet Abrasive Recycling Dispenser) that removes the sludge from an abrasive waterjet cutting tank; separates reusable abrasive from waste; washes and dries the larger abrasive, then screens it once more. With a small footprint and operating on standard shop current, the WARD delivers recycled abrasive, up to new 150 mesh, that cuts faster than new abrasive, notes Ward.
Operating a custom built gantry with Jet Edge cutting heads and a Jet Edge intensifier, Engineering Manufacturing Services (EMS) (Monroe, NC), cuts primarily stainless steel, averaging 0.50” thick using a 0.013” orifice, a 0.040” nozzle, and 1 lb. of abrasive per minute.
EMS saved its used 50 mesh abrasive for over two years in 70 55-gal. drums, totaling nearly 100,000 lb. Because of limited space and the need for an all-in-one solution (removal and recycling along with separate collection of the waste abrasive and the dry abrasive). EMS purchased a WARD system in September 2002 and is running it 12-hours per day, five days a week. EMS recovers an average of 30 lb. of reusable abrasive per hour (300+ lb. each day). Initially, they believed they would receive about 20 lb. per hour.
Within the year they plan to recycle all 100,000 lb. of their saved abrasive, generating more than 75,000 lb. of reusable abrasive. Using around 2,000 lb. per month in operation, EMS estimates it will not have to buy new abrasive again for at least the next eighteen months.
“It’s the closest I have come to printing money,” states Gale Orem, EMS owner.
Orem also notes an added benefit of the recycled abrasive; his waterjet is cutting 15% - 20% faster, while still delivering the required edge finish.
Vatra Industries, Ltd (Manitoba, Canada) does job shop work, cutting all types of material, usually running a 0.013” orifice and 0.040” nozzle combination with 1 lb. of abrasive per minute. Using the larger of two WARD units only two to three hours per day directly from its water jet tank recycled enough abrasive to go for four months without having to purchase any new abrasive material. This equaled a savings of more than $12,000, according Peter Black, Vatra’s general manager.
The company also had the recycled abrasive analyzed by a third party – the results showed that the recycled abrasive was much cleaner than the new abrasive.
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