What's involved in abrasive waterjet maintenance?

What's involved in abrasive waterjet maintenance?
End users of abrasive waterjet cutting machines sometimes underestimate the maintenance that will be involved with new machines. Unexpected downtime because of maintenance can result in a longer return on the investment.

To remain profitable, owners should be able to factor in costs associated with maintenance.These maintenance concerns cover items such as the cutting head, abrasive-feeding apparatus, pneumatic valves, high-pressure delivery lines, and the pump.

Maintenance Waterjet cutting machine

Abrasive waterjet machines are susceptible to destroying themselves. Combine 50,000 pounds per square inch (PSI) of water pressure with abrasive, and any part of the system that comes in contact with either of these elements—or both—will need to be replaced at some point.

The typical cost of operating a waterjet, including the cost for the machine, the operator, and overhead, can run around $85 per hour . If an operator is not careful about how maintenance is performed, that hourly cost can increase by 10 percent or more because of increased consumable usage and downtime to repair or replace items. Depending on market conditions, this increased cost can put a serious crimp in end users' profits.

This maintenance checklist can help fabricators understand their waterjet cutting machines better and learn where the best opportunities are to keep operating costs reasonable and downtime to a minimum.



Check the Water Quality
If fabricators are concerned about water quality at their homes, they should be especially concerned about water quality for their waterjets at their shops. This is perhaps the biggest factor controlling consumable costs. Hard water can cut expected life of consumable items at least in half.



Before making a waterjet purchase, a fabricator should test incoming water. It's imperative that the water quality meets the waterjet manufacturer's specifications if it's to operate as designed. Most pump manufacturers want to see less than 100 parts per million (PPM) of total dissolved solids (TDS), a measurement that tracks the amount of inorganic solids dissolved in the water that contribute to hardness, such as magnesium and calcium. Less than 10 PPM of TDS also can create problems, as the water actually will leach material from any component that it touches.

If the water needs treatment, at a minimum the fabricating operation will have to invest in a water treatment system. A water softener, which can have a price tag of $3,000 to $6,000, costs only pennies per hour to run and is generally all that is required if the incoming water is less than 200 PPM TDS. Overflow from this type of system goes directly to the drain.

If the incoming water is 300 PPM of hardness or greater, a reverse osmosis system may be more cost-effective in the long run. A reverse osmosis system can cost $20,000 to $30,000, which includes a chiller, but it can deliver water with more than 300 PPM of hardness. It costs about $0.20 to $0.30 per hour to run such a system, and the overflow is drained into public sewers.

A water recycling system calls for a similar investment as the reverse osmosis system and produces a similar type of water. However, it's considered a more environmentally friendly system because water is not drained; it's constantly reused. It costs about $2 to $4 per hour to run, which covers filters and electricity. The labor and downtime associated with changing out the filters also should be considered.