It’s astounding that a modern hydraulic breaker provides a useful life measured in years, since under normal operation, one piece of metal attacks another piece of metal up to 1,000 times or more per minute. “Just the mere nature of that activity is destructive,” says Jim Lafon, attachments project manager, Doosan.
The only thing preventing your hammer from turning itself into scrap metal is a good preventive maintenance plan — a necessity to reduce downtime and cost. “A preventive maintenance program allows you to take care of the little things before they turn into something big,” says Keith Becker, product development specialist, construction tools, Atlas Copco Construction Equipment.
Tracking use allows scheduled major maintenance intervals. The industry standard is one year equates to approximately 2,000 hours of carrier operation. Lafon reports that breaker run time is about 25% of carrier operation time. So the average breaker accumulates 500 hours of run time a year. Typically, manufacturers design hammers to be torn down and resealed on a yearly or 500-hour basis.
No matter how much maintenance you perform, as a breaker ages, operating costs will escalate. “Design, material and workmanship have a lot to do with expected lifespan,” says Becker. “As the breaker wears and ages, it may not hold up as it did before, leading to more downtime and increased maintenance cost. There will be a time when the breaker needs to be updated. This is not to say the older unit should be scrapped. It may be good for a backup or for use on lower profile jobs.”
Start with proper setup
The first step in ensuring longevity is to properly set up and size the hammer for the job. “If a small breaker is used on a job that requires a much larger breaker, its life will be shortened. This is due to over-working or forcing the breaker to do more than it was designed to do,” says Becker. “A large breaker can do a smaller job or break smaller material, if it makes sense financially. In this case, the operator has to be cautious, controlling the size and power of the breaker.”
The hydraulic systems must also be set to match the particular hammer used. Hammers are designed to run within a defined range of hydraulic pressures and flows. “If it performs outside the design parameters, something is going to happen,” says Lafon.
A common error is setting the flows and pressures improperly or swapping a hammer from machine to machine and not following up to make sure it is set up correctly. “Flow relates to the speed at which the hammer operates,” says Greg Clinton, district service manager, Tramac. “If you over-speed the hammer and the material is failing to break, you start to bounce. When that happens, the reverberation transfers back up into the carrier.” This results in worn stick pins and bushings, and possible cracks on the arm or stick. “All of that energy has to go somewhere. Basically, it is just self-destructing the hammer.”
Some setups are not as tolerant to incorrect pressure and flow settings. “Because our hammers are variable-speed hammers, they sense when the material is breaking,” says Clinton. “As the material fails to break and the hammer bounces a little bit, our breakers are designed to shift more oil to the power side of the strike piston to lift it up so it hits harder. If you have too much flow or too much backpressure, that will hinder the ability for the hammer to shift and operate properly.”
Running the attachment too slow with low flow or pressure is not a good option either. “You can typically do as much damage running it too slow as you can too fast,” says Clinton.
Grease equals life
Greasing is the most important maintenance task on a breaker. Grease performs a two-phase job: it lubricates and it clears the tool bushing area of debris. But you need to maintain the right amount. “Too much grease and you may get a buildup between the strike piston and the tool top,” says Clinton. This absorbs striking force from the piston to the work tool. “Too little grease, now you have a lapping compound once it is mixed with the dust.”