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A precision stream

New waterjet features deliver more reliability, better uptime and lower total cost of ownership

For the past half century, Hypertherm Inc. has built upon its reputation as a provider of leading industrial cutting solutions. While it’s most widely known for its plasma cutting machines, in 2013, Hypertherm bought Minnesota-based waterjet company, AccuStream, paving the way for entry into a new market.

Hypertherm hired an independent marketing firm to research waterjet companies as part of its due diligence before entering the industry. The researchers found that AccuStream customers came back with the most positive responses, namely hailing product reliability and support services as the company’s top selling points.

Now, AccuStream is a Hypertherm brand focused on aftermarket parts while the line of pumps takes on a more Hypertherm-centric moniker – HyPrecision waterjet systems.

Merging the companies has given the waterjet line access to Hypertherm’s team of high-quality, experienced engineers.

“It’s been a good match,” says David Dumas. “The lean manufacturing and testing procedures that Hypertherm has in place improved the quality and consistency of the waterjet products.”

And Dumas would know. He began his career in the high-pressure water industry in 1987 and started working at AccuStream in 2007. Today, he works out of the company’s headquarters in Minnesota as a Hypertherm OEM sales manager for the waterjet products.

Time to change

Hypertherm is tackling a few different concepts in its approach to waterjets. One of the most important is predictive maintenance, which according to primary and secondary end-user research is high on the list of improvements waterjet users would like to see.

The various components within the pumps that need to be replaced over time is one area where predictive maintenance can be applied. The company has also worked on allowing operators easy accessibility to the main components and consumables, especially the low-pressure poppet valves and seals.

One of the most used consumables with waterjet technology, apart from abrasives, are the seals used in the pumps. In traditional waterjet technology, it is difficult for operators to know exactly when the seals need to be replaced. A few problems can occur because of this.

First, if a seal fails midway through a job, the work has to be stopped, the machine needs to be disassembled to gain access to the seal and there is a possibility that upon restarting the job, the operator causes a divot trying to find the exact place from which they left off. Furthermore, if a seal blows out and the operator doesn’t notice, it can lead to damage in other parts of the pump.

On the other hand, “if you replace the seal too soon,” Dumas says, “you’re wasting money and you have more downtime.”

Seal monitoring

To tackle the issue, Hypertherm created its seal maintenance technology (SMT), which can increase seal utilization by up to 40 percent, in part by closely monitoring the integrity of the seals.

Today, operators are instructed to replace seals when their intensifier is leaking one drop per stroke or more. This is both difficult to discern and relatively conservative.

Another way engineers improved seal life is by optimizing the stroke rate of the pump system. Specifically, they maximized the flow of water with as low of a stroke rate as possible. Part of the solution is Hypertherm’s plungers that are 1 in. in diameter whereas most manufacturers use 7/8th-in. plungers.

The patented SMT method involves detecting the number of drops that occur when a seal begins to go bad. An optical sensor actually counts the drops coming from the dynamic and static seals. The dynamic seal prevents oil from mixing with water in the intensifier. The static seal does not move and holds pressure in the system’s cylinder.

SMT alerts the operator regarding the status of the intensifier seals. For example, if the drop frequency increases beyond a certain point, the operator sees the SMT indicator light start blinking yellow, meaning seal(s) will need to be replaced sometime between 8 and 40 hours.

This can be helpful in several ways. “For example,” Dumas says, “if the drop count has activated the yellow light, which means you have between 8 and 40 hours of seal life remaining, and you have a 12-hour job, you might decide not to change your seals now and continue running.

“So basically, you could hold off changing your seals and opt to do that maintenance at a time that is more convenient to your operation,” he continues. “This allows you to plan for your service rather than do the ‘firefighting’ that is all too common today.”

The SMT feature is standard on a new line of single intensifier pumps called HyPrecision Predictive Pumps, which were unveiled in late October. Availability of dual intensifier predictive maintenance pumps is expected sometime in 2020.

Intensifier tech