Calculating cuts

Waterjet cut calculator app can help generate better throughput/profits

cutting waterjet
Abrasives are often the costliest consumable for waterjets. Using a higher power pump can lead to cost savings.

It’s easy to get locked into a process, feel confident in what has “worked” in the past and stay with the status quo. But in manufacturing, finding more efficient and affordable means of cutting parts can involve shaking up the status quo and instead of asking, “can I cut this?” involves asking, “can I cut this more affordably?”

This is something the folks at KMT Waterjet have put plenty of thought into, developing apps that provide manufacturers and fabricators with information to make cuts more effectively, right at their fingertips. KMT’s Cut and Cost Calculator 2.0 is the newest iteration, bringing in more options for users to dial in their cut performance.

Cut calculator

Bob Pedrazas, marketing manager at KMT Waterjet, says many waterjet users could probably be getting a lot more out of the process if they had a better understanding of what their actual options are. For example, using KMT’s cut calculator app allows users to input all the parameters they currently use, but then punch in the same information with a different size pump to realize how much more throughput and lower the finished cost per part they could be seeing.

performance statistics
KMT’s cut calculator offers easy-to-read graphics that show performance statistics.

Pedrazas uses the analogy of cars on an interstate as an example. A manufacturer can see through using the app that their vehicle is cruising at 50 mph with their current waterjet technology and operating variables. However, they could be doing 70 mph if they made some changes in the pump size and pressure velocity.

“That’s why this cut calculator is so enriching,” Pedrazas says. “It doesn’t have a bias. If you’re a startup – here’s your throughput … I can’t think of anything that would be a better service for the industry than to understand what the horsepower, velocity and pressure mean in terms of cost per part and your profitability.”

New options

Users of the previous KMT cut calculator will be interested to know that the new one has been built from the ground up to offer a better experience. For example, there are more materials to choose from (25 total), and a wider range of pressures, from 55,000 psi up to 90,000 psi. Users also have more horsepower options, from 15 hp up to 125 hp, as well more abrasive rates to input. OEMs will enjoy that they have access to a new cost estimator.

Tom Sanders, KMT Waterjet’s director of sales and marketing, says given the varying degrees of horsepower and pressures, size of orifices and many other variables, “there’s a lot of complexity with waterjet. So, this app is simplifying the process and giving a graphic presentation that users can really enjoy.”

Geoff Ericson, KMT Waterjet’s area sales manager, Midwest, has more than 20 years of experience in the waterjet industry and was instrumental in developing the app. He explains that users first select English or metric as their preferred unit type, select hard rock or alluvial abrasive and the thickness of the material being cut.

KMT’s app
Many waterjet users aren’t aware of important stats, such as cost per part and cost per job. Punch in a few details on variables and KMT’s app will estimate the costs.

“Versus our old calculator,” Ericson says, “we have the ability to go much thinner and go up to 9 in. of material thickness.”

Ericson explains that users will see “Pump 1” on the left side of the screen for higher horsepower and higher pressure pumps and “Pump 2” on the right side for lower horsepower and lower pressure pumps. This gives the user a side-by-side comparison of how one option compares to the other after all the variables are input. After choosing the horsepower and pressue, the other variables include orifice size, focus tube diameter and abrasive rate.

Once these variables are input, the user gets the results, which show how many linear inches per minute they can expect at the corresponding edge qualities, which include rough, course, medium, smooth and fine. For demonstration purposes, Ericson’s scenario was for half-inch aluminum 6061 being cut with a 50-hp pump set at 55,500 psi using hard rock abrasive. The app’s results show he could cut 32.66 ipm at “rough” edge quality, or 7.76 in. at “fine” edge quality.

“What’s really nice about the new application is it gives the ability to see the material and all the cut parameters on the screen now,” Ericson says, “so I can take a screen capture or email myself the results.”

KMT’s app2
Want to know how much time it will take to cut through thick metal? Enter the pump size and pressure into KMT’s app and find out.

Users can tweak their current variables to see if they can improve efficiency. For this example, Ericson changes the orifice size from 0.011 in. he had entered in the original demonstration to the largest orifice size of 0.014 in. The app shows that by simply changing the orifice size, he can gain 34 percent faster throughput speeds at the “rough” and “fine” edge qualities.

Sanders notes that many waterjet users don’t realize that they’re not optimizing the machine and are missing out on higher throughput rates.

“This could be a great tool for someone to really see that increased yield and throughput with a given pump just by changing out the orifices,” Sanders says.

Pump and pressure

KMT Waterjet manufactured the first 90,000-psi intensifier pump in 2008, which marked a significant advancement from the 60,000-psi technology. And while every manufacturer is not going to need 90,000 psi technology in their shop, getting a glimpse at how 90,000-psi pumps can impact throughput can be an eye-opener and a potential money maker. It can also help a customer determine their return on investment should they want to upgrade.

Ericson demonstrates how the app can be used to calculate the differences between a 50 hp pump at 55,000 psi and 60 hp pump at 85,000 psi. Again, using half-inch aluminum and hard rock abrasive as the example, the app quickly shows that upgrading to a 60-hp 90,000-psi pump increases throughput up to 59 percent depending on the edge quality. That scenario represents a modest upgrade, but for a shop that has a need to ramp up production to the extreme, upgrading from a 50-hp 60,000-psi pump to a 90,000-psi, 125-hp pump can dramatically improve throughput by up to 174 percent.

power pump
For waterjet operators looking for improved throughput, upgrading to a higher power pump can be the answer.

“By changing pressure and velocity of the stream,” Sanders says, “we know that this has an impact on a multitude of materials, from cutting aluminum to titanium to carbon steel, the 90,000 pressure does make a significant difference. This app really gives the end customer the black and white evidence required to run your business.”

Cost per cut

While edge quality is often high on the list of priorities and getting better throughput is attractive to any manufacturer, seeing how the cost per part and cost per job is impacted can be a real eye opener, which is something KMT has built into the OEM access portion of the app.

Users begin by entering the number of parts they’re cutting, the length of the cuts, the labor cost per hour, the cost of the abrasive per pound, the desired edge quality, the cooling water and cutting water costs per gallon and finally the electricity rate. Once the user hits “calculate job cost,” a cost comparison summary appears showing how changing the pump will impact costs, in a written comparison as well as a graphical (bar graph) comparison, both of which can be emailed.

In Ericson’s comparison of a 50-hp pump, 60,000-psi pump to a 60-hp, 90,000-psi pump, cut speeds increase from 16 imp to 26 imp and cut times per job decrease from 11 hours to 7 hours. In his demonstration where 300 parts were being cut, he could expect to save $135 on abrasive alone by upgrading to a 60-hp 90,000-psi pump. Those stats are important, but the app also shows that the upgrade would decrease cost per part and cost per job by 34 percent.

“This is something we have tried for many years to emphasize to folks on the front line,” Sanders says of the estimating the cost per part and cost per job numbers. “The cost per part is really where the rubber hits the road.”

KMT Waterjet

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