An ambitious predictive maintenance plan started four years ago is paying off in reduced maintenance costs and improved uptime at Aarrowcast, while an expanding alloy line is attracting new customers and new work.

Shannon Wetzel, Senior Editor

(Click here to see the story as it appears in the July issue of Modern Casting.)

Al Gambsky, predictive maintenance supervisor at Aarrowcast, Shawano, Wis., is at the white board, writing out the seventh bullet point describing the company’s predictive maintenance plan. It’s an abbreviated version of the 52-page document he compiled earlier this year—pages of stats, charts and instrument readings that was submitted for the AFS Plant Engineering award, which Aarrowcast won. Gambsky is clearly passionate about the work, and after three years of steadily increasing the machinery points measured and logged, Aarrowcast sees a direct correlation among predictive maintenance, decreased downtime and increased molds made per hour.

As typical in many manufacturing facilities, Aarrowcast’s maintenance plan involved repairing or replacing machinery and equipment parts on a scheduled basis. Within this plan, sometimes parts broke before scheduled maintenance; other times it seemed parts were being replaced when they still had life left in them. Gambsky had the radical idea to use various monitoring devices to detect when a part was about to fail. The management team at Aarrowcast had the good sense to let him try.

Aarrowcast is an iron casting facility with three sand molding lines, including a unique Georg Fischer high pressure impact sand casting line that makes metal parts in the range of 400 to 1,800 lbs. Installed at Arrowcast in 1997, it is one of the largest jobbing automatic molding lines in the world. In the late 1990s, the metalcasting facility embarked on a $20 million expansion and experienced a surge of growth. Since then, growth had stagnated, but now the casting facility is experiencing a resurgence thanks, in part, to its predictive maintenance program, as well as additional operating metrics, a focus on accountability, quality performance and a growing line of iron grades it pours.

“We have focused on establishing operating metrics and achieving them through accountability, supported through visual management. Our success has come through there,” said Randy Brull, president and COO at Aarrowcast. “Through operational performance, we have been able to lower our cost structure which has helped us become more competitive.”

Heightened Senses

Aarrowcast’s current predictive maintenance plan (the company calls it PdM) began in 2011. At that time, the three molding lines, including the 16 x 20 impact, 36 x 40 jolt squeeze and 60 x 85 high pressure impact molding, were equipped with motor condition monitoring, stroke monitoring and infrared thermography equipment to begin collecting data points. New monitoring equipment has been added each year, including dew point monitoring, power logging, ultrasound and vibration analysis. Gambsky and another full-time predictive maintenance associate on staff read and translate what the collected data is telling them. As Gambsky puts it, “PdM uses test equipment and techniques that enable the extension of the technician’s senses past those limitations imposed by human biology.”

Since the plan was first started in 2011, availability has improved 50% for all three molding lines. The high pressure squeeze molding line—the company’s bread and butter—improved its availability by 3.7% to nearly 96% availability. This has equated to a growth in production from 15 molds per hour to 20, according to Brull.

Closely monitoring working machinery parts helps Aarrowcast avoid unexpected delays caused by repairs. For instance, Gambsky and his predictive maintenance associate monitor the vibration levels and ultrasonic readings of motor bearings in the machinery. They noticed that one bearing had been working fine until the ultrasonic readings indicated a lubrication issue. After lubrication, the dB level in the ultrasonic measurement dropped, but later in the bearing’s life cycle, it started to rise again, as did the vibration levels. This was a red flag to the predictive maintenance team, and they planned for replacement of the part during a scheduled outage. When the bearing was removed and inspected, its wear pattern indicated a ball cage defect, which would have caused the rapid increase in vibration. Aarrowcast avoided an unplanned breakdown from the defective part through the use of its predictive maintenance technologies.

“There was no warning that would have been detected by anyone inspecting this bearing in any traditional way,” Gambsky said. “No heat was being created, and no audible noise was evident.”

Stories like that of the motor bearing have played out time and again at Aarrowcast in the last three years.  

Not only is Aarrowcast avoiding unplanned breakdowns, in some cases it is also using parts longer, leading to maintenance savings.

“One of the benefits is a tremendous savings in maintenance parts expense because we don’t just change parts out on a periodic basis—we run them much closer to their natural failure,” said Jack Smith, Aarrowcast VP operations. “We only change them when they need to be changed.”

Aarrowcast paid special attention to the individual movements of its high pressure impact molding line that occurred at the same time and looked at how that affected the machinery’s performance. What they found was the hydraulic pump in its regular operation was extending oil to its two big cylinders simultaneously, which was starving the system for oil.

“We changed the sequencing so it would extend the oil to cylinder A and then cylinder B.” Smith said. “The summary is we have been able to speed up individual elements of the machine and that has contributed to improved cycle time. The machine runs better because up time is better, but it also runs faster.”

Beyond Gray and Ductile

The increased speed and lower cost structure accorded Aarrowcast by preventive maintenance have given the casting business a competitive edge. Meanwhile, the management team, which consists of several new leaders who brought new initiatives to the operation, also began strategies to improve operations and increase sales.

Smith, who joined the company four years ago, brought with him a behavior-based safety program that he had experienced success with before. This purchased program, called “Safe Start,” was started three years ago to help workers keep safe operations a focus of their daily activity at the facility.

“We have seen a huge improvement in our safety culture, and it is so important to us,” Smith said.

Since 2012, Aarrowcast has seen a 63% reduction in its incident rate, which it attributes to improved employee accountability, better training programs and the implementation of Safe Start.

On the sales side of the equation, the metalcasting facility is taking advantage of the opportunities in developing new grades of alloys that provide customers properties they need at a cost savings.

Aarrowcast had dabbled in various iron alloys but mostly stuck with gray and ductile iron until a customer approached the company with a need for a part with high toughness in cold temperatures. Together with the customer, Aarrowcast developed a method to achieve high toughness at -40F as-cast. The success of that project encouraged the metalcasting facility to pursue more jobs requiring high properties.

With its existing metallurgist Cesar Braga on staff, Aarrowcast experimented with new grades of alloys project by project, focusing on achieving the properties demanded by customers for specific applications. Close collaboration with customers has led to high impact property, high strength and wear resistant as-cast alloys that save in heat treatment costs.

Now, the metalcasting facility pours dozens of grades of iron, including all standard grades, as well as base metal for a number of grades of ADI, high impact property as-cast ductile, and gray iron for heavy sectioned parts.

Aarrowcast’s melt department is set up well for handling a wide variety of alloys. It has six relatively small (9-ton) furnaces and no holding furnaces, so the operation can rapidly change metal grades in the melter throughout the shift. Additionally, Aarrowcast has the ability to send metal from any of the six furnaces to any of the three molding lines. As Smith put it, the metalcasting facility is not hung up with a big holding furnace with just one grade of alloy.

“The ability to pour these exotic grades plus the flexibility of the way we are set up in melting plus the skill of our metallurgists, those are all things we have used to secure new business awards,” he said. “That is ongoing and continuing to grow.”

The potential for the alloys lies in their ability to replace steel fabrications or achieve certain properties as-cast—without heat treatment that can add cost. According to Smith, ADI and its high impact as-cast alloys offers the biggest growth opportunities.

“ADI has more potential than anything. The demand for its high strength is found in applications in just about all of our markets,” Smith said. “The as-cast high impact alloy is finding additional applications and a good bit of that is in the transit market. We don’t have to heat treat while still meeting impact properties.”

In a couple of short years, these more exotic iron alloys have grown to make up about 25% of Aarrowcast’s business, and the company is looking to continue to increase that number.

“We are looking for opportunities in the nonstandard gray and ductile iron grades. We have small furnace sizes and flexibility in pouring different versions,” Brull said. “We see a market for low temperature, strength and resistance properties.”

Aarrowcast is heavily segmented into the agriculture market and seeking to branch out. Potential growth markets include construction, oil and gas or valve body. These markets, Brull believes, are good fits for what Aarrowcast does well: produce heavy iron castings engineered to withstand rough conditions. Its success will hinge on the high pressure impact molding line making these parts. Predictive maintenance has increased its running time. Initiatives like six sigma, accountability metrics and visual management boards have helped reduce scrap considerably and reach 99.5% on-time delivery.

“We are looking at growth at all lines but are focused on the Georg Fischer line,” Brull said. “Aarrowcast comes and goes with that line. We are looking for growth across the board, but the Georg Fischer is the first priority.”