Cores, cores everywhere: many metalcasters are swimming in inventoried cores, but certain strategies can help keep them afloat.
The company had implemented a new enterprise resource planning (ERP) system, which meant completely overhauling the plant's existing databases and recordkeeping. The company is still refining and developing the complex system, and management suspects that the long process has been a drag for the metalcasters.
Today, management believes the employees at the plant must feel like they were thrown a life preserver. It's difficult to say whether the installation of the new resource planning system has been a success or not; the company decided to implement it to update their 20-year-old, homemade resource planning software, not to accomplish any predetermined goals. But by at least one measure, the facility is now operating more efficiently. When one of the company's vice presidents used to walk through the plant, he saw a facility that was storing too many inventoried cores, which can lead to lost orders, cores that are never used, broken cores, and an inefficient use of floor space. The plant no longer has these problems.
According to the executive, who requested that his name be withheld, the metalcasting facility has reduced core inventory by 33% to 50%. The employees think they can improve further. Because the plant is now manufacturing cores to meet molding needs rather than running the core room as its own entity, the vice president said the difference is visible when walking through the plant.
According to several metalcasting consultants, the facility in this story is not an island. Because the core room has to keep up with the rhythm of melting and molding, many facilities suffer from similarly excessive core inventories. Fortunately, installing a company-wide ERP system isn't the only solution. In fact, it's not even a solution in and of itself. The system merely provides a tool that can be used with the proper training and management techniques.
"It's really scheduling, organization, planning and execution," said Peter Macler, president of Peter E. Macler Associates PLLC, Canyon Lake, Texas. "It's training the people on the floor to maintain the organization of the cores in the system. If you can eliminate those wastes, there will be fewer cores scrapped and less unnecessary work in process, so costs will be reduced, quality will go up and there will be fewer interruptions. There are plenty of upsides."
ERP systems like the one at the unnamed plant are updated, computerized versions of the order tracking systems metalcasting facilities have been using for decades. Macler said that some type of resource planning system is necessary for successful scheduling of cores.
"Order entry systems that will handle the breakdown of work, routing and workstation loading will tell you if you have enough core capacity on such and such a day to maintain the production you need," he said. "If you have tools to help you with that, scheduling becomes a bit easier."
But for job shops, proper scheduling can sometimes feel more like walking on water than a walk in the park. When you're shifting between a half dozen different part numbers on any given day, you have to be at least slightly ahead of the curve in order to keep production flowing.
"We try to have the next week's production mapped out, but it doesn't always work 100% correctly," said Jerry Monroe, project manager for General Motor's Saginaw Metal Casting Operations, Saginaw, Mich. "Typically, we plan at least three days in advance and try to maintain two days between making a core and running it."
For example, Monroe said his plant might be running 70% of part A and 30% of part B one week, only to have the volumes flip flop the following week. Because his schedules aren't hard and fast, he simply can't make cores to order, or just-in-time.
If the central goal in streamlining the core room is to minimize the number of cores you produce in excess of what you are molding, but letting your bank of cores sink too low means you risk inflicting a drought on molding and melting (a costly stoppage for any metalcasting facility), how far are you willing to go to keep your plant from being flooded with cores?
To answer this question, job shops can at least take a cue from high production shops, which for the most part can afford to let their core excesses sink a little lower. Those shops have a better understanding of what they will need and when.
"We took the core right out of the machine, processed it, and set it in a fixture to take it to the molding line and set it in the mold," said Norris Luther, president of metalcasting consulting firm Luther and Associates, Tucson, Ariz., and a former manager at a high-production automotive facility. "That meant that we didn't have very much of a bank and never went into a big surge."
Handling and Storage
When it comes to handling in any metalcasting application, less is always more (both for minimizing labor and breakage), so Macler suggested maintaining your core room as close to your molding line as possible. Melting and molding generally already hold a permanent place in the facility. The location of the core room, on the other hand, sometimes can be adjusted to minimize the transfer distance from core room to molding line. Monroe said this strategy works well for the green sand line at Saginaw Metal Casting Operations.
"They're back to back, right beside each other," he said.
Monroe's plant also meticulously organizes its excess cores once they are produced. "Our cores are all stored on color coded racks by part and core type," he said. "For visual control, you know which core is in which row. We store each type of core no more than eight racks deep and double stack the racks."
Macler said all shops should attempt to store cores in such an organized and systematic way, with small cores on racks and large cores in preset locations on the floor of the facility. The storage location ideally should be as close to the molding areas as possible; however, the problem in many shops is that the space required for storage has not been set aside in the first place.
"You have to have sufficient floor space to organize the cores," Macler said. "That's not having 100 sq. ft. over here and 200 over there and kind of a quilt effect."
The shelf life of cores also should be taken into account. Macler said shell cores will keep almost indefinitely, but coldbox cores can pick up moisture from the air within a week if they are not stored in the proper conditions.
"Unless you have a room with controlled humidity, you are going to get more scrap because you soak in moisture or you dry out the core too much," Luther said. "You have to have a controlled storage room."
A disorganized core room often is indicative of a larger, organizational concern.
"It's usually a bigger problem than just the core room," Macler said. "If you walk into a [metalcasting facility] that has a disheveled core room, you're likely to find that throughout the rest of the shop. It is a matter of the total organization and dedicating floor space to certain activities and training people to repeatedly update and retain the quality of an organized system."
The core room workers at Kirsh Foundry Inc., Beaver Dam, Wis., were guilty of being part of just such a larger concern. They were tricking management.
"You'd find out cores you needed tomorrow wouldn't be ready," said Jim Kirsh, company chairman. "But shell cores you would need two weeks from now would be in finished production." The core room had been purposefully performing the jobs that were easier or more lucrative in order to cheat the system and keep Kirsh Foundry from operating as efficiently as possible. But Kirsh and his brother Steve, the company's president, had an ace up their sleeve. They were already using a tried and true method of improving their overall business one process at a time--bringing in Engineered Foundry Systems, St. Louis, Mo., to help reduce material handling.
"You just don't realize how much time you waste handling material, within a department and between departments," Jim Kirsh said. "The process template applies to almost everything. You can overlay it on shakeout, the finishing room and the core room."
In the case of the Kirsh Foundry core room, EFS first looked at the number of employees involved in the production of cores. Several operators were required to work each core machine, but by grouping similar core machines in close proximity (shell with other shell, coldbox with other coldbox), one operator was able to work several machines.
Next, the team focused on the various operations required to produce completed cores. The metalcasting facility had in the past moved the cores in batches from station to station--blowing to filing to coating--placing them in boxes before passing them on. Kirsh Foundry installed an 80 ft. conveyor belt to eliminate this problem. The cores now are blown, placed on a conveyor belt, shuttled to filing, returned to the belt, and so on. They are not put into a batch until they go to the staging area prior to being inserted at molding.
Kirsh admits the core room at his job shop will never flow continuously into molding. But because the company is now making cores faster than they ever had, they produce a smaller bank of cores before going into the staging area.
"The staging area is a small room, and I [told the core makers], that's all the space you have," Kirsh said. "If that space is filled, you're producing too far ahead. Now, we produce only about three days ahead. It's closer to an adjusted time operation than a batch style finished production operation."
What's more, the conveyor system helps the company maintain a first-in-first-out coremaking operation, and the employees can no longer trick management by opting to do certain jobs out of order.
"It was a relatively inexpensive investment in our core room to get a big return on our labor savings," Kirsh said.
For More Information
"The Choice Is Cores," S. Kruse, MODERN CASTING, February 2007, p. 29-32
Shea Gibbs, Senior Editor
Spending the Big Bucks
Capital investments also can help you get your core room ahead. Modern core machines are faster than their predecessors and generally offer improved rates of tool change. According to Norris Luther, president of Luther Associates. Tucson. Ariz.. installing a new core machine with elevated capacity can in some cases be a viable solution for a company that can't produce cores fast enough.
"You have to have a good study of it and determine what value it's going to have and what your production is going to be," he said.
Jerry Monroe. project manager for General Motor's Saginaw Metal Casting Operations. Saginaw. Mich.. agreed that modern core machines can make the best of the sticky situation that is core stockpiling in the job shop.
"On some of our machines, we've gone to a quick tooling change operation." he said. "That helps a lot in turning a core machine over. The [changeover] used to be two to four hours, and now they're down to less than ten minutes for the tool itself. In as little as half hour, we can be making the next core."
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|Date:||Feb 1, 2009|
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