Developers of casting process simulation software release updates with such frequency that its tempting to overlook how much the science has advanced. Much of this progress has resulted from the advent of multicore computing, which makes it possible to run complex programs much faster than was possible when simulation emerged in the 1990s. This has allowed software developers to hone numerous new functions that simulate specific details of the casting process, and it allows users to execute simulation faster and more thoroughly. Effectively, it means that casting simulation is more than a demonstration of a specific process (e.g., coremaking); it is part of the collaborative effort to optimize foundry operations and product design.
Recent months have seen the introduction of ESI Group’s Casting Simulation Suite, which it states allows metalcasters to forecast an entire casting process, including filling and solidification defects, mechanical properties of finished castings, and the nature of complex part defects. The suite includes the ProCAST and QuikCAST programs, and effects rapid visualization of the casting process so operators can make accurate decisions during the design stage.
Another recent update is Magma GmbH’s Magma5, which is proficient for all cast alloys and processes (sand casting, permanent mold casting, and diecasting.) It lets users model the final component, determine the melting practice and casting method, and test the different effects of mold making, heat treatment, and finishing. It simulates every stage of product development, from geometry input to the design of gating, risering and tooling, and coordinates voluminous amounts of relative information, so that the user has a thorough view of the manufacturing process.
A recent introduction by Flow Science Inc. (www.flow3d. com) came with a specific pitch to smaller foundry operations. Its new Flow-3D Cast is an extension of the Flow-3D platform with dynamic meshing for easy model set-up; material libraries for metals, molds, filters and risers; and extensive post-processing capabilities, all accessible from a user interface tailored by casting engineers. “Flow-3D Cast should help make our highly accurate simulation tool accessible to a broader spectrum of users, including smaller shops, leading to reduced energy and material waste and increased productivity,” stated Flow Science Inc. president Thomas Jensen.
Why should simulation software be assumed to favor large foundry operations? True, they have the product volumes that make production planning so critical, and there’s no margin for error if a riser is out place and a long run of castings has to be scrapped. But, those same marginal-cost benefits apply at any foundry, and notably because of the increasing affordability if computer hardware, simulation software is having a dramatic impact on smaller foundries. It gives a small engineering staff the expertise that might not be available in any other way.
Cutting through complexity
Pier Foundry & Pattern Shop, Inc. in St. Paul, MN, would not be considered a large operation. It is a jobbing shop, primarily a green sand foundry (four lines) but with an air-set line available for large-volume pours. It may not be a big operation but it’s a complex one, pouring all grades of gray, ductile, and austempered ductile iron in several flask sizes, for various markets — agriculture, oil and gas, water utility, hydraulics, and power transmission, according to Pier Foundry president and COO Matt Grilz.
Whatever the product, Magmasoft has a central role in Pier Foundry’s production planning. “Once a job is accepted we will run a solid (model) only, on just the part, to see what area needs to be fed with a riser,” Grilz explained. “Then, a gating and riser system is designed using Solidworks and again run in Magmasoft, to verify effectiveness. If any issues are seen, modifications to the gating system are made and re-run in Magmasoft for verification. This process is repeated until favorable results are achieved.” Accelerating and certifying all that calculation is a considerable advantage for any operation seeking to maximize time and resources.
Magma5 is not the first simulation software that Pier Foundry has used, but it’s user-friendliness has made it a much more effective tool than the earlier products. Grilz expressed appreciation for the training and user-support available with the software, and noted that the program’s graphics capabilities make the results easier to read and deploy.
As examples, he explained that Magmasoft allows Pier “to evaluate customers’ designs and give them suggestions that would make for a more cost-effective castings.”
Furthermore, several of the jobs on which Pier has used the program were ones that had been resulting in high levels of scrap. “We have been able to successfully reduce scrap rates on these jobs which in turn opens up capacity,” he said. And in terms of finished product quality, Grilz said the software allows his team “to see the iron flow and potential defects that may be caused by the iron/air interface,” so they’ve been able to adjust their gating designs to improve the parts.
Simulation hasn’t solved every problem for Pier Foundry: Grilz said he’d like to have more insight into the core-gas effects on cast products, and that he’d like a function “to calculate the amount of cope lift,” but it’s plain that Magmasoft has had a positive impact on the business as well as its processes, and on customer service: its design engineers and even sales representatives are able work with casting buyers to make product design more effective for both sides.
Invaluable data
Another “small” company benefiting from simulation software is May Foundry and Machine Co. in Salt Lake City. It’s a 50-person operation with machining and heat-treating capabilities, in addition to pouring ferrous castings in a long list of grades — stainless, low-alloy carbon steel, gray iron, white iron, and ductile irons, among several more. It’s a no-bake molding operation pouring up to 120-in. flasks
Plant manager Mike May reports that his operation also runs Magma5 simulation on all new steel casting orders, and selected iron casting jobs are assessed to ascertain the filling characteristics. “Problem jobs are also identified through scrap analysis,” he said, “and run through the program and evaluated for potential re-rigging of the patterns. We have a continuous list of jobs up for reevaluation,” May indicated.
It is the first simulation software adopted by May Foundry, and the plant manager notes that the ability to “tweak” material relationships to reflect actual conditions seems to be its most valuable effect. “I appreciate the ability to ‘tweak out’ specific materials and their relationship to other materials, to more accurately reflect how we produce castings and to correlate simulation results to our observations,” he said.
May Foundry’s adoption of simulation software may have been delayed because of a misperception that it didn’t need such a capability to maintain its business, but increased competition from foundries around the world had Mike May looking for any competitive advantage. And though it came with a requirement to learn the skills and techniques of simulation, a three-day training program together with some previous experience in solid modeling gave him and his colleagues enough expertise to be effective with the progam.
“We learned a lot during the implementation process,” May recalled. “We have a lot of knowledgeable personnel around here that have years of experience making castings. Once we started using the program and showing that their methods could be improved upon we had fewer skeptics, as better and better castings turned out.
“The other issue during our implementation was ‘data’,” he related. “Trying to determine what process parameters as well as output parameters were relevant and accurate to our foundry took a little while. Like the adage about statistics, you can use (simulation) to prove or disprove every argument surrounding a certain casting. Figuring out what is accurate both on the output side as well as the input, is very important to our results.”
His point is that in addition to improving casting operations, simulation software makes the operators better at what they do because it defines options and results so clearly.
“We had a project we took on that was a weldment-to-casting conversion,” May detailed. “We estimate we saved the customer 30% in terms of overall production and material costs by casting it as a onepiece casting. Just about every casting we successfully run in our simulation program we estimate to have about a 20% cost savings in terms of rework, grinding and finishing, and scrap costs.”
He clarified that the foundry estimates every casting job it optimizes through simulation experiences on average a 30% production-time improvement because defects are reduced. “The specific conversion experienced about a 15% production time improvement overall,” May said.
“Finished product quality is virtually un-comparable when you use a simulation package, versus conventional methods,” Mike May added. “Now, we have a quality level we can rely on rather than wondering if the casting fed correctly or how much slag and oxidation defects we will have to fix on specific pours of metal.”
Simulation software will not solve every problem. May indicated a desire for more realistic determination of sand erosion, and he expects that functionality will emerge. But, for this “small” foundry the advantages have been demonstrable.
“Most of our customers are aware of our capabilities,” he said, noting that May Foundry has won new business and new customers based on its simulation capabilities. “We have now reduced our scrap rate so much, and ironed out the wild runs of scrap that we used to have, that we are starting to gain some customers back that couldn’t deal with the variability in our quality before we added simulation.”