How Does State Line Achieve 98% First-Pass Yield?
In the foundry industry, one of the most important indicators of success is first-pass yield.
If it’s high, customers can count on receiving excellent quality castings on a timely basis. If it’s low, they can expect delays, cost overruns, casting quality issues and other problems.
Thanks to its exceptional people, processes and technology, State Line Foundries maintains a 98% first-pass yield. This stratospheric number benefits its customers immensely – in the form of cost savings, part quality and on-time delivery.
What is first-pass yield?
Technically, first-pass yield is defined as the percentage of work in progress that flows through a process uninterrupted, minus that which is rejected, reworked or scrapped.
Roger Allie, process engineer at State Line Foundries, has his own definition of it:
“It’s the percentage of new castings that are approved by the customer the first time.”
Getting it right – from the beginning – matters. A faulty casting can lead to one or more expensive problems:
- Time lost, with delays sometimes stretching into multiple weeks,
- Expensive after-the-fact modifications to pattern tooling,
- Delayed prototypes,
- Production bottlenecks, and
- Excessive scrap costs.
It’s vital to OEMs that foundries optimize their first-pass yield. State Line accomplishes this in seven ways:
1. Utilizing advanced casting simulation software
Developing new castings historically required a great deal of trial and error, which was time-consuming and costly.
State Line has a more modern approach: It uses mold flow simulation software that enables its engineers to experiment with a variety of casting scenarios – with a very high level of accuracy. This enables it to accomplish in a virtual environment in a few minutes what previously took days or even weeks to perfect on the foundry floor.
“This technology is a big help,” Allie indicates. “You can test a lot of gating and riser configurations to see what’s going to work best. As far as getting good castings is concerned, those are two of the keys.”
These casting simulations can also help the State Line team to accurately predict casting porosity and shrinkage.
2. Real-world experience
Mold flow simulation software is a significant advance. But not everyone can use it effectively.
“You need some foundry knowledge and experience to run it,” Allie points out. “The software requires a lot less effort than the old trial-and-error method, but it’s only as good as the person using it.”
While the software is extremely efficient, considerable expertise is still required to use it well. “Running the simulations takes time,” Allie stresses. “Foundry knowledge helps to make that part of the process go faster, too.”
3. Testing, testing and more testing
Some foundries charge OEMs a fee for every simulation they perform. “We don’t do that at State Line – we just charge a flat fee that is built into the pattern tooling expense,” Allie emphasizes.
That pricing model helps its customers control costs. It also gives State Line the freedom to think creatively and pursue as many options as possible without running up the OEM’s bill.
Allie points out that limiting the number of simulations isn’t in the best interest of the customer, because each simulation that isn’t performed means that additional time must be spent using the older, less efficient – and more expensive – methods to test mold designs.
That’s why State Line will attempt as many simulations as the situation requires – more than a dozen on some projects. “The engineers who run our software are excellent problem solvers. They’re very good at trying multiple variations to find the best solution,” Allie asserts.
State Line’s commitment to robust testing is a key reason why it can achieve such a high first-pass yield. “When you add this rigorous approach to our depth of experience, you have a very good chance of getting castings that are done right the first time,” he declares.
4. Incorporating 3D printing into its processes
Combine the software with new 3D printing technology and the savings – and chances of success – are even greater.
“You can generate 3D printed molds and cores without having to make a pattern,” Allie explains. “You can create samples and do your testing before you build a solid pattern.”
Sand molds and cores can be printed using the customer’s mold designs. “We can do short turns to provide a test casting to see if that’s really what the customer wants,” he reveals.
5. Knowing exactly what the customer wants
Getting a casting right from the start requires upfront communication with customers. Sometimes, customers are unsure or haven’t finalized their design and casting requirements., Allie cautions.
“Ideally, the customer will have all the requirements they want upfront on the drawings, models and on the purchase order,” Allie advises. “If we proceed halfway into the project, and they say, ‘Yeah, we need this, too,’ then you may have problems.”
It does happen. “There have been occasions where customers will come along later and say they needed a material certification or they needed an X-ray,” he says. But they don’t share that until the castings have been poured. State Line Foundries is diligent about asking questions upfront in order to ensure a seamless sampling processes.
“It’s all about communication,” Allie states. State Line’s experienced team knows the right questions to ask, which usually helps to surface those unspoken needs upfront.
6. Solving old problems
Work that is transferring from another foundry to State Line also provides an opportunity for improvement. “Sometimes, a casting has had problems in the past, but the previous foundry was able to figure out a workaround to use it that way,” Allie explains. “It might have been that way for ten years. Now we’re making a new sample, so we can fix that.”
It’s often helpful when a customer shares the history of the tool. “We’ll occasionally have a new job and encounter a problem that we didn’t anticipate,” Allie recalls. “And the customer admits, ‘Oh yeah, we’ve always had that problem.’”
State Line can learn from that history to improve its chances of early success. In other words, these prior failures can help State Line improve its odds of achieving first-pass yield for that casting.
7. Building teamwork and processes
State Line has a system for starting new jobs. It includes capturing customer input and tracking progress as the work advances. All necessary certifications and test bars are readily accessible to all team members.
“We keep the communication going, from design and planning to the people doing the molding, pouring and cleaning,” Allie points out.
State Line’s team on the foundry floor is highly knowledgeable and experienced. “We have outstanding people who take pride in doing a great job,” Allie stresses. “You can have the best plan and design, but if you don’t execute it, you’re not going to get where you need to be.”
State Line Foundries helps you get the results you need – faster – by having the people, processes and knowledge needed to get it done right – the first time.
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Tags: casting design, casting quality, First pass yield, mold flow analysis, prototype castings, Transfer tooling