BESCAST Precision Investment Casting : why Extrude Hone’s contribution is worth it.
Today, we focus on one of our fantastic customers, BESCAST, a company based in Willoughby, Ohio, USA.
CEO Dave Palivec will answer our questions, especially about compressor impellers and the benefit of Abrasive Flow Machining within the Petroleum industry.
Who is Bescast?
Bescast was founded in 1945 and has grown into a premier, 80,000-square-foot, state-of-the-art precision investment casting operation–one of the most advanced in the world.
Bescast specializes in cast airfoil configurations, heavily emphasizing gas turbine engine and compressor components. Examples include :
- integrally cast compressor wheels,
- turbine wheels,
- turbine nozzles,
- fuel pump impellers,
- shrouded gas compressor impellers,
- and combustion swirlers.
As said, we will focus on compressor impellers for gas turbine energy businesses later in the article and interview. These impellers are commonly used in compressors associated with a land gas turbine.
Please wait a second before we dive into the interview with Dave Palivec. Before we do, maybe we can say a few words about Precision Investment Casting, a high-end technique.
What is Precision Investment casting?
Do you need intricately designed parts with thin walls?
Does your application demand precise casting with extremely tight tolerances?
It can be hard to manufacture components like these, but the investment casting process can be the answer for many challenging applications.
Investment casting produces parts with tight tolerances, excellent surface finish, and complex geometries.
This process involves:
- Produce an investment casting die based on a master pattern matching the end product, taking into consideration shrinking.
- Create a wax model of the part to replicate the product.
- Assemble the wax patterns, attaching them to the sprue to create a tree that will allow molten metal to flow in every portion of the cast component.
- Coating the wax with a refractory ceramic material top crate the shell
- Melting out the wax shell to leave a hollow mold matching the shape of the desired components.
- Pouring molten metal into the mold after heating the shell.
- Cool the shell to achieve solidification.
- Remove the ceramic coating.
- Finish the part. Surface enhancement includes fixing the surface default, improving the surface roughness, applying heat treatment, and minor machining.
Interview with Dave Palivec, Bescast CEO.
Bruno Boutantin Extrude Hone: Dave, please share with us a short introduction about yourself.
Dave Palivec: I am the President / CEO of Bescast, Inc. I have been with the company since September of 2021, and prior to that, I have been involved in manufacturing since 1989. Most of my time has been spent in foundries, starting in High Pressure Die Casting and most recently (2015 – Present) in Investment Casting.
BB : Today we decided to focus on compressor impellers. These critical components are combined in multiple stages, up to 10, in compressors that must deliver high efficiency. How challenging is it to produce these impellers?
DP: One of the primary challenges with producing these types of critical application parts is the presence of foreign material (ceramic fragments that are suspended in the molten metal during the pouring process.
These fragments are not allowed per the customer’s requirements, so they must be ground out and repair welded. Many times these fragments lie just below the “as cast” surface, and they are not easily detected without putting the parts through Non-Destructive Testing (NDT).
Latent defects (sub-surface) can be challenging to see and many times require excessive stock removal by way of die grinder.
Using the Extrude-Hone Abrasive Flow Machining Process (AFM), allows us to accelerate the uncovering of these small defects so that we can begin the weld repair process sooner, leading to better part velocity through the plant.
BB: Why is impeller surface enhancement critical?
DP: The part consistency is critical to the application, so the process needs to very controlled and repeatable. These products must meet critical flow and pressure requirements, so consistent passageway volumes are a must.
BB: Why is manual surface improvement not the perfect solution?
DP: Manually grinding out the defects can be very time-consuming, and it also allows for a high degree of variation based upon the operator’s experience. Abrasive Flow Machining allows for a very controlled and repeatable process, so we can minimize product touch times.
BB: What kind of manual finishing alternatives did you investigate before selecting Abrasive Flow Machining?
DP: We have experimented with Abrasive Vibratory Equipment, various types of grinding burrs, and equipment, all of which are not a substitute for the quality and repeatability that we get from Extrude-Hone.
BB: How did you learn about Extrude Hone? How easy was it to connect with us?
DP: I am an avid motorsports fan, and I have know about this process as it is used in cylinder head passage ways, axial flow jet pumps for personal watercraft and various other applications.
BB: How is your overall experience with Extrude Hone?
DP: Extrude-Hone has proven to be a very good partner to Bescast. They were very aggressive at working through the start-up phase, and they have sustained that sense of urgency throughout our relationship.
They are very responsive, and they have spent a great deal of time working with our Engineering Team members to optimize the use of AFM for our customers’ products.
BB: What other investment casting components would be a good AFM candidate as you produce different parts?
DP: We continue to look for applications that would allow us to take advantage of the AFM process. We make many different product families of parts for turbine engine fuel systems, so we are optimistic that we will be able to leverage this technology in the future.
BB: What does Bescast ‘s future look like these days? Any additional thoughts you would like to share?
DP: Bescast is experiencing record growth over the last two years, and we are forecasting a substantially better year in 2025, so we are very happy to have a partner like Extrude-Hone that is willing to do whatever is necessary to help support us into the future.
BB: Thank you, Dave, for your time sharing this great insight into the precision investment casting for compressor impellers.
Interviewer :
Bruno Boutantin
Marketing Director Extrude Hone Group
