Q: We operate a high production foundry that uses the Phenolic Urethane Cold Box (PUCB) coremaking process. We continually struggle with mixed sand build-up in the sand hopper and chute located above the core machines. This build-up gets very hard, and requires significant time and effort to remove. What causes the sand build-up, and how can we prevent it?
A: The sand build-up you are experiencing is most likely a result of the mixed sand exceeding its usable working life (bench life) and beginning to cure before it’s blown into the core box. While this is undesirable, it is common and seems to plague all PUCB operations.
Binder formulations can improve bench life and reduce the build-up that you are experiencing.
However, several factors negatively influence bench life and overcoming these factors with a formulation change is not possible. Factors like mixing speed, sand temperature, moisture (humidity), fugitive amine, and time have an impact on the mixed sand bench life. Therefore, preventing this build-up can be a daunting task that results in significant frustration. In addition to this costly build-up there is also the very real possibility that chunks of sand will get into your sand magazine and blow tubes, resulting in machine downtime.
New technology is now commercially available, through ASK Chemicals, that will greatly reduce the time-consuming chore of removing this build up, reducing costly downtime. The ISOSOCK was designed to provide a barrier between mixed sand and the surface of mixed-sand-handling components (hoppers, chutes, etc.) Made from a proprietary material, the ISOSOCK is tailor-made to fit your equipment. With the ISOSOCK, cleaning becomes very easy and results in very little downtime.
Simply shake the ISOSOCK or run a soft bristled brush down the sides of the ISOSOCK. Many “early adopters” have embraced this technology and are currently reaping the benefits of improved bench life (the ISOSOCK helps guard against fugitive amine, and reduces exposed surface area of mixed sand), quicker clean up, and less downtime due to blow tube plugging. It has also been reported that reducing clean-up time has improved the operator experience. Operational life of the ISOSOCK depends on several factors, like operating environment, volume of mixed sand, and grain fineness number (GFN) of mixed sand (coarseness.) From our experience, the typical operational life of the ISOSOCK can be 3-4 months if cared for properly.
Because each situation is unique, a visit from an ASK representative would be necessary to evaluate the potential application and record critical measurements. Once designed and fabricated the installation of the ISOSOCK is simple and straightforward putting you on the road to quicker clean up and less downtime.
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