Arena-Flow

Case Study: Core Scrap Reduction

look inside virtual tooling to understand and reduce costly scrap rates

The Problem

Core miss-fills can be a major problem; a more subtle problem is scrap reduction. What level of scrap is acceptable? If you have 5% scrap for a particular core, why were nineteen good cores produced for each defective one? How reliable is your quality control to ensure problem cores do not result in problem castings?

The Solution

Arena-flow is the foundry engineering software package used to model the filling and curing of sand cores and molds. Arena-flow's unique Computational Particle Fluid Dynamics (CPFD) numerical formulation models not only the granular sand motion and air flow in the tooling, but also the significant interaction between the two. Using Arena-flow, engineers can numerically "look inside" the tooling to view how the sand is filling the cavity. While nineteen out of twenty cores might fill fine, the underlying filling behavior will be suboptimal - and the calculation will reveal this.

The Cost-Savings

On a bad day, one Arena-flow customer had about a 15% scrap rate for a cylinder block water jacket core; a significant factor in the scrap was a low density defect which intermittently appeared in thin sections. The Arena-flow calculation showed the core filling, as did the foundry - 85% of the time! The Arena-flow calculation further revealed an extremely undesirable fill pattern in the defective regions as certain vents became blocked. The air currents induced would move already-compacted sand, resulting in the defect.

Your Foundry Application

What scrap rate is acceptable at your foundry? Is your core quality control strict enough to detect and eliminate the defective cores, or will those cores produce defective castings? Can your overall quality assurance guarantee lower-quality castings are not sent to customers? What is the perceived quality of your products? Contact us to find out if Arena-flow may help you improve the quality of your high-scrap cores.