Rheocasting vs. Squeeze Casting

CO₂ (R-744) systems operate at markedly higher internal pressures than the traditional R-134A refrigerants, so even small, interconnected pore networks that were once tolerated in conventional HPDC are now causing leak failures.

Squeeze casting solidifies a fully liquid charge under high external pressure inside a closed, pre-heated die. The applied pressure enhances metal–die contact, refines the microstructure, and continuously feeds hot spots as they solidify, thereby eliminating shrinkage porosity, the root cause of leakage.

Squeeze casting imposes a pressure hold on every shot and therefore operates in the minutes-per-cycle regime for typical automotive aluminum parts; that pressure-time is exactly what delivers its shortcoming in high-volume production.

Two squeeze-casting modes are used. Direct squeeze casting pours into an open lower die and then presses directly on the melt, enabling very high in-cavity pressure and superb feeding on chunky sections.

Indirect squeeze casting injects through a shot sleeve and thick gates at low speed, improving reach into more complex features, but with some pressure loss across the gate.

Economics retire Squeeze Castings

Squeeze casting, as well as Rheocasting, eliminates porosity-driven scrap. Rheocasting’s approach to the F-Gas Ban programmes lies in the efficiency. Rheocasting as a retrofit solution on existing HPDC machines with a slurrymaker, tooling adjustments, and tuned shot profiles scales quickly across multi-machine cells and supports automotive volumes in the millions with limited capex.

Squeeze casting requires dedicated presses capable of sustaining high squeeze loads and longer holds; it is therefore a better economic fit for small volumes. Additionally, a higher machining allowance and longer milling time are required to achieve the required tolerances.

When part numbers reach the millions per year, efficiency and, consequently, pricing become key factors. Cycle times of multiple minutes for a single part require an armada of squeeze casting machines to keep up with the Rheocasting process on an HPDC machine.

For HPDC foundries, this opens up an entirely new field of high-volume applications, as the start date for F-Gas Ban-compliant compressors is stipulated in EU law. From 2026 on, every new vehicle platform needs a new climate system. The current suppliers are unable to deliver the required leak-tightness from their HPDC process.

Additionally, this is the application for your small machine segment, which has been starved of profitable contracts long before the current sales crisis.

Rheocasting as a Business Development Tool

The first foundry has already begun switching over its production and presented its line of Rheocasting compressor housings in Japan. Some European foundries have also tried to capitalize on that market segment, but failed in their trials.

The bottleneck is not the technology. The difference was in the preparations and implemented processes before the trial even started. If you don’t want to strike out with your business development, schedule a meeting below and learn more about the Rheocasting Expert on Demand.