For oversized housings, pump bodies or architectural elements, sand casting delivers the size flexibility and tooling economics that high‑pressure die casting (HPDC) can’t match. Our Poznań/Greater Poland operation runs green sand, no‑bake/resin‑bonded molds and advanced core making, combining casting simulation with rigorous metrology so large parts ship on time and to spec.
Where Sand Casting Fits (vs HPDC, Gravity/ Permanent Mold, LPDC & Investment)
Sand casting process: best for large envelopes, low–medium volumes and complex internal cavities via cores.
HPDC / aluminum die casting: unbeatable for thin walls and very high volumes—less suited to massive sections.
Gravity die casting (permanent mold): superior as‑cast finish/dimensional stability at moderate sizes; limited on very large formats.
LPDC (low‑pressure die casting): structural integrity + laminar fill (e.g., wheels/hubs), higher cell CAPEX.
Investment casting (lost‑wax casting / precision casting): excellent detail for smaller, complex shapes at low volumes.
Materials for Large‑Format Work
Aluminum alloys (Al‑Si/Al‑Mg): weight‑sensitive structures, good thermal behavior; post‑finishes (painting, powder, anodic coatings where applicable).
Bronze (tin bronzes) & brass: wear/corrosion resistance for marine, pump, architectural hardware; attractive surface after machining/polishing.
We advise on alloy + heat treatment trade‑offs vs. machining allowances and finishing requirements.
The Sand Casting Workflow (Overview)
Pattern engineering (wood/aluminum/3D‑printed patterns) with draft, radii, datum strategy.
Molding: green sand for productivity; no‑bake for dimensional robustness on large molds.
Core making (shell/no‑bake/cold‑box): core prints designed for stability; venting integrated.
Gating & risering: simulation‑driven placement to feed hot spots and control flow.
Pouring & solidification: controlled temperatures; chills/insulators to guide solidification.
Shakeout, cut‑off & fettling: sprues/runners removed; shot‑blast/vibe finishing.
CNC machining: bores, sealing faces, threads finished to drawing GD&T.
Inspection: CMM, surface checks; optional CT scanning for critical sections.
Tolerances, GD&T & Machining Strategy
Start with ISO 8062 casting tolerances appropriate to part size; call out GD&T for castings on CTQ features (flatness, perpendicularity, position).
Define machining allowances up front—especially on sealing lands, bearing fits and datum faces—to balance cost and capability on large parts.
Include fixturing/handling features at DFM to stabilize heavy components during CNC.
Defect Prevention (What Sand Does Well—and How We Improve It)
Typical casting defects—shrinkage, gas porosity, veining, scabs—are addressed via:
Simulation‑led gating/risers and proper venting/core venting.
Thermal management with chills/insulators; uniform section design.
Melt discipline and mold moisture control (for green sand).
Leak‑critical parts: impregnation as a backstop; defined leak‑test protocol.
Finishing & Surface Options
Shot‑blast/vibe finishing, pickling/passivation for copper alloys, painting/powder for aluminum; selective machining to highlight cosmetic surfaces on architectural pieces.
Applications (Large‑Format)
Pump/compressor housings, valve bodies, impellers, gearcase covers.
Industrial machinery frames, heavy brackets, counterweights.
Architectural/urban hardware: bollards, rail fittings, decorative panels.
RFQ Checklist for Large Sand Castings
3D model with draft & wall map; 2D with ISO 8062 class and GD&T.
Alloy + expected EAU; maximum envelope & mass; lift/handling constraints.
Surface expectations (as‑cast vs machined), paint/powder specs.
Leak‑test values (if applicable) and any NDT/CT requirements.
Bottom line: For big, robust parts, sand casting pairs near‑limitless size flexibility with practical economics. Backed by casting simulation, disciplined core design and CNC, it’s the right lever when HPDC or permanent mold reach their size limits.