Reasonable feeding‑system eliminates hot‑spot shrinkage‑porosity at thin‑wall‑thick‑junction positions. Solidification‑sequence, counter‑pressure holding stage, runner thermal‑retention and mold cooling must cooperate for LPDC, gravity and CPC counter‑pressure casting mold design.
Basic feeding principle: directional solidification. Thin‑wall section solidifies earlier; thick‑junction hot‑spot solidifies later, and maintains connection with riser channel before complete solidification for EV structural‑part mold casting quality control.
CPC counter‑pressure holding‑pressure duration is critical parameter. Holding‑pressure must be maintained until feeding‑runner completely solidified. Early pressure‑release cuts feeding channel; hot‑spot zone loses melt supply and generates shrinkage‑porosity for CPC counter‑pressure casting mold.
Procast solidification‑time‑gradient analysis evaluates feeding‑path continuity. When solidification‑time gradient reverses, feeding‑channel solidifies ahead of casting hot‑spot; even high counter‑pressure cannot deliver feeding melt for gravity casting mold development.
Runner thermal‑retention design: keep runner cross‑section larger than casting hot‑spot section. Runner must solidify later than casting hot‑spot; undersized runner solidifies rapidly and loses feeding‑capacity for LPDC casting mold aluminum wheel mold design.
Local cooling optimisation matches feeding layout: strengthen cooling on thin‑wall area to accelerate its solidification; avoid over‑cooling thick‑junction hot‑spot directly. Wrong cooling layout breaks directional‑solidification sequence for EV structural‑part mold.
Internal cooling channel distance control at thick‑junction zone: channel‑to‑cavity surface distance 20‑24 mm. Too close causes over‑cooling and blocks feeding‑path; too far fails to suppress hot‑spot temperature peak for CPC counter‑pressure casting mold.
Riser overflow‑neck cross‑section design: neck thickness shall not be less than 1/3 of adjacent casting thick‑junction dimension. Over‑narrow neck solidifies prematurely and isolates riser feeding‑function for gravity casting mold gating‑riser optimisation.
Counter‑pressure holding‑magnitude selection: excessive holding‑pressure cannot compensate broken feeding‑path. If feeding‑channel already solidified, higher pressure only increases insert load without eliminating shrinkage‑porosity for LPDC casting mold mass‑production.
Common design error: place vent‑slot directly at hot‑spot thick‑junction. Vent‑slot accelerates local heat dissipation, early solidification of hot‑spot surface shell, seals internal shrinkage cavity and makes shrinkage defect worse for aluminum casting mold.
Validation workflow: simulate solidification‑sequence first, then tune mold cooling layout, finally confirm minimum required CPC holding‑time via trial‑test sample dissection. Simulation output must be verified by real casting section inspection for EV structural‑part batches.
Cross‑border‑project specification note: feeding‑system performance cannot be judged only by appearance. Acceptance test must include casting sectioning or XCT non‑destructive inspection to verify internal shrinkage‑free status for mold pre‑delivery acceptance standard.
FAQ
Q: What core solidification principle supports effective riser feeding‑system design?
A: Establish directional‑solidification; hot‑spot solidifies later than feeding‑runner channel.
Q: What risk occurs if CPC counter‑pressure holding‑pressure is released too early?
A: Feeding‑runner solidifies and cuts melt supply, triggering hot‑spot shrinkage‑porosity.
Q: What runner‑section basic requirement guarantees continuous feeding capacity?
A: Runner cross‑section must be larger than casting hot‑spot cross‑section dimension.
Q: What cooling‑channel‑to‑cavity distance range applies for thick‑junction hot‑spot zone?
A: Maintain 20‑24 mm; avoid over‑cooling or insufficient heat‑control effect.
Q: What minimum neck‑thickness requirement for riser overflow neck structure?
A: Neck thickness shall not be less than 1/3 of adjacent casting thick‑junction thickness.
Q: Can increasing CPC holding‑pressure eliminate shrinkage‑porosity when feeding‑path is blocked?
A: No; higher pressure only raises mold load without fixing solidified feeding‑channel.
Q: Why should vent‑slot avoid direct placement at casting thick‑junction hot‑spot?
A: Vent accelerates local surface cooling, sealing internal shrinkage cavity and aggravating defect.
