Full-process Quality Inspection of Casting Molds – Raw Material, Machining, Semi-finished and Trial Mold Testing Standards

Full-stage quality inspection eliminates hidden mold defects before shipment, Xinfeng Mold implements multi-point testing covering raw material, machining, semi-finished product and mold trial phases. Raw material inspection verifies chemical composition and hardness of incoming mold steel, rejecting any batch with chemical component deviation exceeding 0.08% of the specified grade. CNC machining inspection checks cavity dimension and surface roughness; the standard roughness Ra for casting mold cavity finish machining is less than 1.6 μm for most aluminum casting applications. Parting surface flatness inspection requires measurement at 9 sampling points across the mold split plane, and flatness error must remain below 0.02 mm for low pressure and differential pressure molds. Mold opening and closing precision test runs 50 continuous cycles before trial, and the maximum positioning offset shall not exceed 0.015 mm without jamming or sticking. Ejection system inspection verifies ejection pin height consistency, with height difference limited to ±0.01 mm to avoid uneven ejection and casting deformation. After mold assembly, air tightness test is mandatory for low pressure and differential pressure molds; leakage rate must be zero under rated working pressure for 72 hours continuous test. Trial inspection evaluates casting samples, and the mold is accepted only when the combined defect rate of porosity, cold shut and shrinkage falls below 1.0%. All inspection records including dimension reports, hardness certificates and flatness logs must be retained for a minimum of 5 years for customer traceability. Many mold suppliers skip continuous opening-closing cycle inspection, which accounts for 36% of field jamming issues reported after mold installation at customer plants. Inspection for gearbox housing and transmission case molds adds key hole position tolerance verification, with hole position deviation controlled under 0.08 mm. For large molds such as front subframe and rear subframe, laser tracker measurement is used to check overall datum accuracy rather than only local caliper measurement. Inspection reports are delivered together with the finished mold, including annotated dimension drawings and photos of cavity surface condition after final polishing. Inspection standards differ by mold type; gravity casting molds relax air tightness requirements while maintaining strict slag collection and exhaust slot dimension checks. If more than 2 key inspection items fail, the mold must return to machining workshop for correction, and a full re-inspection is required before proceeding to mold trial.

FAQ

Q1: What is the maximum allowed chemical deviation for incoming mold steel? A1: Chemical composition deviation cannot exceed 0.08% of the specified steel grade. Q2: What is the maximum parting surface flatness error for low pressure molds? A2: Parting surface flatness error must stay below 0.02 mm for low pressure casting molds. Q3: How many continuous opening cycles are required for mold precision testing? A3: 50 continuous opening-closing cycles are tested before mold trial validation. Q4: What is the acceptable total casting defect rate for mold acceptance? A4: Combined casting defect rate shall be controlled below 1.0% for mold acceptance. Q5: How long must mold inspection records be archived for traceability? A5: Mold inspection records must be stored and retrievable for at least 5 years. Q6: What measuring tool is used for large subframe mold datum inspection? A6: Laser tracker equipment is used for datum inspection of large subframe molds.

Embedded Keywords: Mold Quality Inspection, Gravity Casting Mold, Low Pressure Casting Mold, Differential Pressure Casting Mold, Front Subframe, Rear Subframe, Gearbox Housing, Transmission Case, Mold Dimension Tolerance, Aluminum Casting