LPDC customer DFM review checklist, preliminary drawing review, risk identification, cost reduction and avoidance template

LPDC customer DFM review checklist, preliminary drawing review, risk identification, cost reduction and avoidance template
DFM review is the first checkpoint of a project. Many project drawings are directly molded, and problems such as wall thickness, rounded corners, gate position, draft, heat treatment deformation, and machining allowance are only discovered during mold testing. The cost of mold modification is extremely high, and delivery time is delayed.
1、 DFM Review Core Quantitative Verification Item (A356 Metal LPDC)
Structural wall thickness: minimum wall thickness ≥ 2.5mm; wall thickness difference should be ≤ 2 times as much as possible, and significant differences in thickness can easily lead to looseness and deformation.
Rounded corner R: Inner rounded corner R ≥ 1.5mm; Sharp corner hot spot, stress concentration, heat treatment cracking; The priority for rounded corners is R ≥ 1mm.
Draft angle: Appearance surface ≥ 1.5 °; Non appearance processing surface ≥ 1 °; Increase the draft angle of deep cavity and high reinforcement to 2-3 ° to prevent pulling and sticking to aluminum.
Machining allowance: Single side allowance of 1.2-2.0mm; lower limit for thin-walled shells, upper limit for thick walled hot joints, reserved for heat treatment deformation correction.
Gate position: Prioritize placement in hot spots and thick areas, establish sequential solidification; Do not place the sprue at the end of the thin wall.
Exhaust: Reserve exhaust slots at the filling end, high point, and top of the ribs, with a thickness of 0.2-0.3mm.
The DFM review of Xinfeng Machinery outputs a risk list, risk levels, modification suggestions, and cost estimates for mold modification, which are synchronized with customer confirmation.
2、 Simultaneous review of materials, heat treatment, non-destructive testing, and assembly
Material: Confirm A356, whether Sr has deteriorated, T6 heat treatment; If the customer's drawings require high elongation, control the upper limit of Fe content in advance.
Testing requirements: Mark the X-ray/UT testing area, clarify the defect level, and distinguish between allowed looseness and rejected defects.
Sealed pressure bearing: Confirm in advance whether infiltration repair is allowed based on the compression pressure, holding time, and leakage judgment criteria.
Assembly tolerance: Distinguish between casting tolerance, machining tolerance, and compensation for heat treatment deformation reserved tolerance.
3、 Differences in DFM review for overseas clients
Simplify DFM for Southeast Asian customers, only focus on demolding, testing and heat treatment risks, and repeatedly adjust the trial mold.
The North American Tier1 DFM document is a pre PPAP document, and each risk must have an improvement plan. The mold cannot be opened until the risk is closed.
The European customer DFM focuses on fatigue, corrosion, and stress concentration rounded corners, prioritizing structural improvements to enhance reliability and reduce later testing costs.
Middle Eastern engineering machinery parts, DFM focuses on checking wall thickness, thermal joints, impact load stress concentration, and relaxing appearance requirements.
4、 The Failure Chain Caused by DFM Omission
Sharp corners without rounded corners → looseness of hot joints+stress cracking during heat treatment;
Great disparity in wall thickness mutation → cutting off of contraction channels, loosening of hot joints;
Insufficient demoulding → Pulling and sticking of aluminum during demoulding, resulting in poor appearance in batches;
Insufficient machining allowance+heat treatment deformation → insufficient wall thickness after machining, local perforation.
5、 Long tail traffic layout ideas
Low pressure casting DFM review, casting manufacturability review, aluminum alloy casting drawing review, aimed at project engineers and R&D.
keywords LPDC casting DFM checklist、design for manufacturability low pressure aluminum casting；
Problem class: Minimum wall thickness for A356 LPDC;
Comparison category: DFM review before mold opening vs post trial modification.
Suitable for new project development and DFM themed pages.
6、 Common misconceptions in the industry
Misconception 1: If drawings can be drawn, they can be cast. Many structures have natural defects in filling, shrinking, and demolding.
Misconception 2: Rounded corners are just appearance, sharp corners pose a dual risk of thermal cracking and stress concentration, and heat treatment can easily lead to cracking.
Misconception 3: The larger the margin, the better. If the margin is too large, the dense surface will be cut off during machining, exposing internal looseness.
FAQ
Q: What is the recommended minimum wall thickness for LPDC?
A：≥2.5mm。
Q: What is the minimum requirement for rounded corners?
A：R≥1.5mm。
Q: Conventional draft angle (machined surface)?
A: ≥ 1 °; Appearance ≥ 1.5 °.
Q: Single side machining allowance?
A：1.2–2.0mm。
Q: What is the thickness of the exhaust groove?
A：0.2–0.3mm。
Q: Where should the sprue be prioritized?
A: The thick and large hot spot position of the casting is conducive to compensating shrinkage.
Q: What are the core values of DFM?
A: Lock in risks before mold opening to reduce mold changes.
Q: Is there a hidden danger of excessive surplus?
A: Process and peel off the dense surface layer, exposing the internal looseness.