DFM Design Guide · 03
Gate location determines flow direction and green-body density. Mold flow simulation can predict possibilities in design, however, the actual results are only known after sintering.
Gate Design03-A · Gate design influences
· Filling completeness · Internal stress distribution in the green body · Demolding · Post-sintering distortion · Cosmetic surface quality
| Gate Type | Feed Description | Suitable Scope & Characteristics |
|---|---|---|
| Side gate | Localized feeding from the parting line | Suitable for a wide range of medium and small ceramic parts, especially parts with uniform wall thickness |
| Pin-point gate | Feeds from a point on the top or bottom of the product | For small precision ceramic parts. The gate is small and leaves no obvious trace after removal |
| Submarine gate | Feeds from a hidden position on the side of the product | For ceramic parts with high cosmetic requirements. The gate is at the cavity side or a non-cosmetic face and breaks off automatically on ejection, requiring no manual trimming |
| Fan gate | Feeds along a broad section of the product edge | For thin-wall, large planar ceramic parts. The gate has a large contact area and requires post-processing after removal |
| Ring gate | Feeds from a 360-degree ring around the product | For cylindrical ceramic parts. Filling is uniform, but an additional gate-removal operation is needed |
| Tab gate | Feeds from a tab on the side of the product | For thick-wall ceramic parts. The larger gate gives good packing, but leaves an obvious gate mark |
Failure Scenario
A customer designed a rectangular part and requested a side gate. After sintering, the part exhibited overall warpage toward the feed end, with the amount of distortion exceeding the customer's tolerance requirements, resulting in the rejection of the entire batch.03-B · Gate Location vs. A-Grade Cosmetic Face
Rule: The preferred gate location is on the inner surface (non-cosmetic side) of the part. The secondary choice is at the Bottom end (near the parting line) or on an area that will be removed during grinding process. Gate placement on the top front face or at the center of curved surfaces must be avoided.
Gate placed on the side of an A-grade face; gate removal left a ~0.3mm step mark. After grinding, the surface finish no longer matched the surrounding area. Mold had to be reworked.
Solution: design a recessed relief pocket at the gate contact point during the DFM stage, so gate removal happens in that reserved location without touching the main cosmetic face. When submitting for DFM, mark which faces are A-grade and which are B-grade - this is the single most important input for gate-plan design.