✂ Flash removal
Flash removal · Fundición (ISO 10135) · ISO 1101
Example in plan
How to interpret it
On the drawing, “Note: remove parting-line and gate flash” states a flash removal requirement.
What controls
Requirement to remove from the part all material that is not part of its geometry: parting-line flash, riser and sprue remnants, core fins and sand projections. It may be accompanied by a limit on the permissible remnant and an indication of whether the dressing must be flush or simply free of sharp edges. It is a result requirement: it is checked on the part, not in the foundry's procedure.
How to verify
Visual and tactile inspection of the entire perimeter and accessible cavities, with a borescope where there is no direct line of sight. The permissible remnant at the riser cut-off is measured with a dial indicator, straightedge or gauge against the adjacent surface. On circuit parts, the real check is cleanliness: blowing out, washing and particle verification, not just looking at the part.
Common mistakes when interpreting it
- Confusing flash removal with machining: dressing does not replace machining or achieve dimensional tolerance.
- Dressing only what is visible from the outside and leaving flash in internal cavities, which is where it does the most damage.
- Grinding the riser remnant so aggressively that it gouges below the surface and the part ends up out of tolerance.
How to get it in the workshop / if it comes out of tolerance
Receiving parts with flash is not just a cosmetic issue: flash on a locating face throws the setup out of square, and hard flash destroys the cutting edge on the first pass. Dress it, or require it to be dressed, before fixturing, and pay special attention to the inside of cavities, where flash stays put and later breaks loose inside the circuit. On pressure or fluid parts, any loose remnant is a potentially critical defect.
Flash growing along the parting line over the production run indicates poor closure of the molding flasks: it is corrected at the foundry. If the riser cut-off leaves a pad, grind it down with the grinder resting on the adjacent surface so as not to gouge below it. If internal flash appears that cannot be removed mechanically, consider shot blasting or pressure washing before accepting the part.
Related symbols
Other symbols in Foundry (ISO 10135)
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