PROBLEMS WE SOLVE · SINK MARKS
Sink marks on visible surfaces? Find the cause before you add more packing pressure.
Shallow dents appear opposite ribs, bosses or thick sections. On a visible part that means rejects. The usual reaction, more packing pressure or a longer hold time, costs cycle time and can create flash or stress instead.
Typical causes
Thick sections and rib-to-wall ratio: thick areas keep shrinking after the surface has frozen.
Gate freezes too early: the gate seals before the thick area is packed, so no more material can flow in.
Gate too far from the thick section: packing pressure drops along the flow path and never reaches it.
Hot spots in the mold: poor cooling near a boss or rib core keeps that area hot and shrinking.
Packing profile: pressure or hold time too low, or switchover at the wrong point.
How we find it
We simulate packing and cooling and show where volumetric shrinkage and sink risk are highest, and why. You see whether the fix belongs in the part design, the gate, the cooling or the packing profile. That avoids trial-and-error on the press.
BEFORE STEEL IS CUT
Adjust ribs, bosses, wall thickness and gate while it is still CAD.
ON A RUNNING TOOL
Get a packing profile and process changes that target the sink, not just more pressure.
THE RIGHT SERVICE
Mold Check for new tools, or Troubleshooting for Running Tools in production.
DELIVERY
Standard: 2 weeks
Express: 1 week*
Express Plus: 48 hours*
* Express and Express Plus are available for set-up customers only.
Fighting sink marks right now?
Send us a photo of the sink mark and the part data. We’ll set up a 20-minute call.