Flash typically points to issues with the parting line rather than the cavity itself. Years of clamping pressure can deform the mating surfaces, and when they no longer seal tightly, plastic escapes. Regrinding and spotting the parting line costs only a fraction of building a new mold. Parts sticking in the mold are usually caused by ejection system or draft angle issues. Worn ejector pins, scratched cores, or surface polishing against the draw direction can all cause this—and all can be fixed on the workbench within a few days. Cracks are where we exercise particular caution. Small cracks on backing plates can still be welded and remachined, but a crack running through a cavity—or a cavity that has been repeatedly welded—is usually a sign that the mold has reached the end of its service life. Production volume can also change the equation. If your annual volume has increased since the mold was originally built, repairing it is only buying time. In that case, we would recommend a new mold made with harder steel or adding a second cavity, rather than repairing a tool that no longer fits your production needs. Send us your mold, or send photos of the parting line and defective parts. We'll give you an honest recommendation on whether to repair, rebuild components, or build an entirely new mold.