Causes and Solutions for Cracks

(1) Mismatched thermal‑expansion coefficients between epoxy resin and inserts plus inadequate pre‑treatment of inserts result in cracks.

(2) No transition zones exist for uneven‑thickness epoxy‑cast layers. All transition sections of inserts and materials shall adopt specified radians without abrupt changes.

(3) No filleting, sand‑blasting or knurling treatment for inserts at epoxy‑insert contact zones.

(4) Excessively thin epoxy‑resin layers at insert contact areas.

(5) No thermal‑preservation measures after demolding under low‑ambient‑temperature conditions leads to rapid cooling. Under such circumstances, products shall be quickly wrapped with thermal‑insulation materials after demolding and promptly transferred for post‑curing, then naturally cooled to room temperature after post‑curing completion.

(6) Direct oven opening for cooling after product post‑curing without slow cooling to room temperature.

(7) Stress induced by mismatched mold temperature, casting temperature and curing temperature. Strictly control temperature matching among mold temperature, casting‑compound temperature and curing temperature in processes.