Core manufacturing procedure is the important step for sand casting.
1. Make a clear understanding of the core manufacturing request. Assemble and fill in sand correctly. lock the core box effectively, in case the core gets swelled or deformed.
2. Sand content of core iron usually is no less than 50mm. Core iron should not hinder the free shrinkage of castings. Wrap the core iron with straw rope if necessary. Make sure it has enough strength and sand hanging capability.
3. Round corners and working surface specified by the processing technique should be laid with Chrome sand. The working surfaces should have high strength, high hardness and high surface finish. Positions where are not easy to get tight should be compacted by manual.
4. Cores should be manufactured well, set aside effective exhaust channels which could connect with the relate and adjacent exhaust system.
5. When making the cores, set aside lock device which will be connected with the iron when assemble the cores and molds. So as to assemble the cores and fix the box conveniently and pour safely.
6. When making the cores, set aside lock device which will be connected with the iron when assemble the cores and molds. So as to assemble the cores and fix the box conveniently and pour safely.
7. Blow carbon dioxide properly. Should not blow too much so as not to decrease dry strength of the core.
8. If over blowed, the core without enough strength could not be used.
9. The holes used for blowing carbon dioxide should be blocked thoroughly and solidly to make sure no steel water could get in and lead to an accident.
10. After removing the core box, check the compaction, roundness, straightness, flatness, symmetry degree, dimension precision, fillet and shape error, etc. carefully. Any error and sand not solid enough place should be well fixed so as not to affect the casting quality.