What a core box is
A core box is the tooling in which a core is formed: sand mixed with binder is blown or rammed into it and hardened. It can be made of metal (typical of high-output processes such as cold box, hot box and shell), resin or wood for small runs and large cores.
A box can have several cavities: in each cycle it produces several identical cores, or several different cores for the same casting.
Why it should be managed as critical tooling
- No core box, no cores, and without cores there is no moulding.
- A worn box produces cores out of tolerance, with consequences for the casting.
- Many boxes are customer-owned, and must be looked after and returned.
- Some boxes may be at outside core shops or at the pattern maker.
The data to record
- Box code and description, with a photo.
- Items and cores produced, number of cores per box.
- Core weight and production process.
- Box material and storage location.
- Status: available, under maintenance, at a supplier, obsolete.
- Maintenance carried out and next due dates.
- Movements: out and back.
Periodic maintenance
Planned maintenance includes cleaning, checking vents and ejector pins, dimensional inspection and repair of worn surfaces. Setting fixed intervals, or intervals tied to the number of cycles, avoids discovering wear through scrap.
How it is usually handled
Core boxes are often identified by a tag and kept in a tooling store. Status and location are known to the core shop supervisor. Maintenance is done when the core starts causing problems.
The limits of spreadsheets and generic ERP systems
- No link between box, core and casting: nobody knows which items are blocked if a box is out of action.
- Status not visible to the planner.
- Maintenance not planned and not recorded.
- Movements not tracked, especially with outside core shops and pattern makers.
How FOND/WISE handles it
In FOND/WISE every core box has its own record, linked to the items that use it.
- Cores per box, core weight, process (for example cold box) and materials.
- Storage location, status and photos of the box, to recognise and find it immediately.
- Routings for core production with internal or outside operations, supplier and lead time.
- Documents, notes and images for each production operation.
- Periodic maintenance set-up and a log of maintenance on patterns and core boxes.
- Tooling movements (for example to an outside core shop).
- Alert when the core box is under maintenance or unavailable, visible from the casting’s data sheet too.
Key features
Core box records
Cores per box, weight, process, location and status.
Periodic maintenance
Maintenance intervals set for each box.
Movements
Where the box is: in the foundry, at a supplier, under repair.
Alerts
Unavailability warning when working on the item.
Documents per operation
Notes and images for whoever makes the core.
Outside production
Supplier and lead time for bought-in cores.
Worked example
A foundry manages about 400 core boxes, some of them at an outside core shop. On a Monday, moulding schedules a manifold that needs a core made outside. Illustrative values.
- Without records: on Wednesday it turns out that the core box has been at the pattern maker for repair for ten days. The supplier could not make the cores and moulding of the manifold is cancelled.
- With records and movements: the warning “core box not available” appears as soon as the job is scheduled. The production manager moves the manifold to the following week, brings another item forward and informs the customer straight away.
Same technical problem, opposite consequences: the difference is knowing in time where the tooling is and what state it is in.
Frequently asked questions
What is a core box?
It is the tooling, made of metal, resin or wood, in which the core is formed. It can have one or more cavities, so it produces one or more cores per cycle.
How often should a core box be maintained?
It depends on the box material, the process (boxes for hot processes undergo thermal cycling), sand abrasiveness and number of cycles. Many foundries set periodic maintenance and a dimensional check after a certain number of cycles or at regular intervals.
Which defects come from a worn core box?
Cores out of dimensional tolerance, core fins, difficult stripping and breakage. In the casting these become wrong wall thicknesses, internal fins and, in the worst cases, scrap.
How should core boxes at outside core shops be managed?
By recording outgoing and returning movements, as for subcontracting, and linking them to the supplier that makes the cores. That way you always know where they are and can plan accordingly.