Shell core blower….there are many types, but here is ours:
Shell cores are great things: quick to produce, strong, good surface finish, last forever blah, blah. The only downside is that they need metal dies to endure the 200 deg C temp, no cheap arse 3D printed coreboxes will do here.
Despite that, we have one that we half inherited from a mate in Melbourne, and maybe will be used for a specific application. Basically it consists of 2 aluminium dies (no cavities as yet), these being mounted via bolted standoffs to the top and bottom platen of the horizontal die set, actuated by the red air cylinder. As the moving platen (nearest to the air cylinder) retracts, the 4 extended nut/spring units react against the fixed back plate and force the ejector plate towards the dies and, with ejector pins in the die, will eject the sand core. Not shown, but the same principle will also eject the core from the fixed die half.
How does the sand get into the dies? When the dies are closed, the “sand holder” will be swung across until it is directly above the dies. Then the clamp cylinder will then force the clamp plate down on to the sand holder, sandwiching it against the hot dies, but with a heat resistant plate in between. When all clamped, then a large valve will apply a high air flow/pressure (via a connection in the clamp plate) above the sand in the sand holder, and then forcing the sand into the dies. Small strategically placed vents in the die allow air to escape to avoid dead spots.
With the dies around 200 deg C` (in our case heated by a series of small electrical heating insertable elements, around Ø10 mm), a finished core can be made in around 1 – 2 mins, totally dependent od the thickness and mass.
Every now and then, the sand holder will be swung below the sand reservoir (proudly made from an old LPG cylinder....jeez, I love this type of recycling/repurposing) for refilling.
Temp controllers will maintain the die temps using type K thermocouples.
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
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