Anonymous user
Tools/castingcrucible/induction: Difference between revisions
up to a beta level I think
imported>Stever m (Typos) |
imported>Stever (up to a beta level I think) |
||
Line 32:
* Keeping the gas bottle well away from the burners
* Burners are self-lighting and have auto-shutoff
* Selecting suitable metal
** Reused old castings are cheapest, but have increased risk of voids, porosity and poor strength
** Virgin metal of an approved casting alloy will give the best results but at the highest cost
** Choose depending on budget and mechanical loads the part must withstand
Making the mold
Line 117 ⟶ 121:
** Be aware that the burner will re-light once the crucible is returned to the upright position, do not allow the metal in it to become overheated.
After the Pour
* The cast needs a little time to cool before it can be moved or it'll distort
** How long depends on the size of the thickest part of the cast, from a few seconds up to several minutes
* Once the cast has cooled a little then move the casting box away from the crucible
** Position a mold under the spout, either a trough or the baking tray and pour out the remaining metal
** Do not let metal cool in the crucible, it'll be very hard to remove later
Unmolding
* The cast needs to cool down a lot before it can be unmolded
* Times are likely to vary from as little as 5 minutes for a small cast up to an hour for a very large one.
* Once cool take the casting box over to the table and break out the sand to reveal the casting
** Wear welding gloves! Parts of the casting and the sand may still be several hundred degrees
* Collect the sand and riddle it, returning all unburnt sand to the store
* Burnt sand goes in the bin
Casting Flaws
▲* Pouring off surplus
* Examine your finished casting for flaws
** Poor Surface finish - Mold not packed well, mold of poor surface finish, failure to talc the mold, metal too hot, lack of gas vent holes
** Small bubbles in the casting - Poor degassing, sand too wet, metal too hot
** Sunken areas - Spru too small, bad part geometry
** Sand inclusions - Mold not packed well
** Slag inclusions - Poor skimming, bad pour control
** Unfilled areas - Insufficient gating
** Cold joints - Bad gating design, metal had to flow too far through small passages
** Excess flashing - Mold not clamped tightly
* Letting everything cool properly, this may take several hours, allow time for this.
* Examining crucible, discard if visibly cracked and arrange order of new one
* Returning casting equipment to proper location
* Sand into the suitable boxes
* Sweeping up everything
* Putting the casting tray back
* Returning un-used metal to store
* Dust masks to bin, they cannot be re-used
▲3 Cleaning Up
* Re-order any PPE that was damaged
[[Category:Inductions]]
| |||