Casting Problems
| Possible Fault Cause | Solution |
|---|---|
| Incorrect Water or Powder Ratio | Ensure Correct Ratio P:W Conventional Mix 40:100 Vacuum Mix 38:100 |
| Incorrect Burnout Cycle | Follow recommended burnout cycle. Ensure furnace ramp does NOT exceed 250°C/Hr. Ensure first stage burnout temperature is kept in the range 220°C – 250°C and is held for 4.5 hours minimum. If problem still occurs increase hold time. |
| Excessive Casting Forces | Centrifugal casting: Lower torque and RPM settings. Vacuum casting: Reduce over pressure. |
| Disturbed Flask during setting | After investing bench set and do NOT move flask, strip base or remove tape for a minimum of 90 minutes. |
| Over working investment | Ensure all flasks are poured and removed from vacuum tank and put on bench to set by max. 9 minutes from starting mixing. |
| Waxes too close | Waxes too close together creating a very thin wall of investment. Waxes too close to side or top of flask; ensure min. 5mm gap to top and sides of flask. |
| Slurry too hot or cold | Adjust slurry temperature to 21°C +/- 1°C by increasing or decreasing water temperature. |
| Moulds dried out before burnout | If flasks are left on bench for more than 4 hours before burnout place a damp towel over the tops of the flasks to stop them drying out. Do NOT leave flasks in furnace overnight before burnout. |
| Flask base leak during investing | Ensure good seal between wax sprue and base. It is suggested that it be sealed with molten wax. |
| Possible Fault Cause | Solution |
|---|---|
| First stage burnout hold too short | Ensure first stage burnout hold time at 220°C is 4.5 hours. If problem still occurs, increase hold to 5.5 hours. |
| Flasks de-wax at too high a temperature | Ensure first stage burnout temperature is kept in the range 220°C – 250°C (see burnout section). |
| Flasks placed in furnace too soon after investing | Do NOT burn out before minimum 1 hour after investing. |
| Flask placed too close to or touching elements | Leave a minimum of 50mm gap between flasks and elements. |
| Possible Fault Cause | Solution |
|---|---|
| Overheated flasks during burnout | Follow recommended burnout cycle. Ensure furnace ramp does NOT exceed 250°C/Hr. Ensure 1st stage burnout temperature is kept in the range 220°C – 250°C and is held for 4.5 hours minimum. If problem still occurs, increase hold time. |
| Dust on waxes or trees | Ensure once waxes or wax trees are made, they are stored in a dry, clean and dust-free atmosphere. Do NOT store waxes or trees in a dusty environment or investing room. |
| Metal temperature incorrect | Reduce or increase metal temperature (see burnout section). |
| Rough waxes | Ensure excessive talc or release agent is not used, as this will produce rough waxes and therefore rough castings. |
| Flask burns out too quickly | Do NOT burn out before minimum of 90 minutes after investment. |
| Under or over-worked | Follow the recommended mixing instructions (see product pages). |
| Steam de-waxed for too long | Steam de-wax for a maximum of 60 minutes at atmospheric pressure. If steam de-waxed for longer than 90 minutes, the steam will start to erode the surface of the mould. Do NOT steam de-wax in a sealed container. |
| Possible Fault Cause | Solution |
|---|---|
| Metal temperature incorrect | Increase metal temperature first before increasing the flask temperature (see burnout section). |
| Flask temperature incorrect | Increase flask temperature (see burnout section). |
| Incorrect feed/sprue system | Feed or gate should be attached to the thickest part of the casting. It should be at least 25% of the thickness of the casting. |
| Insufficient centrifugal force | Increase torque first and then RPM of the centrifugal casting machine. Only increase by small amounts each time (5%). |
| Low vacuum when vacuum casting | Change oil in pump on a regular basis. Check seals for blockages in the vacuum pipes. |
| Not enough over pressure | Only increase over pressure by small amounts each time (5%). |
| Possible Fault Cause | Solution |
|---|---|
| Bad vacuum | Change oil in vacuum pump. Pump should be serviced on a regular basis. Check for leaks in vacuum pipes and chambers. Check mixing and pouring chamber are pulling equal vacuum levels. |
| Dust on waxes or trees | Ensure once waxes or wax trees are made, they are stored in a dry, clean and dust-free atmosphere. Do NOT store waxes or trees in the same room that you weigh powder or invest in. |
| Rough waxes | Ensure excessive talc or release agent is not used, as this will produce rough waxes and therefore rough castings. |
| Under or over worked | Follow the recommended mixing instructions. |
| Not vacuuming flasks after pouring | Ensure flasks are vacuumed for 1 minute after being poured. |