There will be some cracks inside mould after die casting mould are used for a while.
- The temperature inside die casting mould is too high during production.Water cooling system are highly recommand.
- The mould spray are not used properly during production.
- Heating treatment is not very well.The hardness of steel of die casting mould is not enough.
- The quality of steel is not good.H13 steel is highly recommand.
To make die casting mould last long time,we need to use good quality raw material and proper heating treatment.It is very necessary to avoid stress concentration and control radius size.
After 10,000 shotting done,mould need to send to tempering in order to remove remaining stress,otherwise crack there will be cracks inside mould.By this way,the life span of mould can be longer.
To avoid cracks inside die casting mould,we need to follow rules as below
- Heating treatment is very necessary for cavity and core.The hardness need be HRC43-48
- Pre-heating is necessary before production because of following advantages
2.1 Keep balance on temperture inside mould and die casting parts will form evenly.
2.2 Melted alloy will flow well inside mould,which is useful for parts to get nice surface finishing.
2.3 Reduce quantities of sub-standard products and improve production efficiency.
2.4 Increase life span of die casting mould.
Pre-heating temperature as per following
Aluminum die casting 180-300℃
Zinc die casting 150-200℃
To improve life span of die casting mould,we need to pay attention on material,design,manufacturing,heating treatment and operation.Following factors are very important to die casting mould.
- Good quality mould material
- Proper desing for size and wall thickness of mould
- Inserts are highly recommand
- Radius need to be as big as possible
- The distance between cooling system and surface need to be big enough
- Tempering is necessary after general CNC processing
- Proper heating system and quenching
- Remove and clean area where EDM applied
- Surface can not be highly polished
- Surface need oxidation treatment
- Nitriding can not go deep too much
- Pre-heating die casting mould in proper way
- Start die casting at slow speed for first 5-10pcs parts
- Try to low temperature of aluminum liquid before get right quality product
- Do not shot at high speed.
- Water inside cooling system need to be 40-50℃
- Close mould and reduce cooling water while stop die casting machine temporarily in order to hot impact on mould.
- Stop cooling system when mould surface reach highest temperature.
- To spray too much on mould.
- Do tempering after quite a mount of shotting.