Wax model manufacturing is a key process in investment casting production.The quality of wax model will have direct impact on investment castings.Below are the common defects of wax model in investment casting process:
1.Deformation of wax model:Wax model is taken from investment casting mould,except some small changes about dimensions.Sometimes it could be deformed for worker's wrong operation.As it is common that deflection deformation of wax model is occured in cooling process.So we should be careful to take wax model from casting mould.Besides,wax model could deform as well for it is too soft.
2.Wax model is not injected fully.Main reason is for its low temperature,slow injection speed,so the wax material is cooled quickly in flow process.
3.Wax model surface wrinkles.
4.Wax model surface sag.Mainly is the injection pressure and time is not enough,or wax material is at higher temperature,and cooling time is not enough,surface concave covers large area.Thus it will be difficult to repair,easy to cause waste.
5.wax models exists seam, this is one of the most common defects, namely shin slices run over in the pressed close type, pressure type combination of joint,the joint of core and other places.The reasons are mainly molding precision is not enough,or pressed parting surface is damaged, or rated-locking force is not enough and the injection pressure is too high. Or wax temperature is too high.Burrs must be thoroughly cleared, then wax models can be used.
6.Rough surface of wax models.
7.Wax models exist bubble,one is a surface bubbles that could be visible with the naked eye,and the other is the inside bubble of investment casting wax model,usually is bigger,but can't see with the naked eye.We could found it by local summon,which is caused by wax mould gas expansion.