Idle situation:Consistantly achieving design weight/P.O.weight.

Possible variables causing drift from idle situation.

1. Tooling:The condition of tooling i.e. excess clearances in print leading to core shift and resulting excess weight.The tooling manafacturing through CAD/CAM and wear resistant material will help to achive this objective.

2.Core setting and mould closing process: Optimizing the core setting and mould closing such that with less clearances this can be performed.Mechanisatation of this activity will help to achive this objective. 

3.Pouring: Constant head and flow to optimize the swelling tendency of mould.Use of tundish pour will help to achive this objective. This is necessary to control the buyancy force exerted by liquid metal on mould wall and to optimise the sand additives for a given situation, pouring practices must be controlled.

4.Sand properties:This will play vital role in weight control.Optimising additives w.r.t. weght,foundry defects are the real challenge for foundry process engineer.While optimizing sand properties ,we may have to use multiple regression analysis.

The traditional approaches by foundry process control can not yield higher results. 

To start with, assuming above 3 variables are constant,start ploting average weight of 10 casings, rej% due to sand , G.C.S.,acitive clay and L.O.I. 

Once the data collection is started we can find the trend.Collect minimum of 100 batches and by doing regression analysis,we can achive optimum additives to get consistency in wt and rej% due to sand.

5.Cheistry and innculation practices also have significan impct on weght control.

In addition to all the above the basic diciplaine and good practices established by each foundry must follwed to get consistant results in any foundry.

Article Source: ArticlesBase.com - Necesisity of Component Weght Control in Green Sand Foundry