Need for Pattern Making :
The making of patterns takes its need and importance in different areas of casting. For instance metals while sand cast would surely need patterns for the process to be carried out. Thus patterns are widely required for much process though the equipment used for making of patterns and techniques used for pattern making depends on various factors. Some of the factors to name are the size and the number of products to be cast, design used in casting process and so on. By taking proper stapes and guidelines in the making process of pattern which is widely needed one is sure to produce efficient quality patterns.
Guidelines for the Process of Pattern Making :
Shrinkage Allowance :
It is vital that proper steps and care must be taken to consider the shrinkage allowance also termed contraction allowance. This could be done by determining the type of metal used for casting process, its attributes or properties, the method used for carrying out the process of sand casting and so on. On proper analysis of above attributes the value determined for shrinkage or contraction allowance would vary. This is because some metals or alloys would have the attribute of shrinkage more than other.
Draft allowances :
Allowances like draft must also be taken into account while carrying out pattern making process. That is while taking the pattern out from sand it is very essential to take steps such that the sand also does not come out along with the pattern. One such step in taking care of the above is to allow drafts while designing so that patterns can be narrowed down in side portions and this would make the process of removal in pattern from sand efficient.
Placement Analysis :
It is essential for the person making patterns to review and analyze before hand about the placement of different systems like gating or risers in pattern. Proper predefined analysis on this aspect would enable the pattern making to be carried out efficiently and help in deriving an efficient quality product.





