Draft (engineering)

The draft angle is the minimum allowable deviation from the normal to the mold parting in model and mold making. The resultant taper of the resulting molded enables digging the finished model without damage from the mold. Preference is given to run as the addition of material, the cone can also be designed as a material removal or Maßmittelwert from two possibilities. For areas that need to be machined in subsequent production programs, the draft angle is always run as a material addition.

The draft angle is dependent on method of production or production process, the model size and the materials used. Also the quality of the mold material and surface determines the resulting slope. It is a necessity and limits the construction of production parts, especially in the metal casting.

All pages of the model that are perpendicular to the parting line are provided with a draft angle, with small parts usually 2 °. To generate drafts using conical cutter, called Die.

Standardization

DIN 1511: Production and quality of foundry pattern equipment from April 1978 replaced by DIN EN 12890: patterns, pattern equipment and core boxes for the production of sand molds and sand cores of June 2000 alone, sales by Beuth Verlag GmbH, 10772 Berlin

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