Cereal processing, Pre-cleaning

For more information on perforated sheets for grain drying, separation and grading, hammer mills and malting select under the headings in the left side menu.

Perforated sheets from RMIG used for grain cleaning

Rough cleaning and pre-cleaning screens

RMIG offers the widest range of perforated patterns for rough cleaning and pre-cleaning, providing screens that gently and thoroughly remove unwanted materials from all kinds of crops such as corn, grain, seed, maize, rice, legume etc.

We offer a large range of precision slot and round hole perforation patterns in various thicknesses and materials for your specific need.

Rough cleaning

The purpose for using perforated screens when rough cleaning is to separate as many impurities as possible in order to ensure that the products are cleaned enough for drying and storage until further processing takes place.


The difference between rough cleaning and pre-cleaning is that pre-cleaning may also involve separating items smaller than the main crop. Pre-cleaning in some instances may replace rough cleaning. The purpose of pre-cleaning and the use of perforated sheets in this operation is to improve the storability of the crop, reduce price penalties at time of milling – and improve milling output and quality.

  • Pre-cleaning: Cleaning will improve the storability of the crop and milling output and quality.
  • Grain cleaning: Cleaning will remove straw, chaff, weed, seeds, soil, rubbish and other unwanted materials.
  • Screening/sifting: Smaller materials such as weed seeds, soil particles and stones can be sieved from the grain through a smaller sized screen.

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Pattern catalogue

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