MDO

 MDO stands for machine direction orientation. where cast film is stretched in machine direction. and this process will takes place in three steps. 

At very first film passes through preheat rolls . where film will be pre-heat in order to get stretchable property with the help of heat.

and than main process takes place i.e. stretching, where film will be stretched with the help of stretching rolls which are smaller in size as compared to pre-heat and annealing rolls. and this stretching process will takes place with help of nip rolls acting on stretching rolls. 

 and last step is annealing. where film get more tempearature to minimize the relaxation of it.

Preheat section contains two type of rolls generally called Steel rolls (chrome coated surface) and Teflon ( Rubber surface) rolls.

lets understand with the help of pictorial view.

Now, we will understand what happened in MDO. when film passes through it with the help of another picture.

The film outside of MDO after machine direction orientation process is called MONO film.

Lets have a look, how a real MDO look like.