How many variable speeds are there in Multi-Mill?

How many variable speeds are there in Multi-Mill? Can anyone tell me how and where I can learn more about multi-mill

Dear Md. Saifullah,

Multi mill is generally having VFD measured in terms of RPM/Hertz
Also some multimill is having fixed speed.

For Sustained or modified release tablets the formulation requires specified milling speed, as the particle behaviour change with respect to milling parameters.

You can surf internet or refer lachman book,Unit operation book-RM Mehta.


thanks for ur response. can you tell me
What should be the direction of movement of knife for getting more granules in Multi-Mill?
What are the parameters of Screen to be checked before starting the operation in Multi-Mill?

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Dear Saifullah,
The forward direction will give you more granules.

Integrity of screen should be checked.
Also the screen should not touch the rotar or blade while blank run before start milling.


What do you mean by forward direction?
& how many blade should be used in multi mill?

Multi mill is designed to utilize the principle of variable force having both knife and impact edges rotating within a selected screen to control the particle reduction. This knife or impact position i.e. forword /backword will help us to reduce or course particle.

For more granules we have to select impact in forward direction if product dissolution parameter are meet with this selected direction

For parameters of Screen we have to select integrity checking frequency before and after use. other parameter as said by saifullah

Forward direction means sharp edge of the blade move in forward direction where as If the blade move in opposite direction that is backward direction.

However for the no of blades in the multi mill depends on the make of machine. we have to mention the criteria as the time of new multi mill user requirement specification. Make sure our R&D & Production unit have same kind of equipment design.


Good information sir

Why forward and backward direction in multimill?
What is exact use of forward and backward direction?