IKA MultiDrive MI 250.2 star blade, stainless steel, 0020023167

Kinetics of cutting and shear comminution

In materials science and biological sample preparation, tough, elastic and extremely fibrous matrices (such as plastics, textiles, paper, root tissue or cellulose) present a major physical challenge. Conventional impact devices fail in this context, as elastic materials absorb the kinetic impact energy rather than breaking apart. The IKA MultiDrive MI 250.2 star blade is geometrically engineered for high-precision cutting and shear-based comminution. Driven by the MultiDrive base station at speeds of up to 30,000 revolutions per minute, the sharpened blades sever the macromolecular fibre structures by applying massive, localised shear stresses. This pulling cut continuously disaggregates the sample material and transforms it into a homogeneous, free-flowing matrix.

Fluid mechanics and prevention of rotational blockages

A fundamental mechanical problem in the high-speed grinding of long fibres is the so-called wrapping effect. Fibrous materials tend to wrap themselves around the rotating tool shaft due to flow turbulence within the reactor. This leads to an exponential increase in torsional resistance, which can thermally overload or jam the drive motor in a fraction of a second. The MI 250.2 star blade counteracts this rheological phenomenon thanks to its multi-bladed star geometry. The specific angles of attack of the blades direct the sample material radially outwards towards the chamber wall and systematically cut the fibres into short fragments, long before static wrapping structures can form around the shaft.

Material integrity and mechanical resilience

To withstand the continuous mechanical abrasion caused by tough polymers or woody biomass, the star blade is made from solid, highly wear-resistant stainless steel. The blades retain their microscopic sharpness even during extended grinding intervals under high thermal stress. The corrosion-resistant, single-material design enables laboratories operating in accordance with strict GLP (Good Laboratory Practice) guidelines to carry out thorough chemical decontamination and residue-free thermal sterilisation in an autoclave, thereby preventing any cross-contamination between batches.

Technical details

• Product type: Star blade (cutting tool / spare part)
• Processing principle: Cutting and shear comminution
• Physical scope of application: Tough, elastic and fibrous sample matrices
• Compatibility (vessel): Suitable exclusively for the IKA MultiDrive MI 250 (including the T version)
• Compatibility (drive): IKA MultiDrive basic and MultiDrive control
• Material: Solid, highly wear-resistant stainless steel
• Blade geometry: Multi-bladed star profile to prevent tangling
• Fitting: Tool-free, form-fit replacement in the grinding vessel
• Cleaning and hygiene: Fully autoclavable and chemically sterilisable

Contents

• 1 x IKA MultiDrive MI 250.2 star blade (stainless steel)

(Important note: The MultiDrive drive unit and the MI 250 grinding chamber are not included in the scope of delivery!)

Custom requirements & accessories

The MI 250.2 star blade is the most important wear part in terms of process engineering for cutting and comminution. Processing extremely tough or abrasive plastics (such as glass-fibre-reinforced polymers) inevitably leads to a gradual blunting of the cutting edges due to micro-collisions, which increases the thermodynamic stress on the sample (frictional heat) in the long term. To ensure gentle, thermally stable sample preparation, we recommend having replacement tools ready at an early stage should cutting performance begin to decline. Please contact our procurement service at any time for the strategic procurement of laboratory consumables.