In laboratory mixing, the roller material of a two roll mill plays a crucial role in determining performance, lifespan, and compatibility with the materials being processed.
The two roll laboratory mixing mill equipment is mainly used to knead , mix and disperse the raw material ,together with other additional agents , uniformly for testing, and apply the experiment results for research and laboratories.
The Lab two roll mill machine is applicable for many material ,such as rubber, chemical ,polymer ,plastics , polyolefine, pigments ,PVC, film, coil, ceramic powder, aluminum, color masterbatch, stabilizers, stabilizers and so on.
The two-roll mill mixers consist of two adjacent cylindrical rollers,which work as main component . Thus the quality of roll determine the lifespan and durability of laboratory mixing mill equipment . The material of laboratory mixing mill machine are mainly constructed of two material :
* Chilled Cast Iron
* Stainless Steel
Many people may know its material ,but not sure which material is better for your application? Let us talk here :
1. Material Composition & Hardness of Chilled Cast Iron:
Chilled Cast Iron:
The Composition of Chilled cast iron is High-carbon cast iron with chilled surface, Its surface Hardness can reach up to 60–65 HRC
✅ Chilled rolls have an extremely hard outer shell, excellent for wear resistance.
Stainless Steel:
While The Composition of Chilled cast iron is mainly chromium-based alloy steel, its hardness is not so strong ,usually about 48–55 HRC
✅ Stainless steel rolls are tougher and more resistant to impact or chipping under shock load. Core Toughness Good (softer inner core) Generally tougher throughout
2. Corrosion Resistance
Chilled Cast Iron
Rust Resistance: The chilled cast iron is poor, it is easy to oxidation
Chemical Resistance: Since its composition is iron material , thus it can react with acids or bases and its chemical resistance is low, it is suitable for sensitive or chemical use
✅ Stainless steel is ideal for wet, corrosive, or hygienic environments, such as food-grade or medical-grade materials.
Stainless Steel
Excellent – corrosion-proof
Chemical Resistance: Good
3. Heat Transfer & Cooling
Chilled Cast Iron
Heat Conductivity: Very good – fast and uniform
Cooling Efficiency High – internal channels available
✅ Chilled cast iron provides faster heat dissipation, making it ideal for heat-sensitive polymers.
Stainless Steel
Heat Conductivity: Very good –Moderate
Cooling Efficiency , Also good – but slightly slower
4. Surface Finish
Both materials can be polished to a mirror or matte finish, but:
Stainless steel is easier to polish and clean, suitable for sticky or light-colored materials.
Cast iron can maintain a rougher surface if grip is needed, for high-viscosity materials.
5. Cost Comparison
Chilled Cast Iron
Initial Cost: 20–40% higher
Long-Term Value High for standard mixing
✅ For general-purpose polymer or rubber mixing, chilled cast iron is more cost-effective.
✅ For specialty or sensitive materials, stainless steel pays off in the long run.
Stainless Steel
Initial Cost: Lower Cost
High for cleanroom or reactive processing
✅ Final Decision:
Criteria Best Choice
* Durability & wear Chilled Cast Iron
* Hygiene & corrosion Stainless Steel
* Thermal control Chilled Cast Iron
* Cleaning & versatility Stainless Steel
* Budget-friendly Chilled Cast Iron
➡️ Recommendation:
If you have higher budget and require higher quality on the rollers , then choose chilled cast iron rolls for general-purpose rubber or polymer research.
But if your production process involves corrosive, food-safe, or frequently cleaned materials ,then choose stainless steel rolls if your work
📞 Need Help Choosing?
Contact Simptek Machine for expert guidance on selecting the best roller configuration for your lab two roll mill. We offer both chilled and stainless rolls in standard and custom sizes.
