In the rubber and plastics industry, the two roll mill machine is one of the most widely used machines for compounding, mixing, and sheeting materials.
When a two roll mill is installed with blend stock equipment, it can improve efficiency and reduce labor intensity . What is more , it can enhance the mixing of rubber with fillers, additives, and colorants ,so that create homogeneous rubber compounds mixture.
Here , in this blog ,let us explore the working principle of one open mixing mill with a stock blender, and what benefits does it bring for manufacturer ?
1. What Is an Stock Blender On Open Mixing Mill ?
open mixing mill, also known as two roll mill or rubber compounding mill, it consists of two hollow rolls, which are made from chilled cast iron and the surface are smooth. The two rolls rotate toward each other at different speeds (usually 1:1.25). The material ,like rubber and additives compound are fed between these two rolls. When the mixing mill start working , its two rotating rolls create intensive force ,which shear, compress, and stretch the compound material fully , resulting in thorough mixing.
In order to improve the working efficiency and reduce labor intensity, many manufacturers turn to install another auxiliary device named stock blender on the open mixing mills
A stock blender is an auxiliary device which is installed on the open mixing mill machine. It consists of two or more arms with rollers that continuously turn over and fold the rubber compound during the mixing process.
With the stock blender ,it can work as the role :
* Automatically lift, fold, and return the compound to the mill rolls
* Reduce manual handling
* Improve the uniformity and quality of mixing
2. What Is Open Mixing Mill With Stock Blender?
Basically ,the rear roll typically rotates at a speed different from the front roll , so that create a mixing action to the compound material.
Rubber stock passes between the rolls and is subjected to:
When the compound material is added into the nip of rubber compounding mill, which generating intensive shear force. The compound material is broke down .
Due to the strong compression force generated by the two rolls, the compound material is integrates with additives uniformly and evenly.
As the two rolls rotating , it create frictional heat ,which softens rubber material ,thus it is better and more easily to process.
3. What Size Open Mixing Mill Should Be Equipped with a Stock Blender?
Since this stock blender is so powerful , so shall we install in on every open mixing mill ?
The answer is Not ! Not every mixing mill needs a stock blender. In general:
1. Actually for these small laboratory mixing mills sized 6–12 inches ,
you do not need a stock blender, as the mixing task is for laboratory in small batches and the operators can handle the material by manual.
2. For these medium size two roll mixing mill with blender ,usually larger than 14 inches but smaller than 18 inches , these are medium style , if we install a stock blender ,it would be necessary. As the roll size increases, the batch weight becomes larger, if at this time , we operate ,fold and pull the material , the manual would be not only hard but also less safe ,as both the processed material and rolls would be very hot .
And for these large industrial rubber compounding mill larger than 20 inches. It would become essential to install one stock blender, as the operators need to handle heavy-duty compounds. In order to ensure the safety of operators and product in consistent quality, it is very essential to equip one stock blender on the open mixing mill machine .
As this action happen again and again , the compound material is undergone through folded, cut, and stretched continuously, ultimately a homogeneous rubber mixture is created .
4. Rubber Blending Procedure with Open Mixing Mill
Step 1 — Preheating the Roll of Mixing Mill
Firstly , you need to set the temperatures of two rolls as per the requirement of rubber compound . If process other material ,like silicone , its temperature is different then.
When you set the temperature ,you need to adjust the gap of two roll (nip) ,so that easily feed material .
Step 2 — Feeding Compound Material
Secondly , you need to feed the rubber compound material into the gap of these two rolls.
As the rolls rotating , you can use blending stock material, such as natural rubber + synthetic rubber mixure ,so that enhance the rubber properties.
Step 3 — Fillers & Additives
On the process , as the rolls rotating , you can also add carbon black, silica, softeners, colorants, and other curing agents to the rubber material step by step.
You need to control the sequence in case of uneven distribution occur.
Step 4 — Kneading & Mixing
The mixing process continue , continuously fold and blend the rubber sheet using a cut-and-fold knife.
Maintain proper roll friction ,so that reach the goal of mixing uniformly and evenly .
Step 5 — Homogenous Mixture
You can adjust the gap of these two roll to adjust the thickness as desired.
You can repeat and pass the mixed compound for many times , until achieve a smooth and uniform sheet formed.
5. Benefits of Equipping a Stock Blender on Open Mixing Mill
When one open mixing mill is installed with blend stock equipment ,it provides excellent mixing performance for rubber compounding.
It can bring benefits as follows:
(1) Improved Compound Consistency
The stock blender help the open mixing mill mix rubber automatically, it repeatedly folds and spreads the compound.
Since it is automatic run by machine the whole procedure, it ensures uniform distribution of fillers, pigments, and additives.
And also it reduces hot spots and unmixed zones.
(2) Efficient Production
The machine can run for a longer time , thus it reduces manual handling time and speeds up the mixing cycle .
What is more , it increases output with more consistent batches.
(3) More Safe
On the whole mixing process , the machine can be guided by stock blender . Operators don’t need to constantly pull, cut, and fold the compound material by manual.
Thus it decrease the chance contact with hot rubber and roll directly , it reduces the risk of burns, strain, and accidents due to the rubber machine.
(4) Reduced Labor Intensity
The stock blender installed on a open mixing mill make the machine recycling mix rubber automatically, it help the operator in the mixing of rubber material and chemical ingredients uniformly. It makes large batch processing more manageable.
In conclusion , for laboratory rubber compounding mill,manual operation is easy .but for industrial mixing mill ,it is very essential to equip a stock blender . By installing a stock blender on open mixing mill ,It not only ensures uniform additive distribution, improved compound quality, and better process control , but also enhances operator safety and reduces labor intensity.
At Simptek , No matter you are in the need of laboratory or industrial mixing mill ,we can tailor and supply quality machine as per your needs .
If you want to equip stock blender, we can also supply you and guarantee you quality .