A Inks and Pigment Sigma Mixer (also known as a Sigma Blade Mixer, Z-Blade Mixer, or Sigma Kneader) is a heavy-duty, double-arm kneading machine specifically designed for processing high-viscosity, sticky, and dough-like materials. It is widely used in the manufacturing of inks, pigments, printing inks, pigment pastes, dyes, and flush colors due to its excellent ability to provide intensive mixing, kneading, shearing, and dispersion.
Inks and Pigment Sigma Mixer Video
Key Features and Construction
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Trough Design: The mixer consists of a U-shaped or W-shaped horizontal trough (bowl) with two counter-rotating sigma-shaped (Σ or Z) blades.
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Blades: Two “Z” or sigma blades rotate in opposite directions at differential speeds (often front blade faster, ratio ~3:2 for tangential design). This creates high shear forces, pulling, stretching, folding, compressing, and kneading the material against the blades, saddle, and trough walls.
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Clearance: Minimal gap (~2 mm) between blades and walls for maximum shear and minimal dead spots.
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Configurations: Tangential (blades side-by-side, higher shear for viscous materials) or overlapping (blades intermesh, better for flowable materials).
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Options: Jacketed for heating/cooling, vacuum-capable, extrusion screw discharge, tilting trough, or bottom valve for unloading.
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Materials: Trough and blades typically made of stainless steel (304/316) for corrosion resistance and easy cleaning.
How It Works in Inks and Pigments Production
The mixing action combines:
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Bulk movement and recombining for uniform distribution.
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High shear to break down pigment aggregates, disperse particles evenly in vehicles (binders, solvents, resins), and achieve fine particle size.
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Kneading to incorporate additives, wet pigments, and create homogeneous pastes without air entrapment.
For pigment pastes: Crude pigments are kneaded with salts/solvents; the blades’ extrusion, shearing, and grinding refine particles, alter crystalline structure, and produce high-viscosity concentrates. For inks: Ensures consistent color, viscosity, and flow properties in printing inks by thoroughly dispersing pigments in oils/varnishes.
Loading: Typically 40-65% of trough volume. Discharge: Tilting, bottom valve, or extrusion screw.
Advantages for Inks and Pigments
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Handles extremely viscous materials (millions of centipoise) where other mixers fail.
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Excellent dispersion of pigments, preventing clumping.
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Low dead spots for uniform results.
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Suitable for abrasive materials (hardened blades available).
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Batch process with controlled temperature (jacketed).
Common Applications in This Field
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Printing inks and flush colors.
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Pigment pastes and dispersions.
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Dyes, carbon black, ceramic powders.
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Related: Paints, coatings, adhesives, hot-melts.
Salient Features of Sigma Mixer Machine
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Available in Stainless Steel 316, Stainless Steel 304 and Mild Steel materials.
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Stainless Steel polish to matt & mirror finish as per customer’s requirements.
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Mild Steel finish with one coat of red oxide and two coats of epoxy paint.
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Discharge option of hand wheel operated (manual) or hydraulic operated (automatic) offered.
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Jacket for heating or cooling application can be offered.
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Mineral wool insulation with cladding on jacket.
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Tangential designed ‘Z’ blades offered for uniform mixing.
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PTFE made shaft sealing provided for food grade compatibility.
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Minimum gap between trough inner shell & blades removes possibility of sticking product.
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On demand Spray system, vacuum system
Optional Features/Accessories of Sigma Mixer
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Liquid Spray System
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Vacuum System
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Blades Cooling Arrangement
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Screw System
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Automatic Valve Discharge System
Process Operation of Inks and Pigment Sigma Mixer
In Sigma mixer tangential action of mixing and kneading obtained by ‘Z’ type (SIGMA) shaped kneading blades, which rotates very accurately at different speed towards each other causing product to be transferred from one end to another end. Discharge of the finished product is achieved by tilting the container or through the valves at the bottom or by means of an extrusion screw beside the container.
The mixing action is a combination of bulk movement, stretching, folding, dividing, and recombining of the material. The shearing & tearing action of the material against blades and the side walls causes size reduction of the solids. After the time period required for sterilizing the batch has elapsed, the heating circuit shuts of the pneumatics damper (exhaust) opens and cooling operation commences.
In the tangential design, the blades rotate in the trough meeting tangentially. The front blade generally rotates faster than the rear blade usually in the ratio of 3:2. Tangential blades are generally used for material of higher viscosities such as adhesives, rubber compounds, flush colors, dyes, and pigments.
In the overlapping design, the blades overlap above the saddle of the container. Due to the overlapping action, it is necessary that the relative position of the two blades is unchanged, and as a result, both the blades rotate at the same speed. Materials that flow freely or creep down into the blades are mixed using the overlapping blade action. This design offers a faster interchange of material from one blade compartment of the mixer to the other. Overlapping blade action is used for materials of lighter viscosities such as carbon pastes, clay coating, creams, and ointments. The overlapping blade produces a lower kneading and shearing compared to the tangential blade action.
Technical Specification of Sigma Mixer
| Model | Capacity – Liters | Motor (H.P.) | ||
| Working Capacity approx. | Gross Capacity approx. | General | Heavy Duty | |
| ASM – 50 | 50 Liters | 80 Liters | 5 H.P. | 7.5 H.P. |
| ASM – 75 | 75 Liters | 110 Liters | 7.5 H.P. | 10 H.P. |
| ASM – 100 | 100 Liters | 150 Liters | 10 H.P. | 15 H.P. |
| ASM – 150 | 150 Liters | 200 Liters | 15 H.P. | 20 H.P. |
| ASM – 200 | 200 Liters | 300 Liters | 20 H.P. | 25 H.P. |
| ASM – 400 | 400 Liters | 550 Liters | 30 H.P. | 40 H.P. |
| ASM – 500 | 500 Liters | 750 Liters | 40 H.P. | 50 H.P. |
| ASM – 750 | 750 Liters | 1150 Liters | 50 H.P. | 60 H.P. |
| ASM – 1000 | 1000 Liters | 1500 Liters | 60 H.P. | 70 H.P. |
| ASM – 1500 | 1500 Liters | 2100 Liters | 75 H.P. | 80 H.P. |
| ASM – 2000 | 2000 Liters | 2600 Liters | 80 H.P. | 90 H.P. |
| ASM – 3000 | 3000 Liters | 3800 Liters | 100 H.P. | 120 H.P. |
* Power voltage can be adjusted as per customer’s domestic power voltage requirements.
* Rights of technical improvements & modification reserved.
* Illustrations & dimensions are shown for information purpose only.
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