Sigma Arm mixer are the most commonly used mixers in the family of double arm mixers. Double arm kneader mixers consists of two mixing blades placed in a ‘w’ shaped horizontal trough. The rotation of the blades is either tangential to each other or the blades can overlap within the trough. The blades rotate toward each other at same speeds in case of overlapping blades or at differential speeds for tangential blades. The blades typically move near the container walls and each other at close clearances (~ 2 mm), resulting in homogeneous mixing. The small clearances generate very high shearing action resulting in particle size reduction.

The blade profile of the sigma blade is such that the viscous mass of material is pulled, sheared, compressed, kneaded and folded by the action of the blades against the walls of the mixer trough. Tangential blade is used for material of higher viscosities such as adhesives, rubber compounds, flush colors, dyes and pigments. Overlapping blade action is used for materials of lighter viscosities such as carbon pastes, clay coating, creams, and ointments.

Applications of Sigma Mixer

The sigma arm mixer is the best suited mixer for pasty, sticky, and gritty slurries with high viscosities. The following are some of the commonly used products that are mixed in the sigma mixer kneader.
The sigma blade mixer is a commonly used mixer for high viscosity materials. This article details the construction of the sigma mixer, design and operational features, and its applications. The different variants of the sigma mixer design are discussed.
The sigma mixer is one of the most popular used for mixing and kneading high viscosity materials. It belongs to the family of double arm kneader mixers.
In mixers handling very viscous materials, it is necessary to promote both lateral and transverse motion of the material.
The geometry and profile of the sigma blade is designed such that the viscous mass of material is pulled, sheared, compressed, kneaded, and folded by the action of the blades against the walls of the mixer trough.
The extent to which this happens depends on the action of the blades – tangential or overlapping and the ratio of the speed of rotation of the blades.
The helix angle of the blade can be modified depending on the required shearing

Features of sigma mixer

Materials like dough, putty, rubber solution, adhesives, polymers etc.
The mixing action is a combination of shearing, stretching, folding, dividing, and recombining as the material is processed between the the sigma blades and the container walls.
Jacket arrangement is is provided for heating or cooling.
SIGMA MIXER as the name suggests contains mixing element (Blades) of Sigma type two in number which contra rotates inward to achieve end to end circulation & thorough & uniform mixing at close or specified clearance with the container.
The mixed product can be easily discharged by tilting the container by hand lever manually either by system of gears manually operated or motorised.
Sigma Mixer is a Batch type Mixer
In sigma mixer, Mixing Trough and Blades are fabricated from mild steel, stainless steel 304 and 316 grade.
Blades of sigma mixers are designed to obtain thorough mixing of high viscosity materials.
Sigma Mixers Blades are machined to keep minimum equal gap between through walls and blades.

Sigma Mixer with Extruder

The Sigma Mixer with Extruder product has finished the mixing cycle, discharge/extrusion is performed simply by running the extrusion screw in a forward direction.
The double arm sigma blades normally continue to run throughout the extrusion process providing a thoroughly mixed product at all stages of the production cycle.
By changing the extrusion die heads, the product can be discharged in round, square, “spaghetti”, or any form desired.
Speed variation of the extrusion screw allows adjustment of the product flow, depending on the viscosity.
As an option, a die cutter can be installed outside the die head. This bevel-faced cutter provides transverse cutting and can be pneumatically driven.
Automatic control of blade speed based on product viscosity.
Capability to pass from mix phase to extrusion phase without interruption.
Lateral discharge of product through the extrusion screw without operator interaction
Shape of extruded material is adaptable to customer’s requirements.
Provides cycle automation; loading, mixing, and extrusion.
Temperature control available for handling heat treated products
Enclosed mixing and discharge provides protection from product contamination and greater operator safety
Vacuum and/or pressure designs

Sigma Mixer Kneader Sigma Mixer Extruder Z Blade Sigma Mixer Double Arm Sigma Mixer Food Grade Sigma Mixer Heavy Duty Sigma Mixer Bubble Gum Sigma Mixer Sigma Dough Mixer Liquid Soap Sigma Mixer Lab Sigma Mixer Sigma Mixer Kneader Manufacturer Sigma Mixer Extruder Supplier Z Blade Sigma Mixer Exporter Heavy Duty Sigma Mixer Gujarat Bubble Gum Sigma Mixer Ahmedabad Sigma Dough Mixer India


Sigma Mixer
Sigma Mixer Extruder
Z Blade Sigma Mixer
Double Arm Sigma Mixer
Bubble Gum Sigma Mixer
Sigma Dough Mixer
Lab Sigma Mixer
Soap Sigma Mixer
Heavy Duty Sigma Mixer

Operation of Sigma Blade Mixer

Material is loaded through the top of the container to typically 40 to 65 percent of the mixer’s total volumetric capacity. The rotation of the blades is through heavy duty drive systems typically consisting of a motor, gearbox, couplings, and gears. The tip speed of the sigma mixer is generally limited to 60 metres per minute. Mixing may be carried out at ambient temperature or under controlled temperature conditions. The mixer troughs can be provided with jackets for circulation of hot or cold media to maintain the required temperature conditions within the mixer. The discharge of the material from the mixer container is either by tilting of the mixer container. bottom discharge valve, or through an extruder / screw located in the lower portion between the two trough compartments. The mixer may be equipped with any one of these discharge arrangements.

  • The tilting discharge arrangement is most common. The tilting arrangement of the container may be designed for manual operation or may be mechanized using motorized or hydraulic arrangement.
  • Tilting Discharge For materials of lower viscosity, the bottom discharge valve may be provided on the mixer trough. The design profile of the valve should be flush with the mixer trough to avoid any dead or unmixed pockets of material).
  • Bottom Discharge The extruder/screw discharge has an advantage that materials can be directly discharged, extruded, in the required shape or size for further processing. In addition, the screw design eliminates operator exposure to hot materials if the mixing processes are carried out at high temperatures and/or with materials that are toxic in nature.

Salient Features

  • Sigma Mixer (Kneader) is a Batch Mixer
  • Mixing Trough and Blades are fabricated from Mild Steel / Stainless Steel.
  • Product contacting parts are ground, buffed or smooth and clean working.
  • Blades are designed to obtain thorough mixing of high viscosity materials.
  • Blades are machined on a leading edge to keep minimum equal gap between through walls and blades.
  • Heavy-duty gears are fitted to the blades.
  • Shaft sealing into the stuffing boxes is provided by Teflon Chevron Rings / PTFE breaded gland rope to prevent leaking from blade ends.
  • Guards / Grills and interlocking are provided for maximum safety.

Options Available with us:

  • Both GMP and Non- GMP Models
  • Discharge by tilting container / bottom sliding valves / bottom gates / flush bottom gate valves.
  • Tilting by hand liver / hand wheel with lead screw / electrical arrangements / hydraulic systems.
  • Lifting of lead either manually, with help of counter weights or hydraulically.
  • ‘Z’ Type Spiral blade / Naben / double naben blades to circulate hot / cold water in cases of heavy masses.
  • Jacketed shell for heating or cooling by steam, oil, water etc. with fibre glass insulation over the jacket.
  • Working facility with vacuum or pressure.
  • Spray system for liquid addition / gas purge.
  • Flame proof / Non-flame proof electrical controls.
  • Wireless remote-control operation for toxic materials.
  • Electric Flame Proof or Non-Flameproof motor/ Hydraulic drives.

Applications of Sigma Kneader

  • Adhesives
  • Biscuits doughs
  • Rubber
  • Carbon pastes
  • Ceramics
  • Chemicals
  • Crayon and pencil lead
  • Inks and pigment products
  • Explosives
  • Fiberglass resin doughs
  • Food and confectionery products
  • Gaskets and gland packings
  • Grinding wheel preparations
  • Hot-melts
  • Marzipan
  • Putties
  • Mastics
  • Metal powders
  • Moulding preparations
  • Pencil erasers
  • Pharmaceuticals
  • Plastics
  • Refractories
  • Sealing compounds
  • Silicone
  • Soaps and detergents
  • Solid propellants
  • Sugar pastes
  • Viscous rubber solutions
  • Chewing gum


3 Ltrs. to 2000 Ltrs.

Sigma Arm Mixer
Article Name
Sigma Arm Mixer
Sigma arm mixer used for high viscosity mixer and kneading
Publisher Name
Abster Equipment
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