A sigma mixer kneads very thick, stiff material between two sigma-shaped blades in a trough. It is used for putty, paste and dough-like mixes that a disperser cannot move. Here you will find how a sigma blade mixer works, how it compares with a planetary mixer and what to specify.
A double sigma kneader or paste kneader machine is the same family. The trough is usually jacketed and tilts to discharge.
We help you choose the machine that fits your product, batch size and plant, with specification, commissioning guidance and operator training. IPCS (Indian Paints Consulting Service) guides the selection of sigma mixer, from machine specification to installation, commissioning and operator training.
Sigma Mixer overview
Two sigma blades rotate towards each other at different speeds. They pull material off the trough walls and force it through repeated folding and stretching, so the batch is kneaded and not just stirred. Total vessel volume is larger than the usable batch, and fill level changes how well the batch kneads.
Discharge and temperature
- Tilting trough discharge, common for heavy products
- Extrusion discharge for very stiff material
- Bottom discharge where plant layout allows
- Jacketed trough for heating or cooling during mixing
Paint production applications for Sigma Mixer
It suits products where the mass is stiff and sticky.
Sigma mixer vs planetary mixer: a sigma mixer kneads strongly and tilts to discharge. A planetary mixer sweeps the whole vessel with blades that orbit and is easier to clean.
Technical specifications to review for Sigma Mixer
Ask for these in the quotation.
| Parameter | What to specify | Guide |
|---|---|---|
| Working volume | Net batch size | Gross volume is larger than the net batch |
| Blade type | Standard sigma or dispersion type | Standard blades fold strongly; other designs incorporate faster or give more shear |
| Drive | Motor and speed ratio | Sigma mixer capacity and motor depend on the stiffest product |
| Discharge | Tilting, extrusion or bottom | Match to the product and the filling step |
| Jacket | Steam, oil or cooling water | Needed when viscosity depends on temperature |
| Contact parts | Stainless steel or lined steel | Clean to the standard your product needs |
Capacity and configuration choices for Sigma Mixer
Sigma mixer capacity and motor are set by the stiffest product you will make, because that is when the motor works hardest. Sizes run from small laboratory units to large production troughs. Tell us the product, batch size and discharge method and we match the machine.
Installation & support for Sigma Mixer
Routine care
- Check the blade and trough clearance, and the shaft seals, on a schedule
- Clean the trough fully before the paste sets
- Inspect gearbox oil and the tilt mechanism
- Check jacket connections for leaks
- Log batch times and motor current
What we confirm before we quote
We confirm product and its stiffness, batch size, heating, cooling or vacuum need and discharge method before we quote. Foundation, utility and commissioning guidance follows the confirmed size, and operators are trained on your own product.
Frequently Asked Questions
What is a sigma mixer used for?
A sigma mixer kneads very thick and sticky products such as putty, sealants and adhesives, which a disperser cannot move.
Is a sigma mixer for putty better than a planetary mixer?
A sigma mixer kneads harder and tilts to discharge. A planetary mixer sweeps the whole vessel and is easier to clean. The choice depends on the product and the batch size.
What is sigma mixer capacity and motor?
Capacity depends on the net batch, and the motor depends on the stiffest product. Vessel volume is always larger than the usable batch.
What is a double sigma kneader?
It is a trough with two sigma-shaped blades. The term is used interchangeably with sigma blade mixer.
How is the batch discharged?
Most sigma mixers tilt the trough. Stiff products can use extrusion discharge.
Discuss Sigma Mixer requirements with the machine team
Send us your product list, batch size and country for a sigma mixer quotation. Please include: product and its stiffness, batch size, heating, cooling or vacuum need and discharge method.