Detailed Guide to Grease Filling Machines - Principles, Types, and Selection Guide
Grease filling machines are industrial equipment specifically designed to precisely dispense viscous grease (paste) into various containers. They address core issues with manual filling—low efficiency, high waste, poor accuracy, and inadequate hygiene—making them essential equipment in modern grease production and packaging processes.

1. What Is a Grease Filling Machine?

Simply put, a grease filling machine “packs” grease. It efficiently and accurately transfers bulk grease from large drums into smaller packages for sale or use, such as:

Small-sized : Syringe tubes (e.g., 30g), Aluminum-plastic tubes (e.g., 120g), Plastic cartridges/boxes/jars (e.g., 400g).

Medium-sized : Plastic buckets (e.g., 1kg, 5kg), Steel drums (e.g., 15kg)

Large-sized : Large steel drums (e.g., 180kg)

2. Core Working Principle (Using Mainstream Models as Examples)

The operating principle of most grease filling machines on the market can be likened to two familiar tools: The “syringe” and the “toothpaste squeezer.” Mainstream and Reliable Working Principle: Piston-Type Filling.
This is currently the most common and reliable method for handling grease, especially high-viscosity greases like the commonly used NLGI 2# and 3#.

Working Process (Three-Step Approach):

Material Suction (Intake Phase):

Upon machine startup, the piston retracts, creating negative pressure (vacuum) within the sealed metering cylinder. This suction force draws grease from the storage container through the pipeline—either by vacuum extraction or gravity flow—into the metering cylinder, completing the quantitative intake.

Metering (Quantity Control):

The piston's stroke is precisely controllable. Adjusting the stroke distance determines the volume of grease extracted (and subsequently ejected). This is the core mechanism ensuring filling accuracy. High-end models achieve precision within ±0.5% through servo motor and precision ball screw control.

Filling (Ejection Stage):

When the container is positioned (manually placed or automatically conveyed), the piston moves forward, forcefully ejecting the grease from the metering cylinder. The grease travels through tubing and is injected into the container via a specialized filling nozzle/valve.

At the end of filling, the valve closes instantly with anti-drip and anti-stringing functions, ensuring a clean bottle opening without any trailing residue.

To illustrate: It functions like a giant, motor-controlled medical syringe that first draws a fixed amount of ointment and then precisely injects it into a small bottle.

3. Common Types of Grease Filling Machines on the Market

In addition to the mainstream piston-type described above, the following common types exist based on varying production capacities and material characteristics:

Piston-Type:

Working Principle: Similar to a syringe, where linear piston movement pushes the material.
Advantages: Highest precision, wide viscosity adaptability, minimal waste, easy cleaning.
Disadvantages: Relatively slow speed, requires adjustment for specification changes.
Ideal Scenarios: Suitable for most grease filling applications, especially high-viscosity, high-value greases.

Gear Pump Type:

Working Principle: Similar to a water pump, conveying grease through rotating gears
Advantages: Fast filling speed, suitable for continuous operation
Disadvantages: High wear on high-viscosity greases containing particles; accuracy affected by viscosity
Ideal Scenarios : Semi-fluid greases with good flowability (e.g., 00#, 0#)

Air-Pressure Type (Pressure Barrel):

Working Principle: Similar to an aerosol can, expelling grease with compressed air
Advantages: Simple structure, low cost, suitable for large drums
Disadvantages: Low precision, high waste (residue in drum), prone to air bubbles
Ideal Scenario: Suitable for large-scale initial filling with low precision requirements (e.g., 180kg drums)

Screw-type:

Working Principle: Similar to a meat grinder, using a screw rod to extrude
Advantages: Suitable for ultra-viscous, lumpy pastes
Disadvantages: Complex cleaning, slow speed
Ideal Scenarios: Suitable for extremely hard greases or similar pastes (e.g., NLGI 5#, 6#)

Summary:

For general users filling common greases like lithium-based, calcium-based, or calcium sulfonate complex greases (NLGI 1#-3#), piston-type filling machines are the preferred and standard choice. Specialized models are generally unnecessary.

4. Consolusion

A grease filling machine is essentially a precise, powerful tool for metered dispensing. Mainstream piston-type models mimic the working principle of a syringe, delivering reliable and accurate solutions.

For the vast majority of users, selecting a semi-automatic piston-type filling machine made of stainless steel, servo-driven, and equipped with an anti-stringing valve can resolve over 95% of filling challenges. There's no need to pursue overly complex, expensive, or specialized models. Upgrading from manual filling to such equipment delivers immediate value through enhanced efficiency, reduced waste, and a professional appearance.

In short: It transforms messy, troublesome grease filling into a clean, precise, and efficient process.