In industries such as petroleum, chemical, food, pharmaceutical, and cosmetics, the physical properties of many semi-solid or paste like materials (such as lubricants, asphalt, Vaseline, butter, toothpaste, ointments, etc.) directly affect their effectiveness and process adaptability. Among them, "Penetration" has long been adopted by international standards (such as ASTM D217, GB/T 269, ISO 2137) as a core indicator for measuring the softness, consistency, and plasticity of such materials. The emergence of automatic cone penetration testers has changed the subjectivity and inefficiency of traditional manual testing, becoming the "eye of touch" in modern laboratories with high precision, high repeatability, and intelligent operation.

1、 Definition and Testing Principle of Cone Penetration

Cone penetration refers to the depth of a standard cone (with a mass of 150 grams, cone angle of 30 °, and cone tip curvature radius of 0.1-0.2 mm) vertically penetrating the surface of a specimen under the action of gravity at a specified temperature (usually 25 ℃) and time (usually 5 seconds), measured in 0.1 millimeters (i.e. "cone penetration unit"). For example, a measured cone penetration of 320 indicates a cone penetration depth of 32.0 mm.

The larger the value, the softer and sparser the material; The smaller the value, the harder and thicker the material. For lubricating grease, cone penetration directly affects its starting resistance, pumping performance, and sealing ability; Asphalt affects construction and workability as well as high-temperature stability; For food and ointments, it is related to taste, spreadability, and release characteristics.

Traditional testing relies on manual release of cones and visual readings, resulting in large errors and low efficiency. The automatic cone penetration tester achieves full process automation from constant temperature, release, measurement to data output through mechatronics integration design.

2、 Instrument structure and workflow

A typical automatic cone penetration tester mainly consists of the following modules:

1. Constant temperature bath system: Equipped with a high-precision temperature control device (± 0.1 ℃), it can accommodate multiple sample dishes to ensure that the samples are fully temperature controlled to 25 ℃ (or other set temperatures, such as 0 ℃ for low-temperature performance evaluation) before testing;

2. Cone lifting mechanism: The automatic lifting and impact free release of the standard cone are controlled by a stepper motor or electromagnetic release device, eliminating human operation differences;

3. High precision displacement sensor: using laser displacement meter, grating ruler or high-resolution encoder to capture the depth of cone penetration in real time, with a resolution of up to 0.01 mm (i.e. 0.1 cone penetration unit);

4. Sample platform and positioning system: with horizontal adjustment function to ensure that the cone falls vertically. Some models support multi-point testing (such as testing the working cone penetration after 60 reciprocating cuts);

5. Microcomputer control system and touch screen interface: preset multiple standard methods such as ASTM, ISO, GB, etc., automatically timing, calculating, storing results, and supporting printing or USB export;

6. Cleaning and maintenance auxiliary devices: such as automatic cone cleaning positions, anti drip trays, etc., to improve operational convenience.

The typical testing process is as follows: load the sample into a standard dish → place it in a constant temperature bath for ≥ 1 hour → the instrument automatically locates the cone on the surface of the sample → start the test → the cone falls freely for 5 seconds → the sensor records the penetration depth → display and save the results.

3、 Technological advantages and industry applications

Compared to manual methods, automatic cone penetration testers have significant advantages:

High repeatability and reproducibility: eliminates artificial release force, timing errors, and reading deviations, and RSD (relative standard deviation) can be controlled within 1%;

Multi mode testing support: One click switching between modes such as "Unworking Cone Penetration", "Working Cone Penetration", "Extended Working Cone Penetration", "Block Cone Penetration", etc;

Efficient batch processing: Some models are equipped with 6-station or even 12 workstation constant temperature baths to achieve continuous automatic testing;

Data traceability: automatic recording of testing time, temperature, operator, and results, in compliance with GLP/GMP standards;

High safety: Avoid operators from coming into contact with high-temperature baths or sharp cones.

Its application scenarios are extremely wide:

Lubricating oil and grease production: quality control, product grading (such as NLGI 000 # -6 # grading based on cone penetration);

Road construction: Asphalt penetration (similar to cone penetration principle) is used to evaluate the high-temperature stability of road surfaces;

Food industry: texture analysis of butter, margarine, and jam;

Pharmaceutical and cosmetics: consistency consistency test of ointment, cream and lipstick;

Research institutions: fundamental tools for studying the rheological properties of new materials.

Although the automatic cone penetration meter focuses on a seemingly simple physical quantity - "cone penetration depth", it supports countless product performance boundaries and quality bottom lines behind it. It transforms human's vague perception of "soft and hard" into precise numbers, elevating empirical judgment to scientific decision-making. In today's pursuit of product consistency, process stability, and user experience, this intelligent "tactile eye" not only improves laboratory efficiency, but also becomes a key bridge connecting material microstructure and macroscopic application performance.