The PM 400 is a robust floor model with 4 grinding stations and accepts grinding jars with a nominal volume from 12 ml to 500 ml. It processes up to 8 samples simultaneously which results in a high sample throughput.
The extremely high centrifugal forces of Planetary Ball Mills result in very high pulverization energy and therefore short grinding times.
The mill is ideally suited for tasks in research like mechanochemistry (mechano-synthesis, mechanical alloying and mechanocatalysis), or ultrafine colloidal grinding on a nanometer scale, as well as for routine tasks such as mixing and homogenizing soft, hard, brittle or fibrous materials.
For mechanical alloying of hard-brittle materials, the PM 400 is available in a special “MA” version.
THE HIGH-VOLUME BALL MILL FOR HIGH THROUGHPUT APPLICATIONS
Max. speed 400 rpm, large sun wheel
Up to 10 mm feed size and 0.1 µm final fineness
4 grinding stations for jars from 12 ml up to 500 ml, jars of 12 – 80 ml can be stacked (two jars each)
GrindControl to measure temperature and pressure inside the jar.
Aeriation lids to control the atmosphere inside the jar
Floor model, storable SOPs and cycle programs, 5 different jar materials for dry and wet grinding
FAST & POWERFUL
Loss-free size reduction down to the submicron range
Wet grinding yields particle sizes in the nanometer range (<100 nm)
Variable speed from 30 to 400 rpm,
speed ratio 1:-2 | 1:-2.5 | 1:-3
Batch-wise processing with max. 4 x 220 ml
8 x 20 ml sample per batch with stacked jars
Wide range of materials for contamination free grinding
REPRODUCIBILITY, SAFETY AND EASY HANDLING
Reproducible results due to speed control
Easy and safe clamping of grinding jars
The Safety Slider prevents starting the machine without securely clamped jars
Innovative counterweight and imbalance sensor for unsupervised operation
Comfortable parameter setting via display and ergonomic 1-button operation
Automatic grinding chamber ventilation
10 SOPs can be stored, programmable starting time
Power failure backup ensures storage of remaining processing time
SETTINGS & OPTIONS
Dry and wet grinding possible
Suitable for long-term trials, 99 h max.
Interval operation allows for cooling breaks
Direction reversal helps to minimize caking effects
WET AND NANO-SCALE GRINDING WITH THE PM 400
Wet grinding is used to obtain particle sizes below 5 µm, as small particles tend to get charged on their surfaces and agglomerate, which makes further grinding in dry mode difficult. By adding a liquid or dispersant the particles can be kept separated.
To produce very fine particles of 100 nm or less (nano-scale grinding) by wet grinding, friction rather than impact is required. This is achieved by using a large number of small grinding balls which have a large surface and many friction points. The ideal filling level of the jar should consist of 60 % small grinding balls.
For more details on jar filling, wet grinding and sample recovery watch the video.
The graphic shows the result of grinding glass at 360 rpm in the PM 400. After 1 h of pulverization in ethanol with 1 mm grinding balls, the D90 value of the original sample was reduced from 13 µm to 1.6 µm.
Grinding of glass in ethanol with 1 mm grinding balls.
Blue curve: original sample; green curve: pulverized sample after 60 min.
PM 400 MA FOR MECHANOCHEMICAL APPLICATIONS
RETSCH Planetary Ball Mills are perfectly suited for processes like mechanical alloying or mechanosynthesis. For most reactions, the 1:-2 speed ratio of jar to sun wheel of the models PM 100 and PM 200 is fully adequate, as the ball charge produces enough impact energy. However, greater energy is required for some reactions. Here the PM 400 MA can be used with the increased speed ratio of 1:-2.5 or 1:-3.
The PM 400 MA with an increased speed ratio of 1:-2.5 or 1:-3.0 is designed specifically for these applications. The optimum speed ratio and all other grinding parameters need be determined by trial and error for a specific product.
TYPICAL SAMPLE MATERIALS
RETSCH planetary ball mills are perfectly suitable for size reduction of, for example, alloys, bentonite, bones, carbon fibres, catalysts, cellulose, cement clinker, ceramics, charcoal, chemical products, clay minerals, coal, coke, compost, concrete, electronic scrap, fibres, glass, gypsum, hair, hydroxyapatite, iron ore, kaolin, limestone, metal oxides, minerals, ores, paints and lacquers, paper, pigments, plant materials, polymers, quartz, seeds, semi-precious stones, sewage sludge, slag, soils, tissue, tobacco, waste samples, wood, etc.
Medium-hard, brittle: coal
4 x 150 g sample
500 ml stainless steel grinding jar
25 x 20 mm stainless steel grinding balls
2 min at 350 rpm
Medium-hard, tough: PMMA
4 x 130 g sample
500 ml zirconium oxide grinding jar
15 x 25 mm zirconium oxide grinding balls
30 min pre-grinding at 400 rpm
150 x 10 mm zirconium oxide grinding balls
16 h fine-grinding at 300 rpm
Hard-brittle: granite
4 x 80 g sample
250 ml agate grinding jar
6 x 30 mm agate grinding balls
15 min at 400 rpm
Hard: silicon carbide
4 x 400 g sample
500 ml zirconium oxide grinding jar
60 x 15 mm zirconium oxide grinding balls
25 min at 400 rpm
12 ml / 25 ml / 50 ml / 80 ml / 125 ml / 250 ml / 500 ml
Stackable grinding jars
12 ml / 25 ml / 50 ml / 80 ml
Setting of grinding time
digital, 00:00:01 to 99:59:59
Interval operation
yes, with direction reversal
Interval time
00:00:01 to 99:59:59
Pause time
00:00:01 to 99:59:59
Storable SOPs
10
Measurement of input energy possible
yes
Interface
RS 232 / RS 485
Drive
3-phase asynchronous motor with frequency converter
Drive power
1.5 kW
Electrical supply data
different voltages
Power connection
1-phase
Protection code
IP 30
Power consumption
~ 2100 W (VA)
W x H x D closed
836 x 1220 (1900) x 780 mm
Net weight
~ 290 kg
Standards
CE
Patent / Utility patent
SafetySlider (DE 202008008473)
*depending on feed material and instrument configuration/settings
FUNCTIONAL PRINCIPLE
The grinding jars are arranged eccentrically on the sun wheel of the planetary ball mill. The direction of movement of the sun wheel is opposite to that of the grinding jars in the ratio 1:-2 (or 1:-2.5 or 1:-3).
The grinding balls in the grinding jars are subjected to superimposed rotational movements, the so-called Coriolis forces. The difference in speeds between the balls and grinding jars produces an interaction between frictional and impact forces, which releases high dynamic energies.
The interplay between these forces produces the high and very effective degree of size reduction of the planetary ball mill.
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