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 (co-crystal screening, 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.
Benefit from particularly ergonomic handling while achieving the same finenesses down to the nanometer range.
Operation of the RETSCH planetary ball mills is particularly safe. They feature a robust Safety Slider which ensures that the mill can only be started after the grinding jar has been securely fixed with a clamping device. The self-acting lock ensures that the jar is seated correctly and securely. This proven solid mechanical system is less failure-prone than electronic solutions - the user has full access to the sample at any time. When the electronic system fails, it is not possible to unlock the jars, for example.
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 video shows wet grinding in the Planetary Ball Mill PM 100.
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.
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.
The performance and the result of sample preparation are also determined by the choice of the grinding jar and its ball charge. The EasyFit range of jars has been specially designed for extreme working conditions such as long-term trials, even at maximum speed of 800 rpm, wet grinding, high mechanical loads and maximum speeds as well as for mechanical alloying. This line of jars is suitable for all RETSCH planetary ball mills.
The new EasyFit grinding jar series features a structure on the bottom of the 50-500 ml jars called Advanced Anti-Twist (AAT). This ensures that the jars are tightly fixed without the risk of twisting, even at high speed, and that wear and tear is drastically reduced. Secure clamping of the jars is made much easier: to find the correct clamping position, a maximum twist of 60° is required.
The geometry of the EasyFit jars in the 50 ml and 250 ml sizes has been enlarged in diameter and reduced in height compared to the previous "comfort" models. This offers two advantages: better grinding results and interchangeable lids, as there are only three diameter dimensions for the entire grinding jar range.
Diameter categories
Both the aeration lid and GrindControl can now be equipped with inlays of different materials. Thus, the lid can be used for, e. g. a steel and a zirconium oxide jar by simply exchanging the inlay.
With a special adapter, co-crystal screening can be carried out in a planetary ball mill, using disposable vials such as 1.5 ml GC glass vials. The adapter features 24 positions arranged in an outer ring with 16 positions and an inner ring with 8 positions. The outer ring accepts up to 16 vials, allowing for screening up to 64 samples simultaneously when using the Planetary Ball Mill PM 400. The 8 positions of the inner ring are suitable to perform trials with different energy input, e.g. for mechanosynthesis research.
To produce optimum grinding results, the jar size should be adapted to the sample amount to be processed. The grinding balls are ideally sized 3 times bigger than the largest sample piece. Following this rule of thumb, the number of grinding balls for each ball size and jar volume is indicated in the table below. To pulverize, for example, 200 ml of a sample consisting of 7 mm particles, a 500 ml jar and grinding balls sized at least 20 mm or larger are recommended. According to the table, 25 grinding balls are required.
| Grinding jar nominal volume |
Sample amount | Max. feed size | Recommended ball charge (pieces) | ||||||
| Ø 5 mm | Ø 7 mm | Ø 10 mm | Ø 15 mm | Ø 20 mm | Ø 30 mm | ||||
| 12 ml | до ≤5 ml | <1 mm | 50 | 15 | 5 | - | - | - | |
| 25 ml | до ≤10 ml | <1 mm | 95 – 100 | 25 – 30 | 10 | - | - | - | |
| 50 ml | 5 – 20 ml | <3 mm | 200 | 50 – 70 | 20 | 7 | 3 – 4 | - | |
| 80 ml | 10 – 35 ml | <4 mm | 250 – 330 | 70 – 120 | 30 - 40 | 12 | 5 | - | |
| 125 ml | 15 – 50 ml | <4 mm | 500 | 110 – 180 | 50 – 60 | 18 | 7 | - | |
| 250 ml | 25 – 120 ml | <6 mm | 1100 – 1200 | 220 – 350 | 100 – 120 | 35 – 45 | 15 | 5 | |
| 500 ml | 75 – 220 ml | <10 mm | 2000 | 440 – 700 | 200 – 230 | 70 | 25 | 8 | |
The table shows the recommended charges (in pieces) of differently sized grinding balls in relation to the grinding jar volume, sample amount and maximum feed size.
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, крехък: каменни въглища
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, жилави: 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: гранит
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
To find the best solution for your sample preparation task, visit our application database.
Our instruments are recognized as the benchmark tools for a wide range of application fields in science and research. This is reflected by the extensive citations in scientific publications. Feel free to download and share the articles provided below.
| Приложения | pulverizing, mixing, homogenizing, colloidal milling, mechanical alloying, mechanosynthesis, nano grinding, co-crystal screening |
| Област на приложение | chemistry, биология, геология / металургия, инженеринг / електроника, медицина / фармация, околната среда / рециклиране, селското стопанство, строителни материали, стъкло / керамика |
| Материали | мек, твърд, крехък, влакнести - сухи или мокри |
| Принцип на смилане | удар, триене |
| Максимален размер на захранващият продукт | < 10 мм |
| Големина след смилане* | < 1 микрона, за колоидално смилане < 0.1 микрона |
| Размер на партидата / количество на пробата* | макс. 4 x 220 мл, макс. 8 x 20 мл при ползване на два смилачни цилиндъра в комплект |
| Брой на смилачните станции | 4 / 2 |
| Съотношение на скоростта | 1:-2 / 1:-2.5 / 1:-3 |
| Скорост на слънчевото колело | 30 - 400 об./мин. |
| Диаметър на слънчевото колело | 300 мм |
| G-force | 26.8 G |
| Видове смилачни цилиндри | EasyFit, optional areation covers, safety closure devices |
| Материал на смилащите части | закалена стомана, неръждаема стомана, волфрамов карбид, ахат, спечен алуминиев оксид, силициев нитрид, циркониев оксид |
| Обем на смилачната камера | 12 мл / 25 мл / 50 мл / 80 мл / 125 мл / 250 мл / 500 мл |
| Stackable grinding jars | 12 ml / 25 ml / 50 ml / 80 ml |
| Adapter for single-use glas vials | 24 x 1.5 ml / 7 x 20 ml |
| Настройване времето за смилане | digital, 00:00:01 to 99:59:59 |
| прекъсната работа | да, с обръщане на посоката |
| Време на прекъсванията | 00:00:01 до 99:59:59 |
| Време за пауза | 00:00:01 до 99:59:59 |
| Запаметяване на настройки | 10 |
| Възможност за измерване на вложената енергия | да |
| Интерфейс | RS 232 / RS 485 |
| Задвижване | Трифазен асинхронен мотор с честотен преобразувател |
| Мощност на двигателя | 1.5 кВ |
| Данни за електрозахранването | различни напрежения |
| Захранване | еднофазово |
| Защита | IP 30 |
| Енергийна консумация | ~ 2100 Вата (VA) |
| Размери затворена | 836 x 1220 (1900) x 780 мм |
| Нетно тегло | ~ 290 кг |
| Стандарти | CE |
| Патенти | SafetySlider (DE 202008008473) |
Смилащите цилиндри са закрепени ексцентрично на слънчевото колело. Посоката на движение на слънчевото колело е обратна на посоката на движение на смилащите цилиндри и имат предавателно съотношение 1:-2 (или 1:-2.5, или 1:-3).
Смилащите топки в цилиндърите се движат под въздействието на наслагвани ротационни движения, така наречените Кориолис сили. Взаимодействието на енергиите на смилащите топки и цилиндъра, довеждат до много ефективно намаляване размера на частиците.
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