Pin-Type Micron Bead Mill
A pin rotor at micron scale is not a cheaper nano mill. The pins are thicker, the gap is wider, and the point is different: more energy per pass at a tip speed that does not cook the product.
If you are making one of these, this is the right rotor
At micron scale the disc mill is the default. The pin rotor earns its price in one specific situation: when the problem is the spread of the distribution rather than the median, or when a disc has to be slowed down to reach your fineness.
| What you are making | The problem people arrive with | Why this configuration helps |
|---|---|---|
| General industrial coating | Hiding power has plateaued — adding more pigment is the only lever left, and it is the expensive one | A narrow 1–3 µm band gives more scattering interfaces per kilogram than the same solids at a wide spread |
| Agrochemical suspension concentrate | Suspension fails on storage — the coarse tail settles and will not redisperse | Closing the tail removes the particles that settle first; the fine fraction stays in suspension |
| LFP cathode slurry | Iron contamination and over-grinding both cost capacity | PU or ceramic wetted parts, and a residence time short enough to avoid lattice damage |
| Paper and board coating | The mill is the bottleneck, not the fineness — you need tonnage at a steady 1–2 µm | The pin field keeps shear high at flow rates a disc mill has to slow down for |
| Textile pigment paste | Batch-to-batch shade variation that customers notice at the fabric | Residence-time distribution is narrow, so every batch sees the same energy history |
| Ceramic glaze and frit | Media wear shows up as iron specks in the fired glaze | Ceramic rotor and lining available, with low-wear media in the 0.6 – 0.8 mm range |
If yours is not on the list, the question is still the same three: target D90, acceptable spread, and how many tonnes per shift. Everything else follows.
What you are paying for
Four differences from a disc mill, each one answering a specific way the process fails at micron scale.
Pins sized for 0.3 – 0.8 mm media
- Feature
- Pins are thicker and spaced wider than on a nano rotor, so 0.6 mm beads pass the pin gaps without bridging.
- Advantage
- No media packing, and no torque spike on start-up with a cold, settled charge.
- Benefit
- You can run the media size the fineness actually needs, instead of the largest one the rotor will tolerate.
More energy per pass, at lower tip speed
- Feature
- The pin field forces every particle through the high-shear zone on every revolution of the shaft.
- Advantage
- The same size reduction is reached in fewer passes, at a tip speed roughly 20 – 30% lower than a disc mill needs.
- Benefit
- Less heat per tonne — a heat-sensitive binder survives, and the chiller load drops with it.
Screen or dynamic gap, matched to the media
- Feature
- From 0.3 mm upward a slotted screen is practical; below that we fit the dynamic gap instead.
- Advantage
- The separator is chosen against your media size, not a catalogue default.
- Benefit
- You are not paying for a centrifugal separator you do not need, and not fighting a screen that blinds.
Parts you can actually replace
- Feature
- Rotor, pins and discs are separate components, not a welded assembly.
- Advantage
- You replace the worn item, not the shaft and the bearing stack with it.
- Benefit
- Maintenance cost per tonne stays predictable — which matters more than purchase price on a machine running two shifts.
PM-MP models and working envelope
PM-MP is one configuration of the PM-M series, so the sizes match the series. Two models are quoted as standard; larger chambers are built to order.
| Model | Chamber volume | Motor power | Media range | Throughput | Target fineness |
|---|---|---|---|---|---|
| PM-MP30 | 30 L | 30 kW | 0.3 – 0.8 mm | 150 – 600 L/h | D90 1 – 10 µm |
| PM-MP60 | 60 L | 55 kW | 0.3 – 0.8 mm | 400 – 1,200 L/h | D90 1 – 10 µm |
| PM-MP150 | 150 L | 110 kW | 0.4 – 0.8 mm | 1,000 – 3,000 L/h | D90 1 – 10 µm |
Model figures are typical for this configuration — the binding specification comes with your quotation. If your duty sits between two models, we will tell you which one to take and why, including the case where the smaller one is enough.
Common to every PM-MP
- Wetted parts: SS316L, polyurethane, silicon carbide or zirconia, per your contamination limit
- Separator: slotted screen for 0.3 mm and above; dynamic gap below that
- Cooling: full chamber jacket, chilled water, product outlet target
- Seal: double mechanical seal with barrier fluid
- Control: PLC + HMI, recipe storage, temperature and pressure interlocks
- Options: ATEX configuration, ceramic rotor, CIP connections, wear-compensated pins
When this is the wrong machine
We would rather say this now than after commissioning. If any of these four describe you, the machine you want is elsewhere on this site.
You actually need sub-100 nm
Below about 0.3 mm media the pin gap has to close, and the rotor becomes a nano rotor. That is a different machine, not a different setting.
PM-NP pin-type nano mill →Throughput matters more than the spread
A disc rotor moves more volume per kilowatt between 3 and 10 µm. If the spec is simply 'under 10 µm, as much as possible', the disc mill is cheaper and simpler.
PM-MD disc-type mill →Your material is a paste
Above roughly 30,000 cP a horizontal chamber starves, whatever the motor nameplate says.
PM-V high-viscosity mill →You change formulation every batch
If cleaning time dominates and every batch is different, a single-vessel basket mill avoids the pump, the loop and the flush in between.
PM-B basket mill →One case is not a different machine but a different build: if contamination is the constraint rather than fineness, this mill is available with ceramic discs, a ceramic-lined chamber and a ceramic rotor — same envelope, different materials.
Before you buy, send us a kilogram
We run your material on a PM-MP in the configuration we would quote, and send back the particle size curve with the model and media we used. No charge, and the report is yours whether you buy or not.
Send 1 kg of your material
Slurry if you have it; powder plus the carrier you intend to use if you do not. We will send the address and the customs description to use, so it clears without a hold.
We run a size-reduction series
On the configuration we would actually quote. D10 / D50 / D90 after each pass, plus product temperature, so you can see where the curve flattens.
You get the curve, the model and a budget price
Whether or not you buy. The report is yours to show your own board or your customer.
Grinding something else?
PM-MP covers 1 – 10 µm in low-to-medium viscosity slurry. Everything else we build sits in seven other configurations — pick by what your material does, not by model number.
Nano Bead Mill Most requested
Small media, gap or centrifugal separation, aggressive chamber cooling.
Choose it when: Worth it only if your application genuinely needs sub-100 nm.
Lab & Pilot Mill Most requested
Same media and tip speed as the production machine, so results scale.
Choose it when: Start here if you need to prove a target before buying capacity.
Basket Mill
Single-vessel dispersion — no external pump or recirculation loop.
Choose it when: Best for many formulations in small batches, or when cleaning time dominates.
Dry Grinding Mill
Dry micronisation with air classification and dust collection.
Choose it when: For powders that cannot be processed wet — no drying step downstream.
High-Viscosity Mill
Built for high-solid and high-viscosity material, with screw discharge.
Choose it when: For pastes and highly loaded compounds a standard mill will not move.
Mining & Large-Scale Mill
Stirred media mills sized for mineral slurry at plant throughput.
Choose it when: Selected on throughput and media consumption, not on fineness alone.
Complementary Equipment
Three-roll mills, inline pre-dispersion, mixers and spray dryers.
Choose it when: Often the cheapest throughput gain is better pre-dispersion, not a bigger mill.
All eight configurations
The complete index — wet and dry, 0.5 L laboratory units through to plant-scale stirred media mills.
Open the equipment index →Before you ask
Pin or disc — how do I actually decide?
Two questions. Is the spread of the distribution part of your specification, or only the median? And does the disc have to be slowed down to reach your fineness? Two yes answers point at the pin rotor; two no answers point at the disc.
What media size should I start with?
Work back from the target. Media diameter sets a floor on achievable fineness at roughly 1/500 to 1/1000 of the bead diameter. For 1 – 3 µm that usually means 0.3 – 0.4 mm; for 3 – 10 µm, 0.6 – 0.8 mm.
Can I run this as a nano mill later?
No. The pin spacing and the separator are built around the media range. Running 0.1 mm media in a rotor designed for 0.6 mm bridges the pins and packs the chamber. If nano is on your roadmap, say so at the enquiry stage.
Screen or dynamic separator?
Screen from 0.3 mm upward — it is cheaper, simpler and uses no extra power. Below 0.3 mm the slots become too fine to stay open, and we fit the dynamic gap.
How much can you test at once?
One to two kilograms is enough for a full pass series on a production configuration. A few hundred millilitres is enough on the laboratory unit, which uses the same geometry.
Not sure the pin rotor is worth it at your fineness?
Send the target D90 and the spread you can accept. If a disc mill meets both, we will say so — it is cheaper for you and simpler to run.