Robotics ｜ Powder dispensing
Powder weighing, controlled automatically to the target mass
Real-time reading of an off-the-shelf analytical balance × automatic feed-rate control × automatic logging of the final mass. Far from the target the system feeds quickly; as it approaches, it slows the motor to land on the value. In the demo, against a 200 mg target, it closes to within 0.100 mg of the target.
Demo video
The sequence runs from selecting the sample profile, entering the target mass, coarse feed, fine approach, through to logging.
* Recording of the actual hardware, played at 1.5× speed. No audio.
The problem
Weighing powder by hand gets harder the smaller the quantity.You cannot take powder back once you have added too much, so operators add it cautiously in small increments, and the time per sample grows.
Where to stop also depends on the operator's judgement. For the same target mass, the achieved value and the time taken vary from person to person, and the record is usually typed in by hand.
What we built
Weighing, control and logging are automated end to end.
01 Select the sample profile
Different powders flow differently, so the motor-speed settings for that sample are loaded.
02 Enter the target mass
The desired mass is entered. The demo uses 200 mg.
03 Coarse feed
While far from the target, powder is fed quickly at a high motor speed.
04 Fine approach
As the remaining amount shrinks, the motor slows so the system lands without overshooting.
05 Logging
The achieved mass and the whole trace are logged directly. No transcription, no copying errors.
Because the feed rate drops with the remaining amount, overshooting and starting again no longer happens.The achieved mass and the trace remain on the control side, so there is no need to copy the weighing record by hand.
Achievable accuracy depends on the properties of the powder and the environment.
Where it applies
Manufacturing & quality control
Small-quantity weighing of raw materials and additives, with every formulation logged. Who weighed how many mg and when is recorded automatically, replacing handwritten and hand-typed records and giving traceability. Rework from overshooting drops, and the time per sample becomes predictable.
R&D
Preparations where small amounts must be weighed accurately, such as catalysts and battery materials. Repeating the same target mass across dozens of samples can be left to run overnight. The weighing data connects directly to machine learning and Bayesian optimisation.
Swappable components
Balance (off-the-shelf → your own model) / material (powder → granules, pellets) / target (mass → blend ratio). A configuration that keeps your balance and automates only weighing and logging is also possible.
Summary
By using an off-the-shelf analytical balance as it is and controlling the feed rate from the mass it reads, powder weighing can close automatically on the target. Rework from overshooting and operator-to-operator variation in the achieved value are both reduced.
* This system is a proof-of-concept demonstration. Specific configurations, specifications and implementation details are discussed individually on enquiry.
Tell us about the experiment you want automated
We will ask about the target operation, the instruments you have and your sample throughput, then propose where to start.
- Unattended weighing, dispensing and sample exchange
- Control systems built around your existing instruments
- PoCs that connect automatically acquired data to analysis and experimental design