Volumetric vs Gravimetric Body Colour Batching for Porcelain Tiles
Body colour batching controls how pigments, stains or coloured powders enter a porcelain tile body. The difference between volumetric and gravimetric dosing matters because small colour errors can show across a full fired batch.
Quick choice
| Need | Better option | Why |
|---|---|---|
| Highest shade repeatability | Gravimetric batching | Weight control handles bulk-density variation better. |
| Simple low-cost dosing | Volumetric batching | Equipment is simpler when material flow is stable. |
| Frequent colour changes | Gravimetric batching | Recipes can be controlled and audited by mass. |
| Stable single colour with known powder | Volumetric batching | Can work if calibration is maintained. |
Volumetric batching
Volumetric batching doses material by screw speed, pocket volume, feeder opening or timed discharge. It assumes that a given volume delivers a predictable amount of material.
The risk is bulk-density drift. If pigment, granule or coloured powder becomes more aerated, compacted, moist or segregated, the same volume can carry a different mass. That change can shift fired shade.
Gravimetric batching
Gravimetric batching doses by weight, usually with load cells, loss-in-weight feeders or weigh hoppers. It is better suited to body colour systems where shade consistency, recipe traceability and batch records matter.
The trade-off is cost and maintenance. Load cells, feeder tuning and calibration need discipline. A gravimetric system that is not calibrated can give false confidence.
Comparison table
| Factor | Volumetric | Gravimetric |
|---|---|---|
| Control basis | Volume or time | Weight |
| Shade repeatability | Good only with stable bulk density | Better across material variation |
| Equipment cost | Lower | Higher |
| Recipe traceability | Weaker | Stronger |
| Main risk | Density drift, bridging, segregation | Calibration error, feeder instability, load-cell issues |
Control checks
- Measure pigment or coloured-powder bulk density at startup and after refilling.
- Calibrate feeders with real material, not only theoretical screw output.
- Track fired L*a*b* values or agreed shade standards.
- Clean feeders fully between colour families.
- Keep records of recipe, feeder rate, batch weight and fired result.
Bottom line
Use volumetric batching when the material is stable and the colour tolerance is forgiving. Use gravimetric batching when shade repeatability, auditability and recipe control matter. For porcelain body colour, weight-based control is usually the safer choice for premium or repeat orders.
Frequently Asked Questions
What is volumetric body colour batching?
Volumetric batching doses syrup and base slip by volumetric flow rate (litres per minute). Each colour sits in its own tank with a controlled feed pump. A magnetic flow meter measures actual flow and the controller adjusts pump speed to hit the target.
What is massic body colour batching?
Massic batching doses by density measurement. A combined flow + density sensor (Coriolis or nuclear) reads the slip in real time. The controller calculates mass flow as volume times density, so any change in slip density is captured and corrected.
Which is more accurate, volumetric or massic?
Massic is more accurate when slip density varies. Volumetric error grows by the same percentage as the density drift. Massic auto-corrects. For stable slip, both methods give similar results.
Why does slip density change during a shift?
Temperature rise reduces density slightly. Water addition or syrup ageing changes pigment-to-water ratio. Recovered fines and recycled scrap can shift density. A 5 percent density rise gives a 5 percent pigment mass error in volumetric dosing.
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Written by
Venkatmani
Ceramic industry professional & content contributor.
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