Process tool
Coating pan speed and tangential velocity calculator
Tangential bed velocity from pan diameter and RPM, with the range most film coating runs sit in.
- Runs in the browserNothing is submitted anywhere
- Working shownCheck every line by hand
- Plant figuresThe bands our grades run in
- Free, no sign-inNo account, no email
Written by the Rglax Pharma technical team, who formulate and manufacture every grade named on this calculator at our WHO-GMP works in Tahliwal, Una (drug manufacturing licence NNZ/23/238). Reviewed 3 September 2026. Licences and certificates.
Result
Tangential velocity
0.383 m/s
Inside the usual window of 0.25 to 0.75 m/s. Slower and the bed does not turn over, faster and tablets abrade at the edge
- Pan diameter
- 0.914 m
- Assessment
- Within the usual band
- Bed turnover
- 8 rev/min
How this was worked out
- pan diameter = 36 in × 25.4 ÷ 1000 = 0.914 m
- tangential velocity = π × 0.914 m × 8 rpm ÷ 60 = 0.383 m/s
Formula
v (m/s) = π × pan diameter (m) × RPM ÷ 60
Why this number matters
Two pans of different size at the same RPM are not running the same process. A 24 inch pan at 14 RPM and a 48 inch pan at 7 RPM put roughly the same surface speed through the spray zone, which is why scaling a coating process on RPM alone goes wrong. Tangential velocity is the number that transfers between pan sizes.
Where it goes wrong
Friable cores, and most herbal and nutraceutical cores, need the lower end of the band. Attrition at the pan wall shows as edge wear and fines long before it shows as a failed friability test.
Worked example
With pan diameter of 36 inch and pan speed of 8 RPM, the calculation gives:
- Pan diameter
- 0.914 m
- Tangential velocity
- 0.383 m/s
- Assessment
- Within the usual band
- Bed turnover
- 8 rev/min
The arithmetic is one line, shown beside the result above so it can be checked by hand: v (m/s) = π × pan diameter (m) × RPM ÷ 60.
Other calculators
- Coating weight gainHow much dry coating material a batch needs at a target percentage weight gain, including process loss.
- Coating dispersionWater or solvent needed to disperse a ready-mix powder at a given solids concentration.
- Spray rateSpray rate per gun and total run time from your dispersion quantity and available process window.
- Drying capacityHow much water your inlet air can actually carry away, and the spray rate that supports.
- Dispersion vesselVessel volume, diameter and impeller size for the dispersion quantity you are making.
- Surface area and build-upSurface area per tablet and coating build-up in mg per square centimetre, which is how enteric coats are specified.
Every grade page carries the process parameters it was developed on, so you can start from a known point rather than a calculated one. Browse the grades.
Read next
- Sugar coating systemA sugar shell is built over many passes, so pan speed sets how long the build takes.
- Picking and stickingWhat a bed that is turning too slowly produces.
- Tablet coating weight gain calculatorHow much dry coating material a batch needs at a target percentage weight gain, including process loss.
- Coating dispersion and solids calculatorWater or solvent needed to disperse a ready-mix powder at a given solids concentration.
- Coating spray rate calculatorSpray rate per gun and total run time from your dispersion quantity and available process window.
Need a second opinion
Talk to our technical team.
Send the core, the coater and the target and we will tell you what we would run, and which grade we would run it with.
From the calculation to the pan.