Roller coating transfers coating from a rotating applicator roll to metal sheet. Actual transfer depends on the machine, coating and operating conditions, so this calculator does not infer film thickness from a roller gap.
Tinplate Lacquering Machine Interactive Calculator
Enter a nominal dry coat mass, measured coat-mass spread, sheet rate and sheet dimensions. Results are arithmetic material-balance quantities, not coating-process predictions.
Equation Used
- Sheet width and length are nominal rectangular dimensions.
- Nominal dry coat mass is entered directly in grams per square metre.
- Sheet rate is treated as a constant arithmetic rate.
- Measured coat-mass spread is entered directly and multiplied by sheet area.
- Wet-film thickness, transfer efficiency, rejects, edge losses, actual liquid consumption, cure and emissions are omitted.
Roller Coating of Metal Sheet
The European Commission surface-treatment BREF describes roller coating as coating applied from a rotating rubber roller to flat sheet, coil or cylindrical metal. For sheeted material, a support roller carries the sheet and a scraper removes coating transferred during gaps between sheets.
Coating thickness depends on the equipment pressure and operating arrangement described in that reference. For this material balance, enter a measured or specified dry coat mass; roller gap alone does not determine the result.
What This Calculator Does
The tool calculates rectangular sheet area, nominal dry coating mass per sheet, nominal dry coating throughput at an entered sheet rate, and the mass-per-sheet equivalent of an entered coat-mass spread.
Dry coat mass can be established gravimetrically by comparing a sheet before coating and after coating and drying, as described in the cited EPA method context.
Dry-coating Material Balance
msheet = q A
M = q A N / 1000
Delta msheet = Delta q A
W and L are in millimetres, q and Delta q are in g/m squared, N is sheets/hour, A is m squared, and M is kg/hour.
Worked Arithmetic Example
For an 800 by 1000 mm sheet, area is 0.800 m squared. At 8 g/m squared, nominal dry coating mass is 6.40 g/sheet. At 4000 sheets/hour, nominal dry-coating throughput is 25.60 kg/hour. A 0.5 g/m squared measured spread corresponds to 0.40 g/sheet.
Assumptions and Limits
- Reference context: roller-coating topology and gravimetric dry-coating measurement.
- Calculated: rectangular area and direct dry-mass multiplication.
- Not calculated: wet-film thickness, solids fraction, density, viscosity, roll pressure, roll speed or direction, doctor gap, transfer efficiency, edge losses, rejects, actual liquid consumption, volatile emissions, cure time, cure temperature, peak metal temperature, oven path, adhesion, appearance, quality limits or equipment suitability.
Frequently Asked Questions
Does roller gap determine the result?
No. Gap is not an input and no gap-to-film relation is asserted.
Is nominal dry coat mass a measured value?
It should come from a specification or an appropriate measurement method.
Does hourly throughput equal purchased liquid coating?
No. It is nominal dry coating on sheets only; liquid solids, transfer losses, rejects and waste are omitted.
Does spread mass per sheet predict stripes or defects?
No. It only converts an entered g/m squared spread into grams per sheet.
Does the tool set oven conditions?
No.
Can it approve a coating line or product?
No.
References
- European Commission Joint Research Centre, Surface Treatment Using Organic Solvents including Preservation of Wood and Wood Products with Chemicals BAT Reference Document: roller-coating topology, sheet support roll, scraper and pressure-based adjustment context.
- U.S. EPA, Industrial Surface Coating: gravimetric dry-coating mass determined from sheet mass before coating and after coating and drying.
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