How we size booths, ovens and lines

Every booth, oven, pretreatment tunnel and conveyor we build is sized from three inputs: the largest part you coat, the way it hangs, and the line speed or the parts per hour you need. This page shows the arithmetic we use for each station, with worked examples from lines we have built, so you can check a proposal yourself.

Powder booth: opening, length, extraction

Opening height equals the tallest part plus the hanger plus 200 mm clearance. Booth length gives the operator reach at both ends of the part, or lets the part pass fully inside an automatic booth. Extraction airflow equals the open area multiplied by the face velocity that keeps powder inside; we design at 0.5 m/s low pressure. Cartridge count follows the airflow at about 1,000 m³/h per Ø100 x 1,900 mm cartridge.

Our standard manual booth: 3,000 x 2,200 x 1,400 mm, 12,000 m³/h, 4 kW fan, twelve cartridges.

Inputs

Largest part: W x L x H
Hanging pattern and hanger length
Manual or automatic application
Colour changes per week

Curing oven: length from line speed

Dwell time equals heat-up time plus hold time. Heat-up is the time the part's steel needs to reach the cure temperature; hold is what the powder supplier specifies at that temperature. Length equals line speed multiplied by dwell time. Cross-section equals the part envelope plus clearance for the hanger and the air ducts.

A 20 m curing tunnel at 1 m/min gives 20 minutes of dwell: for a 3 mm steel part that needs 8 minutes to reach 180 °C and 10 minutes of hold, the margin is 2 minutes. At 1.5 m/min the same tunnel gives 13 minutes, which is too short for that part.

Inputs

Line speed or parts per hour
Part thickness and steel mass per hanger
Powder cure window from the supplier's data sheet

Box oven: volume and heating power

Internal size equals the rack or trolley plus 150 mm of air space on each side and above. Heating power follows the steel mass of a batch, the temperature rise and the heat-up time you accept, plus the losses through 150 mm of rock wool and the door.

Our example box oven: 1.5 x 1.8 x 4 m internal, 60 kW electric thermoblock, 250 °C design temperature, 150 mm rock wool, digital thermostat and timer. A typical rack of 400 kg of steel reaches 200 °C in about 25 minutes.

Inputs

Rack or trolley size
Batch weight in steel
Cycles per shift

Drying oven after washing

The part must leave the dryer dry and warm enough not to condense in the booth. Dwell follows the part's mass and the water it carries out of the last rinse; length follows the line speed as for the curing oven, usually at a lower temperature.

The example line uses a 10 m drying tunnel after two spray stages at the same line speed as the 20 m curing tunnel.

Inputs

Line speed
Part mass and shape (cavities hold water)
Rinse temperature

Pretreatment: stages, contact time, tank volume

Stage count follows the process: degrease and rinse as a minimum; conversion coat and rinses for adhesion and corrosion class; etch and conversion for architectural aluminium. Stage length equals contact time multiplied by line speed. Tank volume follows the spray flow and the drag-out between stages.

The example line has two spray stages; a QUALICOAT-class aluminium line has five to seven.

Inputs

Metal and its surface condition
Corrosion or durability class to reach
Chemical supplier's process sheet

Conveyor: pitch, load, speed

Hanger pitch equals the longest part plus a gap that prevents parts touching on curves. Load per hanger equals the heaviest part plus its hanger. Line speed follows the longest oven and its dwell. A cardan chain carries heavier loads and turns in two planes; a 3-inch web conveyor suits light parts.

The 11 m U-turn oven we built runs on a 3-inch web conveyor; the example plant runs on a cardan chain.

Inputs

Longest and heaviest part
Parts per hour
Hall layout with turns and levels

Questions before the quote

Answered in full. Category pages carry the questions specific to each product.

What should I send for a first sizing?

The largest part with dimensions and weight, a photograph of the parts you coat most, the parts per hour or per shift, the coating (powder or liquid, and the cure window if you know it), and a sketch of the hall with the free area. Drawings are welcome but not required for the first proposal.

Can you size a line if I only know my monthly output?

Yes. Monthly output divided by working hours gives parts per hour; with the hanging pattern that gives the line speed, and the rest follows.

How do low-temperature-cure powders change the oven?

They cure at roughly 120 to 160 °C instead of 180 to 200 °C, so heat-up is shorter and the same tunnel allows a higher line speed, or a new line needs a shorter tunnel. The powder data sheet gives the cure window we size to.

Do I need a cooling zone?

If parts are handled or packed right after the oven, yes: a cooling zone or an open conveyor stretch brings them to a temperature operators can touch. The length follows the part mass and the line speed.

How much floor space does the example line take?

The example line with a 10 m dryer and a 20 m curing tunnel fits in a hall of about 40 x 12 m with the conveyor loop.

Gas or electric?

Electric is simpler and reacts fast; gas is cheaper to run per kWh in most of Europe and is the usual choice for long tunnels. Both are available on every oven. Heat recovery on gas-fired tunnels is available on request.

Can I start with a booth and a box oven and add the line later?

Yes, and that is the common path for job coaters. Booths are knock-down and can be moved into a later line; the box oven stays as a batch oven for oversize or rework parts.

What if my parts are longer than the standard booth?

The booth is built to the part. Length, opening and extraction scale together; the spec table on the proposal states the values for your size.

How long is delivery?

Eight to twelve weeks from order for a line of the example size, four to six weeks for a single booth or box oven.

Who commissions the PLC?

Our own electrical team, on site, with your operators present.

What to send for a sized proposal

Six items are enough for a proposal with dimensions, powers and airflows. Photographs replace drawings at this stage.

Largest part: W x L x H and weight
Hanging pattern: hooks per part, parts per hanger
Parts per hour or per shift
Coating: powder or liquid, cure window
Hall sketch with free area and ceiling height
Utilities: electrical supply, gas, compressed air, water

The arithmetic of each section runs in the engineering tools: line speed and oven length, oven energy, booth extraction, pretreatment tunnel.

Send the six items, get a sized proposal

We reply within two working days.

Request a technical quote +90 216 599 19 69