Why this guide?
Choosing the right curing technology is one of the highest‑impact decisions you’ll make when bringing powder coating or wet paint in‑house. The oven you specify sets your line speed, floor‑space requirement, energy bill and finish quality for the next 20 years.
Below we break down three core heat technologies—direct‑impingement, traditional convection and infrared (IR)—using performance data taken directly from GAT Finishing Systems’ process‑oven range. By the end, you’ll understand how each method works, where it shines, and how to size the best solution for your parts and production targets.
1 | What is a “process oven”?
In the finishing world, a process oven is a continuous or batch thermal chamber designed to flash‑off solvents, dry parts or fully cure coatings at controlled temperatures. Unlike a standard industrial furnace, it pairs precise time/temperature recipes with airflow management and safety systems that meet NFPA 86 Class A/B compliance for flammable finishes. GAT process ovens are modular in 24‑inch sections and hold ±5 °F uniformity, even at conveyor speeds up to 90 ft min.
2 | Direct‑Impingement: the “turbo” version of convection
Most powder‑coat and wet‑paint lines rely on gas‑fired convection. GAT pushes the concept further with direct‑impingement plenums: high‑velocity jets positioned above and below the belt so heated air slams directly into the part surface.
| Key engineering details | Payoff to your plant |
|---|---|
| High‑velocity plenums over and under the conveyor | Shorter oven length for the same ramp rate—freeing floor space |
| Patented Air‑Seal vestibules with counter‑flow curtains | Up to 15 % gas savings and cooler aisles |
| 6‑inch mineral‑wool panels (tongue‑and‑groove) | ±5 °F part‑to‑part uniformity |
When to choose direct‑impingement
- High line speeds (flash‑off at > 75 fpm).
- Mixed‑metal loads where rapid ramp minimises colour shift.
- Facilities that can vent combustion products and value lower CAPEX vs. full IR.
3 | Standard Convection: the workhorse
Not every application demands the “turbo” air velocity of impingement. GAT’s COV‑300 / 400 / HD series use recirculating convection with adjustable roof louvers—ideal for 450–600 °F targets and heavy steel loads. Tool‑free access doors every six feet keep maintenance to 5 minutes per nozzle check.
Strengths
- Versatility—handles e‑coat, liquid primer, urethane topcoats and powder.
- Low noise compared with impingement or IR boost fans.
- Simpler controls—single PID loop may suffice on small batches.
Watch‑outs
- Longer heat‑up time equals higher idle energy.
- Footprint can reach 50–70 % longer than an IR tunnel for the same cure, especially on thin‑wall parts.
4 | Infrared Ovens: instant heat in half the length
Infrared curing swaps moving air for radiant energy. GAT offers electric short‑wave (SW), electric medium‑wave (MW) and gas catalytic (GC) modules that bolt together in 4‑ to 8‑foot lengths. Elements reach set‑point in < 60 seconds, delivering peak cure in tunnels 50–70 % shorter than convection.
| Advantage | Engineering detail | Typical gain |
|---|---|---|
| Near‑instant heat‑up | Quartz or catalytic emitters | Slash idle gas/kWh; fast colour changeovers |
| Zoned PID control | Individually fired emitter banks | Fine‑tune heat to part mass; prevent plastic warp |
| 95 % radiant efficiency (catalytic) | Surface temps to 500 °F | Up to 40 % gas savings vs. convection |
Ideal use cases
- Footprint‑constrained plants—IR tunnels start at 4 ft.
- Pre‑gel boosters to halve downstream convection length.
- Energy‑sensitive operations where catalytic IR pays back in < 18 months.
5 | Hybrid Zones: best of both worlds
Many high‑throughput lines today use a combo of IR boost + convection finisher:
- IR booster: brings powder to gel in 60–120 seconds.
- Convection zone: completes cross‑link through heavy weldments.
GAT’s IR‑HYB series merges both in a 12‑foot module, delivering ≤ 12‑minute powder cure at 400 °F on mixed loads.
6 | Performance metrics that matter
| Metric | Why it matters | GAT data point |
|---|---|---|
| Ramp rate (°F min‑¹) | Sets oven length at a given belt speed | Direct‑impingement reaches temp faster; IR is near‑instant |
| Temperature uniformity (°F) | Drives gloss, adhesion & colour match | ±5 °F across 60‑in. belt on GAT convection & IR |
| Energy per lb of steel (BTU/lb) | OPEX and carbon footprint | Up to 40 % fuel savings with IR‑GC replacing convection |
| Maintenance downtime | Lost production hours | Tool‑free louver access; IR elements swap in < 15 min |
7 | Decision checklist for buyers
- Part size & mass
Heavy castings hold heat longer—lean towards convection or catalytic IR. - Finish chemistry
Powder polyesters tolerate IR; high‑gloss liquid enamels may prefer convection’s gentler gradient. - Line speed & takt time
At > 75 fpm, direct‑impingement or IR boosters help keep length reasonable. - Floor space
If real estate is tight, IR or hybrid beats long convection tunnels hands down. - Utility rates
Gas vs. electricity costs, ESG targets and rebates can swing ROI toward catalytic IR or electric MW. - Regulatory class
Solvent‑borne coatings demand Class A safety (leak‑test valves, purge timers)—standard on every GAT gas train. - Maintenance resources
A plant with limited in‑house techs benefits from tool‑free plenums and remote PLC diagnostics—features included in all GAT lines.
8 | Frequently asked questions
Can an IR oven replace my entire convection cure?
Often yes. GAT’s gas catalytic IR achieves full cross‑link on most polyester and urethane powders; hybrids are recommended for thick steel.
Are electric IR elements expensive to run?
Elements duty‑cycle only when parts are present, so total kWh is often lower than a constantly fired convection oven.
What’s the expected life of IR emitters?
Quartz SW lasts ≈ 12,000 hrs; catalytic pads 20,000 hrs—and swap in < 15 min.
Can one oven handle multiple coatings?
Yes—store separate PLC recipes for polyester, epoxy or liquid paint and switch at the HMI.
9 | Specifying your oven—next steps
- Run a cure audit on your current parts (mass, coating, target gloss).
- Model heat‑up vs. belt speed using GAT’s free online calculators (link in Resources).
- Request a modular layout—remember GAT ovens bolt in 24‑inch increments, so you’re never boxed in.
- Plan for growth: include an IR booster flange or extra convection module in the quote; you can install it later without tearing up the line.
10 | Key take‑aways
- Direct‑impingement is still the champion for high‑velocity airflow and all‑round versatility.
- Convection remains the workhorse for heavy parts and multi‑chemistry lines.
- Infrared (especially catalytic) wins on footprint and energy—or as a booster in hybrid builds.
- GAT’s modular design lets you mix & match zones, keeping options open as production evolves.
Ready to run the numbers?
Whether you need a compact IR cell to speed up colour changes or a 120‑foot convection tunnel for 24/7 OEM throughput, GAT’s engineering team can model cure time, fuel use and ROI in a single call. Request a free layout and thermal analysis today—and turn your heat budget into measurable profit.
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