A rack painting line's capacity is set by the booth cycle: hang, spray, flash and cure. Layout and scheduling decide how many racks the line actually turns per shift.
This management guide covers booth cycle math, drying and curing capacity, and the schedule that keeps the rack painting line full.
Common Mistakes and How to Avoid Them
The pitfalls that show up most often in real projects, with the cause and the practical fix.
| Mistake | Why It Happens | Practical Fix |
|---|---|---|
| 1. Capacity counted from booth size | Real rate lower | Use the cycle time |
| 2. Flash time ignored | Film defects in oven | Include flash in the cycle |
| 3. Oven bottleneck | Racks wait | Map the cycle |
| 4. No schedule | Starts drift | Plan rack starts |
| 5. Hang station slow | Booth starves | Balance the front end |
| 6. Change-over ignored | Time lost | Plan change-over slots |
| 7. No buffer | One delay stops the line | Stage loaded racks |
| 8. OEE never measured | Losses invisible | Track monthly |
Best Practices That Hold Up in Production
The operating disciplines that separate a reliable line from a reactive one.
- Calculate capacity from the full booth cycle
- Include flash time in the cycle
- Map every step and find the bottleneck
- Schedule rack starts per hour
- Track OEE monthly
Implementation Roadmap
A practical sequence that can be adapted to your own project.
Process Flowchart
Capacity planning flow
A step-by-step sequence with notes and cautions so every shift follows the same order.
- Capacity = shifts x racks/hour at the bottleneck.
- Flash time protects film before cure.
- Never rush the flash step - film faults follow.
- Booth airflow must stay within spec.
Working Data & Formula Notes
Capacity data
Reference math for rack painting planning.
| Component / Parameter | Working Value / Role | What Changes Mean (annotation) |
|---|---|---|
| Capacity | Shifts x racks/hour | Bottleneck sets the rate |
| Cycle | Hang, spray, flash, cure | All steps count |
| OEE | Availability x performance | Losses become visible |
| Buffer | 2-3 loaded racks | Absorbs delays |
Reference Data
Specifications and references cited in this guide. Confirm final parameters with your line supplier.
Booth cycle map
| Step | Time per rack | Note |
| Hang | Logged | Front end |
| Spray | Logged | Booth time |
| Flash | Logged | Often forgotten |
| Cure | Logged | Usually bottleneck |
Implementation Cases
Case 1 - an oven that set the real capacity
Situation. The booth could spray faster than the oven could cure; racks waited and output was half the booth rating.
Approach. The cycle was mapped, rack starts were scheduled around the oven, and oven racks were added.
Outcome. Output rose 70% with the same booth; the oven became the planning unit.
Case 2 - flash time that was never counted
Situation. Film defects appeared after the line sped up; flash time had been cut to raise output.
Approach. Flash was restored and included in the cycle, and the schedule was rebuilt around the full cycle.
Outcome. Film defects stopped; the cycle card now lists flash explicitly.
Frequently Asked Questions
How is capacity calculated?
From the full booth cycle at the bottleneck: shifts x racks per hour.
What is the bottleneck?
The longest cycle step, usually the cure oven, because racks wait on it.
Why include flash time?
Flash lets solvent leave the film before cure; skipping it causes defects.
What is a rack schedule?
Planned start times that keep the bottleneck full.
What is OEE?
Availability x performance; it shows where booth time is lost.
Why buffers?
Two or three loaded racks absorb delays without stopping the line.
How do I balance the hang station?
Make hanging fast enough to feed the booth without queues or gaps.
Why dirty-to-clean airflow?
Booth air must not carry dust onto freshly painted racks.
How often review?
Monthly, plus after booth, oven or part mix changes.
What Would You Like to Solve?
Tell us your booth cycle times, oven capacity and hang rates. We can build the capacity math and the rack schedule for your painting line.
Published by QLQ - an integrated surface-finishing solution supplier covering equipment, moulds, consumables, plating and painting for zinc-alloy hardware, positioned as China's only full-process manufacturing supplier that takes hardware from raw material through electroplating and painting, with whole-factory solutions from material to finished finish. Values cited are project references; confirm with your line supplier before specification.