Film Thickness Windows by Part Geometry: Setting Gun Parameters for Boxes and Deep Recesses.
This is a working reference, not theory: every table and checklist here is designed to be printed and used at the line. It complements the failure case studies published in the Technician Hub with the standard documents those cases eventually produced.
Common Mistakes and How to Avoid Them
| Mistake | Why It Happens | Practical Fix |
|---|---|---|
| 1. Blending dirty reclaim | Fines and contamination cause pinholes | Sieve reclaim; cap blend at 30% |
| 2. Judging cure by colour alone | Under-cure passes colour but fails impact | Verify with oven recorder strips weekly |
Best Practices
- Recorder strip archive per oven per week
- Sieve reclaim before every blend
- Impact test coupon daily
Booth Reset Sequence
- Clean guns and nozzles - Check electrode (Worn electrodes cause wrap loss)
- Sieve and weigh reclaim - Blend cap 30% (Dirty reclaim = pinholes)
- First-part cure check - Recorder strip in oven (Colour is not cure)
Reset card posted at booth entry | Strips archived per week
Powder Coating Process Reference
Typical windows for hardware powder coating lines.
| Parameter | Reference | Why It Matters |
|---|---|---|
| Object cure temperature | 180 °C × 12 min | Verify with recorder strips, not colour |
| Gun distance | 150-250 mm | Too close backs up charge; too far loses wrap |
| Reclaim blend cap | ≤30% into virgin | Higher ratios risk pinholes and gloss drift |
| Booth reset | Every colour change and shift | Contamination causes fisheyes |
Recorder strips caught a dying heater
Scenario. Parts passed colour checks but failed impact tests intermittently.
Action. Weekly recorder strip review; the oven's bottom heater was cycling late.
Result. Heater replaced before a major lot rejection; impact failures stopped.
Frequently Asked Questions
The colour looks cured is it?
Not necessarily. Under-cure passes colour and fails impact testing. Verify with recorder strips weekly.
Why cap reclaim at 30%?
Reclaim carries fines and contamination. Higher ratios drive pinholes and gloss drift.
How often should the booth be fully reset?
Every colour change and every shift start. Fisheyes trace back to missed resets.
Implementation Roadmap
| Step | Frequency |
|---|---|
| Booth reset checklist live | Day 1 |
| Recorder strip review meeting | Weekly |
| Reclaim cap policy | Month 1 |
What Would You Like to Solve?
If you would like this checklist or template adapted to your own line and part mix, contact QLQ we supply the full equipment and chemistry package along with the working documents that make it run.
FAQ - Film Thickness Windows by Part Geometry: Setting Gun Parameters for Bo
Straight answers from the shop floor. Ask us on WhatsApp if your case is different.