UV painting is the most popular technology in lots of industries for various products surface finishing. Unlike most other type painting line system that can be easily operated, UV painting line has extremely high cleanness requirement. Not only to machine itself but also entire workshop construction. For some high end production requirements, the painting line clean room setup is same as medical grade. In this article we will indepth describe the operation process flow and some crucial parts technical configuration.
Above is a typical UVpainting line layout for plastic vacuum metalization paint shop. Following is detailed process description
| NO. | Content | Method | TEMP,℃ | Time | NOTE |
| 1 | Load workpiece to fixture | Manual | RT | Fix product on custom jig | |
| 2 | Load fixture to conveyor | Manual | RT | ||
| 3 | Electrostatic dust leaning | Electrostatic nozzle | RT | Dust cleaning by electrostatic electric and compressed air | |
| 4 | Flamming | Flamming gun | RT | 2sec | Activate surface for better contact with paint(only for PP or PC material) |
| 5 | Electrostatic dust leaning | Electrostatic nozzle | RT | dust cleaning again for guaranteed cleanness | |
| 6 | Preheat | Automatic | 60-80℃ | 2min | Dry off any moisture on product |
| 7 | Solvent spraying | Automatic /robotic | RT | PP solvent spraying for pp/pc material | |
| 8 | Flash off | IR heater | 60-80℃ | 3min | Solvent flash off |
| 9 | UV painting | Automatic /robotic | RT | UV paint spraying | |
| 10 | Leveling | Automatic | RT | 3min | To stay few minutes on conveyor for smooth paint thickness |
| 11 | IR drying | IR heater | 60-80℃ | 6min | IR |
| 12 | UV curing | UV light | <65℃ | 0.8min | Quick curing under uv light |
| 13 | Cooling | Automatic | RT | Can be configured with forced air flow | |
| 14 | Unload | Manual | RT | Take off conveyor | |
| 15 | QC, Packing | Manual | RT |
Crucial components in uv painting line
UV painting line is formed by various components via central programming control. Here we pick up the most crucial parts and explain it’s technical configuration.
1- Chain conveyor system
Basic but most important system. A well designed conveyor system will make each operation stage goes smoothly with less space requirement, operator can also maintain it better in future days. Here’s quick list of this chain conveyor system setup:
- Line speed: adjustable by inverter control
- Conveyor type: ground type chain spindle conveyor
- Conveyor chain: 38.1 /50.8mm double pitch roller chain
- Support frame: 50*50*1.2mm steel tubes welding with powder coating, top face is attached with stainless steel plate. Foot cup is configured for height adjusting
- Chain track: enclosed guide by steel plate pressing
- Drive motor: 5HP CPG motor with 1:60 gear box, inverter control
There will be slightly difference depends the actual workpiece for painting. Chain and fixtures etc all can be special design to fulfill production requirements.
2- Dust cleaning booth
The purpose of this booth is to remove any dust particle on object face via static nozzle and compressed air flow. Its very crucial part for high quality finishing. A tiny dust on product surface can not pass QC checking, so if it’s not handled properly it will cause high rate material wastes. Dust cleaning booth configuration details as below
- Dimensions: W2000*D2300*H2200mm
- Booth chamber by 1.5mm stainless steel plates
- Water curtain board by SUS304 T1.2mm plate, water tank by 2.0mm stainless steel plates
- Gas exhaust: 3HP paint booth blower
- Illumination: 40W explosion proof lamp
- Air pressure stabilizer: stabilize air flow from AHU
- Each electrostaitc cleaning booth is configured with: STAITIC nozzle 8 sets & electrostatic producer
3- Spray booth
The spray booth is a mixed purification type spray booth, it provides advantages from both Vortex Rotary type and water curtain type spray booth. Smooth airflow with no paint fog or bounded paint pollution during operation, waste paint collection rate is up to 80%.
- Dimensions: W3000*D3200*H2400
- Chamber is made by SUS304 1.5mm stainless steel plates.
- 1.2mm SUS304 ss plates for curtain board.
- 2.0mm ss plates for water tank.
- Exhaust fan: 7.5HP paint booth fan. Air volume: 19200M³/H. Air pressure: 1274Pa
- Air pressure stabilizer: stable airflow, dust barrier
- Illumination: two sets 40W explosion proof lamp
- Water tube: P.V.C and galvanized steel tubes
According to local environment needs, it can be designed for water curtain or dry filter system.
4- IR drying tunnel
The purpose of IR is to heat on workpiece and eliminate solvent in paint so only paint will stay. After this process, it will fix some common quality problems such as bubble and wave like result etc. Technical configuration as below
- 50mm rock wool boards for chamber
- ARC aluminum corners, maintenance door on side
- Heater: high quality infrared ceramic heater
- Position adjusting unit for IR heater
- 0.6mm mirror type stainless steel reflector
- Temperature Control: room temperature ~ 80 ℃ adjustable
- Hot air mixing: 1/2HP fan
- Fan blade: φ9＂
- Type: cage type
- Blade material: galvanized steel production
- Gas exhaust: 2HP multi-blade exhaust fan
- Electric control: Material: PID smart temperature controller
5- UV oven
The last stage of uv paint curing. Only few seconds, liquid paint will be cured under uv light and produce will be shinning with high gloss. UV oven general setup details as following
- Uv lamp adjustment: Front-back, up and down adjustable
- Control system: PID temperature controller, contact, switches, indicator light, counter
- Advantages: UV lamp temperature monitored(keep air exhausting temperature under 65℃)
- Light-on will be delayed if lamps are too hot
- Cooling by air blowing
- UV lamp working time counter enabled
- Electric current monitored and controlled
- Temperature control and alert functions(keep product temperature under 65℃)
- Product rotating for uv light curing
- Blower shutdown will be delayed after system powered off.
- Low noise centrifugal cooling blower; Blowing rate: 12000m3/Hr and adjustable.
- Security protection unit configured
- UV lamp: 5.6KW primarc or same level products
- Lamp cover: SS UV reflector board
- U.V fresh air supply: H13 paper type filter.
- Chamber surface is made by δ1.2mm steel plates with painting, inner side is made by δ0.6mm mirror stainless steel plates.
- Electronic control box is made by 1.2㎜ steel plate
Above is technical list and configuration of uv painting line crucial parts. If you are interested to check more or make a custom design, feel free to contact.
