9524 Single and Double Side LPISM Spray Application Systems

The 9524 series spray applicator was designed to apply Liquid Photoimageable Solder Mask (LPISM) coatings to circuit boards. The 9524 employs an HVLP atomizing spray head which is mounted to the shuttle conveyor assembly. The HVLP spray head is quickly swept from side to side as the panel passes below on the Pin conveyor. Controlling the sweep width minimizes materials usage. Application thickness is accurately controllable and highly repeatable by adjustments on the atomization nozzle orifice, LPISM flow rate and conveyor speed. The 9524 LPISM spray applicator provides a high degree of control and simplifies the LPISM application process significantly.

Panels, which are sprayed, may be tack dried and processed using traditional techniques. Argus International markets an innovative Tackdry Oven, which employs infrared heating to tack-dry LPISM-coated boards in about 3 minutes rather than the 30-60 minutes currently, required. This unit allows boards to pass directly from the spray coater into the Tackdry Oven for reduced handling. Typical process speed is 4.0FPM (1.2 m/min).

Available Options

Quick-Tack IR Tackdry Oven: Employs infrared panels to speed the drying process to a highly efficient 3 minutes.

Electrical Service Requirements

Circuit Breaker service is 3-phase configuration with a good Ground.

Item

208/240/480V 50/60Hz

380/400/415V 50Hz

Power

9524 Single Side

30A

30A

3kVA

9524 Double Side

30A

30A

6kVA

Compressed Air Requirements

The 9524 requires a continuous filtered air supply of 100PSI (6.8 bar). Air consumption is approximately 60 to 80CFM. The air line running to the machine should be 2” (51mm) Diameter Pipe. The connection on the machine is ½FNPT.

Exhaust Requirements

Machine includes blower(s).

Item

Exhaust Volume

Port Quantity and Size

9524 Single Side

2000 cu ft/min (57 cu m/min)

One, 10” (254mm) Diameter

9524 Double Side

3500 cu ft/min (99 cu m/min)

Two, 10” (254mm) Diameter

Blowers supplied with the machine.

WARNING

Make-up air to the installation area must be at least 3500 cu ft/min (99 cu m/min) for the 9524Double sided and at least 2000 cu ft/min (57 cu m/min) for the 9524Single sided. Insufficient make-up air will result in fumes and over-spray in the work area, causing the machine to operate improperly. If the 9724 Tackdry Oven is in line with the Spray Machine add another 1000 cu ft/min (28 cu m/min) to the make-up air total.

Shipping Data

Item

Crate Size

Crated Weight

Air Freight

Common Carrier

9524 Single Side

102" x 63" x 68"

1,800 lbs.

2,000 lbs.

9524 Double Side

150" x 63" x 68"

2,800 lbs.

3,000 lbs.

Note: Crating dimensions and weights are approximate and may vary within 10%.

Practical LPISM Application Guide

It is important at this point to reiterate that Argus International must be viewed as a full partner in aiding in the development of a complete understanding of the LPISM Application process. LPISM Application is not an exact science, principally because of the variations in PCB surfaces, LPISM suppliers, cleanliness, maintenance and many other details. The operator must have a firm understanding of the causes and effects of variables in LPISM application. This section of the manual is devoted to furthering that understanding.

Parameters Overview

Quality LPISM coatings result from attention to detail. Assuming the PCBs arrive at the spray applicator with a quality surface, the following parameters will have major effects on the final coating:

Parameter

Normal Adjustment Range

Minimum

Maximum

Conveyor Speed FPM (m/min)

2 to 6 (.6-2)

2 (.6)

6 (2)

Atomization Air Pressure PSI (bar)

30 to 50 (2.1-3.4)

0 (0)

60 (4.1)

LPISM Tank Pressure PSI (bar)

12 to 20 (.8-1.4)

0 (0)

30 (2.0)

Spray Gun Temperature o C

80 to 90

50

100

Atomization Air Temperature o C

75 to 95

50

120

The following general rules are based upon experience learned during product development and PCB processing done by Argus International Process Engineering Group and Argus International PC FAB Processing Group.

  1. LPISM Tank Pressure, LPISM Viscosity and Conveyor Speed are the primary variables that affect LPISM thickness.

  2. Orange Peel surface is the result of spray particles which are too large. Particle size may be reduced by increasing the atomization pressure, or by reducing the LPISM Viscosity.

  3. LPISM usage may be significantly improved by processing panel’s nose to tail; boards are loaded onto the conveyor without a gap in between. The HVLP spray head will then run continuously in AUTO MODE.

  4. For a given LPISM, the supplier will recommend a solvent dilutant. The dilutant should be used to clean all LPISM delivery components. Incompatible solvents may cause a coagulation of materials in the LPISM delivery tubes. The effect on the panel will appear as concentric rings of thinned LPISM, known as fish eyes’ or ‘craters’.

  5. The ability of an LPISM to adhere to the edges of traces is largely a property of the selected LPISM. However, it is possible to reduce the trace-covering properties of the LPISM by excessively thinning the material or setting the atomization pressure too high. It is best to run the LPISM Viscosity as high as possible and the atomization pressure as low as possible, without producing significant ‘mottling’ or ‘orange peel’.

  6. LPISM uniformity on the board is largely affected by the Z-pitch (SPRAY PITCH), which is the distance between each return stroke of the shuttle. Z-pitch ranges from 1.0-3.0 inches (25-75mm), but it is best to set the SPRAY PITCH as low as possible without going beyond the shuttle speed limit. If this happens, the touch screen will display PARAMETERS OUT OF RANGE. Reduce CONVEYOR SPEED or increase SPRAY PITCH settings until the message is cleared.

9524 Right-Hand Controls Facilities Floor Plan

 

9524 Left-Hand Controls Facilities Floor Plan


 

Control and Operation

The 9524 is equipped with several key components, and the following figure identifies the major elements of the machine. The operator should be completely familiar with these elements prior to attempting to operate the equipment. Argus International will provide on site training for process, operation and maintenance upon request.

Figure: Major Components of the 9524D Spray System with right-hand controls

 

Figure: Major Components of the 9524D Spray System with left-hand controls

  1. Edge Conveyor System - The PCB must move through the spray chamber with a minimal contact area. A pin conveyor, which can be adjusted to the individual board width, fills this requirement. The conveyor speed may be adjusted from 2 to 6 feet per minute (.6 to 2 meters per minute). Shielding is provided inside the spray chamber to protect the conveyor rails from LPISM build-up.

  2. HVLP Spray Head - The LPISM is sprayed onto the panel via a high-volume; low-pressure (HVLP) spray head. The HVLP spray head utilizes opposed air jets directed at a continuous stream of LPISM to generate atomized particles, which are directed at the PCB by the atomization pressure coupled with directed air flow. Spray pattern, air pressures, LPISM flow rate and orifice size all affect spray head operation. See Appendix M in Manual.

  3. Heating System - Both the atomization air and gun body are heated during spray, which momentarily drops the viscosity of the LPISM, making it easier to atomize. The heaters are controlled from the touch screens.

  4. Shuttle Conveyor - The Shuttle Conveyor Assembly, which is driven by a stepper motor, is designed to move the HVLP Spray Head in a horizontal sweeping motion perpendicular to the direction of PCB travel. Sophisticated electronics allow very high Shuttle Conveyor speeds with exceptional smoothness and lack of vibration. The pitch setting on the touch screen adjusts the shuttle speed, relative to the conveyor speed, and sweep width. It is possible to adjust the sweep width both left and right of center to allow complete coating of the PCB with minimal over-spray.

  5. Exhaust Port(s) - The exhaust system for the 9524 is designed so that air exhausts directly from the spray chamber, as solvents driven from the LPISM during atomization must be removed to prevent operator exposure. The exhaust port(s) must be connected in accordance with local environmental laws. See Appendix A, in Manual, - Facilities and Machine Specifications for details on exhaust requirements.

  6. LPISM Reservoir (Pressure Vessel) - The LPISM reservoir supplies the HVLP spray head with a continuous flow of LPISM. An adjustable air pressure is supplied through the top of the reservoir; this applies pressure to the top of the LPISM pool, and the supply tube, located in the reservoir, allows LPISM to be pushed out and delivered to the HVLP spray head.

  7. Touch Screen - The main control method is through touch screen, allowing adjustment of conveyor speed, shuttle pitch, sweep distance, spray pattern and heat settings.

  8. Emergency-Stop Switches - These switches cut power to the conveyor, shuttle(s), heaters and pneumatic controls. These switches do not cut the main power to the machine or blower (see Circuit Breaker).

  9. Pneumatic Controls - Pressure adjustments and gauges for atomization air and LPISM reservoir air are located on the Plenum(s).

  10. Chain Cleaning System and Conveyor Drive - See Appendix K in Manual.

  11. Conveyor Rail Width Adjustment / Stepper Motor Assemblies - See Appendix L in Manual.

  12. Conveyor Direction Reversal Control and Indicator - This control is built into the touch screen, and is provided so the operator or maintenance personnel can change the direction of the conveyor chain should it become jammed or extremely coated with ink.

  13. Circuit Breaker - This is where the electrician connects the main power to the machine, and where main power of the machine can be powered to ‘ON’ or ‘OFF’.

  14. Power Indicators - These Indicator lights alert the operator or maintenance personal that power is connected to the machine.

  15. Start/Stop Exhaust Control and Indicator - This control is built into the touch screen to power on and off the exhaust(s). The touch screen indicator, EXHAUST ON, alerts the operator or maintenance personal that the exhaust is activated.

  16. Start System Control and Indicator - This control is built into the touch screen and starts the conveyor, and prepares system for activation. The touch screen indicator, SYSTEM STARTED, alerts the operator or maintenance personal that the system is activated.

  17. Shuttle and Pneumatic Component Plenum(s) – This cabinet contains electrical wiring for the shuttle and pneumatic components and controls for the spray.

  18. Electrical Component Enclosure - This cabinet contains the electrical wiring, control boards and PLC controls.

9524 Spray Application Systems

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