- Conveyor Speed is controlled to within 1% of set speed. Conveyor speed is a variable in LPISM coating thickness.
- Atomization Air Pressure is
controlled with a regulator, and generally affects spray pattern and particle size.
- LPISM Tank Pressure is controlled with a regulator,
and directly affects the flow rate and thickness of the LPISM coating.
- LPISM Viscosity is measured with a Zahn or Ford Cup. As a general
rule, the LPISM flow rate to the HVLP spray head is a function of the LPISM Tank Pressure.
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.
- LPISM Tank Pressure, LPISM Viscosity and Conveyor Speed are the primary variables that affect
- 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.
- 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.
- 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’.
- 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’.
- 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.
COMPRESSED AIR SERVICE REQUIREMENTS
Copyright © 1997-2017 Argus International. All rights reserved.
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 4.0 fpm [1.2mpm].
SIDE COATING AND SIDE CONTROLS: Single Side or Double Side Spray with Left or Right Operator Controls.
INK LINES AND PRESSURE TANKS: 3
to 5 Spray Lines and (2.5, 5 or 10 gal.) [9.5, 19 or 38 liter] Vessels Sizes.
PARTS: Recommended Spare Parts Package.
USER INTERFACE UNIT
OF MEASURES: English or Metric Units.
USER INTERFACE LANGUAGE: English with Metric Units and one of the following: Chinese, Danish,
German, Italian, Russian or Spanish.
QUICK TACKDRY OVEN: Employs infrared panels to speed the drying process to a highly efficient
ELECTRICAL SERVICE REQUIREMENTS
Circuit Breaker service is 3-phase configuration with a good Ground.
9524 Single Side
9524 Double Side
EXHAUST SERVICE REQUIREMENTS
Machine is supplied with a blower for each spray chamber.
Machine is equipped with an interlock that will not allow activation of the heat sources without proper exhaust.
||Port Quantity and Size|
9524 Single Side
||2000 cu ft/min [57 cu m/min]
||One 10" [254mm] Diameter|
9524 Double Side
cu ft/min [99 cu m/min]
||Two 10" [254mm] Diameter|
Make-up air to the installation area must be at least 3500 cu ft/min [99 cu m/min] for the 9524D Double Sided and at least 2000 cu ft/min [57 cu m/min] for the 9524S Single 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.
102" x 63" x 68"
[2.6m x 1.6m x 1.7m]
150" x 63" x 68"
[3.8m x 1.6m x 1.7m]
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.
Crating dimensions and weights are approximate and may vary within 10%.
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:
||Normal Adjustment Range
|Conveyor Speed fpm [mpm]
||2 to 6 [.6 to 2]
|Atomization Air Pressure psi [bar]
to 50 [2.1 to 3.4]
|| 0 
|LPISM Tank Pressure psi [bar]
||12 to 20 [.8 to 1.4]
|Spay Gun Temperature ° C
||80 to 90
Air ° C
||75 to 95
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
- 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.
- 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.
- 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.
- 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.
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.
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.
- Touch Screen - The main control method is through
touch screen, allowing adjustment of conveyor speed, shuttle pitch, sweep distance, spray pattern and heat settings.
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).
- Pneumatic Controls - Pressure adjustments and gauges for atomization air and
LPISM reservoir air are located on the Plenum(s).
- Chain Cleaning System and Conveyor Drive - See Appendix K in Manual.
- Conveyor Rail
Width Adjustment / Stepper Motor Assemblies - See Appendix L in Manual.
- 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.
- 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’.
- Power Indicators - These Indicator lights alert
the operator or maintenance personal that power is connected to the machine.
- 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.
- 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.
- Shuttle and Pneumatic Component Plenum(s) – This cabinet contains electrical wiring for the
shuttle and pneumatic components and controls for the spray.
- Electrical Component Enclosure - This cabinet contains the electrical
wiring, control boards and PLC controls.