Weller WQB2000 - Manual (Page 2)

2
MACHINE PLATFORM
The machine platform is comprised of the following items:
Slide Assembly
The accuracy of the slide assembly is the result of precision ball slides and the use of vacuum to pick-up components during operation. Three (3)
ball slides are used (see Figure 1). One for the hot air nozzle, one for the component pick-up and one for the solder paste stencil pick-up. Left to
right positioning of the vacuum pick-ups and nozzle during operation is accomplished with a spring-loaded plunger and “V” notched slide bar.
Pneumatic Enclosure
The pneumatics are housed in the rear enclosure. Incoming air pressure is turned on and off with a lever on the top of the enclosure (see Figure
1). The system air pressure can be adjusted with the front panel pressure regulator. Inside the enclosure there are two (2) vacuum transducers,
one for each vacuum pick-up, and two (2) air valves used to provide cooling air and the extension of the component vacuum lift inside the nozzle.
A quick connect air fitting is provided in the rear of the enclosure to provide an air supply to the WQB-A hot air unit. A connector for the timer is
located on the rear of the enclosure. The vacuum pick-up transducers are always on when the unit is in operation, therefore in-line air filters are
provided to prevent dirt particles from reaching the transducers and causing a malfunction.
Caution: Do not run system without these filters in place.
Heater in Table
The radiant heater (see Figure 1) built into the machine platform base provides bottom heat to the circuit board during the soldering operation, this
allows a slow uniform ramp up of the circuit board temperature to above the solder melt temperature.
ACCESSORIES
BGA HOT AIR NOZZLE
The closed nozzle housing permits optimum heating of the BGA component being soldered by guiding the hot air uniformly around the component
body and exiting the nozzle via exhaust ports in the top of the nozzle. During BGA soldering the nozzle is positioned against the PC board to effect
the proper air circulation and prevent adjacent components from being heated. Hot air temperature is controlled by a sensor fixed in the nozzle
manifold.
During component removal a vacuum lift (see Figure 1) is automatically activated to remove the BGA from the circuit board at the end of the
heating cycle.
The BGA nozzle can also be used for QFP components. Typically when used for QFP’s the nozzle is not placed against the circuit board but
positioned slightly above the QFP. Select a size to match the outer edges of the QFP leads.
BGA and QFP Templates and Stencils
The positioning accuracy of this system is the result of the unique design of the templates. The templates serve three (3) functions: 1) Alignment
of the component to the circuit board pads, 2) alignment of the solder paste stencil to the circuit board pads, and 3) alignment of the nozzle to the
circuit board pads (see Figure 5).
In use the template is visually aligned with the corner pads on the circuit board using the sighting holes provided in the template. Very fine pitch
QFP’s will require magnification during alignment. After proper alignment the template is temporarily secured to the circuit board with Kapton ® tape.
Training Kit for BGA and QFP Components
This kit includes two (2) copper test boards with six (6) patterns for BGA and QFP components. Two (2) clear practice boards for placement
training. One each of a BGA and QFP component for practice or test. Boards and components match the templates, stencils, and nozzle provided
with the WQB2000
COMPONENTS AND ITEMS INCLUDED
The WQB2000 comes with the following items:
• Instruction Manual
• Machine platform - See Figure 1 for machine nomenclature
• Coalescent air filter and air hose
• Portable Vacuum pencil with (2) tips and extra suction cups
• 3 Sets (6) registration pins (2 each in sizes ш.093, ш.125, ш.156)
• 3 Sets (6) of 1/2" registration pin spacers (2 each in sizes ш.093, ш.125, ш.156)
• 2 spacer blocks, 1/2" square x 3"
• Compliant vacuum nozzle: with extra O-Rings (.500 dia.)
- Small vacuum nozzle adapter (.375" dia.)
- Mini vacuum nozzle adapter (.200" dia.)
• Standard vacuum nozzle (.500" dia.)
• BGA (QFP) hot air nozzle
• Plastic case for pins and nozzles
• Training Kit with Plastic case, 2 Dummy components (1 BGA and 1 QFP), 2 copper PC Boards and 2 clear PC boards for machine set-up,
testing and training
• 2 standard alignment templates and printing stencils (Other JEDEC QFP and BGA templates are available, consult with your distributor or
the Weller factory)