Single Cassette Unit (SCU)

The Single Cassette Unit consists of a garage with attached docking station, and a cassette on a cart.

Cassette/Cart | Docking Station | Garage

See also Commands | NVS Parameters | Parts | Procedures | Troubleshooting

Garage

Air Knives (Separators) | Blower | Doors | Plenum

The garage can handle 300 lb of impact, but does not provide for any significant impact absorption from the cassette being docked. It must be carefully aligned with the cassette and with the table (see the VLF Trendsetter AL Installation - Alignment Checklist.)

The garage has a plenum, air knives, blower, two doors - the garage door and the picker door - and a docking station.

Plenum, air knives, and blower

The plenum is a one-piece design that forms the opening for the picker to move into the garage, pick a plate, and move it out to the load table. Reed switches for firmware and for the safety loop are mounted on the plenum.

The blower is mounted on one side of the garage to feed the end of the plenum. It helps to float large plates so that they don't contact the plate below during the pick, and to float thin plates so their top surface doesn't contact the cover bar or the picker p-cups. Its flow is adjustable, using an anemometer to measure the flow and a potentiometer to increase or reduce the fan speed. Target airflow is 9.6m/s to 10m/s. The factory-set airflow may need adjustment where there are extreme changes in ambient air pressure or humidity (e.g., in the mountains).

Some plenum holes are plugged to allow for good float results on all plate sizes and thicknesses. These plugged holes are indicated on the assembly drawings (link when available).

Firmware controls the operation of the blower:

• short engagement of the blower for the plate float to picker vacuum
• float on to remove the plate from the cassette/garage

Firmware controls the operation of the air knives (separators):

• air knives turned on when the plate pick sequence starts
• air knives turned off when the p-cups are lowered onto the plate for the pick

Doors (garage and picker)

The doors are vertical, sliding type, connected to an air cylinder through a level, shaft, and another lever. The assembly is an FRU.

The speed of the air cylinder is controlled with fixed orifices. These orifices may get dirty, and must be checked as part of regular maintenance.

Optical interrupt sensors are used to indicate whether the door is up or down.  The adjustment is set at the factory. The door should just touch the plenum when the cylinders are fully retracted. There should be equal contact along the length of the door.

Firmware controls the motion of the doors:

• both doors open for pick
• garage door closed after pick
• garage door opened for fetch
• both doors closed after the fetch is completed

Note: Tape the doors together before doing any disassembly work.

Docking station

The docking station is attached to the back of the garage. It engages and holds the cassette cart in position relative to the table, using an air cylinder. The cylinder moves with a spring, and is fed by an airline from the garage. The docking station is capable of 225lb of impact.

Reed switches on the plenum of the garage engage magnets on the cassette to tell firmware whether the cassette is present or not.  If the reed switch engagement is broken, the valve solenoid on the docking station will release the cassette cart.

Cassette/Cart