VTX “Automated” Loading and Picking Guidelines
Recommended Device Loading Method
- When placing the devices on the VTX textured surface, make certain that they lay flat for full contact.
- The devices should be allowed to rest on the VTX surface for a minimum of 1 minute to ensure proper adhesion before testing the holding force of the tray.
Recommended Device Pick Method
- Use continuous vacuum pickup tip. Static PenVac is not recommended.
- Minimize pickup tip downforce during device engagement as this increases the contact area with VTX surface and thus increases the required unload force. Depending on the Pick & Place (P&P) tool, this can be controlled either by travel distance (Travel Control) or spring constant (Force Control).
- Start with the lowest possible setting. Typically less than 25um over-travel or less than 20gm down force.
- The vacuum pickup tip should reach a minimum of 20 inches of Hg (4.7psia) before initiating pickup. This typically takes less than 100ms for most commercial P&P tools.
- Pickup speed should be between 1mm/sec to 3mm/sec until the device separates from the VTX surface. Time to achieve this displacement usually takes less than 100ms, beyond which the pickup tip can move at any desired speed.
- If picking is not successful, optimize the process by adjusting a) pickup tip downforce, b) pickup tip vacuum, c) and/or pickup speed.
- During process optimization, select a different device on the tray with every new trial setting until successful. Do not attempt to repeatedly pick same device as repeated downforce can temporarily increase holding force.