This video shows the process of iPad glass-only repair, with two LCD refurbishing machines involved.
Warm Promt: This broken screen refurbishing service for iPad series would cover iPad mini 4, iPad Air 2 and iPad Pro.
For LCD Refurbishing Machine and Materials
For Third-Party LCD Refurbishing Solution
For iPad Air 2 Spare Parts
Tools & Materials list:
Replacement for iPad Air 2 Glass Lens
Manual LCD Separator
Bubble Removing and Glass Laminating Machine
Anti-static Wrist Strap