You must put a check mark in the "Use Crafted Equipment Items as Materials" option to use equipment that you have already crafted as materials in a new crafting project.
You will then be able to see the required materials when using your own equipment.
*Equipment registered to your Favorite Equipment cannot be used as crafting materials.
You can also check the amounts of equipment to be consumed by looking at the "Crafting" and "Held" numbers.
Crafting: Shows the number to be crafted without using your equipment.
Held: Shows the number of held equipment pieces to be used.
Example: If you want to batch craft a Longsword +2 with a Longsword +1 (Lv. 10) in your possession.