Figure 1. Pin configuration directly affects meta-grid area and source visit number

Each pin in the print tool will print a single patch or sub-grid of spots. The sum total of sub-grids printed by one print tool is called a meta-grid. Pin configuration directly affects meta-grid area because the spotting pins have a fixed plate-specific pitch to enable adjacent pins in the tool to enter adjacent wells of the microtitre plates. 96-well print tools have a pitch of 9 mm, 384-well print tools have a pitch of 4.5 mm, and 1536-well print tools have a 2.25 mm pitch. SimArray estimates maximum meta-grid area by simply multiplying the number of pins in each axis by the pin pitch. SimArray will thus overestimate the meta-grid area, when a reduced spot pitch is employed because spot pitch is not taken into consideration. Pin configuration also defines how many spots need to be printed per sub-grid, as more pins means that fewer pin loadings or source visits need to be performed. For example, a 4x12 print tool will print all probes in a 384-well plate with just 8 source visits, meaning that each pin will print just 8 spots per sub-grid. Whereas, a 4x4 tool would require 24 source visits, and a 2x2 tool requires 96 source visits.