The Find The Needle U Splitter and U Joiner split and merge your lanes: a U-Splitter divides one route into several so you can inspect or distribute the flow, and a U-Joiner merges separate lanes back together. Both were added in Demo V8, and the pattern that matters is: split into parallel scanning lanes, scan each one, and only then merge them.
Find The Needle U Splitter and U Joiner: what they do
- U-Splitter: takes one incoming route and divides it across multiple outputs.
- U-Joiner: takes several incoming routes and combines them into one output.
- They connect to four machine types: the Hay Sell Stand, the U-Splitter, the U-Joiner and the Needle Scanner.
Using them is how you turn one slow line into several, which is the core of laying out a factory that does not stall on a single machine.
The lane pattern that works
- Split the main route with a U-Splitter into parallel lanes.
- Put a scanner on each lane. Every product route has to pass through a scanner, and a main belt alone is not enough if another branch bypasses it.
- Test each lane on its own before you merge anything. Merging does not guarantee the throughput you expect, so a lane that works alone can still fail once it is joined.
- Join the lanes with a U-Joiner only after each one has been scanned.
Joining lanes before they are scanned is how a needle gets carried straight past the scanners to the sell stand.
If queues are already building in front of the scanners, the scanner bottleneck page has the throughput numbers to compare against.
If the built-in splitter gives you one input and three outputs
A two-in, two-out configuration has been asked for as an idea for the four-way splitters. If your built-in splitter only gives you one input and three outputs, work with the lane design you have rather than waiting for a different splitter — build the lane count your factory actually needs.