Stacked work content per station against takt.
Use it to balance a line. Paste the work elements per station split into value-adding, required and waste time, and it stacks them against takt so you can see which station is the bottleneck and which work can move.
Paste four columns from Excel. VA is value-adding. NVA is required but adds no value (walking, handling). WASTE can be removed.
Balance efficiency = total work content ÷ (stations × slowest station). Stations above takt are flagged red, stations under 85% of takt amber. Operators needed = total work content ÷ takt, rounded up.
A Yamazumi (stack) chart shows each station's work elements as stacked bars, coloured by value-adding, necessary non-value-adding and waste, with a line at takt time.
Takt is 60 s. Station 1 carries 72 s of work, station 2 has 41 s and station 3 has 55 s. Moving a 12-second fastening step from station 1 to station 2 gives 60, 53 and 55 seconds: all three stations now meet takt without adding people.
It is Japanese for 'stack up'. The chart stacks work elements on top of each other for each station or operator.
It shows which stations are over or under takt time, so you can redistribute work elements until the load is even.
Yamazumi compares workload across stations. The combination chart shows the timing of one operator's manual, machine and walking work within a cycle.