Definition
The Standardized Work Combination Table (標準作業組合せ票, hyōjun sagyō kumiawase hyō) is a detailed time-study chart that maps the relationship between three categories of time across a full operator work cycle:
- Manual work time (手作業, te-sagyō) — time the operator spends doing hands-on work (loading, unloading, inspecting, deburring, etc.)
- Walking time (歩行, hokō) — time the operator spends moving between machines or workstations
- Machine automatic time (自動送り時間, jidō okuri jikan) — time a machine runs its cycle automatically while the operator moves to the next task
These three time elements are plotted against a horizontal time axis, with takt time marked as a vertical reference line. The result is a visual chart that shows exactly how the operator’s manual work, walking, and machine cycles interleave across the full cycle — and whether the total fits within takt time.
Japanese Origin
標準作業 (hyōjun sagyō) means “standard work.” 組合せ (kumiawase) means “combination” — the fitting together of parts. 票 (hyō) means “chart” or “form.” Together: “standard work combination chart” — the document that shows how manual work, walking, and machine time combine within one cycle.
The word 組合せ is the key: it is specifically about how different time elements are combined — fitted together like interlocking pieces — to form a complete, efficient work cycle.
History at Toyota
The Combination Table is inseparable from the history of multi-machine operation at Toyota. In the 1950s and 1960s, as Ohno pushed to combine previously separate manual machine operations into connected cells, the fundamental challenge was coordination: how does one operator manage multiple machines, each with its own cycle time, without any machine sitting idle and without the operator waiting?
Standardized work creation in man-machine combination areas is a rigorous and detailed process. The Combination Table is the analytical tool that makes this coordination visible — it shows the time relationship between what the operator is doing and what each machine is doing, highlights any wait time where the operator or a machine sits idle, and provides the basis for redesigning the sequence or layout to eliminate that waste.
The historical context matters: Toyota was working with manual machine tools — lathes, drilling machines, milling machines — that were being physically rearranged from isolated departmental layouts into L-shaped or U-shaped cells for one-piece flow. The question driving the Combination Table was practical: given this set of machines with these cycle times, how many can one operator run within takt time, and what is the exact sequence and timing?
How It Works
The Time Axis
The Combination Table uses a horizontal time axis, typically scaled in seconds. A vertical line marks takt time — the boundary within which the entire work cycle must fit. The chart shows one complete operator cycle from start to finish.
Three Time Elements, Visually Distinguished
Each step in the operator’s work cycle is plotted as a horizontal bar on the chart:
- Manual work — typically shown as a solid line or bar. This is hands-on time: the operator is physically working on the part or machine.
- Walking — typically shown as a dashed or wavy line. This is transit time between machines. It adds to the cycle but produces no value.
- Machine automatic time — typically shown as a dotted line or different-colored bar extending from the point where the operator starts the machine to the point where the machine cycle completes. During this time, the operator is free to walk to another machine and perform manual work there.
The key insight the chart reveals is the overlap: while Machine A runs automatically, the operator walks to Machine B, performs manual work, starts Machine B, walks to Machine C, and so on. The operator’s manual work and walking fill the gaps between machine automatic cycles. When designed well, the operator returns to Machine A just as its automatic cycle finishes — no idle time for the operator, no idle time for the machines.
Reading the Chart
A well-designed Combination Table shows:
- Operator utilization — how much of the cycle is manual work versus walking versus waiting. Waiting (idle time) means the operator has slack — either the work content is less than takt, or the cycle can be redesigned to add another machine.
- Machine utilization — whether any machine sits idle waiting for the operator. If so, the work sequence may need adjustment.
- Fit to takt — whether the total cycle (manual + walking) finishes before the takt time line. If it exceeds takt, the operation as designed cannot meet customer demand with one operator.
- Walking waste — how much of the cycle is consumed by walking between machines. Excessive walking time suggests the layout should be tightened.
The Relationship to Cell Design
The Combination Table and the physical cell layout are developed together. Changing the layout changes the walking distances, which changes the walking times, which changes whether the combination fits within takt. This is why Toyota designs cells by iterating between the Combination Table (time analysis) and the floor layout (physical arrangement) until the combination works.
The L-shaped and U-shaped cell layouts that are characteristic of TPS are not arbitrary preferences — they are the physical arrangements that minimize walking distance for a multi-machine operator cycle. The U-shape in particular allows the operator’s start point and end point to be adjacent, eliminating a long return walk.
How It Relates to the Other Standardized Work Documents
The Combination Table is the second of three core standardized work documents:
- Process Capacity Sheet — calculated first to determine each machine’s capacity and identify the bottleneck
- Standardized Work Combination Table — created second to design the operator’s cycle by combining manual, walking, and machine time against takt
- Standardized Work Chart — created last as the visual summary posted at the workstation
The Combination Table is the most analytically intensive of the three. It requires stopwatch time studies of each manual work element, measured walking times between stations, and known machine cycle times. The resulting chart is the engineering foundation that proves the operation will work before committing to it.
Common Mistakes
Skipping the Combination Table and going straight to the Standardized Work Chart. Without the time combination analysis, the chart is a guess. The Combination Table is where you discover whether the designed operation actually fits within takt time — or whether you need to reassign work, change the layout, or add an operator. Skipping it means discovering these problems in production rather than on paper.
Ignoring walking time. In a multi-machine cell, walking time can consume a significant portion of the cycle. The Combination Table makes walking time visible. If walking accounts for 15 of a 60-second cycle, that is 25% of the operator’s time spent moving rather than working — a clear target for layout improvement.
Treating it as a one-time exercise. Like all standardized work documents, the Combination Table must be updated whenever the process changes — new takt time, different product mix, changed machine cycle, modified layout. It is a living document, not a project deliverable.
Confusing it with a general time study. A time study measures how long tasks take. The Combination Table does something more specific: it maps how multiple time elements (manual, walking, machine) from multiple machines interleave within one operator cycle against takt. The interleaving — the combination — is the point. A flat list of task times does not reveal whether the operation works as a coordinated system.
Using simplified versions that omit machine automatic time. Some consultant versions of this document show only manual work and walking, omitting the machine automatic time bars. This defeats the purpose. The entire value of the Combination Table is showing the overlap between what the operator does and what the machines do simultaneously. Without the machine time, you cannot see the overlap, and you cannot design the combination.