The right question: tool or system
Many people treat kanban and pull production as synonyms. They are not. Pull production is the principle: work only enters the process when there is a consumption signal downstream. Kanban is one way of transmitting that signal, using cards and limited quantities.
Saying "kanban or pull production" is like asking "hammer or construction." The useful question is a different one: which pull mechanism fits my product and my demand? For the principle, see just in time. For the mechanism, see the kanban guide.
Push versus pull, in one line
In push production, central scheduling releases orders based on a forecast, and each department passes along what it has made. In pull, consumption triggers replenishment. Traditional MRP and production planning (PCP) plan and push; kanban replenishes and pulls. Many plants combine the two.
The difference shows when something goes wrong. In a push system, a stopped machine makes inventory pile up in front of it and run short behind it, and the shortage is only noticed days later. In a pull system, the next station stops right away because it received no signal, and the problem becomes an immediate topic. Pull trades comfort for fast information.
Kanban: card-based pull at every point
Each station has a supermarket and cards that control what can be replenished. It works well when there are repetitive items, small lots, a stable flow and a nearby supplier. It demands discipline, leveling and reliable processes. The calculation details are in kanban sizing.
It is also a learning system: the number of cards is a lever for exposing problems, as the 4 golden rules of kanban show. The detailed card mechanism is covered in how kanban works.
Alternatives for pulling production
CONWIP
CONWIP (constant work in process) keeps the total amount of work constant across the entire line, rather than at each station. A new lot only enters when another one leaves. It suits cases where the mix varies a lot and keeping a supermarket for every item becomes difficult. Visibility by station is lower.
Reorder point replenishment
When inventory falls to a calculated level, a replenishment order is triggered. It is pulled by consumption, but without a card. It appears in storerooms and for purchased items. See reorder point and economic order quantity.
Drum-buffer-rope
It comes from the Theory of Constraints. The bottleneck resource is the drum and sets the pace. The buffer is a protective inventory in front of the bottleneck. The rope is the signal that releases material at the start of the line at the bottleneck's pace. It works well when there is a clear and stable bottleneck.
None of these alternatives removes the need for a stable process. They only change where the inventory limit sits and how the signal travels. Anyone who applies CONWIP to a chaotic process will get chaotic queues inside the limit, only smaller ones.
Comparison table
| Criterion | Kanban | CONWIP | Reorder point | Drum-buffer-rope |
|---|---|---|---|---|
| Where it limits inventory | At each station | Across the whole line | Per item, by replenishment level | In the buffer before the bottleneck |
| Type of demand | Stable and repetitive | Varied mix | Continuous consumption, fast-moving items | Any, with a clear bottleneck |
| Item variety | Low to medium | High | Medium to high | High |
| Visibility | High, by card | Medium | Low, depends on a system | Medium, at the bottleneck |
| Discipline required | Very high | Medium | Medium | High at the bottleneck |
| Example of use | Repetitive assembly | Line with different routings | Storeroom, purchasing | Plant with one critical resource |
Selection criteria
- Demand stability: stable demand favors kanban; fluctuating demand calls for leveling first or another mechanism.
- Item variety: many variants make a supermarket per item unworkable.
- Existence of a bottleneck: if one resource limits everything, drum-buffer-rope attacks that point.
- Replenishment time: long lead times require larger safety stock or advance planning.
- Shop-floor maturity: kanban requires standards, discipline and reliable processes.
- Cost of stopping: if stopping is expensive, the system needs well-defined buffers.
A high-turnover, low-variety item fits kanban well. A low-turnover, high-variety item tends toward a reorder point or make-to-order production.
If more than one criterion points to different mechanisms, split the portfolio. Class A items, with high turnover, go to the most rigid mechanism. Class C items, with low turnover, stay with the simplest one.
Read the table as a starting point, not a rigid rule. The same item can migrate from one mechanism to another when its demand changes. A new product with uncertain demand starts on a reorder point; when it becomes routine and stabilizes, it moves to kanban.
Hybrid systems are normal
The lean plant is not one single thing. It is common for leveling to set the pace, kanban to control the high-turnover items on the line, a reorder point to replenish purchased components, and MRP to cover expensive items with long lead times. The mistake is applying one mechanism to everything because it is fashionable.
An illustrative example of a combination: a manufacturer of mechanical assemblies uses kanban between machining and assembly for the 20 fastest-moving parts, a reorder point for purchased screws and washers, and MRP for the forged shaft, which has a six-week lead time. Each group gets the control that matches its behavior. The cost is maintaining three sets of operating rules, and the team needs to know which one applies to each item.
Next step
List your items and classify them by turnover and variety using the ABC curve. Mark which ones are stable, which have irregular demand and where the bottleneck is. Choose one mechanism for each group and test it in a pilot flow before scaling up.
Frequently asked questions
Are kanban and pull production the same thing?
No. Pull production is the principle of producing from consumption. Kanban is a tool, using cards, to transmit that signal.
What is CONWIP?
It is a pull system that keeps the total amount of work across the entire line constant. A new lot only enters when another one leaves.
When should I use drum-buffer-rope?
When there is a clear and stable bottleneck. The drum sets the pace, the buffer protects it and the rope releases material at the entry at the same pace.
Can I combine kanban with MRP?
Yes. It is common to use MRP for expensive items with long lead times and kanban for fast-moving items with stable demand.
Does kanban work for highly variable demand?
It struggles. In those cases, level production first or use CONWIP or a reorder point.
Keep learning
Sources
- SMALLEY, A. Criando o Sistema Puxado Nivelado. Lean Institute Brasil.
- MONDEN, Y. Toyota Production System: An Integrated Approach to Just-in-Time. CRC Press.
- Lean Enterprise Institute. Theory of constraints (glossário Lean). https://www.lean.org/lexicon-terms/theory-of-constraints/
- Lean Enterprise Institute. Kanban (glossário Lean). https://www.lean.org/lexicon-terms/kanban/
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About the author
Lean Manufacturing & Behavioral Management Specialist
Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.
