lean water spider

What is a lean water spider?

Lean water spider, or water spider, is a term used in manufacturing that refers to a position in a production environment or warehouse. This position has the main task of ensuring materials are supplied where and when they are needed. Among other tasks, a water spider is responsible for keeping workstations fully stocked with materials, ultimately contributing to overall higher productivity of other workers.

The position is sometimes confused with a material handler or thought of as a "gopher" in terms of retrieving and delivering materials; however, the position plays a much more important role. Lean water spiders are required to be knowledgeable about all the processes surrounding the materials and tools they manage. They also travel from workstation to workstation, checking each in a regular rotation to ease the flow of production and ensure continuous productivity.

The water spider plays a critical role in lean manufacturing. Having someone dedicated to adding value to tasks will reduce extra strain and allow a continuous flow of production. Without this position, workers have to move materials between their own workstations, creating more transportation waste and time sinks. Having one person in this role makes it possible to create an environment with as little variation as possible while optimizing any existing processes by eliminating inefficiencies.

The idea of a lean water spider comes from Japan, where it is called "mizusumashi," or in kanji, 水澄まし.

Goals of lean water spiders

Lean water spiders move through a defined work sequence in normal rounds. They must know the processes of the operations they are supporting. This knowledge helps identify any inefficiencies and ultimately reduce slowdowns in production.

Creating systematic routes and timelines is also important in ensuring JIT work gets done. Aside from having a specific sequence for location-to-location movement, water spiders should also create a standardization process for their tasks.

Water spiders should have a clear set of defined tasks. Tasks should be performed the same way each time. Different tasks can include moving materials, parts or tools, removing waste materials, dropping off kanban cards to a post or updating status boards. Tasks could even extend to keeping an eye on less experienced personnel. The leaner operations become, the less spare time a water spider will have -- their work should leave little room for variation.

In whatever spare time a water spider does have, they should be able to take up occasional extra tasks to further facilitate flow in a warehouse or process. These tasks don't often occur within production cycles, such as replacing tools. Water spiders should not be seen as flexible, but rather as a way to minimize variation for other workers on the production floor.

Pros and cons of lean water spiders

There are a number of benefits to creating a lean water spider position; however, it can also come with some downsides if they are not utilized properly. Some benefits of the position include the following:

  • reduces wasted time spent by floor workers;
  • makes tasks easier to standardize;
  • helps enable lean manufacturing;
  • optimizes complex production processes; and
  • decreases variations.

Some potential downsides to water spiders, however, may include the following:

  • Managers, if not properly informed, may see the role as less important than it is. If they see it as secondary to production, then additional tasks may be added to their process. This will make for a less productive output. In addition, with less time to dedicate to their main tasks, the productivity of other workers will be affected.
  • Water spiders may also sometimes make empty rounds. This could be due to unseen production inefficiencies.
  • Larger operations may be more difficult to support if a water spider has to maintain multiple work areas.

Lean water spider job responsibilities

When looking for a lean water spider position, job seekers may see postings that express specific responsibilities and look for certain characteristics. For example, a company looking for a lean water spider may seek someone who will carry out the following tasks:

  • Take various materials, parts and assemblies from a warehouse or staging location to production.
  • Prepare those materials for proper use.
  • Use enterprise resource planning (ERP) software.
  • Use continuous improvement methods to decrease any errors.
  • Replenish materials and tools as needed or if found defective.
  • Manage kanbans.
  • Ensure proper communication among teams.

Employers may also look for key characteristics, including the following:

  • The water spider must be knowledgeable of specific processes.
  • The water spider needs to be process-driven and take a systematic approach in completing their rounds and processes.
  • The water spider also needs to be perpetually on the move, as they have to move materials from one place to another and travel between workstations.

Lean water spider position growth

While the water spider position may sometimes be seen as less important than it really is, the position does also hold a lot of potential for growth. An individual in this position will learn much about the production floor and how the organization they're working for operates. Ideally, they will get to know the people there and the individual challenges in day-to-day work. This role is a good experience to have in order to become a future manager, supervisor or team leader. Knowing what work is like on the floor before moving into a leadership role gives previous lean water spiders an appreciation for the work process everyone needs to go through, what the workflow is currently like and how it can be kept lean. The position can also provide more professional growth in lean and Six Sigma manufacturing approaches.

This was last updated in January 2023

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