Reduce Risk with Karakuri Ergonomics
Maggie Rutkowski, OTD/S, CEAS II
If you search the word “karakuri” you will most likely see an automated puppet toy appear. That’s because the word originates back to 17th century Japan when these mechanical dolls were created. These dolls involved the use of mechanical mechanisms to make the dolls moveable without the use of electricity, hydraulics, or pneumatics. The word karakuri is generally translated to mean gimmick, mechanism, machinery, or device.
Now, if you search “karakuri kaizen,” a popular lean manufacturing concept will appear. Kaizen translates to continuous improvement of working practices and personal efficiency. Karakuri kaizen is the use of mechanical devices to assist with tasks with limited or no electric, pneumatic, or hydraulic power sources.
So, how does this relate to ergonomics and continuous improvement? Put the two together and essentially karakuri ergonomics is the process of utilizing a mechanical device that is intended to improve an overall work process that involves reducing or eliminating ergonomic risks within the process.
The Basic Principles of Karakuri Ergonomics are:
Don’t use the human hand. Move objects automatically.
Don’t spend money.
Use the force of your equipment.
Build it with the wisdom and creativity of the people of the shop floor.
For safety, don’t just rely on paying attention, but build a device that stops automatically.
Why Implement Karakuri Ergonomics?
As the world of manufacturing is evolving and technology is expanding, most manufacturers may opt for a high-tech solution, when in reality improving the work process and the quality and safety of the working environment may be able to be solved more simply. Karakuri ergonomics has several benefits. The first is that it is more cost efficient. A computerized system or robotic solution often costs more money, as well as maintenance costs and the risk of the machine malfunctioning. Karakuri devices often rely on gravity and inertia which typically do not change in the environment. Along with that, these machines are easier to maintain and, if built onsite, employees know the ins and outs of the machine and parts tend to be less costly.
It also increases engagement with the entire team. Involving those who will directly use the device in the design and creation will allow for shop floor workers to be involved in the continuous improvement of the machine in which they can have the autonomy to adapt the devices for the better. Lastly, the simplicity and knowledge of the device, if built by the entire team, will reduce human error and mistakes.
Overall, karakuri is a design principle that is well recognized in lean manufacturing among a variety of companies. As the manufacturing industry expands, ergonomists should keep in mind this practice as an applicable and relevant solution.
For more information on ergonomics, industrial injury prevention, and continuous improvement, contact us at 828-214-5045 or connect@risingworkplace.com
References:
Floyd, T. (2021). What is karakuri? Geolean. https://geoleanusa.com/what-is-karakuri/
Japan Institute of Plant Maintenance. (n.d.). Karakuri kaizen. JIPM. https://jipmglobal.com/activity/karakuri-kaizen
Japan Plant Maintenance Association. (n.d.). What is karakuri kaizen? JAPM. https://jipm-event.com/karakuri/about
Karakuri (n.d.). Lean Six Sigma Definition. Retrieved July 11, 2023, from https://www.leansixsigmadefinition.com/glossary/karakuri/
Roser, C. (2017, October 10). Introduction to karakuri kaizen. AllAboutLean. https://www.allaboutlean.com/karakuri-introduction/
Kaizen Institute: www.kaizen.com
AllAboutLean. (2017, September 30). Karakuri kaizen example from Toyota kaikan museum [Video]. YouTube. https://www.youtube.com/watch?v=8_AY4IgADiI