Single-piece production and halved lead time.
GE Healthcare is a multinational company that is part of the GE group and manufactures laboratory instruments and equipment for medical diagnostics. We have worked together for many years.
In connection with the move to our current facility, we took the opportunity to perform value stream mapping for our workstation for GE Healthcare. The challenge we set ourselves was to halve the work area and still shorten lead time.
Value stream mapping
Value stream mapping is one of our most important tools in continuous improvement. The method involves visualizing the flows in work processes. You could say that it’s about getting an overall picture of an activity by identifying the relationships between the information and material flows involved. We look at throughput time, changeover times, interim storage and reliability in processes, for example.
The value stream mapping provides answers to important questions such as: How long is the throughput time? Is there any unnecessary interim storage? Time thieves? Bottlenecks? What is adding value in the process? What is not adding value?
Four steps of value stream mapping:
- We select an important component/part of the production chain that we follow from the beginning to the end of the process. In this way, we can follow the flows at a detailed level.
- We identify and draw the workstation’s layout and flow as they look at present. Then we analyze any problems that exist. We identify what is adding value, and what is not.
- We define the ideal state, what we want the value stream to look like, and draw it.
- Finally, we produce an action plan and implement the new work flow.
Previously, the workstation had a linear layout with a number of intermediate steps, where a large proportion of the throughput time was storage time. The work was organized so as to assemble several parts at once, so when the material arrived at the workstation, the operator built up a pre-assembly storage pile for him/herself. A traditional way of setting up an assembly station using what is termed a push flow.
Value stream mapping made it clear what time and what resources were adding value, and which were not. The time that the parts are lying in pre-assembly and interim storage piles adds no value, so we concentrated on eliminating this time and creating a work process with a needs-based or pull flow.
The layout of the workstation was completely changed so that the operator was its focus. The pre-assembly and interim storage piles were removed completely, so the operator now produces components at the same rate as they are requested. In this way, we have created a single-piece, pull flow that is customer-driven. This means that each individual product is constantly in motion through the workstation and never waiting to be processed in any interim storage. It means that we can be flexible in relation to demand from GE Healthcare and maximize value-adding time.
Our planned objective was to halve the working area at the workstation, and we did. The second objective was to reduce lead time, and there we exceeded all our expectations. We managed to halve the order lead time, from 14 days to just 7. An impressive reduction!
But the solution also means that we have been able to free up time and resources for a more efficient flow of information, as well as productive maintenance. Quality has also improved. It is now easier for the operator to detect any faults and then deal with them directly. Single-piece production means significantly less scrapping.
We and our customer GE Healthcare are extremely satisfied with the outcome of this value stream mapping. A positive step in our continuous improvement efforts.