Standards at workstations
Dear Gemba Coach,
Our corporate production system asks us to post standard work at workstations, but we feel that the paperwork clutters the stations and operators tell us they don’t use it in any case. Should standards be posted at the workstation?
- Standardized work chart: this is a graphic chart which fits on an A4 paper (8 1/2 x 11inches) and draws the cell from the ceiling, numbering operations and essentially describing the standard sequence of steps the operator has to follow to realize the work within target cycle time (a few seconds lower than takt time), with the number of standard parts in the process, and visual indications of safety and quality checkpoints. This is the only “standards” document we’ll post on the workstation.
- Operations standard instruction sheet: this is a list detailing each step to actually make the part, the key point to note at each step and drawings or photos to clarify tricky operations which involve unnatural hand movements and so on. As the work on standardized work progresses, this instruction sheet can grow to several sheets as a result of analyzing movements in greater and greater detail. Consequently, this will not be posted on the workstation, but typically held in a nearby binder, close to the workstation.
- Standardized work combination table: this a synthetic sheet showing the full cycle divided in tiny time increments and visualizing as in a GANTT chart the manual work, walking time and machine work necessary to make the part. The work combination table is essentially about timing each of the key job components to make the part and is linked to the supervisor’s work with the stopwatch to identify the best times (repeatable minimums) and train operators to pace their work accordingly. It will not be posted on the cell either.
- Process capacity sheet: this last, essential document, is, for some reason, rarely seen in corporate production systems. It focuses on machine work and lists step by step the manual time, the machine time, the total completion time for the step, the changeover time, enabling people to determine the standard number of parts one can expect from each piece of equipment during one shift. Knowing the processing capacity of each machine per shift is essential to check whether machines are performing at standard and identifying the bottlenecks in each cell.
Of these four documents, only the standardized work chart should be posted on the cell: it’s an A4 drawing and doesn’t take too much space so it shouldn’t add to the clutter. Of the four documents this is the only one likely to be used by operators and team leaders during a work cycle.
The fundamental question to ask yourself is: who are these documents for? The operators? They do the work, day in day out, so they know what they’re doing (even if they sometimes don’t do it right). Why should they need paperwork to tell them their jobs? And in practice, other than with a very fresh temp (and even so), one rarely sees any operator refer to the long operations standard sheets which are posted on many cells, sometimes in binders hanging loosely over their heads.
Using the Whatchamacallit
Why is there so much muda in any workstation? Typically, engineers understand what needs to be done to build a part (or perform a service job), but not how to do it. They can tell your that the gizmo has to be clipped into the thingy and then you need to apply the whatchamacallit, but they can’t tell you that in order to clip the gizmo, you’ve got to push it in lightly then turn slightly, as opposed to forcing it in until it fits. Only operators will know how to actually do the work with the least mental and physical burden. That’s because they explore the work hundreds of times a shift and will eventually hit upon the tricks of the trade that reduce the muda inherent with the design.
Understanding work at this level of detail is key for frontline management. To some extent, in lean, eradicating muda from workstations by working with operators on standardized work is the main aspect of frontline management. This is a privileged moment to work with operators, improve the process and develop mutual trust. Yet, because supervisors are not on the line making parts, they need tools to understand the detail of the work and see what operators do.
My sensei recently showed me a workstation where the operator had to place four small pins in a metal base, add a lid and then place the assembly in a small press activated by putting both hands on two manual buttons. For safety reasons, both hands have to be on the triggers to make sure the operator hasn’t got a hand near the tool. Since the part is fairly small and light it’s tempting to pick it up with one hand, place it in the jig and trigger the press with the other hand at the same time – but quite scary from a safety perspective.
Stopwatch in hand, he timed the operation (a few seconds, I’ll never be that good at taking times!) for one worker, and then we came back for a second timing after shift change. The second person was significantly faster. I stared and stared but could not see any difference in the way the faster operator was working. He was following the same sequence of steps, in the same position, and basically doing the same “standard” job as the first one. Until my sensei pointed out the position of his wrists. Rather than use his hands to press the start buttons, the second operator rested his wrists on them, which enabled him to go much faster in placing and pressing, but also kept his hands much closer to the press tool when it came down. I’ve been watching factory operations for decades by now, and still need to wash my eyes of the dirt that stops me from seeing! (none of the other guys working in the factory had seen it either – but that’s no excuse).
Where Kaizen Begins
This is exactly the level of detail we need to operate at when working with operators to help them execute safely and find ideas for Kaizen that removes muda. The standardized work sheets are a tool for managers to learn to see and to work with operators to improve their own workstations. Without these sheets and the observation they generate, the conversation will stick with generalities and never be narrowed down to the real difference-making “hows.”
As such, standardized work documents should be somewhere close to the workstation, but not necessarily posted. Each workstation should have a folder nearby with its operation standards, work combination and process capacity sheets, fully completed and updated, but not posted. These documents will be pulled out by the supervisor in training exercises to check with the operators they’re following the standards or if not why? This is where Kaizen begins: it’s rarely a matter of compliance. Usually, something is happening in the workstation’s environment that makes following the standard impractical if you have to do it 700 times a shift and operators have found a workaround. Identifying these workarounds, understanding their root cause and asking for suggestions to keep or improve the standard is precisely the supervisor’s job in a lean workplace.
The one exception is the standardized work chart, which will be posted on the workstation. When an operator is having trouble keeping up with the cycle (which will show up by making the next person in the line wait) or is having trouble with quality aspects (which she will detect, will be blocked by a poka-yoke or hopefully picked up by the next person), it’s the team leader’s role to rush to the station and see what happened and help decide whether to call for a line stop to solve the problem.
The first place to start is checking whether the operator is following the set sequence of steps outlined in the standardized work sheet. In this case, having it on the workstation is a support for the operator/team leader conversation: this is an objective teamwork document that removes the subjective elements of “this is how I do the work.” A quick check is usually enough to see whether a step is missing (such as missing a component, or losing time by getting a sequence of assembly wrong) and the team leader can teach the person how to do the work correctly on the spot. Having checked that the sequence is carried out correctly, the problem remains, the team leader will have to stop the line, call the supervisor and start the investigation to figure out what is really wrong at the station.
The standardized work chart is the basic teamwork document that draws how we’ve agreed to do the work. It’s just one A4 per station, and I’ve yet to see a process where it can’t be astutely posted visibly without getting in the operator’s way.
Frontline Management Tools
To answer your question directly, the reflex question I have been taught to develop is to ask myself: what is the operator’s role with this tool? If the operator doesn’t do anything with the tool within the cycle, it shouldn’t be posted on the cell – period. The standardized work chart will be used as a teamwork tool to support the operator/team leader conversation on how work is going, so it has a legitimate place on the station. All the other documents are tools for frontline management, not directly for operators.
If your own central team argues that operators should read from the operations standards to figure out how to build the parts right, my recommendation is you suggest they try assembling parts for a few consecutive shifts, and see how easy it is to figure out the proper movement from a sheet of paper. The charts are support for the supervisor’s understanding of the job and training of the operators – not “instructions” for the operator on the line to read and deal with himself or herself.
In a way, as lean guys, we should ask the same question of every lean tool: who uses it to do what and how? And we have the same problems supervisors face everyday. It’s easy to pick up the tools on the web or in a book, but the templates only tell you’re the “what”. Our problem is to figure out the “who” to use them correctly. To do so, we need to focus on the roles each person has in using each tool.