Faced with growing challenges such as labor shortage and rapid technological change, manufacturing companies must continuously optimize their operations to serve the needs of an ever more demanding customer base. Standardized work and 5S are already widespread. But have you ever heard of workcells? Falling within the concept of Lean Manufacturing, workcells reinforce flexibility on the work floor in order to improve performance and reduce waste.
What Is a Workcell?
A workcell is a group of machines, worktables and related components that are joined together based on the object to be manufactured. This equipment will process the object and transform it into its final state in an uninterrupted sequence.
What Are the Benefits of a Workcell?
When implementing a workcell, care should be taken to balance the workload so that each workstation performs at around 80 % of takt time. Takt time is the production rate needed to keep pace with the expected demand of units. In doing so, there is added flexibility if issues should arise and result in production delays, thus preventing the situation from jeopardizing delivery to the customer.
What’s more, implementing workcells can improve product quality in two ways. To illustrate the first way, let’s think of a factory divided into several cells processing batches of 100 parts. Workstation #1 produces a non-compliant part, but the defect is only detected at workstation #3. Some 200 maybe 300 parts will have been produced in vain before the problem is reported. It is possible to prevent such a waste of resources using one-piece flow. Using this method, only two or three parts would have been produced before the anomaly was observed. That is why implementing workcells helps to improve quality.
Moreover, workcells promote collaboration, and the sharing of good practices. The mixing of diverse experiences is fostered in order to facilitate the transfer of knowledge to novice workers. In addition to being beneficial on a human and professional level, this approach helps the team improve their overall performance in terms of quality.
How to Implement a Workcell
When implementing a workcell, two crucial questions arise before carrying on with the next steps. First, what is the object to be produced? And second, what is the production rate needed, or takt time?
After identifying the ideal manufacturing sequence, you have to determine the number of employees required to meet the manufacturing cycle time. In doing so, you will know how to divide the time and assign the right tasks to the right people. The results of this thought process will help you determine the positioning of each workstation in the workcell.
When mapping the cell, you need to account for three types of flow: information flow, human flow, and material flow. These three should be analyzed to prevent them from overlapping, which would result in waste and chaos. Indeed, such an overlap could lead to ergonomics and supply chain problems, and could also create a risk of confusion regarding the information conveyed to employees.
On the other hand, it is important to consider the reality of employees when setting up the cell. To do so, it’s useful to question yourself on the best ways to optimize their time. How should we present them with parts? Should the parts be presented flat, upright, on the side? Can workers hold one part in each hand, so that both hands start and finish the process at the same time, rather than retrieving the parts one at a time? You also need to think of the shape and dimensions of the parts and of the actual devices that will hold them to make sure the employees work efficiently and avoid handling them several times during assembly. However, it is also important to gather feedback from the employees in question. They are the ones who can tell which tasks are the most laborious and strenuous. All things considered, you want to create a win-win situation where production is optimal, and employees tireless.
Resource flexibility is a prerequisite to keep in mind when implementing a workcell. You need to rely on employees capable of performing multiple tasks. This flexibility is key to balancing workloads and ensuring the continuity of production. It only makes sense to opt for a cell-based layout with a number of workcells greater than the number of employees. Workers will then have access to several “floating” workstations to establish a natural balance between operators if a problem occurs with a manufactured part. If so, the rest of the cell will be able to pursue its operations despite the complication. Yet this method calls for versatile employees who can rotate through different roles.
U-Shaped Cells: Why?
U-shaped layout is usually favored during workcell implementation. On the one hand, setting up the cells in such fashion saves significant space. In reality, factories seldom have sufficient linear range to install several machines and workstations in succession.
On the other hand, this layout also results in accessibility gains. Workstations have to be conveniently accessible to the workers who are part of them. A U-shaped layout allows an employee posted at the last station to access the first station simply by turning around.
In the same vein, forklift trucks are used to feed the cell in raw parts and collect finished products. Naturally, the main aisles have to be wide enough to accommodate the trucks. This can complicate matters if there is a long line with two separate, distant locations that need to be accessed by the trucks.
At What Point Is a Company Ready to Install a Workcell?
Even if implementing workcells seems simple at first, it doesn’t mean they blend in well with any business environment. It’s a procedure that relies on product stability. In cases where a workcell is implemented to manufacture a product with a high defect rate, one would end up suspending the production very often, and diverting the part to correct the irregularity. The ensuing chaos within the cell would then result in considerable productivity loss.
And so, stability is a base prerequisite for any fully functional cell in terms of layout, quality and supply. In reality, if a workstation runs low on a certain component due to excessive consumption caused by repeated material failure, the unit will be stuck at that station, and production will not be able to resume. Mature companies are more likely to benefit and profit from this type of factory floor layout.
Bottom line, transitioning to a cell-based layout is not an end in itself but rather the starting point of a cultural shift toward a collaborative approach that builds on teamwork. To ensure a smooth process, it is crucial to establish leadership in the cell in order to keep the production pace. Need more information on workcell implementation based on your reality and your needs? Contact us today!