Line balancing is simply the assignment of the right machines and the right number of employees to each line to meet the target rate required by the customer which is called the takt time. For a given production line, if production time is exactly equal to takt time, then the line is perfectly balanced. Otherwise, resources should be reallocated or rearranged to remove bottlenecks or excess capacity. Benefits derived from a line balancing exercise include:

• Reduce waiting time

• Reduce inventory

• Better understanding of internal and external irregularities

• Reduce production costs and unlock greater value

When line balancing is achieved it leads to employees and machines that perform in a fully synchronised manner. In other words, employees and machine capacity are optimised. Such process efficiency represents reduced costs and greater profitability. Listed below is a five step methodology to achieve line balancing:

1. Calculate takt time

Since the goal of line balancing is to match the production rate to takt time, being aware of your takt time is essential. Takt time is calculated by dividing the available production time by customer demand, where available production time can be defined as the time needed to build a product from start to finish.

2. Perform method studies

The goal of a method study is to establish the time required to complete each task along a production line. In other words, you want to find out how long employees and machines spend on each part of a process.

3. Identify bottlenecks and excess capacity

When it comes time to analyse the data from your time studies, notice which parts of the process are taking longer than takt time. Exceeding takt time means late deliveries, high shipping costs or unhappy customers. It is also worth noting which parts are taking less than takt time. That means excess capacity in those places.

4. Reallocate resources

Start by considering task precedence, which is the sequence in which tasks must be carried out. For example, if a step requires a certain part, you need to make sure that part is completed before reaching that step. A flowchart or value stream map can come in handy.

Then, rearrange tasks to reduce excess capacity and bottlenecks. For example, move resources–employees and equipment–from parts of the line that have excess capacity to bottlenecks. In other words, aim to alleviate the workload where there are blockages, and move it to places where excess capacity can be filled by absorbing more work. This will reduce the waiting waste in the places where there was excess capacity. It will also help improve production flow where there were bottlenecks.

Try to organise elementary tasks into groups that minimise operators’ idle time and that maximise the utilisation of machines and equipment. Share the workload among operators in the most logical way, considering the data on operator performance that you have gathered. Ideally, each group of tasks should be completed in the same amount of time to achieve synchronisation.

Wherever you have several operators performing consecutive tasks and working as a unit, you should strive to reduce the imbalance between employees and workloads. Proper arrangement and allocation of tasks in production lines help maximise output at the desired time.

5. Make other improvements

The analysis of the data collected on your lines can also reveal other opportunities for improvement that could enhance your manufacturing facility. To implement process improvement, you can manipulate three parameters: operator time, machine time, and setup time. For instance, you can give additional training to employees that take longer to complete tasks or facilitate transitions to reduce changeover times. You can also upgrade machines or make sure operators follow proper machine setup and maintenance standard operating procedures.

Line balancing is an optimisation process with significant industrial importance. By improving the efficiency of their lines, organisations can reduce wastes and unlock greater value.

Ray is a Lean Business Coach with LEAN TeamGB based in Cumbria. He runs his own company which specialises in combining Lean Thinking and the “Deployment of an Army of Problem-Solvers.” Ray is currently running business excellence programmes with four sites within the Albert Bartlett Group – the Airdrie-based “red rooster” potato company: as a director of ARC Associates (Cumbria) Ltd and as a Lean partner with a number of companies including Armstrong Watson - Accountants, Business & Financial Advisers, Bella & Duke - premium pet food supplier. Ray is a Chartered Engineer, gained a BSc (Hons) degree in Glasgow, an MBA with the Open University and a PGCE teaching degree at Huddersfield University. Ray includes a Lean Six Sigma Master Black Belt among his many Lean Management and Business Improvement qualifications. If you or your company is looking to exploit better line balancing in your manufacturing facility, Ray will guide you through the entire process