The Principles of Lean Manufacturing Explained

Lean, which can be defined as a system, method or way of thinking, was born in manufacturing facilities – namely those used by Toyota to make their cars. But in recent times, the concept has made its way into many different areas of business as a means of improving quality and productivity while reducing waste.

When lean production principles were applied at a flour factory in Kenya, the following benefits were identified:

• 80% less waste
• 50% lower production costs
• 50% increased workforce productivity
• 80% – 90% reduction in unsold stock
• 90% cheaper to make quality products

Not bad, right? For most businesses, those are game-changing numbers. If you want to see the same benefits in your company, the following key principles can help you make it happen.

Waste Reduction

As you can probably guess, the elimination of anything unnecessary is core to lean as a practice. The word itself refers to “with minimal excess” in this context. To that end, you need to make sure that as little waste as possible is rendered during every step of the production process. Every unit of waste that gets eliminated translates to money saved.

You can do this in several ways. Here are some examples:

• Reducing standing inventory
• Avoiding making unusable by-products
• Decreasing empty space between workstations
• Preventing bottlenecks
• Assigning workers to tasks more efficiently
• Using automation where possible

It’s difficult to cover all the possibilities, as waste can be reduced in virtually everything you do. Documenting your workflows and keeping track of processes can help you identify more opportunities.

Continuous Improvement

This goes hand-in-hand with the previous principle, as continuing to improve your business processes will inevitably lead to the reduction of waste in one way or another. Beyond that, taking this approach to any repetitive task is bound to create better results moving forward.

As with reducing waste, you need to document your processes first. This helps to reveal potential gaps or inefficiencies. From there, it’s a matter of determining which improvements will have the greatest effect. Make sure to be accurate and honest when tracking procedures. Talk to employees and find out what’s really going on.

Respect for Human Elements

There’s no way to achieve great results with anything you do unless the people responsible for bringing those results about are happy and motivated. This is why respect for humanity is a key principle of lean manufacturing. It’s also a relatively easy one to implement, as there are only a few core elements that you need to keep in mind:

• Don’t overwork staff
• Emphasize the purpose behind what they do (why it’s meaningful)
• Align said purpose with their goals
• Maintain accountability for wins and losses
• Listen and get to the root of the problem when discussing issues
• Minimize friction with tasks
• Provide challenging (engaging) work that isn’t demanding
• Make work stable while maintaining variety

Since you’re dealing with people and not predictable machines, having effective communication skills is important. Show your employees the respect they deserve and let them know that they’re valued.

This is paramount when setting up a lean manufacturing facility or incorporating the principles in your existing business. You can learn more with Kettering University. This post on the Kettering University Online blog has some informative tips on establishing a successful lean production process.

Level Production

The Japanese word “Heijunka” is relevant here, as it refers to “leveling production” in the context of lean manufacturing. This means ensuring that your day-to-day output is consistent.

By considering your average order amount, you can determine how much you should be producing. When you make more than you sell, the excess is put into a dedicated category called fluctuation or safety stock. In theory, this should help you avoid having to rush to meet a larger order.

That might seem contradictory to the waste reduction principle, but it isn’t nearly as bad as having a ton of inventory and nothing to do with it. The key is to meticulously calculate the ideal production rate to order amount ratio, as well as the ideal fluctuation stock size. This will inevitably take some trial and error, but it will pay off in the long run.

One Piece Flow

Done right, this principle can reduce your operations time by almost 100%. The goal of one-piece flow is to ensure that a product is always being worked on at any stage of the production process and nothing is kept waiting in line.

In doing so, you can vastly improve both the quality and efficiency of your output. Using a “U” shaped floor plan tends to make this possible while also reducing floor space, not to mention minimizing travel time. Granted, the effectiveness of this method depends on what you’re making and how you’re making it.

It’s possible that employees can lose motivation as they may be put in a position where they’re working on the same monotonous task. This is one of many areas where automation can save the day.

Detect Defects with Automation

Another area where you can leverage the power of automation is detecting defects. This makes it possible to completely remove human error from the equation. In a clothing production line, for example, a machine can detect when the thread on the loom breaks by being set up to perform checks automatically.

Mistake Proofing

This lean principle is aimed at improving quality. The relevant Japanese term is “poka-yoke” which roughly translates to mistake-proofing. The idea is that through re-engineering, a process can be modified to eliminate any mistakes. Alternatively, the task can be fortified by specific measures that ensure any issues are quickly identified and corrected.

Here’s a simple example: You might have a task for attaching wheels to a toy car. Let’s say this involves adding springs before clipping the components into place. Human error can result in someone forgetting to attach a spring. This can be difficult to spot at first, so the solution is to add two extra springs in advance instead of waiting for the mistake to occur.

Done right, lean manufacturing can revolutionize your processes. Be sure to consider how you can implement them in your business moving forward.