The principles of lean manufacturing are very similar to what they sound like: take a sometimes bloated manufacturing process and make it leaner by cutting down on waste and improving efficiency. Pioneered by Toyota and other Japanese companies, lean manufacturing principles are a cornerstone of modern manufacturing. But how exactly do you make a process lean, and can you make things too lean?
At Method CRM, we’ve been working with QuickBooks-based manufacturers since 2010, and have seen factories turn lean manufacturing principles into significant profits. In this guide, we’ll give you an inside look at lean manufacturing, how it works, how it’s utilized today, and how you can take advantage of it through Method, without the need for an ERP. Let’s break it all down below.
What is lean manufacturing?
Lean manufacturing is a production methodology that focuses on hardcore efficiency by maximizing value while minimizing waste during the production process. “Value” is defined by what the customer needs and is willing to pay for. “Waste” is everything else that consumes time, materials, labor, or capacity without improving the product outcome. Lean manufacturing improves speed and cost by redesigning how work flows and removing anything that gets in the way.
Lean production has its roots in Japanese manufacturing and the Toyota Production System (TPS). Below are some of the outcomes of lean manufacturing and why they matter for small and medium-sized manufacturers.
| Lean outcome | What improves | Why it matters for SMEs |
|---|---|---|
| Shorter lead times | Less waiting for raw materials and batching | Improves delivery promises and customer trust |
| Lower costs | Less scrap, rework, and excess inventory | Protects margins without raising prices |
| Better quality | Faster detection of issues | Reduces returns, warranty work, and expediting |
| Higher throughput | Constraints become visible | Increases capacity without adding headcount first |
The five core lean manufacturing principles
Define value
Before establishing how to achieve maximum value with the least inputs, it’s important to define what we mean by value. Value isn’t really defined by you; it’s defined by the market, and thus, it’s really how customers perceive your product and what’s important to them; that’s value. Fit, function, spec compliance, delivery timing, documentation, and service expectations can all be important to how customers “value” your product. Lean starts by clarifying how your customers perceive value and what exactly it means to them. Remember, customer demands, customer satisfaction, and customer value are important; at the end of the day, it’s all about how the marketplace sees you. For example, a customer buying cosmetics might not care as much about the production as they do about delivery and documentation.
Once the value is defined, lean principles sort them into three buckets, and these three buckets will define what you do with processes. The three buckets are
- Value-added work – Changes the part or assembly toward customer requirements.
Lean decision: Protect it and make it flow. - Necessary but non-value work – Required due to current constraints (for example, certain inspections).
Lean decision: Reduce it over time through better process control. - Pure waste – Consumes time or materials without improving the product outcome.
Lean decision: Eliminate first.
The table below shows an example breakdown of labor time across value-added work, necessary but non-value-added activities, and pure waste. With this snapshot, you can immediately see what might be affected by lean principles. The 20 hours of pure waste will be the first to go.
| Category | Share of weekly labor time (%) |
|---|---|
| Value-added | 52 |
| Necessary but non-value | 28 |
| Pure waste | 20 |
Map the value stream
Value stream mapping shows how work actually moves from order to shipment, not how you think it moves, or what someone told you. This is important because it gives you insight into the real data. For SMEs, this is where hidden lead time appears: jobs sitting in queues, waiting for inspection, waiting for materials, waiting for a shared machine, waiting for a sign-off, or invoicing. Mapping helps you see the constraints and blockages and then optimize accordingly.
| Step | Cycle time | Average wait time | Common waste revealed |
|---|---|---|---|
| Material prep | 20 min | 1 day | Waiting, transportation |
| Machining | 14 min | 2 days | Queue before constraint |
| Inspection | 6 min | 1 day | Batching, rework loop |
| Assembly & pack | 18 min | 1 day | Missing parts, re-handling |
Create flow
Flow means work moves through production with minimal stops. Small and medium-sized manufacturers are faced with a break in flow when differnet variables such as setup time and routing changes are unclear or incorrect. Improving flow usually starts with a simple question: “Where does work pile up?” That pile is your constraint.
Work piles up between steps.
- Long queues and waiting
- High WIP hides defects
- Slow feedback on issues
Workloads match capacity.
- Fewer bottlenecks
- More predictable schedules
- Less expediting
Minimal waiting and handoffs.
- Shorter lead times
- Faster defect detection
- Better on-time delivery
Establish a pull system
A pull system means work only starts when there is a real need for it, not just because people or machines are available. Instead of building ahead “just in case,” production waits for a clear signal that the next step or the customer actually needs the part. In plain terms, this keeps inventory from piling up and exposes problems faster. For example, rather than producing 500 units to stay busy, a shop might only build more once the previous batch is used, which keeps priorities clear and reduces rework, waiting, and last-minute firefighting. It’s one of the features that Toyota’s “Just in Time JIT” ultra-lean manufacturing ideology is centered around. “You don’t do anything unless you absolutely have to.” This is great most of the time, but when there are interruptions in one part of the supply chain, the lack of inventory and head start can be detrimental. (see COVID-19 pandemic)
| Push production | Pull production | What changes operationally |
|---|---|---|
| Start work to stay busy | Start work based on the demand signal | Less WIP, clearer priorities |
| Inventory used as a buffer | Flow is used as a buffer | Problems surface sooner |
| Defects discovered late | Defects discovered earlier | Lower rework and expediting |
Pursue perfection
The pursuit of perfection doens’t mean everything has to be perfect because this is rare. Instead, it’s about streamlining workflows and continuous improvement ( Kaizen). Measuring performance, running targeted changes, verifying results, and standardizing what works. That doesn’t sound so complicated, but in the pursuit of perfection, steps cannot be missed.
Lean manufacturing tools and techniques
There are tools and techniques that companies use to achieve lean manufacturing targets some of which are as follows:
| Tool | What it does | Best use case in SMEs | Metric to track |
|---|---|---|---|
| 5S | Organizes work areas to reduce motion and errors | High-mix shops where tools/materials are frequently searched | Time-to-find / setup time |
| Kanban | Visual signals for pull replenishment | Stable consumption components or WIP limits at constraint | WIP levels / stockouts |
| SMED | Reduces changeover time | Shared machines with frequent setups | Setup time trend |
| Standard work | Defines the best-known method for a task | Repeatable operations where variation drives defects | First pass yield |
| Takt time | Aligns production pace to demand | Lines/cells where flow is the priority | Throughput vs demand |
The chart below shows anexample of how 5S audit scores can improve over time across different areas of a facility. While the scores shown are not tied to a specific operation, this type of trend view helps teams see whether workplace organization efforts are working or if there needs to be some type of overhaul.
Typical inefficiencies that lean addresses
Lean targets the most common sources of operational drag (often called Muda). The point isn’t to label waste for the sake of it, it’s to identify what’s consuming capacity and cash, then remove it systematically. Here are some common examples almost everyone in the manufacturing world will have experienced at one point or another.
| Waste type | What it looks like | Root cause to investigate | Lean countermeasure |
|---|---|---|---|
| Overproduction | Building ahead of demand “just in case.” | Forecast uncertainty, long setups | Pull, SMED, WIP limits |
| Waiting | Jobs queued between steps | Constraint imbalance, approvals | Flow, standard work, routing clarity |
| Transportation | Excess movement of parts/materials | Layout, batching, unclear staging | Cell design, point-of-use storage |
| Defects | Rework, scrap, returns | Variation, training gaps, unstable process | Standard work, process control, faster feedback |
| Over-processing | Doing more than spec requires | Unclear requirements, “we always do it this way.” | Define value, revise standards |
How to implement lean manufacturing
Lean works best as a staged transformation: start small, measure clearly, standardize what works, and then expand. The fastest wins usually come from improving flow at the constraint and reducing WIP. The most sustainable wins come from standard work, consistent measurement, and leadership routines that keep improvements alive.
1. Baseline
Start by mapping the value stream and identifying the primary constraint. Set clear, measurable targets so everyone is aligned on what “better” looks like.
- What you do: Map the value stream, identify the constraint, and set initial targets
- What you measure: Lead time, WIP, first pass yield
- What success looks like: One shared source of truth for current performance
2. Stabilize
Before pushing for speed, reduce variation. Stabilizing the process makes problems visible and prevents improvements from collapsing under daily noise.
- What you do: Introduce standard work, apply 5S, reduce setup time where needed
- What you measure: Setup time, defect rates, downtime
- What success looks like: Less variation and fewer operational surprises
3. Create flow
With a stable baseline, focus on flow. Reduce batching and clarify routing so work moves forward instead of piling up.
- What you do: Balance work, reduce batching, improve routing clarity
- What you measure: Queue time, throughput
- What success looks like: Work moves without constant expediting
4. Establish pull
Pull systems align production with real demand. WIP limits and kanban signals help control inventory and surface problems early.
- What you do: Introduce kanban, set WIP limits, define replenishment triggers
- What you measure: WIP levels, stockouts, lead time
- What success looks like: Lower inventory and faster feedback loops
5. Sustain and improve
Lean only sticks when improvement becomes routine. Regular reviews and simple scorecards keep momentum from fading.
- What you do: Run daily and weekly routines, review trends,a kaizen cadence
- What you measure: Trend lines by area or process
- What success looks like: Improvements compound instead of fading over time
Lean principles in today’s manufacturing environment
Lean is more sustainable when supported by real-time visibility and automation. This helps avoid easy fixes down the line, like excess inventory when dealing with inventory management. Digital workflows reduce manual tracking, make deviations visible faster, and keep improvement work connected to operational reality.
This is where Method fits: as an operational backbone that connects lean workflows (standard work, task routing, approvals, exceptions) to the systems manufacturers already rely on, especially QuickBooks, so you can measure and sustain improvements and metrics without forcing a full ERP replacement and overhauling manufacturing operations. When your workflows and your data stay connected, lean isn’t a one-off initiative; it becomes the way work runs.
Lean manufacturing vs other improvement methodologies
Lean is often paired with other methodologies. The main difference is focus: Lean targets flow and waste; Six Sigma targets variation and defects. Many SMEs use a blended approach over time, starting with lean to stabilize flow, then applying Six Sigma tools to reduce variation where quality is super important.
| Approach | Primary focus | Best fit | Typical output |
|---|---|---|---|
| Lean | Waste reduction and flow | Lead time, WIP, throughput challenges | Faster delivery, lower inventory |
| Six Sigma | Variation reduction | Defect drivers, process stability issues | Higher yield, lower defects |
| Lean Six Sigma | Flow + variation | End-to-end improvement maturity | Efficiency + quality improvements together |
Conclusion
Lean manufacturing principles help SMEs reduce waste, improve flow, cut lead times, and deliver more consistently. The most effective lean programs are practical and measurable: they target the constraint, limit WIP, standardize work, and build routines that sustain gains. When lean is operationalized inside daily workflows, instead of living in disconnected documents, improvements compound and performance stabilizes.
FAQs
What is Lean Six Sigma?
Lean Six Sigma combines lean’s waste reduction with Six Sigma’s data-driven approach to reducing variation, defects, and overproduction. Many manufacturers use lean to improve flow first, then apply Six Sigma tools to stabilize critical processes.
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