Lean manufacturing gets lots of press and for good reason. It drives waste out of manufacturing facilities and makes them more profitable. It's relatively easy to see waste in manufacturing because you can touch it. But it's not so obvious in engineering departments. Still, lean-manufacturing principles apply there as well. In fact, engineering departments are good places to start lean-manufacturing programs.
The essence of lean, as it's often called, concentrates on removing waste while improving operations. Six Sigma principles, frequently mentioned in the same breath with lean ideas, are closely associated and focus on reducing defects, a form of waste. Together they form a notion of Lean Product Development/Lean Design, a method of removing waste from products before they get to the manufacturing floor.
Starting a lean-engineering program is beyond the scope of this article. However, one of its critical elements will be engineering software that eliminates the time lost to data translations, provides a database for reusing company ideas and best practices, and includes simulation and analysis software that eliminates prototypes.
LOOKING FOR WASTE
To find the waste in the engineer department, it's useful to first examine where waste comes from on the shop floor where it's easy to spot, and then work back to the design department. Experts say there are seven categories of manufacturing waste. They are listed in the accompanying table "Seven deadly wastes." Toyota often gets credit for compiling the list.
To illustrate how costs are unnecessarily added to designs, consider the production of railway rolling stock. An A.T.
Kearney study from 2003, The Line on Design, How to Reduce Material Cost by Eliminating Design Waste, found a total of 58% of the cost for internal production and material were wasted. More costs came from failing to use deign experience, overdesign, and making designs difficult to manufacture. The table "Waste in action" summarizes the finding and tells a sad tale of lazy management. The good news is that the total cost of the vehicle could be reduced by 30% over two years by simply attacking these areas.
If your company struggles with the following issues, it might benefit from improving its software and how it's used. Look for:
- Process delays and time lost looking for information, waiting for test results, and feedback.
- Unnecessary documents and physical prototypes.
- Designs never used, completed, or delivered.
- Poor designs that generate warranty issues.
- Under use of design knowledge, as in costly parts.
- Late identification of manufacturing errors.
SUPPORTING LEAN WITH SOFTWARE
In a nutshell, lean should help companies reduce delays, maximize design reuse, reduce defects, and improve process efficiency. One way to tie these ideas together would be with a design or modeling system that eliminates recreating data. Simulation in sufficient detail could predict performance without building physical prototypes. And a capable data-management system would track the mountains of information generated in modern projects. These capabilities support lean initiatives by eliminating the waste of delays, errors, and data loss through development stages, with improvements in overall process efficiency and cycle time.
The data-management system mentioned would be a structured repository for all product and process data required for development. This includes data created in computer-aided design, engineering, and manufacturing, along with information needed for development. Managed environments let companies capture workflows that route information to teams when needed, eliminating time wasted looking for, waiting for, and recreating product data.
A few other key software capabilities to complement lean engineering would include:
Associativity. In engineering software, it can eliminate the waste of missed updates.
Associativity often links CAD and CAM systems so that when a model updates, its NC work also updates. But when applied company wide, an updated model would kickoff updates everyplace that uses or mentions the model, such as manuals, drawings, and NC toolpaths.
Knowledge-driven automation. It lets manufacturers capture and reuse knowledge to automate development tasks. Knowledge-driven automation works several ways. It captures knowledge and best practices for specialized tasks such as structural analysis and mold and tooling designs.
Knowledge-driven automation programs would apply the experience of experts to frequent engineering tasks, such as stress analysis. In knowledge-driven automation, a rules-evaluation engine lets companies drive designs with external requirements and knowledge databases, those specific to the company and its products.
Simulation, validation, and optimization. Simulation lets engineers see how products carry loads, where designs are weakest, or how they react to heat, among other things. Comprehensive simulation predicts performance early in development, when a design is easiest and least expensive to alter. Structural and motion-analysis tools let users simulate early without requiring engineering analysis specialists.
Validation implies, for example, finding interference fits to eliminate manufacturing defects. And optimizations can be applied several ways. For instance, weight optimization takes unneeded material out of assemblies, and cost optimization, such as design for manufacturing, cuts the number of parts needed in an assembly.
System-based modeling reduces waste several ways. Take a jet engine, for example. High-level system modeling might run through a set of inputs and design-rules to define a framework, sheet metal, and volumes for subsystems such as a turbine section and fuel systems. Product or subsystem templates would then build on the outputs of the system model to detail the turbine section and fuel system.
System-design software lets companies standardize design practices and rapidly create product variants, reusing knowledge, and eliminating engineeringrework. Systems modeling also reduces engineering errors and defects among product options, variants, and derivative platforms by preserving highlevel design parameters and interfaces between systems and components.
SEVEN DEADLY WASTES
|Manufacturing waste||Design waste|
Movement and transport
|Looking for information and waiting for test results
Unnecessary documents, physical prototypes
| Excess and early production
| Not learning from past design experiences
Too many features
Designs are not used, completed, or delivered
|Poor process design
Inefficient performance of process
|Underuse of design knowledge
Late discovery of manufacturing errors
|Making defective parts||Poor designs
WASTE IN ACTION
|Quantifying waste||From the railway vehicle|
|Gold plating, 8%||Functions and features customers do not need or want.|
|Excessive safety factors, overspecifications, and unnecessary requirements or those left over from previous designs, 11%.||High-grade fire-resistant train seats. These are usually required on trains traveling through tunnels, but are put on a train that never goes through a tunnel.|
|Suboptimal concepts, 15%||Inferior solutions but already in production on other vehicles. For instance, a floor that is 40% more expensive but no more capable than other floors.|
|Lazy designs, 7%||Designs that do not fully use the components or materials better than those required.|
|Poor application of design for manufacturing and assembly, 5%||A complex seat attachment. If simplified, assembly time could be cut by 60%.|
|Failure to design for supply, 12%||Panels purchased from domestic suppliers with high costs.|
|The table identifies and evaluates waste found in the design of a railway vehicle. It comes from The Line on Design study by A.T. Kerney.|
A lean dictionary
Here are a few frequently encountered terms in the lean literature: Five Ss are sort, straighten, shine, standardize, and sustain. These apply to a shop machine as well as an office desk.
Kaizen: Continuous improvement.
Kaizen event: A group effort that identifies waste and devises methods to eliminate it, or an action intended to improve existing processes.
Kanban: A tool for JIT. It signals replenishment for materials and maintains orderly and efficient flows of material through manufacturing.
Project board: A bulletin board with a timeline, action items, and duties for the team. It tells who is responsible for what.
Six Sigma: A statistical method to measure and improve a company's performance, practices, and systems by identifying and preventing manufacturing and service-related defects.
Stand-up meetings: Usually conducted at the start of the day at the project board to discuss what needs doing and what actions needs help. Standing up ensures brevity.
Value-stream mapping: Initiates a lean engineering or manufacturing program. It's a flowchart that shows movements of material and information through an office.
OPPORTUNITIES FOR REDUCING WASTED DESIGN WORK
|Areas of waste reduction||Percentage of design waste|
|Designs never used, completed, or delivered||Unknown|
|Downtime from hunting for information and waiting for test results
Unnecessary documents and prototypes
|33 to 50%|
|Underuse of design knowledge that leads to costly parts
Overdesign such as features customers don't need
Identifying manufacturing errors late in the design process
Designs that lead to defects
|The figures come from an analysis of automotive Tier 1 suppliers and the A.T. Kerney study The Line on Design, 2003.|
Lean lessons at work
B/E Aerospace previously spent up to two days a week turning concept designs into engineering designs. The often-imperfect translations resulted in misinterpretations and lost design intent.
After adopting engineering software with features for both functions, the company eliminated data translations. Better yet, it let conceptual designs and engineering proceed concurrently. The effort paid off when Japan Airlines gave the company an order for lie-flat, first-class seats. The project's challenge was to pack several components, such as electronics, motors, and mechanisms into a small space. This required close collaboration between industrial designers and engineers. An award-winning design came out of the collaboration effort.
Denso, a manufacturer of auto electronic components, develops systems that meet the needs of multiple customers. The company makes sure its parts are interchangeable and can be used on a wide range of car platforms, thereby freeing resources for other tasks and minimizing defects.
GE Aircraft Engines once struggled with design problems because components were designed in isolation without knowing how they impacted other parts in the system. Today, using comprehensive engineering software, they gained the benefit of twice the previous number of design iterations including validation analysis in 25% of the time.