10 Lean Lessons Learned Print E-mail
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Written by Chris Munroe   
Saturday, 28 February 2009 19:00
Getting Lean

The right plant layout simplifies process and materials flow.

Most companies engaged in Lean manufacturing can easily discuss the changes they’ve implemented, but which changes really contribute the most? At EPIC, we developed a list of the top 10 lessons we’ve learned in our Lean journey. Our January column covered lessons six to 10, and this month we look at lessons one to five.

5. DfM/DfT. EPIC puts significant focus on ensuring products are manufacturable and testable. Minimizing the number of process steps and standardizing processes to minimize changeover time are key points of focus. Single-sided assemblies and assemblies that are either 100% SMT or 100% through-hole are most efficiently processed. Assemblies that place mixed technology on both sides of the board typically drive additional automated and manual processing time, additional tooling costs and a greater potential for handling or thermal shock-related defects. Standardization of designs or panelizations also reduces costs both in terms of driving better PCB pricing and in terms of minimizing setup and changeover time.

Test strategies based on Lean principles typically use standardized test platforms. Efficient ICT requires a PCB designed to consensus industry standards with good access points. According to an Agilent study, analysis of manufacturing defect root causes suggests 10 to 15% of defects are attributable to nonfunctioning parts or defective materials, rather than assembly processes. EPIC has seen similar statistics in internal defects analysis. A robust test process helps ensure that these “embedded” component defects are caught prior to assembled product shipment.

4. Robust Kanban inventory management. From a supply base standpoint, our Lean philosophy incorporates the following principles:

  • Strong focus on developing and qualifying suppliers that embrace Lean manufacturing principles of short cycle times, flexible batch sizes and high quality.
  • Suppliers take responsibility for managing production to forecast, yet deliver to “pull signals” vs. requiring firm release dates over an extended lead-time.
  • Appropriate buffer sizes for current production rates must be established, maintained and continuously monitored for adequacy.
  • Material buffers maintained in close proximity to the manufacturing facilities to permit frequent release of small batches to the production floor and maximum flexibility in responding to changing demands.
  • Proactive, regular monitoring of the material pipeline over the medium-to-long-term horizon through bond reports to identify and resolve potential supply disruptions.

The company uses a Kanban “pull” system, postponement of commitments and electronic data interchange (EDI). Strategic suppliers produce to the MRP forecast and ship to EDI release signals. Buffers are established at key locations in the pipeline and are regularly reviewed and revised as market and demand conditions vary. Consignment, in-house stores and vendor-managed inventory (VMI) programs are used with strategic suppliers to maintain buffers closest to the point of use.

Pipeline status or “bond” reports are regularly reviewed with supplier teams to ensure buffers and replenishment streams are able to support planned production within a range of variation levels based on past historical demand, current forecasts, customer service lead-time guarantees to their end market, manufacturing lead-times and transit lead-times.

On the factory floor, a two-bin system and color-coded cards identify raw material and WIP status. Material shortages are easily visible on a walk-through of the material area. Between facilities, an “E-Kanban” system allows employees to electronically view the status of inbound material shipped from suppliers.

3. Cross-training programs. Training is a vital aspect in Lean manufacturing. No matter what Lean philosophy is used, ensuring the workforce has the ability to change with the flow is extremely important. At EPIC, cross training starts with identifying a roadmap of qualifications for each operator and technical member, and a master matrix maintained to show competence of the staff, and areas to improve flexibility. Operators are trained on a pull system and demand flow to allow them to stay productive either through changeover process, or moving to another work center where they are certified.

2. Plant floor layout. Plant floor layout plays a large role in the implementation of Lean. We have all experienced good and bad instructions in our lifetime. Those with pictures and simple flow diagrams are easiest to follow, while those that are all text or have “if-then” statements can be hard to follow. Plant floor layout is conceptually similar. When the manufacturing process flow can be visualized easily, such as on a walk through the facility, it tends to be more efficient in terms of material flow. Operators understand the wheres and whys of the next process; bottlenecks will become very visible, and anything that is out of place can be seen and corrected quickly. Programs such as a well-structured 5S program will help drive a lean flow and improve the visual flow, and standardized floor models and flows within multi-facility operations will set the tone for standardized work. All this can lead to a safe, enjoyable workplace for employees and improve efficiency of operations.

1. Enterprise-wide SFM. EPIC’s Lean manufacturing philosophy is known as synchronous flow manufacturing (SFM). SFM focuses on increasing factory throughput by optimizing and standardizing production. Rather than optimizing the factory floor process-by-process, it takes a large-scale systems approach. Key implementation elements included:

  • Detailed process mapping, to understand key processes involved in transforming production inputs to customer-desired outputs.
  • Identification of constraints in key processes that limited flexibility.
  • Strategies to eliminate constraints, which included working with equipment suppliers, material suppliers and employees to develop unique solutions for maximum flexibility.
  • Standardizing the manufacturing solution through common equipment selections, which further improves assembly process flexibility.
  • Development of simple tools that ensure rapid exchange of real-time information.

Chris Munroe is director of engineering at EPIC Technologies (epictech.com); This e-mail address is being protected from spambots. You need JavaScript enabled to view it . His column appears bimonthly.

 

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