Root Cause Analysis and The Five Whys help cable manufacturer regain control of production cell

Root Cause Analysis and The Five Whys help cable manufacturer regain control of production cell

Daniel Penn Success Stories

When a product’s safety is everything, and one defect can mean critical failure with the customer, any error brings production to a halt. Without the right systems, procedures and training, stringent manufacturing requirements can also exact a high price on the company’s bottom line.

For a precision cable manufacturer, one glitch during the production of a thousand foot or longer cable results in a lost run and a scrap cable. More than 25% of the manufacturer’s lost run scrap material was coming from just one of its production cells. Material, labor and productivity losses were piling up with every lost run. Daniel Penn Associates helped their team apply root cause analysis and apply The Five Whys to develop a systemic improvement plan. The long-term goal: Reduce lost runs and scrap for the cell by 50%.

Begin with the data

Supported by DPA senior consultant Mike Beauregard, the company’s Kaizen team analyzed lost run data to look for potential root causes, develop an action plan to address those causes, and recommend systems and training to support improvements.

They discovered that over an eight-month period, the production cell averaged four lost runs per month and more than 280,000 lost feet of cable product.

The team analyzed lost run data to look for potential root cause sources. No correlations in the data could be found. They then brainstormed potential causes of lost runs by process equipment, identifying more than 50 causes and potential causes.

Cause & Effect and The Five Whys

Using Cause & Effects Diagrams and The Five Whys among other RCA tools, the team bored down into the process to look for root causes. Once root causes were identified, the team identified 74 potential improvements that could eliminate or minimize lost runs.

The team identified systemic issues that were contributing to lost runs and scrap. They referred production cell items, approaches to training and accountability issues to company management.

The team also examined and addressed specific causes for the cell’s lost runs. They found that the production cell’s process book lacked critical procedures and set-up documents; there were no documents for training new operators or for seasoned operators to refer to.

Lost run diagram

Mistake-proofing the process

Once all systemic and specific root causes were identified, the team began to work on solutions.  They re-wrote the cell’s start-up and shutdown procedures. They completed a start-up checklist. They completed a One-Point Lesson for the incoming cable strip. They eliminated an adjustment on the cell’s cross-welder to mistake-proof that process. The cell was labeled with the start-up and shutdown sequence matching the procedures. Action plans were developed for the remaining planned activities, including retraining.

The team’s action plans addressed root causes for 32 (78%) of the production cell’s 41 lost runs. If the cell is rebuilt, all 41 causes would be addressed. Improvements to the reels and the tip line for incoming coil product would eliminate nine sources of lost runs all at once.

Development of work instructions, set-up checklists and set-up sheets – along with the sequencing of the line – will eliminate up to 22 potential causes once they are in place and the operators are trained and/or retrained.


During an audit held 90 days after the Kaizen event, the company reported that during the past three months, it had lost only two runs, an 83% reduction compared with its initial four lost runs per month baseline.

Applying successful actions across the facility

Management anticipates that with fewer lost runs and rework, more time will be available on this cell to produce more products. Once all possible improvements have been implemented and tested, the company’s management anticipates that changes made in this cell could be applied to other cells that make similar products.

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