How Do Your Manufacturing Errors Rank on the List?

Eleanor Roosevelt once said, “Learn from the mistakes of others. You can’t live long enough to make them all yourself.” Apparently, she never worked in a truss plant, where I think everyone will make them all at least once. But humor aside, let’s take a look at the following: a list of the top ten errors found in recent visits throughout the southeastern United States, measured in one quarter from plant inspection data.

The list of errors is ranked with the most commonly found as #1 and the least common as #10. The difference between #1 and #10 is significant because, thankfully, we rarely see #10 occur. For each item listed, I’ve included potential causes or remedies to consider. The cause list is not exhaustive, but it does include the most common causes.

Now, try reviewing your plant’s manufacturing system. How do you address each item?

1. Excessive Wane in Plated Area
        Improper lumber picking
        Culling not utilized at the table
        Inappropriate use
        Plate upsizing not used to an advantage
        Lack of training
2. Missing Connector Plates
        Mis-adjustment of gantry tables
        Improper plate setting
        Poor inspection procedures
3. Improper Plate Embedment
        Broken finish roller
        Broken floor truss machine
        Improper procedures to verify embedment
4. Member to Member Gaps
        Rotation of lumber in feed conveyor using component saws
        Poor building techniques
        Lack of understanding of floating chase concept
5. Incorrect Plate Sizes Used
        Poor training
        Plates not prepicked
        Table information not available to all builders
6. Plates Not in Proper Position
        Poor placement caused by lack of information
        Lack of guidance and supervision
        Misunderstanding design drawings
        Introduction of non-standard plate placement situations
7. Truss Profiles Vary Truss to Truss
        Slack in jigging
        Adjustments made as trusses are built
        Variations in lumber cutting
8. Poorly Marked Trusses Cause Mis-application in Field
        Lack of truss tags
        Tags vary from design drawings
        Field installers do not read or follow design drawings
9. Incorrect Lumber Grades
        Mixed lumber bundles from the mill
        Poor material management
        Receiving issues do not address clear segregation measures
        Bunk lumber poorly marked
10. Repairs Not Made Correctly
         50% reduction when replating is not considered
         Repairing by removing connectors causes additional damage to truss
         Improper understanding as to what can be repaired

In summary, it’s important to acknowledge your plant’s errors so you can correct them. One has to ask of their workers the tough questions. Are you meeting the requirements? You have to create a plan to improve by making it harder to mess up. For each problem discovered, write a clear list of why this problem happened and why you don’t want to make this mistake again. Most importantly of all, problems don’t disappear immediately. It takes constant improvements.

Glenn Traylor is an independent consultant with almost four decades of experience in the structural building components industry. While he is a TPI 3^rd Party In-Plant Quality Assurance Authorized Agent covering the Southeastern United States and performs 3^rd party safety auditor services, these articles represent his personal views, knowledge, and experience. Glenn serves as a trainer-evaluator-auditor covering sales, design, PM, QA, customer service, and production elements of the truss industry. He also provides project management specifically pertaining to structural building components, including on-site inspections and ANSI/TPI 1 compliance assessments. Glenn provides new plant and retrofit designs, equipment evaluations, ROI, capacity analysis, and CPM analysis.