Case 004: Dumbbell Connection Clearance Risk
About six months after delivery, the customer reported movement, noise and signs of loosening at the dumbbell connection point. The products had passed inspection before shipment.
A problem that did not show up during final inspection.
Because the products had passed inspection before shipment, the issue was not something obvious that had simply been missed. OneSC needed to understand what was happening inside the connection after repeated use.
Inspect the finished product again
- Checks current appearance and function
- May miss a risk that develops after repeated use
- Does not explain why movement appears inside the connection
Go back to the fit
- Measure the shaft and bore dimensions
- Review the actual assembly clearance
- Discuss the fit with the production and assembly team
We went back to the fit between the shaft and bore.
The next production run used the improved assembly method.
The key fit dimensions and assembly condition were checked before shipment. That shipment has now been in the market for approximately 10 months, and so far the customer has not reported the same movement, noise or loosening problem again.
Start from field use
The risk only became visible after months of actual use.
Measure the fit
The real issue was a small tolerance and assembly condition inside the product.
Change the process
The shim was added to the production method, not just used as a one-time repair.
Reduce repeat risk
The purpose was to make the same problem less likely to come back.
Some quality problems cannot be controlled by final inspection alone.
OneSC's job is to understand why a problem happened and make sure the same problem is less likely to come back.Do you have products that pass inspection but fail in the field?
Start with one critical process. OneSC can review the factory-side cause and help close the same risk before the next shipment.