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Poka-Yoke Solution for Oil Pump Housing


Two different oil pump models were assembled at the same manufacturing location. Due to design constraints, the manufacturer was unable to standardize on a single Solid Pin, and therefore they used two unique Solid Pins - one for each assembly. The Solid Pins were the same length, but had different diameters. Due to the similarities, the operators would sometimes install the wrong Solid Pin into an oil pump.

When a Solid Pin with the smaller diameter was installed into an oil pump with the larger hole, it would fall out of the assembly and be detected by vision sensing equipment. However, when a Solid Pin with the larger diameter was installed into an oil pump with the smaller hole, it would cause permanent damage to the host and go undetected by the vision sensing equipment. This introduced a risk of field failures and product recalls.

The customer enlisted SPIROL’s help to improve daily production rates and mitigate the risk of product defects. A poka-yoke solution was needed and color coding was not an option for this application.


SPIROL Engineering recommended adding a divot to the head of the Solid Pin with the smaller diameter. This allowed operators to visually differentiate between the two pins. Additionally, the vision sensing equipment was updated to detect whether the pin had a divot to ensure that improper installations would be flagged.

Ideally, the automotive manufacturer would have standardized on the same Solid Pin across both oil pump assemblies when they were in the initial design stage. Fortunately, they involved SPIROL early enough to provide a cost effective solution before they experienced any field failures or recalls. As experts in cold headed Solid Pins and Pin Installation Equipment, SPIROL designed a unique feature that had minimal impact to pin cost and improved the ease-of-assembly. The divot was implemented by using the previous manufacturing process with a simple change of tool dies.

This poka-yoke solution eliminated the risk of field failures and product defects caused by installing the wrong pin into the oil pump assembly!

Complimentary Applications Engineering Support: SPIROL Engineers will review your application needs and work with your design team to recommend the best solution.