Physical inspection of the device yielded the following: " the components have been received in and have been inspected for all characteristics that can lead to screw head disassociation.To summarize, all critical features on the returned devices have been found to be within tolerance and all paperwork records indicate all batches were manufactured to the correct specifications.The screw (lower level part number 422-263) returned with the complaint is from batch 396886.The screw head diameter and shaft diameter measured at.2965"-.2968" (head diameter) and.1803" (shaft diameter).These measurements are well within tolerance.The ra value of the screw head cannot be accurately measured, as assembly and disassembly of the screw removes a substantial amount of surface roughness.However, the dhr for batch 396886 was looked up in papervision.Blasting personnel record the ra values on the first and last screw blasted in a batch.The dhr records show recorded values of 64 and 62 ra, which is right in the middle of the allowed tolerance.No issues were reported in assembly for this batch of screws, and no scrap was claimed on the production order.The core (part number 432-970) returned with the complaint came from one of two batches: 395261 or 399047.Since 44 cores from 399047 went into order 1396886, and only 6 cores from batch 395261 went into the order, the core returned for inspection most likely came from batch 399047.The core had to be disassembled from the yoke in order to inspect it.Because the core had been assembled and disassembled it could not be accurately inspected due to its substantial deformation.However, all inspection records indicate that both batches of cores were manufactured within tolerance.From investigations performed for capa 200029533 (capa created for streamline mis disassociation), it has been determined that the oal,.312" diameter, and core sphere diameter can greatly affect the likelihood of head disassociation.The dhr records indicate the oal on both batches were manufactured at around nominal.Additionally, the.312" dimension and core sphere diameter records indicate they were within tolerance.The recorded blast ra values for the batches are 49/54, 48/54, 53/48, and 50/21.All these recordings are well within the tolerance band.It's worth noting that this part number has been rev'd up recently to tighten the tolerances on the.312" diameter and oal to help decrease the likelihood of head disassociation in the field.Both of these batches were manufactured before the revision change, so they were not manufactured to the tightened tolerances.The yoke (part number 433-063, lower level part number 431-019) returned with the complaint came from batch 395665.Batch 395665 was made using lower level yokes from batch 398032.The yoke had to be disassembled from the core for proper inspection.From the investigation for capa 200029533, it has been determined that three features on the yoke have been shown to affect the likelihood of head disassociation.One of these features is the "shelf depth".The yoke returned for inspection measured at.3795"-.3802".Nominal for this feature is.380" with a profile tolerance of.006", so the returned yoke is well within tolerance.The "core housing diameter" is another feature known to affect head disassociation.The returned yoke measured at roughly.3805", which is well within spec as nominal for the feature is.380" with a.002" tolerance.The.318" diameter is the last feature known to affect head disassociation.This feature is inspected using gage pins.Nominal for the feature is.318" with a profile tolerance of.002".The returned part passed the gage pin requirement.It's worth noting that this part number has been rev'd up in the recent past, which tightened the tolerances of these three features.This batch of yokes was manufactured before the rev change, so they were not manufactured to the tightened tolerances.However, the returned part does not meet the requirements of the new revision on two of the features: the.380" shelf depth and the.380" core housing diameter.All paperwork for this batch of yokes shows that nothing out of the ordinary happened during production of this batch.All three returned components were found to be conforming to the requirements they were manufactured to." repeated inquiries to gather more information about this case have not resulted in any additional information beyond what is listed in this report at this time.
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