Hello,
I have an application with a simple journal bearing and I'm using Acetal for the shaft and Noryl for the bearing. For the shaft I have parts in both Celcon M90 and a Lubricomp grade that uses a silicone additive. There is only a small torque applied to the shaft so minimizing friction is important. Imagine trying to turn a large water wheel using only a garden hose, only on a much smaller scale and using air.
My design works initially, but after several cleaning cycles the performance drops. To clean the device, we use two methods: 15min soak in soap & water, or 5 min soak in a 1:50 bleach/water solution. The device is then rinsed in clean water and left to air dry. I should note that the two parts mentioned above remain assembled during cleaning.
I'm thinking the cleaning is changing the coefficient of friction between the two materials, or the acetal is absorbing water and creating more friction. The testing we've done has conflicting results. We've tried to measure the coefficient of friction between the two parts and noticed an increase after cleaning. On the other hand, parts that failed after a few cleaning cycles start to work again after drying for a few days.
Does anyone have any insight into what failure mode is occurring here?
Thanks in advance.
I have an application with a simple journal bearing and I'm using Acetal for the shaft and Noryl for the bearing. For the shaft I have parts in both Celcon M90 and a Lubricomp grade that uses a silicone additive. There is only a small torque applied to the shaft so minimizing friction is important. Imagine trying to turn a large water wheel using only a garden hose, only on a much smaller scale and using air.
My design works initially, but after several cleaning cycles the performance drops. To clean the device, we use two methods: 15min soak in soap & water, or 5 min soak in a 1:50 bleach/water solution. The device is then rinsed in clean water and left to air dry. I should note that the two parts mentioned above remain assembled during cleaning.
I'm thinking the cleaning is changing the coefficient of friction between the two materials, or the acetal is absorbing water and creating more friction. The testing we've done has conflicting results. We've tried to measure the coefficient of friction between the two parts and noticed an increase after cleaning. On the other hand, parts that failed after a few cleaning cycles start to work again after drying for a few days.
Does anyone have any insight into what failure mode is occurring here?
Thanks in advance.