We have received some rods that have fine dark dust on them and will need to provide supplier with workmanship standard for their rods.
I would advise having production personnel who put smooth rods on assemblies/sub assemblies do a quick wipe down with the blue shop paper towels until we can get the problem is resolved on the supplier's end. A number of people have told me they think that it may be contributing to binding, as a pretty significant amount of dust comes off the smooth rods when they are wiped down. Fine dark brown/black dust is primarily how I would describe what I see on the paper towels after wiping down smooth rods.
Smooth rods used for vertical and horizontal motion on the Mini and various TAZ printers such as the HD-RD0018, HD-RD0035, HD-RD0047, HD-RD0061, HD-RD0066, HD-RD0070 will need to be wiped down prior to being put on assemblies. Calibrators have told me that this used to be done by people who do pre-finals assemblies, but that the process seems to have lapsed in being maintained among our current pre-finals personnel.
The specifications for our smooth rods currently have a note saying that they need to be "free of sharp edges and debris". The definition of "debris" as it relates to what we are seeing should be clarified with suppliers, as I think that it is implied that dust of any sort is not desirable, but maybe the term"debris" isn't communicating that clearly enough. To date, I don't believe we have rejected any shipments for having dust, and it would be better give them a warning on this issue and clarify what we want to give them a chance to improve prior to sending parts back that are needed for production currently.
Except for the darkest accumulations seen in these pictures, the dust isn't readily visible for the most part. Wiping down all sides twice has the effect of lightening ring patterns, cleaning some of the darker spots, as well as giving the rod a brighter general appearance.
I talked with @robert and asked him to include any time he cleans the rods to include it on their defect tracking sheet so I can get a better idea of how often this is really mattering in calibration. My worry to is that dust is going to be building up on these parts while they are sitting on our shelf out in production besides just coming from the supplier.
I think the wipe down should occur prior to finals, at the point they are taken out of the box, because as soon as the bearings start moving on the rods, those bearings become contaminated. I'm less concerned about the light dust that is in the building than what already on the rods when they are received.
Until we can get a workmanship standard with more clarity to vendor, I think we can implement a process to wipe down each rod as it comes out of the box to be installed/used just like we used to do.