Kiln roller misalignment Banding
Is there any reason for circumferential marks on tire and rollers? A ridge on the kiln tire and matching grooves on both rollers as shown on the above sketch continue around the whole circumference in the middle of their widths. Would you please describe a cause for this? WeAli T. writes;
guessed the reason may be foreign particles but it seems if that was the case then we should see them only on one roller not both of them.
PKS KD reply:
The most likely cause is simple roller mis-alignment. Banding, that is ridges and grooves, develop on the rolling surfaces when the roller skew is aggressive. Aggressive skew causes the metal on the surfaces to flow. This can be verified by wiping the surface of the roller from left to right and then right to left using a cotton rag. When aggressive skew is present the surface will be
noticeably rougher in one direction vs. the other.
With reference to the illustration below, if one roller is pushing hard uphill and the opposite one is pushing hard downhill the metal on the tire surface is pushed to the center. This will cause a build up in the center of the tire, a ridge, which is then imprinted on the rollers.
To correct this problem both rollers and tires need to be ground smooth and then the rollers need
to be adjusted so that they are parallel and skewed very lightly. A very light skew means a bearing move in the order of 0.1 to 0.2 mm off the roller float position.
Posted by Walter Gebhart