I need help with a recurring problem - spirals on CG bars at our facility:
Our machine is a fives landis; the wheel size is 18x10x8. We almost always use a carbide tipped blade. We exclusively grind titanium bars roughly 1" and smaller. More recently we've begun to do sizes over 1". One thing we've observed is that the spirals do not happen on bars under 1", the problem happens with anything over that size (roughly)
A recent order of 1.25" diameter started using a carbide tipped blade. Half way through the first pass we switched to a brass blade - it made no difference. The first pass was made with sprials down the entire length of the bar (.003" removal). The second pass was intermittent spirals (.003" removal) Some bars came out clean and some had spots here and there. The final pass came out with spirals on two bars and the rest were fine.
During this order we ran the machine with the hood pulled back which allowed us to see the wheel. The spiral is taking place on the blade in front of the grinding wheel or right after it. It also moves around - the start location with jump inches either way and continue to mark the bar. I think that we're dealing with swarf that is getting wedged onto the blade and marking the bar.
I think this because after the brass blade wore in (Just happened to be on final pass) and there was not a gap on the grinding wheel side of the blade, no swarf could get into that location and cause a mark.
Has anyone else seen or heard of this problem?
How did you address it?
Our machine is a fives landis; the wheel size is 18x10x8. We almost always use a carbide tipped blade. We exclusively grind titanium bars roughly 1" and smaller. More recently we've begun to do sizes over 1". One thing we've observed is that the spirals do not happen on bars under 1", the problem happens with anything over that size (roughly)
A recent order of 1.25" diameter started using a carbide tipped blade. Half way through the first pass we switched to a brass blade - it made no difference. The first pass was made with sprials down the entire length of the bar (.003" removal). The second pass was intermittent spirals (.003" removal) Some bars came out clean and some had spots here and there. The final pass came out with spirals on two bars and the rest were fine.
During this order we ran the machine with the hood pulled back which allowed us to see the wheel. The spiral is taking place on the blade in front of the grinding wheel or right after it. It also moves around - the start location with jump inches either way and continue to mark the bar. I think that we're dealing with swarf that is getting wedged onto the blade and marking the bar.
I think this because after the brass blade wore in (Just happened to be on final pass) and there was not a gap on the grinding wheel side of the blade, no swarf could get into that location and cause a mark.
Has anyone else seen or heard of this problem?
How did you address it?