newbreed
Plastic
- Joined
- Jun 10, 2019
- Location
- Wisconsin, USA
Hello everyone. First time posting here. Been using this site for some time, but finally made the leap to become a member. I'm hoping someone can help me with an issue were having at work. we have a Mazak VQC 30/50b vertical machining center. The machine is very inconsistent when it comes to tool changes. Some days(very rare) the tool change operation goes very smoothly and you wouldnt even guess the machine has any issues. But most days i have to reduce rapid and sloooowly bump the spindle towards the magazine. Which is costing untold amounts of money, in the form of time, due to the fact we primarily work with custom castings and most jobs have a few dozen tool changes throughout them. Also because it cannot be trusted i cant walk away from known programs and i have to be right there to "babysit" every. single. tool change. What happens is when the machine is positioned to perform tool changes the spindle will orient and start heading positive in y. When it reaches the magazine and comes into contact with the u shaped holders the spindle will torque(sometimes just a few degrees sometimes a full 90 degrees) if you feed hold it will bounce back to orientation. Some days it will only torque once and then you can bump(cycle start feed hold) smoothly into the tool holder. Some days every time you bump it in, even the smallest distance it will torque sideways. If left to complete the tool changes on its own it will torque out of position and slam the tool holder flange that has no slot for the dog(because its torques out of position) into the dog on the u shaped holder and crash and bend things up real good.(has happened) Initially i figured the u shaped holders that hold the tool holders in the magazine had to be skewed in some way causing excessive drag on one side of the tool holder flange and thus torquing the spindle in one direction of another. So i spent and entire day making sure every single u shaped holder was at the same level, was not skewed rotationally, and had the same gap between the ends of the u shape. It did absolutely nothing to help the cause. Therefore i'm fairly convinced the issue is in the spindle because it varies so much from day to day with zero changes being made to anything in the magazine area. on some days lets say i put back tool number 11 and it torques sideways throughout the tool change process a lot. The very next time i put that tool back(could even be 5 minutes later) it will have a totally different reaction. Additionally on the days the tool changes go well the spindle purrs and nothing sounds out of place. on the bad days you can tell right when the spindle turns on you'll have issues. you can hear something rattling in the spindle housing. not grinding at all and not rubbing at all. it almost sounds like someone took a single piece of gravel and threw it in there, and its just lightly bouncing around. its especially bad as the machine is building spindle speed, and heard decently while idling, but not heard during cuts. my thought was spindle bearing, but something tells me that wouldn't have anything to do with the machine being able to hold position after orientation. we are a small shop and we need every part we run to make the bottom line. that being said we dont want to shut down production on the machine and just start tearing into it with out any direction. any suggestions as to what could be causing this condition will be GREATLY appreciated. Thank you in advance!