Mitsubishi LXP
Ballscrew Guys have extensive experience field servicing the Mitsubishi LXP CNC laser line. The accuracy of the dual X-Axis and the single Y-Axis on a typical LXP can be restored in one production shift.
The Mitsubishi LXP 2512 (4x8) and LXP 3015 (5x10) Lasers are one of the most pleasant machines to service. They have twin X-Axis ball screws, one on either side. These screws are typically quality Japanese NSK screws with all steel components. These work as a fixed screw with the ball screw shaft locked in place on either end of the axis stroke and ball nut spinning inside of a rotation bearing.
Here we are pulling back the covers and starting to clean the dual X-Axis Ball Screws and Linear Way Guide systems. The most important factors in keeping the LXP motion system running smooth over the years is making sure that all protective covers are intact and properly installed. The more the bearing systems under the covers are kept cleaned and lubricated, the longer they will last.
The main issue with the LXP X-Axis from an accuracy standpoint is a lack of lubrication delivery system. The ball screw assembly is greased upon manufacture, then installed into your machine never receiving additional lube in its lifetime unless someone opens it up for refurbishment. The secondary issue for lost accuracy are the tears and holes in the bellows covers seen after years of work (and abuse). Sometimes they are destroyed completely and never replaced. Either way, lack of protective covers allows fine debris from the cutting process to settle on the screw. The debris eventually migrates through the seals, wearing down the ball bearings inside the ball screw.
One of the key issues technicians servicing any dual X-Axis CNC Machining system is being able to service them where the sides stay in alignment. It is one thing to refurbish a ball screw to tighten it up, removing deadband and backlash. This is not helpful however if the dual X-Axis servos are not in alignment. We have some tricks to prevent this from happening.... most of the the time. The machine establishes axis home once it moves back and trips the motion sensors. However, there are times where this is not enough. In these cases, “Grid Shift” in the controller is required to bring the axes into synchronization. While we will have to break out the manuals and calculate a new parameter value and find which pulse of the encoder has been skipped or jumped, then enter that value into the controller to align the axis where it needs to be. With a little luck, your Mitsubishi controller will be set to display in English. However, we have done this in Japanese.