Mori Seiki SH-400 Spindle Repair

Mori Seiki SH-400 Spindle Repair

The Mori Seiki SH-400 is a CNC horizontal machining center.  It comes equipped with an oil mist lubricated and stator driven spindle capable of running up to 12,000 rpm.

Mori Seiki SH-400 Spindle Repair

CHALLENGE

Our customer was experiencing poor part finish and assumed correctly that the bearings had lost preload. They initially did not provide the drawbar assembly, front splash ring, nor the coolant assemblies. During our pre-quote evaluation we determined that the front quad set of bearings had failed from coolant contamination. The spindle was full of a sticky coolant residue and the inner races of the #1 and #2 bearings had spalling damage. The inner bearing spacer was corroded onto the spindle shaft but fortunately the bearing journals were not adversely affected. We observed pitting of the tooling taper ID with excessive runout of >6µ. We also noticed that the rear roller journal had been previously plated and ground slightly oversized, but not to a significant degree.

 

SOLUTION

We corrected the runout in the tooling taper by kiss grinding it on one of our Kellenberger universal grinding machines. We rebuilt the spindle with new bearings, o-rings, oil lines, ferrules, and assembly screws. We did not replace the coolant assemblies as the customer opted to replace them when the spindle was reinstalled. At our request, the customer supplied the drawbar assembly so we could balance the entire spindle. In this particular case, the customer asked us not to service the drawbar assembly as they felt it required no attention.

 

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.

DETAILED CAUSE OF FAILURE

  • Mori Seiki SH-400 Spindle Repair

    Fretting of the shaft from the front set of bearings.

  • Mori Seiki SH-400 Spindle Repair

    The ID raceway bearing damage.

  • Mori Seiki SH-400 Spindle Repair

    View of the taper as it arrived here.

  • Mori Seiki SH-400 Spindle Repair

    Taper damage shown after we polished it.

  • Mori Seiki SH-400 Spindle Repair

    Damaged rotary union ceramic disc.

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More Case Studies

Repair History - Here are examples of similar spindle repairs that may contain additional information that will help you. If you have additional questions, please contact us.

I really didn’t expect this; You guys really pulled it off! My many thanks to your outstanding crew for helping us get back into production.
— Dan Eaton, Taylor Metalworks
Its great not to be sending spindles out on a regular basis since you addressed my problems, but I know they will still be coming sooner or later. Never a problem when we get them back , run better than new. Hope everything is ok there. Please tell everyone there that we here appreciate everything that you do to keep us up and running and the quick turnarounds. Have delt with the rest now deal with the best. Have a great week end and up and coming holiday.
— Northland Customer
Thank you NTE just received spindle today and WOW ! what a nice job. Can’t wait to use it. Thank the Northland team for us for a job well done 
— Northland Customer
Both of the spindles that you repaired are on the machines and running great. We don’t have any spares for those grinders. We probably will not be purchasing a spare, as you have been able to turn around the repairs quickly and the price of a spare is cost prohibitive.
— Northland Customer
I am writing to thank Northland Tool for going the extra mile and saving my company from expensive machine downtime and expensive repairs. We have always sent our Chiron spindles for repair as a shaft with bearings. None of our previous rebuilders pointed out the bearing fretting or the fact that the housing in the machine was out of tolerance and causing premature failure to the spindles. After Northland fixed the housings the spindles have never sounded as good or run as well! Great job guys!
— Northland Customer
The detailed cause of failure reports and the expert technical advice that Northland Tool provides is bar none the best I have ever seen. We struggled to keep two of our large our milling spindles running for longer than 6 to 12 months. Northland Tools evaluation showed that the hydraulic nuts were not holding the assembly together causing premature spindle failure. We discussed this in detail and mutually decided to modify the spindle shaft to prevent this from occurring again. The first spindle we performed this on is still in the machine running like new after 3 years. That’s over three times the life of previous repairs and it’s still going strong. Easily over $40,000.00 of savings so far on that one machine and counting.
— Northland Customer
Your people go above and beyond the call of duty when it comes to spindle repair. When we had difficulty with the spindle installation and we were able to talk directly to a spindle technician that helped us troubleshoot the issue it helped us out of a bind. We have sent several spindles to you and have nothing but great things to say.
— Northland Customer
Thank you for your attention with my quick turn spindle repair. Your status updates allowed me to plan around machine downtime and I now know that you deliver on your promises. In the past other spindle repair vendors talked a big game and consistently failed to deliver. You not only delivered my spindle before the due date but you kept me informed throughout the entire repair process.
— Northland Customer
You performed a miracle with my BIG PLUS spindle. After crashing the spindle severely damaging the taper we found that a replacement spindle was not only cost prohibitive but had a long delivery. Your repair was a fraction of the cost of new and you never would know that the spindle was damaged to the extent it was.
— Northland Customer
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