Heller MCH250 Spindle Upgrade

Our customer owned several Heller Cat 50 taper horizontal CNC milling machines set up for cutting aluminium at high speeds. They received an order to mill cast parts and found the spindles were failing frequently during the production run. The OEM gave them the option of purchasing new spindles with a high price and long lead time. We sat with them and reviewed their process and the spindle issues they were having.

1) The feed rates had to be reduced to get the spindles to last more than a month. This made the cycle times far to long to remain profitable making the part.
2) When we evaluated the spindles we found the retention force on the tool holder was significantly lower than it should be. We found the tool was being pulled out of the taper during cuts. This caused taper damage (bell-mouthing and uneven wear). This also caused damage to the gripper fingers adding to the retention force issues.
3) The taper damage caused tool runout which in turn shortened the life of the tooling. It also caused chatter on the part.
Northland Tool redesigned the spindles drawbar system and brought the drawbar force from 2200 pounds to 4800 pounds. We redesigned the bearing complement to increase the load capabilities in the axial and radial positions.
It has been 3 years since the first conversion of many was done. We have not experienced a single failure since we started repairing the Heller spindles. Cost savings was shown in spindle repair expenditures, tooling life, tool holder life, gripper replacement costs, improved cycle times and machine downtime.



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I really didn’t expect this; You guys really pulled it off! My many thanks to Sandy, Louis and your outstanding crew for helping us get back into production.

Dan Eaton, Taylor Metalworks

Lou all in all everything is running good. Just had a call from Sandy just the other day, its funny great minds think alike. 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 Debbie 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