HST Supports the Pacific Rim

December 18th, 2012

November was a busy month with HST visiting loyal customers in Thailand and Taiwan. We teamed up with NSK Precision Bearings to provide all day seminars designed to help our customers get the maximum life from their spindles. In between seminars customers examined displays and videos designed to demonstrate the proper care and feeding of precision bearings and CNC spindles.

During Break, HST General
Manager explains some
best practices for spindle
maintenance.		 Mr. Takuya Okamoto explains
proper care of NSK Bearings		 HST Presentation in
conjunction with NSK and PTC

Thai manufacturing has shown incredible resilience. Less than a year ago many factories were knee deep in water. Today everything is humming along at full pace. In attendance were representatives from many large manufacturing firms and especially the automotive line. Some recognizable names included Toyota, Nissan, GM, JTETK, GKN Drive Line, Aisin, as well as dozens of others.

In the morning several representatives from NSK presented information on how to specify and care for supper precision spindle bearings. After lunch HST took the stage and explained many of the procedures that go into the repair of a super precision spindle. Additionally we provided many helpful tips and methods that can help extend the life of a high performance CNC spindle.

Wafer dicing machines. Taiwan’s High Speed Rail Breakfast in Thailand isn’t
what you’d find at McDonald’s.
Sautéed squid with celery and
baby octopus in spicy red sauce.

HST has been repairing spindles in Pacific Rim countries for many years and we enjoy a good reputation in many nations. This presentation was an opportunity to help our customers extend the life of their spindles. The response was excellent and we were able to field many questions during breaks and after the presentation.

For the rest of the week we visited customers and reviewed processes. Besides large industrial spindles HST also repairs ultra-precision wafer dicing spindles.

After 10 days in Thailand it was off to Taiwan. Most of our customers there are associated with the semi-conductor industry. Taiwan’s industries are along the west coast. In 2007 Taiwan opened their high speed rail service between Taipei and Kaohsiung; a distance a little less than Boston to New York. At 186 MPH the train makes the trip in about 90 minutes.

When I first visited these countries back in the mid-90s I remember struggling using a payphone to make a call back to the states. In 2012 my wife dialed just my 7 digit local cell number and reached me in seconds as I was tearing across the Taiwan countryside at 186 MPH. Technology is moving fast. That is why HST continually updates their skill sets.

If your company would like us to present some ways to get more life out of your spindles don’t hesitate to contact us. We’ll go to the ends of the earth to help our customers.

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Franz Kessler / DMG 80-H Spindle Repair

November 7th, 2012

INTIAL OBSERVATIONS: This spindle came in with an internal leak and the drawbar seat was very worn and pitted. The pitting was preventing the drawbar seals from keeping the coolant out of the spindle, resulting with an E-1 alarm (wet encoder).

Franz Kessler Spindle as received. Precision Lubrication on a
Franz Kessler Bearing

The lube within most of the bearings was washed with coolant. A fully loaded roller bearing operating at its nominally rated speed with no lubrication will fail immediately.

CAUSE OF FAILURE: Run out of the spindle measured at that the taper ID and some minor pitting was observed. This surface required a Kiss Grind only. The four bearings in the front of the assembly were completely washed with coolant and particulate contamination, Fretting corrosion observed on both motor bearings. The most common cause of spindle failure that we encounter is a result of contamination. This shouldn’t be surprising. High speed spindles are particularly susceptible to contamination. The through tool coolant ID of the drawbar was severely corroded and required repair. The Drawbar springs were found intact but were replaced with new. The gripper assembly was in good overall condition and did not require replacement at that time.

One bearing fit so loose within the housing that the outer race was spinning. Another bearing showed strong indications of a misalignment within the housing bore, both housing bores where two different bearings seat require Grind-Plate-Grind to specification. The four bearings in the front of the assembly were completely washed with coolant and particulate contamination. Fretting corrosion observed on both motor bearings. A different bearing fit so loose within the housing that the outer race was spinning. The last bearing showed strong indications of a misalignment within the housing bore.

FINAL RESULTS: Our GPG process restored the taper to better than 90% contact an <1µm run out. The spindle received a comprehensive repair using only with top name brand Super Precision spindle bearings.

If you have a Franz Kessler DMG 80-H spindle that you would like to have running like factory new, HST can do that for you without charging factory new prices.

Franz Kessler Bearings
were washed and contaminated		 Franz Kessler spindle with poor
bearing fit caused misalignment
needs GPG.		 Illustrating bearing contamination
in a Franz Kessler Spindle.

Our stringent acceptance testing proved that the spindle performed like OEM factory new when it shipped.

At HST every detail counts with your spindle repair.

Your Spindle leaves here not only running like new but also looking like new!

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How long will a roller bearing last in the absence of lubrication?

August 20th, 2012

Tom M. a maintenance supervisor at GSO &M sent us the above question.

The short answer to this question is not very long at all. In fact, a fully loaded roller bearing operating at its nominally rated speed with no lubrication will fail immediately. This is true for any rolling element bearing properly installed and loaded. We won’t ask how an installed bearing came to have no lubrication.

Please let me explain a little of why the bearing will fail without lubrication and hence the importance of proper lubrication. Obviously a roller bearing consists of two races an inner and an outer with rolling elements (rollers) in between. The distance the roller rolls on the outer race is longer than the distance the roller has to roll on the inner race. For that reason the rolling element must slip somewhat on one or both of the races to compensate for the difference.

The lubrication provides a film on which the rolling elements can slip. The steel on steel coefficient of friction is very high so without the lubrication film the friction between the steel roller and the steel race is so high that it can cause the steel to gall or tear. This can happen immediately.

Bearing ratings (speed, load) and preload settings are affected by the type of lubricant and the method of lubrication. Grease lubricated bearings normally run slower and handle higher loads. Oil mist or oil injection bearings run at higher speeds. Exceeding the load rating can have a similar effect as no lubrication. In a high load situation the rolling element can pierce the lubricant film and generate a metal to metal contact and cause the race to tear.

Another factor that can result in a similar type of failure is water contamination. A minute amount of water can displace the oil film in places on the race. Where that happens, the rolling element will make contact with the race with the resultant tear or galling effect.

These two photos show different modes of failure. However, in both photos race deformation is evident.

Excessive Load Lubriction Failure

If you have a question please do not hesitate ask us or if you have a helpful comment we’d love to hear it.

Please visit our FAQ page to see some of the more frequently asked questions.

 

 

 

 

 

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Mazak VTC 16 Spindle Repair

August 13th, 2012

At High Speed Technologies, Inc. we repair Mazak VTC 16 Spindles to original factory condition. Our repairs come with a one year warranty.

The Mazak VTC series spindles employ a robust design in a relatively small package. Large diameter bearings and long center spacers make for a stout spindle.

At HST we really like this spindle; straight forward and solid. We have many Mazak VTC 16 spindle repairs under our belt. If you have a Mazak VTC series spindle that you would like to have running like factory new, HST can do that for you without charging factory new prices.

The Mazak VTC 16 is a robust spindle

This spindle came to us seized with a catastrophic bearing failure and a dinged up taper ID.

Mazak VTC 16 Taper Before and After

Our GPG process restored the taper to better than 90% contact an <1µm run out. The spindle received a comprehensive repair using only with top name brand Super Precision spindle bearings.

Our stringent acceptance testing proved that the spindle performed like factory new when it shipped.

Your Mazak VTC 16 spindle will receive a fresh coat of paint so it will look as good as it preforms. People treat good looking components better.

This Mazak VTC 16 is ready
for inspection		 Mazak VTC 16 coming out of
the paint booth

At HST every detail counts with your spindle repair.

 

 

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Mazak VTC 20 Spindle Repair

July 27th, 2012

At High Speed Technologies, Inc. we repair Mazak VTC Spindles to original factory condition. Our repairs come with a one year warranty. This spindle was sent to us because of vibration and poor part finish. After our comprehensive repair the spindle performed like new.

Our inspection revealed 8 micron run out at the taper and a failed rear bearing.

Mazak VTC 20 Spindle Before and After Repair

It was evident that the taper ID was damaged and needed our GPG process. So that was started right away. All of the bearings were replaced with top name brand Super Precision spindle bearings.

All of our comprehensive spindle repairs include new seals. If the spindle has a drawbar the actuator is rebuilt with new springs and tested for proper pull force.

Pitted and Damaged Taper
on a Mazak Spindle.		 Mazak Taper after our GPG repair. Vibration Testing a Mazak VTC
20 Spindle.

If your Mazak VTC spindle needs repair call us. We’re Mazak Spindle repair experts.

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Mori Seiki NH 5000 Spindle Repair

July 27th, 2012

At High Speed Technologies, Inc. we repair Mori Seiki NH 5000 Spindles to original factory condition. Our repairs come with a one year warranty.

This spindle was sent to us because the front bearings were damaged from contamination. Our comprehensive evaluation showed that the spindle had excessive run out at the taper ID. The contact area on the taper was damaged and tool contact was well below acceptable limits.


Mori Seiki NH 5000 Spindle ready to ship

As we dismantled the spindle we found that contamination had migrated past the front seal and migrated into bearings #1 and # 2. This link speaks to some of the problems associated with high speed spindle seals.


# 2 Bearing badly contaminated

Mori Seiki uses a special quad set of bearings with tolerances specific to this model spindle; so not just any bearings will work.

The taper ID was damaged bad enough to require our GPG process to restore it. This machine had a Big Plus taper. HST is a certified Big Plus repair house. To comply with Big Plus specifications HST must grind to extraordinarily tight tolerances.

We always ship the Mazak NH series spindles with a new Super Precision rear roller bearing. With this series spindles the rear roller must be installed on-site by a qualified technician.

If you have a problem with a Mori Seiki spindle contact us. We’re experts on Mori Seiki spindle repairs.

Mori NH 5000 parts cleaned and ready
for inspection.		 Mori Seiki NH 5000 Big Plus
Taper.		 HST is Big Plus Certified.

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Mori Seiki NH 4000 Spindle Repair

July 27th, 2012

At High Speed Technologies, Inc. we repair Mori Seiki NH 4000 Spindles to original factory condition. Our repairs come with a one year warranty.


Mori Seiki NH 4000 Spindle.

This spindle was sent to us because of a drawbar malfunction and when we turned it by hand there were definite indication of bearing damage.


Thick Residual Grease Not Recommended

During our initial inspection it became apparent that the spindle had been recently repaired by another shop. This was evident by the fact that there was still heavy residual grease in the bearings. (NH 4000 spindles are oil lubricated) The Mori Seiki NH 4000 spindle is very fast, 14000 RPMs. Only a very thin film of grease should be applied during assembly if any. Grease can saturate with oil causing heat buildup. HST does not use grease with oil lubricated bearings and we do not recommend its’ use.


Multiple Tracks.

As we went through the spindle we found some other issues with the drawbar. The front bearings had Brinelling indicating a crash at some point. The balls displayed multiple track lines suggestive of unloading that is often a sign of insufficient preload.


Taper Ground Below Gage.

With the Mori Seiki NH series spindles the rear housing stays with the machine. This requires that the rear roller is installed by a qualified service technician. We always provide the correct ABEC 7 Super Precision roller bearing along with the repair.

Mori Seiki spindles are very fast. Because of their high speed the Mori engineers use oil mist jets that deliver the correct amount of lubricant directly to the bearings. To achieve this, all of the minute orifices and passages must be carefully cleaned and properly installed. At HST we’re experts at repairing Mori Seiki spindles.

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OKK Spindle Repair

July 23rd, 2012

Damaged OKK spindle Shaft

At High Speed Technologies, Inc. we repair OKK Spindles to original factory performance with a full warranty. We have 26 years of experience repairing spindles. So if your OKK spindle requires rebuilding, you can trust HST to restore it to like new. And our repairs come with a like new one year warranty.


Setting up an OKK spindle shaft for 1st grind on our Kellenberger Grinder

Our customer sent in this OKK spindle after it was crashed. Our evaluation revealed that the spindle suffered damage to the shaft. We measured more than 20 µm run out on the taper before breakdown. It was determined that the damage was repairable using our GPG process. After our repair was completed assembled run out was 2µm.

 


Trim balancing an OKK spindle Shaft

Anytime a shaft or rotating component is repaired it is possible for the mass distribution to change and this will affect the balance.


Perfectly balanced OKK Spindle Shaft

When we repair a shaft for an OKK spindle or any other brand there are several steps to guarantee a perfect balance. The first step is to get rotating components on our Schenck dynamic balancing machine. This procedure will help us dial-in the core rotating components.

Once the spindle is assembled it will still require trim balancing at high speed. OKK spindles provide a rotating balancing disc with tapped holes. High speed trim balancing is accomplished by inserting different length set screw into the appropriate position.

 

 


OKK Machining Copy Center

Contaminated bearings out of an OKK Spindle

Because of the high shaft rotation speeds most machine tool spindles use non-contact seals. These come in different forms and configurations and have various levels of success keeping out contamination. (click here for more info on labyrinth seals). Like most high speed spindles the OKK units use a non-contact labyrinth seal.


 

 


Contamination behind the front cover of an OKK Spindle

High speed machining has two opposing conditions, non-contact shaft seals, high pressure coolant inundating the work piece. Coolant fluid can ricochet off of the work piece and impinge on the labyrinth seal. After time the coolant with cutting debris and any other contaminates penetrate the seal area.


Only top name brand bearings are used to repair your OKK Spindle

Tool coolant should never be directed at the spindle shaft. Additionally we recommend leaving the spindle running for several minutes after your last cut to allow the shaft to sling off residual tool coolant. Unfortunately, each time your spindle does a tool change it stops for a few moments and allows tool coolant to “wick” into the front seal area.

The group of four photos on the left show how severe contamination migrated past the front labyrinth seal on this OKK spindle. Once past the front cover there is nothing preventing the contamination from reaching the bearings.

Of course once the contamination reaches the bearings the spindle life is shortened.


OKK Spindle repaired to “Like New” condition.

And when it comes to replacing bearings in your OKK spindle, we only use top name brand ABEC 7 Super Precision spindle bearings purchased from authorized dealers. So you will only get the best. And because we only purchase from authorized distributors you never have to worry about counterfeit bearings.

Prior to assembly all parts are thoroughly cleaned, degreased and prepped for assembly. Spacers are ground and lapped to micron tolerances to provide the perfect preload for maximum bearing life. We replace all seals and o-rings as well as drawbar springs.

After OKK spindle repair is complete it must pass exhaustive testing. Run-out, drawbar tension and vibration are some of the test that your spindle must pass before we ship it.

At High Speed Technologies, Inc. we have all of the equipment and expertise required to repair you OKK spindle to like new condition. Not only will your OKK spindle look like new it will run like new. And we back up our spindle repairs with an OEM equivalent warranty.

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