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Looking for a new CNC cylindrical grinder

Joined
Nov 15, 2005
Location
Illinois
So far we reached out to several manufacturers and one question I have a hard time getting a clear answer. Some grinders have hydrostatic wheel bearings while other units have ball bearings. I've always been a big fan of hydrostatic but actually would I know the difference? Does anyone have any experience between the two. What manufacturers have a main branch in Illinois? So far I am considering Toyoda, Shigiya, Okamoto, and Hardinge group. They all have a large presence in IL. Am I missing someone.

I think as far as options I am looking into shoulder probing and Marposs in process measuring system. Any other options that can help?
 
Both Kellenberger and Struder are nice.
One of these in your competitor's shop around here and it works fairly well grinding holders.
I like the idea of hydro bearings, have some in a few machines but I don't think you will see any difference.
Ball ones seem a tad stiffer and allow you to pour more power into them needing less sparkout time.
I would think the probing and a gap detection system would be a must have for your parts.
Be aware that the probing just kills your cycle time, you don't want to do this every cycle.
The spark gap system makes things run faster and saves wheels.

I should say that I'm making an off the cuff guess as to what this machine is gonna be doing.......
Bob
 
What are you doing with this machine? OD's only? OD and ID in one setup? Straight or angle wheel? What size machine are you looking for? I will tell you what I think (if it make any difference) when I know what you are doing.

Donovan
 
I will be using this only for od work. Taper grinding, straight shaft grinding, maybe some radius work. 5" od X 15" between centers is all I need. I will be bumping some shoulders, but only a few thou.
 
I would look at Okamoto and Toyoda. I would get the largest wheel you can afford. Okamoto Straight wheels might be only 14" OD. I would like that to be at least a 16" wheel. Toyoda GE4 would be a fine machine also and it has 16" left hand wheels if I remember correctly. PM me and I would be glad to call you and talk grinders with you. My family and I own a small grinding shop in Colorado and finding good grinding operators is hard to do. So we went the cnc route. I have bought 2 new cnc grinders. The first was a Danobat CNC and the Second was a Kellenberger Kel-Vista. I like the Kellenberger but I have had problems with it. Good Luck.

Donovan
 
As part of my job, I program, set up, run, and repair an older studer s31 universal.
It is a fantastically well built machine, however there are a few things I absolutely hate about it.

1 - The lube system is closed. This means, if you have a coolant leak ANYWHERE, it ends up moving through the entire hydraulic system. The hydraulic system is what lubricates the ways on this particular machine. Not good
2 - The raise - lower - rotation portion of the wheel head is prone to eating seals. If you use copious amounts of coolant (generally due to many different workpieces) and not have the "right coolant nozzles", you will see ingress of coolant at the rotation base.... this gets back into the lube system. Not good
3 - Studer used a "communicator" on this machine. Its essentially a translator between the PLC and the machine I\O. It sucks ass, and is about $15K to replace. Theres no sending to the local CNC electronics place (tried that)

Im sure the newer machines are superior, the money for a new studer is crazy. The picto-programming is very nice though, especially if doing different jobs all the time.
When the machine is happy, everyone is happy. When its angry... well, its Mr. Fixit time for me.
Support has been good, but like most MTB's if you needs parts, get ready to bend WAY over... IMO
 
MACDS, thanks for the Studer info. So far I am not considering them. I dont think they have enough presence in my area and that is a big deal for me. I have looked at Okomato, Toyoda, Shigiya, and Jones and Shipman. All are nice machines and each have their strong points.
 
Just another point of data. We have 2 CNC Studers (1999 S40 and brand new S41), 1 CNC Danobat (roughly 8-9ft between centers), 1 CNC Usach 300 ODL (about 12ft between centers), and a manual SMTW.

I love the Studers, they're easy to program, and run like a top. Our cycle times are great, but that all depends on how well controlled the previous operations are. We grind OD's and ID's, tapers, and recently contour grinding. Materials in a wide variety: soft steel, hard steel, carbide tungsten coating, other various hard coatings, aluminum, stainless, Inconel, stellite, waspolloy... We're a job shop, so high volume is not our game. We do not have in-process gaging, and don't need it for our lot sizes. We use digital snap gages with wireless transmission on most everything that is a straight OD.

There are a lot of Studers in US, I believe Honda had just ordered 40+ a couple years ago. Around the same time we ordered our new one. Our S41 has 2 OD spindles, both 20" wheels, and an ID spindle. Both OD spindles have integral automatic wheel balancing and touch-detect. Although, I don't use the touch detect for anything other than monitoring. Our process is good enough that I don't spend much time at all grinding air. My stock allowance is usually about .001"-.002" on diameter above the finish turn operation max material condition, so using the touch/gap detect wouldn't save much. Our lot sizes typically are from 5 to 10 pcs.

The only complaint I have about the new Studer is there are too many prox switches on our accessories! I can't put in the steady rest or tailstock without plugging a bunch of stuff in, and then having to tell the setup in the control that it is connected before I can do anything with it. Just adds a few minutes to every setup, where the old Studer had none of that. At the same time, the new Studer rapids at 800ipm vs 200ipm on the old one. It's much faster in all aspects. Probing is extremely quick, we probe often since we grind lengths often. Every machine has their quirks, and our Studers are MUCH favored over the other brands we own due to ease of running, repeatability, and overall ability. Studer is also very good with their customer service.

For what it's worth, on a forged steel shaft, we can grind OD's and ID's in the same setup, and average # of OD features is around 5-6, tolerances down to +/- .00015" on OD and ID, and we do a fair amount of ID taper grinding, with a +/- .001" on length between gage dia's, and an overall length from a gage dia to an OD shoulder, and we can grind all the OD's to size and ID to size in about 45-55 minutes (includes part change). This generic part would be about 3ft long, and 3-6" dia OD, with .0002" total runout on most features, and .0001" circularity on others.

Hope this helps.
Any Studer or process related questions, I'll be happy to answer to the best of my ability.
 
Thanks guys for all the great info and tips. We have decided to go with Toyoda. The Select G-100. I must say it was a very tough decision. All dealers were willing to bend over backwards and really gave some amazing offers and prices. We didn't go with the cheapest but also didnt go with the priciest.

The Toyoda G-100 has a wheelhead that can manually rotated to be an angle grinder or straight wheel grinder. We plan on grinding a lot of shoulders so this in a nice feature. I also like the fact that the spindle is hydrostatic and the meachine is really beefy, over 11,000 lbs. 40" between centers is overkill for us but we have some future plans that may require this length.

Shoulder probe is standard and all grinding software can with the machine. Other manufactuers make even taper grinding and taper plunge grinding an option.

I will be sure to post some pics and give some details on our experience with this machine.

As a side note I did take up Donovan on his offer and I called him. We spoke for a good 20 minutes and he is very knowledgeable. Its nice to get some real world info, sometimes machine tool salesman and engineers are in their own little bubble. Thank you again Donovan !! If you guys ever need some grinding I think he would be a great vendor to try out.
 
Toyoda spindle bearings

Hello:
Does the G-100 use the hydrostatic -hydrodynamic spindle bearing design or is this a full hydrostatic bearing?
The combination bearing uses a low pressure (300 psi) hydrostatic bearing for spindle spin up. When it is up to speed the spindle is primarily supported by the tilt shoe hydrodynamic bearing. The full hydrostatic bearing would be a 1000 Psi system. I am using a 15 year old reference to describe this. Things may have changed.

What design does the G-100 use for the guide ways? Hydrostatic, squeeze film with end of stroke oil pump, textured plastic inlay, preloaded roller bearing guides? The Toyoda web site does not say.

Robert
 
It is hydrostatic. The tech guy explained that once the pump is on the spindle lifts into position off of the bronze bearing and is always on a film of oil. It is so frictionless you can balance the wheel on the machine. All you need to do is remove the 3 drive belts so the friction from the motor doesn't put any drag on the spindle. Unlike my Shigiya that has a Hydrodynamic spindle, the spindle lifts into place after the shaft starts spinning. As long as you maintain the oil and filter the spindle has a virtually infinite lifespan.

The 2 guideways are flat and "v" and are hydrostatic. Hand scrapped cast iron.
 
Machine just came in. Picture of the head is shown without guarding. Drive belts go on the left and the grinding wheel goes on the right. It uses a 20" diameter wheel. Hopefully this machine will serve me well for many years to come. Now that I have the machine i've been looking at everything with a fine tooth comb. My first impression, rock solid. Everything looks very well build. Anything that moves is either in an oil bath or has a way for easy oiling. I can't wait to use the shoulder touch probe.





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Thats a fast delivery time too! Shoulder probe sounds useful in your line of work!
 
Yes they had the machine in stock, 20 miles north of me. So it was just a matter of having my finance company wire the deposit and set a time that was good for the riggers.

Shoulder probe will definantly help in locating proper gage line while grinding the taper. It will also help when grinding dual contact tool holders.
 








 
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