Four final details before purchase

Hello, forum

I work for a small screw machine parts manufacturer using all conventional and cam operated machinery. we're taking the leap soon and getting a CNC lathe.

Okuma Howa ACT-35 and Fanuc 18T controller. is that a good machine? we've compared to Haas and done some research and hired a local guy to consult on the soundness of the machine itself, so I guess my question is about availability of parts for the Okuma Howa.

Then again, how often am I going to need parts, just every time I wreck it right?

Is that a controller a newbie can learn easily, is that controller very powerful?

The machine specs say 20 horsepower motor for 30 minutes, 15 horsepower use. the drive is 35-3500 RPM. when cutting things like stainless 316 and such, will the motor have enough power to drive at low RPM? We'll be putting 4' lengths of 3" steel in this thing, and we're concerned about the surface feet per minute feeds/speeds bringing the RPM down to like 400. Should I find a torque curve for that motor before deciding on this machine? 15 horsepower on a 3" machine running bars seems a little light to me.. but I don't know, and I'm especially concerned that the variable frequency driven motor won't have much power at that low speed.

finally, does anyone have any opinions on Okuma Howa 1995 or know of any past instances of problems people had with them? How about that Fanuc 18T?

I would GREATLY appreciate any advice, and remain conversational about it if you give me a head's up. this is a family owned business and I have put alot of time into finding this machine already. I would sure like to make the right decision..

I'm not familiar with any of these machines, but all I can tell you of, a shop just like yours with screw machines, has taken the leap with" Gildemeister".

atetsade
I dont think I would worry to much about the Okuma machine. Nor would I worry about the controller. Okuma has been around for a good while and they make some fine machinery. Same for Fanuc. As far as the speed and power of the motor I think that the controller will take care of all of your worries. Consider how long the cycle time is compared to the twenty hp rating for thirty minutes. How long is the part cycle time? Remeber as you make the transition from a cam operated machine, I am thinking W&S chucker, to a CNC you will not be using large form tools anymore, you will be taking smaller cuts at a blinding surface speed. You will be amazed at the small amount of horsepower that this takes compared to a form tool.
Good Luck
Fred T

Well, now the Haas man has been by to tempt the boss with their fabled service.

Personally I am against the purchase of a new Haas SL-30. I don't hear enough good things about Haas lathes or Haas service, and I think buying anything new (whether discounted demo model or what) is missing out on the machine market that we have out there right now.

Okuma & Howa is a good machine, but what about parts & service? Any input appreciated!

Whatever the make of the machine, take the time to call service with the serial number and check into the service history and parts availability. Okuma has an excellent reputation but I have never dealt with them. One cnc manufacturer I know would not support used equipment until you bought a new one as well( guess which brand I will never buy again....) and I learned that after the sale. For what you are after you want a heavy big bore machine. Chances are low rpm torque won't be an issue if you buy a machine suited to the job in the first place. Okuma should be able to clue you in if this machine won't suit your purpose. If this is your first CNC I recomend finding someone to do a training session with you. The Okuma guys would rank first, GE Fanuc a close second. Note Fanuc is separate from GE Fanuc. GE Fanuc has better support services. All those guys are expensive but sometimes worth it. You really can't go far wrong with any machine running Fanuc drives and controls. Parts availability is usually 20 years or more.

Okuma & Howa is different from Okuma, Okuma makes alot of lathes from what I see. Okuma & Howa is a small Japanese company. www.okumahowa.com, I think they have like 500 employees?

Of course, those 500 are buddhist monks employed deep in the igneous hills of Japan and their machinery is known for amazing feats of strength through concentration.

HOWEVER, if this machine has been used to broach NASCAR transmission shafts and parts, it could be used up. (this is grapevine vintage information I'm privvy to)

Now I'm torqued because this 4,755 hour machine could well be used up. I was so happy a minute ago. >:

Okuma&Howa is imported thru KGKI America out of Chicago. There are over 5,000 machines in the U.S. and their service and support is highly regarded. They are owned 15% by Okuma and design machines for Okuma. They use fanuc controls in the U.S. and the OSP control in Japan.

It's an excellent machine tool, and I would take a 10,000 hour used Okuma&Howa over a brand new Haas....

Just my opinion.......

I heartily agree, mattei. When I called the Okuma&Howa service network in Chicago, I was surprised about their service. The guy who answered the phone was the guy who could answer my questions. They have 100% Okuma Howa parts stocked in Chicago, and he said if I had a problem today he could have a guy out to this central Wisconsin shop tomorrow morning.

He answered all of my questions and explained some things I didn't even know about. The machine is a great machine, it is offered at www.machinetools.com for a great price, but again I think it has been used primarily for broaching.

This is our first CNC, and while Haas is not the quality of Okuma Howa in most respects, it is guaranteed to work. new machines are pretty cheap right now too.

the 1995 Okuma & Howa 3" machine is 58% faster than a brand new Haas SL-30.

if a great machine is built better than anything and used for broaching for 5000 hours, is it used up?

what is the worst case cost of replacing the parts burned up by the broaching? how much is ball screw repair on a CNC? how much are installed spindle bearings? is there even a thrust bearing in a CNC spindle, or will we come to find that those great forces have damaged something irreplaceable?

God, I can't imagine I'm actually leaning toward Haas, but what we do here is not so complex. we basically make hardware and are finding that some of the hardware we make is sophisticated enough to require CNC machining.

Worst case involving Haas is we are dissatisfied with the machine, that it isn't built as well as the Okuma & Howa ACT-35, and that it gets hooked up to a bar feeder and pounds out parts for the next two decades. eventually it'll be sitting next to a nice CNC..

worst case involving the used ACT-35 is replacing the ball screws or the "ball", finding that ways have been damaged or worn, finding that the turret has been crashed and damaged, finding that the great forces involved in broaching have damaged something irrepairable.

They most likely were using collets in their operations, and if you use collets in that particular machine without an air dam device in the spindle, the bearings inside get exposed to the weather.

I don't know. what are your thoughts?

Lets say you are the buyer, and you go to see a used CNC machine. Beside details concerning its construction and availability of service & parts, how would you basically check the machine out for wear and tear?

spindle noise, spindle heat, spindle alignment & run-out is something I would feel confident in checking, but I know nothing about CNC spindles. how would you proceed there and what to check for? how long should the spindle run under what RPM and what temperature should it stay under?

backlash? can you check for backlash and ballscrew condition along the entire length of the drive shaft? maybe only 1" or one particular rotation is worn?

turret? I know nothing about CNC turrets, how do you shake it down for problems?

are there marks you can check for on a ground CNC way to notice wear, something like the little injection points on a new car tire? how about the performance of those ways?

are there methods to check out a controller for defects, self-diagnostics, etc?

heh.

For your first CNC, it will be diffcult to know what you need to be looking at when you gop look at it. The nicest part about a new Haas is the training. The warranty is what the boss looks at, but the curve of figuring out how the "logic" of the control works sometimes is not easy. when looking at a used cnc the things I generally do:
1. run the spindle full range no load, listen for out of place sounds, etc.
2. try to hear it under load. If it is making parts, inspect a few to see tolerances.
3. see if you can get them to some long full rapid moves. excessive noise points to ballscrew or thrust bearing issues.
4. see the manuals in person. Find the electrical prints.
5. do some tool changes, etc. try to see it doing what you want to do.
Sometimes the logic used in the controls is not very logical to me. Certain procedures are " why isn't Pi an even number" type questions that you just have answer as " because it's not..." and do the wacked procedure the machine came with( although it made perfect sense to whoever developed it). The time to the first part should be less with a new machine because of the included training.

[This message has been edited by WILLEO6709 (edited 04-01-2003).]

I would stay away from any used Cnc lathe that did broaching.....

Look at a new Kia www.khiusa.com

They built machines for Hitachi and the quality is amazing and will run and run..And the pricing will be just a little bit higher than a Haas...

Haas makes the worst lathe on the market..

That's why they are cheap, not inexpensive...

Small ballscrews, motors, drives, etc. the verticals are a little better, but overall they are built to last 2 years and Gene Haas will even tell you that......

Also, look at romi G series, they have the same conversational programming as an ezpath combo lathe.......

www.romiusa.com

good luck.......