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Buying a small CNC lathe (Mori Seiki SL 15 M)

sasky115

Plastic
Joined
Mar 21, 2022
First of all hi to everyone here, this is my first post.

First some background. I have worked on CNC lathes for the past 3 years (2 Mazaks - 2018 QT200 MSY, QT250M and a 1997-ish Mori Seiki SL200). Last year I opened a business with two of my friends producing electric repair stands for e-bikes. We rented my former boss's shop for a few weekends and did all the pieces ourselves. This was a relatively small batch of about 50 pcs, 10 or so different workpieces. Now we are planning a new product that is more widely accessible (home users) and are expecting batches of about 100-200 pcs. As I have some spare time I got the fine idea of opening my own side business, buying an older CNC lathe and machining the pieces myself. Would also come in handy for prototyping instead of paying someone like we are now. Would also find some other work for the machine so it's not standing. Workpieces are not very big (125mm/5" max) but some extra headroom is always good to have.

I'm thinking either just turning, having the pieces that require milling and drilling finished at the former workplace. As far as my quick research suggests, a machine like that would cost me about 10-15k EUR.

The other option I found is this Mori Seiki SL 15 M that would allow me to do some drilling and milling:
▷ Used CNC lathe Mori Seiki SL 15 M for sale - Machineseeker.com

Comes with all the tools in the photos, live toolholders and is supposedly in perfect running condition. As far as I managed to find out about these machines it's a solid choice (the SL200 I operated was on some days temperamental with a sensor or some small thing like that but continued to crank out perfect parts every day).

Unfortunately I have been in this industry far too little time to know about what to look for in a machine. What to ask the owner, what to be careful about, is there anything specific that you guys see is concerning or wrong? The offer is 23k EUR (25k USD).

What is the difference between a SL 15 M and a SL 15 MC. M is for milling and C is for C axis? But doesn't milling automatically require C axis control? All the MCs that I found listed on the internet have only SL 15 M stickers next to the door.

I tried to look up the MSD 516II capabilities but found almost nothing. Sorry for a possibly stupid question but does this machine allow for XC milling, or only fixed C operations? We didn't have milling on that SL200 so I'm a little lost here.

Right now I'm only looking at Mori Seikis (and maybe Mazaks) because I already know how to operate them. If I can somehow get a mill-turn post processor for Fusion 360 for it, I can make most of the parts myself.

Probably forgot a few questions I had, will add them as I go, just wanted to make this first post to get some replies. I'm really excited to expand my business but at the same time very unsure as to what to expect when trying to buy a machine this old.

I'm attaching photos of some pieces we're making.
 

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CITIZEN F16

Titanium
Joined
May 2, 2021
Not familiar with that machine, but I am familiar with Fanuc controls. They are by far the most popular, and you can still find parts support for models going back to the late 70's. Used components are all over E-bay, and many electronic repair houses specialize in various generations of that control. Whatever you do stay away from machines with controls that are no longer supported, with electronic parts being scarce.
 

chad883

Cast Iron
Joined
Jan 12, 2012
Location
indiana, usa
I have a SL-25Y. My turret is different than the one in the link. The one linked looks like the one on a different machine I used to run. If it is the same as that one, only the inner tool pockets can be used for live tools. You will likely have a maximum of 6 live tools. My SL-25 is about the same vintage, but does not have that control on it. I would bet the control crapped out and they had to upgrade to the one on it. I had another Mori and had to do that also. If this machine is just the little brother to my SL-25, it is a very capable and accurate machine. It will serve you well if it the correct machine for your work. Good luck.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
You would be smarter to buy a lathe and a mill. Live tools have limited power, rigidity, RPM and lifespan. Lathes with live tooling are usually best for lathe parts that need just a little milling like a drilled and chamfered hole or a slot milled. You can make mill parts on the right lathe, but it's a bigger undertaking than you might expect. Best to make your parts the way you know for 100$ sure will work- Buy a lathe and mill to start. If you find you need 10 billion widgets that are perfect to mill on a lathe then buy the perfect machine to do it.
 

sasky115

Plastic
Joined
Mar 21, 2022
I see it has a C axis, but I thought it can't NOT have a C axis if it's also to be used for milling. But what is the MC model then? They clearly exist as separate machines.
IMG_20220321_220309.jpg

Basically what I'm not sure about is whether or not I can do simultaneous XC milling, not just let's say clamp C on a certain position and basically just drill there (like a Haas has on the sub spindle but at least it has a Y axis).
IMG_20220321_220331.jpg
This is from a MSC-518 manual.

I'll try to get a contact of someone who does inspections on used machines and maybe go have a look at this one. As many opinions as I can get, I'm gonna take :)
 

scollins

Plastic
Joined
Mar 26, 2005
Location
Sheffield, Yorkshire UK
Some just have an indexing spindle while true C axis spindle can contour.

As Vancbiker says:-
I bought a Mori Seiki SL25MC in 1989 and the C denotes full contouring while milling, lathe main spindle can rotate under C axis control. As far as I know the 'M' models have basic spindle indexing allowing for example drilling of holes on a PCD in the end face of a part.
 

sasky115

Plastic
Joined
Mar 21, 2022
As Vancbiker says:-
I bought a Mori Seiki SL25MC in 1989 and the C denotes full contouring while milling, lathe main spindle can rotate under C axis control. As far as I know the 'M' models have basic spindle indexing allowing for example drilling of holes on a PCD in the end face of a part.

Exactly what I was afraid of...brings the capabilities of the machine down quite a bit.

Does anyone think it can be retrofitted or are major parts different?

Anyway, I'll try looking at some Mazaks now as Mazatrol is so good for programming at the machine and hopefully find one that can do contour milling as well.
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
......Does anyone think it can be retrofitted or are major parts different?.....

It could be done but you'll end up spending more than just finding a machine with C axis if you really need it. Something to consider is, do you really need it? Anything that adds complexity to a machine increases the number of things that can go wrong.
 

sasky115

Plastic
Joined
Mar 21, 2022
Yeah, I don't think I want to get into a retrofit job for a machine that old. I would either like to have full C axis capabilities or no milling at all because a machine would be significantly cheaper. Because I would have to do other work besides just for our company I think I would be severely limited regarding the jobs I could take with just turning (I know from my ex-workplace how many workpieces require only turning)...

Looking at Mazaks now as I know how to work with them very well and it seems Mazatrol was already quite functional in the 90's.

▷ Used CNC LATHE Mazak SQT 28 MS for sale - Machineseeker.com
20k EUR - ish

Doesn't come with much extra tooling though, live toolholders are expensive...
 








 
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