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New B-axis machine - experience Doosan SMX2100, Nakamura CTRX-300

groyk

Plastic
Joined
Nov 18, 2023
Hi all

Does anyone here have experience with Doosan and/or Nakamura B-Axis machines.

We are looking for a new b-axis machine. Don't know if lower turret is necessary, as we mostly produce 1-20 pieces.
It could be other than mentioned machines, but we like Fanuc :-)

So far we have looked at
- Doosan SMX2100
- Nakamura CTRX-300
- Nakamura JX-200

I believe the CAM gets more complicated with the lower turret. (Read: takes more time to get start turning/milling for small quantities).
 
Former DN/Doosan here. I used to teach the MX/SMX classes at Pine Brook.
The SMX is a wild machine. Very productive. Basically, both a VMC and a TC on a single base.
Really not that hard to program and DN provides the machine's specifics to the major CAM builders.
Lower turrets are easy peasy and simultaneous work is a matter of M900 synch codes.
Nice thing about a lower turret is that you can be cutting on the sub (or main) while the upper path is doing something else on the main (or sub).
 
Former DN/Doosan here. I used to teach the MX/SMX classes at Pine Brook.
The SMX is a wild machine. Very productive. Basically, both a VMC and a TC on a single base.
Really not that hard to program and DN provides the machine's specifics to the major CAM builders.
Lower turrets are easy peasy and simultaneous work is a matter of M900 synch codes.
Nice thing about a lower turret is that you can be cutting on the sub (or main) while the upper path is doing something else on the main (or sub).
You also get a LOT more Z axis if you're drilling/doing end work with the lower turret.
The mill head will use up 20"+ of your usable Z if you're doing end work.
 
You also get a LOT more Z axis if you're drilling/doing end work with the lower turret.
The mill head will use up 20"+ of your usable Z if you're doing end work.

DMG Mori have a huge edge on the competition in this regard. I was blown away by how compact the head was on the NTX, and by how much power and torque it had in such a tiny package.
 
Jx200 has one of the physically smallest baxis heads out there from what I can tell. You want the lower turret as it's much better for turning if your still going to do a lot of it.
 
Just curious but what do these type machines go for these days, probably getting near a Mil by the time it's making any thing?
 
2020 UK prices FWIW:

NTX2500, simultaneous 5x, counterspindle, 40atc, no lower £430k
Multus U3000, equivalent spec, £440k
SMX3100, equivalent spec, £330k

2020 was about 1.4 dollars to the pound

SMX was very tempting at the time, but there are some significant compromises made for the saved money.
 
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What are the main compromises?

Rigidity, accuracy, speed, work envelope ergonomics.

Not to say it's a bad machine, but there are reasons why it's in a different price bracket.

Rigidity and accuracy suffer compared to the others because of the Z-Y construction. DMG approached this by using twice as many trucks per rail with tight spacing, Okuma by using massive heavy castings. Doosan has a relatively lightweight casting with a lot of span on the trucks. I don't have any hard data, but the X column looks a lot less dense on the SMX too. SMX3100 is 10% lighter overall than the NTX2500/U4000 - maybe doesn't sound a lot but that's basically 2 metric tonnes lighter for the same capacity.

SMX is probably comparable speed wise in XYZ, but B axis rotation is a lot slower.

Work envelope - SMX has a very tall head compared to the competition.

When I was doing my due diligence on these machines I was made aware of two UK companies who were unhappy with their SMX machines, one going as far as to refuse acceptance. Cited reasons, poor rigidity and inability to hold promised tolerances.
 
FWIW, We have a Multus U3000. We also have another Multus U3000 on order to be delivered in March of next year. When we ordered we didn't think we could live with the lead time so we looked into Doosan and Nak. We use the lower turret on every part so the NTRX was not viable. The JX-250 was a bit more money than the Okuma or Doosan. We went to a shop that had a couple SMX machines and after seeing the control and rigidity in action we decided to wait for the Okuma. The Okuma control was way more operator friendly. I had a list of questions relating to how we interface our automation with the Okuma and the Doosan AE's couldn't get me an answer on how to do the the same or similar thing in the Doosan.
 
Thanks for all the good answers so far.

I have also looked at the Nakamura JX-200 with the lower turret.

Normally we only do small batches, why speed is not an issue, but i believe in the steady rest and the tailstock function.
 








 
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