Questions aboutscrew machines

[namder1]

I have been machining for many years, both manual and cnc(VMC & bar feed lathe). However, never a screw machine. The shop I am in now is bringing in formerly out sourced parts and I feel they should be done on a screw machine. Most all parts are small and lot sizes run from 1,000 to 50,000 parts. My qustions are .....are these machines very hard to program and do you use normal software such as SurfCam or is there a particular software just for screw machines. Lastly,what is a good, reliable and affordable machine?

[underthetire]

I used to work for the Tsugami dealer, but I can't help with software. I will tell you to buy a Citizen. The Stars seem to be ok as well, and the Tsugamis were ok to, but I always told great things about the Citizens from my customers.

[gizmo_454]

Difficulty programming and complexity of the part to be made go hand in hand. I program our Citizen by hand, but there are supposed to be some decent software packages out there. I am not sure of their names...Maybe someone else can pipe up and spit some out...

Like your shop, our shop has CNC lathe and mill equipment. I found the foundations to be the same, for example, if you understand G/M code and have a pretty good idea what needs to go into the part to make it, it's not all that different.

On the other hand, it's the details that count:

Remember that you would be completing the part on one machine now, not 2, 3, or more. Setup times will be much longer. Jobs that I normally setup in our lathe for one op and then mill for a second op, may take 1/2 hour to 1 hour each setup while the swiss typically will take me 4 to 5 hours.

Also, swiss machines are typically smaller with smaller amounts of HP. Don't think this is your 30HP Mori or Okuma and try taking a 0.300" depth of cut at 0.010" feed per rev. Not going to happen! In fact, depending on the material, you may not be able to feed hard enough to break the chip. Stringers then become a problem. There are ways to deal with it, but experience with it will help bunches.

Unlike your typical turning center, you don't need a tail stock to turn long slender parts since the turning tool is literally less than an 1/8" from the guide bushing holding the material. I have had no chatter related issues on our Citizen at all.

Need hex or square material but can't find it in the type or size of material you need to use? Make it. Most swiss have live tools.

Typically, a swiss will hold much tighter tolerances than turning center. We turn our Citizen on in the morning, check the first part or 2 and then walk away for 2 to 3 hours running parts with 0.0005" to 0.001" total tolerances all over.

There are obviously more differences than I can possibly describe here. For the most part, like I was told:

"If the part is under 1-1/4" in diameter, it should be made in a swiss. I fully believe that based on my experience.

Good luck!

Mike

[namder1]

Thanks, guys big help! I recomended a Citizen to my boss and his boss wants a Tsugami.....sssshhhh.

[hacdlux]

i run a tsugami ss 32

of all the swisses you will probabbly find it has the smallest learning curve

your biggest trick is going to be convincing your boss to buy good stock you either want cold drawn or centerless ground depending on the tolerance of your part

tsugamis come with the abile software which is very intuitive for basic to intermidiate parts but you probabbly wont use it very long because it is faster to program by hand

i have to go in and bail my boss out now he hit the e-stop on accident

[namder1]

what about delcam????

[DCogswell]

Namder1,

Tsugami's are very sound machines, from ease of set-up and programming software to rigidity and reliability. I've got 4 Tsugami's, 2 of them are 20 years old and they are still running 24/7.

I also have 2 Citizens, and they are the most finicky and frustrating machines I've come across in a long time.

Personally, I've ran Stars, Tsugami's, Citizens, Tornos & Hanwha's. And I would have to say the only reason why I wouldn't buy a Tsugami is if there were none available and I couldn't wait for inventory.

What kind of parts are you looking at making?

[abgoel]

DCogswell - can you tell me in order of best to worse between Tsugami, Hanwha, and citizen?

[DCogswell]

Originally Posted by abgoel DCogswell - can you tell me in order of best to worse between Tsugami, Hanwha, and citizen?

I would lean towards Tsugami for most applications however, I say that with personal bias. I have a lot of experience on those machines and I feel they have a very professional support system.

I don't have too much experience on later model Citizens so any opinion I might have would be limited. I have been running Citizen R04's for the past year and I'm not really impressed with them.

What kind of application do you have?

[littlebrewman]

i have run tsugami swiss turns before.they are ok.i currently am running 3 brand new NEXTURN and they are awesome!i use mastercam to program them with and i mostly run titanium and hardened stainless steel on them.they hold great tolerances and are well outfitted for tooling.i also run hangsterfers oil in them as well as ground stock.the oil has been great with drilling and turning and tapping and gives extended tool life.ground stock is a must if you want to hold tolerances. it also has to be ground if u dont want the machine to lock up cause it cant get the bar thru the guide bushing.material cant be bowed or bent either.one thing to remeber is that whatever runout u have in the bar stock you will see it in the finished part.

[dookie2022]

All I can say is that all other machine tool companies copy Star and Citizen machines so why buy copies when you can get the originals.

[abgoel]

We are using them for cannulated bone screw application. I have heard mixed opinion about Citizen and some customers have shifted to Hanwha from Citizen because they were more complex and did not deliver features as promised.

I am waiting on Tsugami application and also Tornos as well.

In the end, we evaluate on

1. repeatability,

2. surface finish,

3. productivity,

4. deep thread cutting

5. Deep bore drilling upto 100mm (and preferably 120mm)

Diameter in the range of 12-14mm.