[robwashu]

Hi

I am new to swissturning and am in the process of bringing a spool we currently purchase in-house. The od of the part is .290 and 4 in long and is made of 6061-T6. We will be making 100,000 parts per year with a 10% increase per year based on history. We are looking at Star SR-20III, Star SB-20, Tsugami BE20, and Citizen A20VII. We plan to run lights out, unattended since we are running a high volume of the same part and do not intend to run anything else but R&D parts a couple of times a year.

My questions are:

Where do get quotes for Swiss quality aluminum bar stock and what tolerances do I ask for?

Any suggestions on machines? What to look for when comparing machines? Strengths and weaknesses of the machines?

What do I need to pay attention to when running lights out, unattended?

Rob

[UK-Engineer]

Material spec - Aluminium is notoriously variable in diameter when you buy it from your stockholder but general H9 spec for raw material. If you were running lots of aluminium I'd look at adaptive guide bush which automatically adjusts via air pressure to allow for variations in the bar.

Machines - All the Japanese manufactured machines are of good quality and although some are better than others IMO you're better seeing machines in the flesh and how you like to operate/program it. If you're new to swiss turning you'll need good service and programming backup to start off with so see how you get on with each dealer

Lights out running - If you run neat cutting oil on machine then its normal practice to fit fire extinguisher on machine wired into the machine shutdown procedure on activation. If part lends itself to it you can set up tool life monitoring either via control or write a macro. You'll also need high capacity finished parts storage so a parts conveyor or dedicated unloader to an external high capacity storage bin is a must. Also look at a chip conveyor to get rid of the chips from the tank during machining. Other things to consider are high pressure coolant for swarf control (for which you'll also need oil mist extractor) or if you can't stretch to this in your budget a subspindle coolant wash to clean sub collet out during pickoff

Good luck with whatever you decide

[g-code_junkie]

the a220 would be my choice but I would add chip & parts conveyor along with fire supression,hp coolant and mist collection a plus.Also think about tool breakage detection.I have seen the a20 running aluminum and brass 24/7.The adaptive guide bushing would help with the stock variance of aluminum but stock should run +/- .002 for consistency of the process.you could get wild and add a paging system to the machine for notification when it alarms.
good luck

[steve3three]

Personally I would just make sure to buy precision ground stock with a .0005 total tolerance. you could go tighter but I don't think it would be needed unless your trying to hold a tolerance tighter than .0005. I'm not a big fan of the variable bushings. I've heard good and bad things about them, and imo if you plan on running unmanned aka lights out then I think it would be much safer with precision stock and no variable bushing.

High Pressure coolant wouldn't be needed in alum, but it will help alot with chip removal.

Machine wise, you looking at a smaller part .29 OD. I think SB-16E would be a wise choice http://starcnc.com/products/SB-16E.html. It's a very capable machine, very stout, stronger than most 20 and 32 size machines (not that it's a huge concern turner alum). If I'm right you can get a SB 16E with barfeeder for about 100k. Now I'm not a big fan of the Star barfeeder they supply with it, so if your looking for a higher quality bar feeder I would be that seperate which in turn will up your cost a bit but still be very reasonable. My personal favorite is Iemca barfeeders http://www.iemca.us/Products.htm#SlidingHeadstock. The boss 332 is what I use alot, very reliable.

I'll agree with the other guys, you want self extinguisher system http://www.firetrace.com/english/app...e=cnc-machines. You also need a chip conveyor and High Pressure coolant. Personally my favorite coolant is ILOcut 334 http://www.castrol.com/liveassets/bp...334_us_tds.pdf. I've used many types of coolants and yet to find anything to even compare.

I hope I was of help. Take note that the Type E is a very capable machine. if your job is much more simple and you dont plan on running complex parts there you may want to look into getting the C or D version instead.

as for the A220, and all citizen machines, the only real beef I have with them as that they are backwards. your working for right to left. barfeeder being on the right side. It just seems weird to me and if your use to left to right, it could be an adjustment that I personally aren't will to take. But as far as swiss machines go, I would never even dream of buying anything outside of Star or Citizen. They are both High grade companys and they are basically each others only real competition.

[dookie2022]

I agree with the comments being made about the high pressure coolant for chip removal and I would advise to get a guide bush that adapts to bar size changes such as Rotary guide bush magic as supplied by Star and as for the SR20RIII it is a very fast machine and is very popular machine here in Australia.
If you are considering a chip conveyor we have found that a scraper type works well with aluminium and brass but not so good for other materials.
Basically Star are # 1 in sales / Citizen #2 in the world and the two companies control about 63% of the world market in swiss machines.

[hacdlux]

the tolerance of the stock determines the precision of the part.

i run cold drawn stock fom kaiser exclusively.
i also run a standard fixed guide bushing, water soluble coolant, and no high pressure. we run 24/7 for weeks on end

my machine is a tsugami ss32 due to the complexity of the parts.
if your looking at a BE i would look at the s205. you gain a lot of extra capabilities for sligtly more investment.

the two main challenges i will tell you are getting straight bars and getting them in useable condition. tell yoour supplier you want the stock either boxed or boarded becauce road rash and dings from forklifts will absolutely ruin your day