Micro Mark

[xa_shall]

Ok i need help im a newbie. If i bought a micro mark were should i purchase the ball screws for xyz axis. I want to mill turbines and compressors with dimensional tolerances of about +/-0.001 if possible and overall working accuracy +/- 0.0005 if this is right. Also can i mill turbines and compressors with a 4 axis by adding rotary table to micro mark or do i need 5 axis? Here are some pics of what my designer did for me. Somebody please give me a starting point.

[JFettig]

Those are some pretty crazy tollerances you want there, honestly, dont count on it from that machine. You would need a very nice machine and even then you would likely have to tweak offsets and everything. To mill something like that, you also would need a 4th axis.

Is it possible that I could get ahold of that drawing?

Thanks,
Jon

[xa_shall]

What do you mean get a hold of the drawing you cant download them you should be able to. Or are you talking about the 3d files? I only give 3d files to someone who can quote me on this job. I need these parts made and i dont know where the to go without some money hungry charging me $3000 for 2 parts when a machine is that much. What do i need to do?

[JFettig]

Those are gonna be some spendy parts to make, If I had the capabilities for those kind of tollerances I would consider it. I don't think you could get much of a machine that would be capable to do that for that much.

I would like to get ahold of the 3d files, I sent you a PM.

There are a few around here who have the capabilities.

Thanks,
Jon

[fyffe555]

Whats the overall dimensions and materials you're planning to use?. Those tolerances are pretty hard to achieve unless you're experienced and have the equipment to do it with, such as a VMC for example. For a turbine wheel you're talking about materials that are hard to machine which makes it even more difficult. Commercially compressors and turbines are investment cast so I don't think they are to such high tolerances.. IF this is a short run then wouldn't it be cheaper to buy compressor and turbine wheels from the thouands of sizes available from turbochargers?

[xa_shall]

These parts will be made out of plastics preferably composites for educational use and composite analysis. No inconel or aluminum. I cannot just buy parts from turbo venders because they are not made of composites they are made of iconel and aluminum which is the last thing i need. I posted up in the Rfq zone i got 8 reply's for an rfq 3 already said that they cannot do it. Just waiting for others. I had a guy in maylasia charge me super low price however hes not responding anymore i dont know what happened to him or maybe hes busy $500 bucks per part was his quote which was pretty good but that is out the window possibly. I think i made a mistake dimensional tolerance (bare with me im a newbie) +/- 0.001 bores was +/- 0.0002. What are the typical tolerances of an investment cast if they are less tolerance i might consider machined parts to investment cast tolerance.

[fyffe555]

Interesting. Is this to machine the component or a mold? Still not knowing enough about their use to really comment but if the part was, say, under 4" dia and you could stand tolerances of 15-20 thou (0.02") then you could machine it on a small mill with a bit of practice and a lot of machining time. There are some very skilled people that produce some amazing things on those machines but not commercially to those tolerances. I just looked up the tolerances on high spec investment cast turbines and compressor wheels, as cast linear tolerance on an AL. 4" part was 0.016", Geometric tolerance 0.02", machining tolerance afterwards , such as bores is another issue. So , does your application need 0.0005? - and in plastic they will move by way more than that with temperature?
If you're machining a homogeneous plastic from solid then you're also have a problem with part deformation while cutting which will make it very difficult at that tolerance. If the composite part is a solid molded up prior to machining you'll have the same problem plus how will you determine the position of the reinforcment and avoid cutting it? you're not going to be able to produce a consistant product and the cutting will expose the fibre. If the educational purpose is anything materials related that would be a problem.. How about molding/casting the part?

[xa_shall]

Yea 0.0005 was wrong im confused with tolerance that is way too crazy . What would molding this cost ultem 1010? Also Inducer on compressor is about 1.797 if geometric tolerance was 0.02 then what would that increase/decrease my inducer by same for turbine 1.587?

[fyffe555]

Originally Posted by xa_shall What would molding this cost ultem 1010?

Don't understand? OK- maybe I do - Ultem 1010 is the material? PEI Resin? I have no idea what the cost might be. The cost will be driven by the complexity of the part and the mold needed to produce it. Having curved blades makes the molding process complex since you'd have to destroy the mold to release the part..

Originally Posted by xa_shall Also Inducer on compressor is about 1.797 if geometric tolerance was 0.02 then what would that increase/decrease my inducer by same for turbine 1.587?

1.797? that's diameter or radius? either way that's small and you'll have problems machining the root of the blade as drawn.

Geometric tolerance is a bunch of measurements related to alignment, out of round, square etc. If you're asking what the cast tolerance would do to a wheel 1.797 dia then the thing would be out of round and so possibly measure 1.777 one way and 1.817 another. Remember these wheels are usually cast then turned round, bored and balanced..

[xa_shall]

Fyffe555

Do you have yahoo messenger. I need some better conversation so that i can clear this up im confused with tolerance. My Messange name is yellowf40 aim is ehdstar7 can you log on so i can get some help. Machined parts to 0.01 is ok to me now that you cleared it up for me.

[fyffe555]

No IM sorry..

Tolerance is pretty easy, measuring it or keeping it is hard! DO a google and that will sort out the idea. Your part as drawn is to some very stringent tolerances that the 'real' part doesn't need.

As drawn its got complex blades which will make it expensive to produce does your version need that?

As drawn the root of each blade has a very small radius and xsection which make it difficult to machine and the part weak. 'Real' turbines and compressors usually have a blade profile that gets thicker towards the back disk.

If the application allows it a wheel with straight blades, bigger radius and lower tolerances would be far easier and hence cheaper to produce. Tolerances of 0.02 on a small machine on such a part this complex would be possible with a bit of practice.

[fyffe555]

Another thought occured. I'd assume you're cnc'ing this! You've got to add the costs of the cnc conversion to the Machine cost, the tooling could be almost the cost of the machine and, unless you have access the software costs to produce G-code the CAM software costs will be painful..