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dberndt
12-24-2004, 02:04 AM
Well I'm new to just about everything about machining but I've always wanted a mill and lathe. Now with christmas here and a few fortunate events I have enough cash to get a taig cnc mill but first I feel like I need to ask some questions.

1. I've read extensively but never actually seen this mill and I think that I understand that any slop in the ways and backlash can be taken care of with the gib screws and adjusting the net to get reasonable accuracy at the expense of some more friction. Is this more or less the case.

2. I plan to use this for hobby use, not production. But I am a bit of a perfectionist so I do expect to be within something like .001 or so at most times. I plan to work with alot of aluminum, no real desire to work with anything like steel or SS 99% of the time. I would use the machine to do some pcb engraving atleast initially until I used it to build the parts for a dedicated engraver/router. My first two projects will be a giant cd changer (6x6 feet wallmount) and a router/engraver. Is this machine up to the task?

3. Coming from a point where I have nothing in the shop but a few drillbits what accessories should I look for right off the start. So far I think I'd want a standard drill chuck, a few good endmills and a fly cutter, any other suggestions. I guess I'd want to build/buy a rotary table at some point but the price on them seems a bit high from what I've seen, hopefully I could put something together myself.

4. From a control perspective, I'm comfortable in autocad, atleast in 2d, and a bit of 3d. I can get what I need done most of the time and I can muck about in other programs reasonably well (I'm a programmer by trade) and I'm thinking that maybe bobcad-cam is the way to go. Either that or just stick with something like autocad+mach2. I dont want to be stuck with designing absolutely everything so its important to me that I have a controller that lets me more or less manually run the mill from the keyboard. Being able to input jogging a set number of steps or whatever manually just because It seems to me that some simple operations aren't worth the time modelling when I can just do them right then and there in the raw as it were. Any recommendations on what will give me the best compromise for what I want?

alpay
12-26-2004, 04:10 PM
I'm eager for an answer to this question too. I plan to only machine aluminum plate. I want to do custom faceplates for pc-cases (a product I'm developing for which I use an oem pc case). I have no experience with the gear involved but I'm proficient in a few 3D apps.

I wonder if it's smarter to farm the work out to some of the guys on these forums. I'll end up needing batches of 10 or 20 of these 12"x12"x1" plates. with the "mini" mills like the Taig (usually go for $1000-2500 on ebay) I'd have to make smaller plates to bolt on to the case, which is fine.

Any advice is appreciated.
Alpay

ESjaavik
12-26-2004, 06:42 PM
@Dberndt:
1. The slides should be fine until they start to wear, then you may not be able to adjust out the slop without binding at the extremes of the movement. The backlash in the screws can be adjusted on some mills, but the same as with the ways apply.

2. I don't agree that milling aluminum requires less power and a less sturdy machine than steel. SS is a *****, depending on what kind it is. Some of them work harden so you just cannot take fine cuts. PCB engraving does not need much power, but high RPM and speed of movement is absolutely high on the wish list. I suggest you etch the board using laser transfer, and use the mill to drill the holes.

3. For a small mill, I'd drop the flycutter, it needs a beefier machine or it will very easily chatter. But you should not mount your cutters in a drill chuck! It will creep out of it as you work. I suggest a collet chuck.

4. Browse the forums here. This can't be answered easily, and it depends so much on your needs, preferences, budget and lots of other factors. My suggestion is you start out learning G-code basics first while you look around. It will not be a waste whatever program you choose. Since you're a programmer, I think you would be able to do many simple tasks by just feeding Mach2 the codes as you go instead of turning the handwheels.



@Alpay: You don't say what you will do to those 12"x12"x1" plates.
Since you use 1" plate, I suppose you want to remove quite a bit of aluminum, at least on parts of it?
If that is the case, you will need quite a bit of patience using a Taig or similar size! Unless you just want to round the edges it seems to me you will be carrying out many buckets of swarf, and need a lot more grunt to make it.

Other options are casting it, pressing it or hydraulic shaping from sheet metal. A friend showed me a prototype aluminum cover cast in plaster, and it looked like it was die cast. Very straight, smooth and with fine details. For casting you could mill your master from CibaTool or a similar plastic. Then you can go really fast even if you don't have a powerful machine.

nervis1
12-26-2004, 07:21 PM
Based on what you will be doing I don't think a Taig wil make you happy. I had one for a year or so that I converted to CNC with a flashcut system. It took about three hrs to machine some .25 deep pockets in a 5" X 5" 6061 plate. The Taig has a 1/8 hp spindle so heavy cuts are fantasy, think 0.05 or less at 20 ipm or less. Steel will take longer. You also have to stand there the whole time with a squirt bottle of your fav lube / coolant, and it makes a BIG mess.

Running a fly cutter? Max cutter diameter for me was 3/8ths and that stalled quite a bit.

dberndt
12-26-2004, 08:10 PM
Thanks for the replies.

I'm pretty patient and if a part takes a few hours to machine that's fine. I'll build some sort of coolant system and just let it run. As for machine wear and slop, this concerns me a bit more. Just how quickly does the machine wear? I know I'm getting a machine with an acme lead screw which is a sub-optimal solution but I'd be willing to retrofit with ballscrews at some point in the future. As for wear on the ways, well this is a bigger problem because replacing the ways/retrofitting them with something else really means rebuilding the entire table, maybe something I'd get to eventually but not right away. I don't know how this is typically measured but i'd say that in a year if I reduced 30lbs of aluminum to chips that'd be a really large amount for me in my after-work tinkering time.

I hear the new mills are shipping with a 1/4hp motor now, and if thats not enough retrofitting something else, like the sherline motor shouldnt be a problem either. I don't mind spending some money on upgrades as long as I'm not wasting just throwing money away.

As for fly cutting, well if I cant flycut, even with a bigger motor then forget it, this isnt optional.

So if anyone has any suggestions on other machines I should look at within my ~3000cad price range let me know. The machine still needs to be a "benchtop" type machine or the lightest and smallest floor standing machine ever. I dont have the desire or the space to have a bridgeport sitting in my basement.

nervis1
12-26-2004, 09:04 PM
Having gone that route a few years back I would say spend your money on the biggest machine that will fit your space. Unless you are making jewlery, or other very small items the Taig is just too small to do what I think you want to do with it.

Any other Taig giys here want to refute those statements please chime in, I'm sure there are others here who would say different.

Taig makes a solid, very accurate machine. Wear will happen but with the usage you are talking about it would take years.

Retrofitting ball screws, replecing the ways? I'd just get a bigger mill to begin with and save the headaches.

Another issue with the Taig is that the colum is bolted to the base, one little whack and it needs to be trammed again. That was a big issue for me.

sendkeys
12-26-2004, 10:34 PM
bigger is always better :) but for what i seen made with the taig mill on the yahoo taig forum. i would say it can do anything you want with time :) Main problem you will find with larger mill is the spindle rpm. Most will max at 5k or so. others benchmill gearhards might only do 2k. if you're lucky. atleast in the price range of a normal person :P

if you are doing pcb boards or other stuff running at 2k rpm with a 1/16 cutter on a large mill . that taig will be alot faster running at 10k rpm.

nervis1
12-26-2004, 10:40 PM
Taig comes with a 5200 rpm spindle if my memory is still holding, it was not 10k.

I had planned on replacing the motor with a VFD treadmill unit but gave up on the thing.

EDIT...

I just visited their site, looks like they upgraded the motor and pullies, now has 10k rpm. Cool.

sendkeys
12-26-2004, 10:43 PM
hi nervis :)

http://www.taigtools.com/cmill.html
says upto 10k. but they seam to change often so who knows :P
--edit--
ahh went a looked. looks like the none cnc one does run at 5200 and maxs at 7k. kind of funny.... so do they change the bearings for the cnc ver.? or maybe they just preload them less ?

nervis1
12-26-2004, 10:52 PM
Must have...my old one was 5200 max, did not have much HP at that speed either. I was using 1/32, 1/16th and 1/8" cutters and going 3 ipm I remember, It was agonizing.

They must use a different spindle and pulley arrangement for the CNC version.

ViperTX
12-27-2004, 01:34 AM
At a minimum...I would suggest a Sieg X3 for a mill (mini-mill)...what size of work envelope do you need?

alpay
12-27-2004, 05:12 AM
@ESjaavik
Thanks for the info, everyone's info was helpful too. From the 1" thickness, i'd be taking out .25" out of it as a logo and some very simple graphic design. some cuts would go clear through it as they'd be for ventilation and a slot-loading dvd-rom drive. the vent cuts would work with the overall design. the idea of the final plate being 1" thick is overkill. I didn't give that part much thought at all. it can be much much thinner. the whole thing is getting auto-paint and clear coat.

It sounds like I'd want a much bigger, and more expensive mill in the end. I've got more learning to do.... I've decided that's best left for the future and I'll simply create some files in Rhino3D for someone else to cut. I'll be sure to post here in the forums for an RFC when I'm at that point.

Thanks again.
Alpay


>You don't say what you will do to those 12"x12"x1" plates. Since you use 1" plate, I suppose you want to remove quite a bit of aluminum, at least on parts of it? If that is the case, you will need quite a bit of patience using a Taig or similar size! Unless you just want to round the edges it seems to me you will be carrying out many buckets of swarf, and need a lot more grunt to make it.

jkeyser14
12-28-2004, 07:41 PM
all that work milling those pretty pieces and you are going to paint them????

You seem like a good do it yourself person. Read up on anodizing. It costs very little if you have a power supply or something like a car battery charger. An hour and $5 in materials will give you a nice beautiful and strong finish that won't scratch easily.

alpay
12-28-2004, 08:12 PM
@jkeyser14
I'm still thinking of the simple beauty of the straight metal look but I am using an existing case for structure, just need to "upgrade" the face in a very dramatic way. The idea of high-quality paint came from the possibility that the box might not look uniform any other way. I was most moved by some custom work like...

http://www.NYCRenderfarm.com/hoojum.jpg

simple design. simple paint. simply not tacky looking. I'm not going for the bends or anything to complicate matters. I'm just chucking a plastic bezel full of drivebay doors and making it streamlined like what you see above.

I will read up on anodizing though... Thanks!

jkeyser14
12-28-2004, 10:36 PM
I understand wanting to keep it simple, you can clear anodize you know :) Plus, you can get awesome frosted looks by bead blasting before ano'ing.

Anyway, good luck with what you're doing, I am waiting for my taig right now so I can't really tell you how it performs at the moment. A good first project for the mill you get would probably be machining a nice housing for your cpu and controller.