All the are to know about milling!
 

Hi

I have some problem making my fins smaller than 2 mm wide, crappy quality and taking days to complete (using a full-size NC mill).
Therefore I going to change to a CNC (3 axes) but I need some help.

Therefore I have some questions.
All questions are for 1 material (there are different answers for different materials)

1. What size are your cutting tools (the drill).

2. What rpm?

3. Cutting speed (xy and z)?

4. Cooling?

5. Are there any thing else that you thing I should think about?

(If the added info is good then make this sticky?)

On a small sherline minimill.
1. 0.8mm up to 9.5mm
2. 2500RPM or as fast as possible for small endmills, as low as 300 for 9.5mm, whatever feels right and gives nice chips.
3.<0.5-1mm/sec
4.WD40 or CRC 5-56

If it applies...

While developing my block (Radius, linked in sig) it was suggested that a radial saw be used to cut the grooves. These are easily available and have been used succesfully for making slits less than 1 mm wide.

Unfortunately, it didn't work for my design. :(

For small channels you need to use a slitting saw.

Looks like a demel tool...
going to try thatone!

I have dicided to build my own CNC mill thats has a dremel as motor (33000rpm= HighSpeedCutting!!!)

Incoherent-> Have U modified the mill to cnc?
Om du har det var köpte du stegmotorerna?

My manual mill I converted to cnc I run 3000rpm up to 3/8" end mills, and little lower on smaller ones, this is in copper and aluminum, with steel, I would go 3000 only up to about 1/8" then much lower to about 1200 for a 1/2" end mill.


Jon

Can you make your mill go faster than that? (in rpms)
What feeding speed do you use in copper (1/8" (3mm) and smaller sizes)?

No. It's totally manual. I don't know where you'd get stepper motors, Elfa maybe but that'd be pretty expensive.

I have played with pully ratios a little bit, had it up to 6700rpm but with the little 3/4hp motor thats on it, it cannot handle a half decent chipload.

with a 1/8" end mill taking a .05" deep pass I typically run it 3-4ipm(I would have to take a look at an old program to remember;)) With a 1/16" end mill I think it was between 1 and 2ipm, yet again, I have to take a look at an old program(would now but Im resizing partitions) All this is in copper. I may soon do some 1mm work on it:D. What I really want to do is get a 2-3hp router and make a new head for the mill, have a high speed and high power spindle:D the only problem would be interchanging them, because it wouldnt be so pretty trying to drill with that.

-edit- I have run a 1/16" ball end mill at 7ipm through aluminum before:eek: but that was milling a picture with the Z and X axis moving at the same time almost all the time. I think I hit 20+ipm with a 1/8" ball mill doing the same.
-edit2- heres a pic:D
http://jfettig.wc101.com/cnc/flood5.jpg
more in http://jfettig.wc101.com/cnc/

Jon

http://www.elfa.se/elfa-bin/dyndok.p...0&dok=5808.htm
the have a stepp motor with 1,27 Nm for 577SKR

Im working with my medium manual Mill and a small Kosy 900watts Desktop CNCmachine.

with the manual the smallest diameter is about 2mm.
for the cnc i have some 0.5mm millingtools which can make some really nice pins oder fins. But this tools break as soon as you look at them LOL
Very good to make some small and efficient cooling pattern to direct jets onto it, are engravers. A 60° engraver is doing really good in makin tiny pins of 1,5*1,5mm or less. 30° engravers are getting blunt really quick impossible to make more than one cooler with the same 30°engraver.

For all Channels i normally use a 2mm fishtail tool spinning with a 900watts kressmotor at 18.000 (plexi) to 28.000 rounds per minute. The more rounds the better, only with plexi not more than 18.000.
I don't know the korrekt english vocabs for that, so i wrote it in german:
Vorschub(x/y): 20-30mm/s
Zustellung(z): 0.1mm in copper, 1mm in plexi

Really important is the special cutting oil when you cut copper. i had better results in copper without watercooling than with only oil.
In Plexi it is indispensably to cool with water and a little bit of green soap (directly on the material would be good).


@mwolfman: A dremel has by far not eneough power to drill anything other than balsawood ;)
Try some little bigger things. There are some millingtools from which are usually used for carpenting and milling things into wood. These have aroung 700-900watts, are not much bigger than a dremel, but much more useful in a milling machine. with only a dremel as motor you will absolutely not have the results which you may have expected.

Kosy 900watts Desktop CNCmachine, what did you pay? I find them rather expencive...

a kosyA4 lies about 2800?~3400$. I paid a little less than that.

Kosy machines are designed for cnc and have a very different formfactor to other conferted machines like Jfettigs one.
In my opinion even the former manual but now converted machines for about 1200$ are much more expensive than a kosy from what you get. Converted machines are not designed for cnc use, neither are they precisely enough and haven't enough rpms for really small drills, which are the sequel for good waterblocks.

The mill that I use can only go to 3000rpm...(edit:3500) that's not what you want when using 3mm cutter...
and the driver motor only works in one direction... (broken)
I bout at dremel copy... just to play with...

I see nothing wrong with trying the Dremel idea. Worse case you have to replace it with a better cutting tool. If you got the stepper motors and such down, changing your cutting tool shouldn't be a big issue. Just go to a pawn shop, get a router, take out the motor and gear it to get your speed(s). I've had good success using a Dremel to cut PC cases with the carbide cutters (I hate their wheels). If your CNC is set up to go slow enough it should work. It'd be kind of slow to finish the block but cheaper. I am thinking of doing the same thing. I saced 3 broken printers for the steppers,gears and bars. And building the frame out of T-slotted aluminum. Using extra rollerskate bearings for making moving it easier. Last but not least, getting two extra parallel ports to control the steppers directly.

mwolfman - I think since were working on the same idea... We sould brain storm.

I saw a CNC today... not a mill but a holder (for laser scanning or something like that) and they had used aluminum parts for everyting, and it was solid as a rock...

I talked to one of the technichans that build it but he was to stressed to talk about it and was afraid that I should take there machine...
Going to try to talk to the younger one of them... and try to make him build one for me... ;)
If I get that one... then we arnt talking about dremels but rater a 1000W + mill ;)

IE we should start a new thread about the making of a CNC mill for home use that can make waterblocks!

well I am pretty sure you couldnt make a cnc mill that would mill copper for less than you could buy a better one. 1000w isnt all that much. the ones I play with at work around 15,000watts;)

Jon

Building a milling machine, the motor will be the least of your worries.

Easier I think to just build a cruise missile and then start making demands.

I'm a student and my budget is very limited...
1000W is overkill for a waterblock mill, what you need is rpm!

Hmm... I'm not from IRAK!
No the problem is to find "strong" step/server motors at a low price and the linarsystem (to move the mill around)...

did you make lathe´s?

wolfman, to acheive rpm you need power, I ran my spindle up to 7000rpm and I could stop it with my hand.


and the lathe, no I bought it its a seige lathe available at most discout tool stores here in the usa. I wanted to convert it to cnc over the summer, I made the cash but I spent it all;) I got plenty of BIG cnc lathes at work to play with;)



Jon

Ok, all mwolfman and I hear is you can't do this you can't do that. We both need a cheap CNC and are throwing ideas around. If a hand held Dremel with the right bit will form a block why won't a computer controlled Dremel? Granted its not the fastest thing in the world but the factors we're looking for are cost and ability. If it takes me days to mill my block I don't care if the milling is free. I I can build a CNC for under $500 then after like 4 blocks I've saved money. And once the machine is up and running there will always be the ability to make it better. Stronger motor, better stepper motors, better software, once you know how to build the basics upgrading isn't too hard. I'm not looking to match a $10,000 machine. There will be things I can't do and things that take a long time. Also, even if the whole thing flopps, I'll know how to control steppers from my computer among a dozen other things that I'll pick up along the way. Since I took up this project I've already learned how to use Autocad, pin outs for a serial port, how to hook up steppers to a serial port, how to read alittle info in .dxf files, and where to get t slotted aluminum. I will have a Dremel mounted on a moving head I control form my PC. If it mills aluminum and copper great. If not I've learned alot using mostly scrap parts and the web. Also, I'll atleast be able to mill MDF for various car projects.

sure, cncing a dremel isnt that hard, it may do the job, but the dremel is gonna be your cheapest peice of equiptment. I know I put probably $1500 into my mill cncing it.

Jon

The reason a Dremel won't cut it, automated, but will suffice for many duties in human hands, is that we humans work with both finesse and feedback. No robot yet comes close to our proficiency. We intuitively compensate for dull bits, for burrs, for variations in material hardness or machine condition, before we start. As we work, we constantly and voraciously process feedback including dust consistency, vibration nuances, sound, smell, and of course we relentlessly scan and rescan the operation with the greatest precision instruments on earth: human eyes. Asking a robot to carve with a Dremel is like asking one to write with a pencil.

This is not to say a robot can't produce virtually anything, and do it better than we, with the right setup, on its own terms.

CNC requires brute force and fine preparation, because CNC is the poorest craftsman and will blame its tools as a matter of course. A machine will break a hand-Dremel unless the passes are excruciatingly light, or slow. This strategy, paradoxically, raises the bar for rigidity and accuracy in your mill because deflection of the underpowered cutter becomes a big issue.

You really should consider the cruise missile.

***

OK, a helpful suggestion: The electronics, and possibly the mechanism if just for very light work, could be salvaged out of an old desktop plotter. These things had their day, and you could likely find one cheap or free, forgotten in a draftsman's basement or print-shop warehouse. Many were built for use with early PCs.

***

My father picked up a radial-arm saw for tinkering with. Today he happened to speculate on adapting it as a router, because the motor/shaft is freely position-able - it can be set perpendicular over the table for example - and obviously deals with radial load much better than a drill press. I'm afraid an axial load would kill it though.

***

Here is a heavy-duty Dremel. It will take up to 1/4" shanks. You could set the chuck ("hand-piece") on without the flex-shaft, I think. Or find a modern plastic plunge router that's had some part broken but otherwise runs fine. The bearings of a plunge router should be able to handle all types of loads.

thx, Kobuchi said the explanation to that what i couldn't explain in english.
for a cnc you should have nothing less than 600Watts. I have a 900watts kress highspeed millingmotor, but could have more, would probably make more fun hehe