Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: VOTS on February 03, 2007, 01:21:00 AM

Title: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 03, 2007, 01:21:00 AM: So you guys here got me through my last major hurdle so I could actually use Mach3 on my new CNC mill. Back to ask another question.... This is more in line with milling itself.

I'm using Sheetcam to generate tool paths so I can cut patterns out of 1/16th" aluminum. Once I got my machine figured out, and actually got to cutting, I have a weird problem. (I have a manual mill and this doesn't happen on that one.)

What I'm getting, I'll call 'Mill dust' for lack of a better term. (Think saw dust) Anyway, On my other mill, the dust falls away or hops up on the piece I'm milling or generally, just stays out of the way. But on my CNC mill, using a 1/16th end mill. It not only doesn't get out of the way, it binds itself into the cut. And when I say bind, this is almost like welded in there. (I know it not a heat problem, the metal is ice cold) It binds so bad that even after a part is cut, i litterally have to pry it out. I posted a picture along with this post to give you a better idea of what I'm up against. The holes you see, are where I had to pry the little pieces out. The other 'holes' you can see the part is still stuck in there. This 'binding' has cost me two bits so far. I'll be going along cutting and then I hear that dreadful little *poink* that means I'm out another $15.00. I tried vacuuming the 'dust' while it was milling, but even with a mega shop vac, the binding still occurs. Ideas? Words of wisdom? Experience?

I'm luv'n this CNC jazz so far despite the setbacks!

(http://www.wikkid-widgets.com/images/Mill%20dust.jpg)

A bad picture, but a good illustration of the issue. The line that suddenly ends there all mangled like, is where the end mill met it demise. As you can see, even thought the cut was all the way through, the 'dust' 'welded' its way right behind the end mill. Even when I take a piece out, this 'dust' of mine is very well attached to the cut out parts. Although, the hole is very clean...

Hep me!
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Garrett on February 03, 2007, 03:01:37 AM: Tried some form of coolant/lubrication? Puddle a little water on there, or oil, next time. If that helps you might want to hook up a coolant pump or dripper.
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Hood on February 03, 2007, 04:11:05 AM: Alu is a pain to cut at the best of times, especialy if its a silicone alloy, magnesium alloys are much nicer. Lots of coolant or a spray mist is the answer. One thing you said is it doesnt happen on the manual machine so look at the feeds and spindle speeds you use on the manual and use the same for the CNC and you should get the same reults.
Hood
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Garrett on February 03, 2007, 04:22:59 AM: Also, your "Mill Dust" is called swarf. ;)
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 03, 2007, 09:06:00 AM: Swarf?!?!!?

ROFL...ooooh you can't imagine how that made me laugh for some odd reason. (Doctor, I have a Swarf problem!)

Anyway, Lubricant eh? I alway thought the lube-job was to keep the heat down. I have been milling metal for a couple years now manually. I gave up on lube a long while back because I didn't have any heat problems, and it's just plain messy. But hey, I will definitely give that a shot! thank you much gentle people!
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 03, 2007, 12:13:43 PM: OOOOOH YA!!!

You guys n gals RuLeZ!

Not only did the lubricant (WD-40 in my case) do the trick, I noted that it cut a helluva lot faster than it had before. I'm surmising that the speed increase was do the the built in 'missed step' correction that my CNC controller has built in. I think it was binding so bad that it was missing hundreds of steps. hehe, but the lube job did the trick!!

*breaks into a dance number thats far to provocative to describe on a forum dedicated to CNC schtuff*

Go MaCh3... it's your birthday... Go MaCh3 it's your birthday
[/size]
Go MaCh3... it's your birthday... Go MaCh3 it's your birthday
[/size]
Go MaCh3... it's your birthday... Go MaCh3 it's your birthday
[/size]
Go MaCh3... it's your birthday... Go MaCh3 it's your birthday
[/size]
Go MaCh3... it's your birthday... Go MaCh3 it's your birthday
[/size]
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Chaoticone on February 03, 2007, 08:44:20 PM: LOL, I know the feeling......................YES.

Might want to check on a micro mist system. Flood is my method but boy, what a mess.

Brett
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Brian Barker on February 04, 2007, 09:51:48 AM: I am a flood man as well.... The bigger the mess the more I like IT!!!!!! (I have a bit of a problem)
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 04, 2007, 10:57:49 AM: :)

I might as well accept the fact that I'm going to have to use a lubricant system here eventually. I was trying to find one of these 'Micro mist' systems that Chaoticone spoke of, but the ones i found look like they could be just as messy. At least with a flood system, I could predict where the lube would go. Are there like full systems available? Like a pump, filter, lube, catch pan, etc, etc. out there?
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Hood on February 04, 2007, 11:58:11 AM: Quote from: Brian Barker on February 04, 2007, 09:51:48 AM
I am a flood man as well.... The bigger the mess the more I like IT!!!!!! (I have a bit of a problem)
Always wondered why they called you Diaper Man ;)
Hood
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Graham Waterworth on February 04, 2007, 12:00:43 PM: You can get one here

Graham.

http://www.chronos.ltd.uk/acatalog/index.html?http%3A//www.chronos.ltd.uk/acatalog/Chronos_Catalogue_Coolant_Systems___Coolant_26.html&CatalogBody
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Hood on February 04, 2007, 12:01:46 PM: Quote from: VOTS on February 04, 2007, 10:57:49 AM
:)

I might as well accept the fact that I'm going to have to use a lubricant system here eventually. I was trying to find one of these 'Micro mist' systems that Chaoticone spoke of, but the ones i found look like they could be just as messy. At least with a flood system, I could predict where the lube would go. Are there like full systems available? Like a pump, filter, lube, catch pan, etc, etc. out there?
I have a Bijur spray mister and flood on my Bridgeport, the Bijur is great for Alu and there is hardly any mess with it. The drawback is you need a compressor to supply the air.
There are flood systems sold here in the UK, I am sure there must be the equivilent in the USA. Have a look on eBay under coolant tank and you might come up with something.
BTW what kind of mill do you have?
Hood
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 04, 2007, 12:57:39 PM: Already out there snooping on eBay for a coolant system. I found the Bljur system out there, but I think that was is a little over kill for my little mill.

My fist mill was the Harbor freight Micro mill. I absolutely love that thing and have made oodles of gizmo's with it. A fella out on eBay is using the Harbor Freight mill as the base for a full blow 4 Axis CNC mill, so, I bought one of those.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=12584&item=220068969126

So far I really like it!!

Going to make a CNC router one day.... one day.
hehe
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: Chaoticone on February 04, 2007, 08:15:54 PM: Google McMaster Carr, MSC industrial, J and L supply. All three should have either system.

Brett
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: chad on February 09, 2007, 01:15:16 PM: Hi VOTS,

I have a fog buster ( www.fogbuster.com (http://www.fogbuster.com) ) and am very happy with it! Here is the deal with cutting aluminum. You have to use lubricant and you need a nice sharp bit. When cutting with small bits if the aluminium galls (sticks to the bit) then it looses it's cutting power and will just try to push the metal out of the way resulting in a broken bit and a crappy cut. Some people say not to use carbide bits with aluminum but that is all i use had have had great luck!

.02

Chad
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: VOTS on February 09, 2007, 02:36:24 PM: Thanks Chad... Still debating whether or not to get one at all. Been having decent luck with just plain ole WD40 and a shop vac. (Redneck CNC milling!) Allot of my issue was also due to feed rate, I've taken to r-e-a-l-l-y slow milling. It is a bit frustrating to do so, but the success rate compared to before is significant. Trial and (expensive) error at this point. I also am piddling with using a larger bit, and using offsets. Marginal success here as the stuff I'm mill is pretty darn small. Using a 1/8th bit I'm getting decent result with the exception of (the obvious) over lap in the width of the cut. Ordered some more 1/16th bits, as my last one went to that great machine shop in the sky....

:)
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: chad on February 09, 2007, 02:51:30 PM: I have been using these. It is a 1/8 carbide end mill 3 flute high helix angle. http://www.discount-tools.com/endmills/3300.cfm I use 33008.

I order them from my local tooling supplier but the prices are comparable. They work very well.
Just a comment on the fogbuster ( i have no affiliation) the nice thing is you can adjust how much lube you use and the air blows the chips out so you don't re cut them and keeps the bit cool. I can not imagine milling now without it. Sorry I keep harping on it but it has made that big of a difference in my machining.

Chad
Title: Re: 'Mill dust' and breaking bits... Advice please...
Post by: bicycleguy on February 09, 2007, 11:11:33 PM: Hi,
You didn't mention what kind of aluminum you are machining but it looks soft. The hardness of the aluminum makes a great difference in machinability. The hardness is determined by the kind and treatment. Dead soft aluminum such as 1100 series gums. 6061-T4 is probably the best for machining and general use and is not that much more expensive. Look up aluminum at http://www.mcmaster.com/ for some good info.