Too much vibration with my X2.

[alexccmeister]

Hi all,

Been test cutting aluminium flat bar (about 5mm thick) with different sizes of 2 flute HSS endmill. But the cut produces a lot of vibrations. So much so until the screws at the base of my quick vise was shaken loose. In fact the table was shaken loose as well. I have already bolted the mill down. If I hadn't, the vibration was worse.

My question is this the result of using 2 flute end mill? I have seen X2 cutting brass and aluminium so I know it can do it.

Anyway, still getting use to the X2 and trying to cut different material and seeing which feedrate will be best for cutting different material. Thanks.

Alex

[digits]

Originally Posted by alexccmeister Hi all, Been test cutting aluminium flat bar (about 5mm thick) with different sizes of 2 flute HSS endmill. But the cut produces a lot of vibrations. So much so until the screws at the base of my quick vise was shaken loose. In fact the table was shaken loose as well. I have already bolted the mill down. If I hadn't, the vibration was worse. My question is this the result of using 2 flute end mill? I have seen X2 cutting brass and aluminium so I know it can do it. Anyway, still getting use to the X2 and trying to cut different material and seeing which feedrate will be best for cutting different material. Thanks. Alex

What depth of cut are you attempting - surely not the full 5mm in one go - that's a bad idea, especially with an end mill of < 10mm diameter.

Try an 1/4"/6mm mill 1mm deep at 2000 or whatever max rpm is and 10-15IPM/300mm/min and see what happens.

[alexccmeister]

Hi Digits,

You are right, I was trying to cut full 5mm depth. What would you suggest would be the ideal cut depth? Isn't 1mm a bit low? That would mean I need to cut 5 rounds? I guess I can try that. Its just that I have seen people cutting bigger chunk off aluminium before.

My mill isn't cnc'ed yet so I am just having a feel for the machine itself and my own hand cranking the wheel.

[LongRat]

You'll be lucky to cut a 5mm D.O.C. with ANY cutter on an X2. Make sure your jibs are adjusted correctly, all unused axes are locked and your rig is properly lubed. The type of tool holder you use also has a lot of effect on vibration, the stiffest setup would be a direct MT3 or R8 collet (depending on the version of the mill you have). The biggest cuts I can take comfortably with the X2 would be about 3mm deep with a 10mm 2-flute or 4-flute end mill. Spraying light oil like WD40 onto the job also makes a marked difference, if you don't have the luxury of a proper coolant system.

[alexccmeister]

Hi Longrat,

Thanks for your comments. I am using an MT3 collet. Will try what you suggest. Thanks.

Alex

[ZipSnipe]

Hey Alex , also try a nice carbide face mill and you,ll see a difference in cutting depth and finish. But remember the X2 is just a baby when it comes to cutting metal. And do conventional milling technique.

Check this out
http://www.americanmachinetools.com/...ng_machine.htm
How to use a Milling Machine

http://www.jjjtrain.com/vms/cutting_..._lathe_00.html
CAD/CAM Systems

http://www.toolingu.com/resources_calc.aspx#
Calculators | Tooling University

That should help ya out.

[alexccmeister]

Hi Zip,

Thanks for the links. Will check them out. I am generally going to be doing plastic milling. But good to have a handy tool for metal as well. I have seen some X2 doing great job at cutting aluminium without a hitch.

Will try to order some carbide end mill as well. Thanks.

[ZipSnipe]

Your best bet is to get one off Ebay similar to this one

http://cgi.ebay.com/NICE-SANDVIK-3-I...QQcmdZViewItem
eBay: NICE!! SANDVIK 3" INDEXABLE FACEMILL W/ R8 SHANK (item 130119584308 end time Jun-05-07 18:53:47 PDT)

Thats a 3" you would be better off with 1" to 2" sized one. For plastic the X2 should be fine , also try bolting a large metal plate beneath the mill 1/2 to 1" thick. I used the x2 milling head in a mill I built and it has been great. However now I work nights at a Mold shop and have access to Bridgeport(now I,m spoiled)

[alexccmeister]

Hi Zip,

Thanks for the info. I did another run of cutting an alum flat bar. Just playing around. I normally cut in both directions. But I find one way cuts better with less vibration than the other. I remember reading somewhere that there is a technique to cutting along the feed or against it or something like that. I think I will need to read some more on this topic before doing larger cuts. Thanks.

[tai42]

Originally Posted by alexccmeister I remember reading somewhere that there is a technique to cutting along the feed or against it or something like that. I think I will need to read some more on this topic before doing larger cuts. Thanks.

In one direction is called "conventional milling" and the other is called "climb milling." A quick Google search will yield a wealth of information on the differences. On my X2, I will do climb milling for final few thousandths of the cut for a nice finish. However, climb milling requires a very ridged machine (which the X2 is not) so for larger cuts you may need to do conventional milling.

[alexccmeister]

Hi Tai42,

Thanks for the reply and the links. Lots of info.

Alex

[LongRat]

The biggest problem with climb milling is pulling the table through its backlash. If you try this on the X2 with more than a very light cut, you can smash your tool and work right up. On my CNC converted X2 I am running ballscrews all round (backlash effectively gone) and I only ever climb mill.