Depth of Cuts

Hi guys,

I am relatively new to CNC Milling. The company i work for recently put in a Hartford VMC. I have made many parts without issue however my question relates to cut depths and feed rates. Basically, i see all these videos on Youtube of people absolutely ripping into parts, steel aluminium etc. The chips are flying off and all seems to be happening at relative easy. However, the job i am currently working on uses a 20mm 3 Flute Carbide End Mill on aluminium and anything deeper than a 2.5mm cut just makes the tool sound like its cutting horribly. The tool is sticking out approx 70mm. I just cant fathom how these people on youtube can rip into materials harder than what im cutting and not snap tools/get bad finishes etc. I use GWIzard to calculate my speeds and feeds and am still having low success.
Basically, i understand that these people of youtube are likely ramping up their feeds/speeds to show off a bit but the bottom line is i am hoping there is some way i can improve my current cutting conditions to increase productivity.
Thanks in advance for any advice you can offer.

Hartford VMC - Max RPM 8000 - Taegutec/Guhring Tools.

Without more information.... it's tough to say exactly. The diameter to projection ratio is good. Are you climb milling? What is the spindle taper? How is the tool being held(holder style)? What is the radial depth of cut? On 6061-T6 1000 sfm and 0.003 should be a good start. Also, does the machine have enough HP? Rule of thumb 1/3 HP per cubic inch per minute in aluminum.(16.4CC) Set RPM and Feed. Adjust DOC according to machine HP.