I have the 5 pro with 65mm 110V VFD spindle. Using an Amana Tool 51458 CNC Flat End Mill 1/4" SH, 1/4" D - Aluminum Cutting bit. 1" thick cylinder of 6061. I am trying to drill holes of 9.55mm diameter (~3/8") all the way through, and holes of 8mm halfway through. then on the sides (the round edges of the cylinder), I need to make 2 holes 37/64" diameter partway through.
I am running 18,000RPM, 36inch/min feed rate, .015 DOC, and cutting .2" deep at a time with pauses in between. Using pocketing tool paths as the holes are larger in diameter than my bit is. I have the air kit setup, but I am having a multitude of issues.
My chip size seems far too large, and by the end of even just a .2" deep cut it seems that the heat becomes too much, the chips don’t eject from the holes, and my bit gets stuck + the spindle stalls. I have been able to work around this by absolutely dumping tap magic into the hole as it cuts but this is messy, unsafe, and according to the tutorial videos on youtube, shouldn’t be needed.
Vibration. The machine vibrates enough to knock out the knurled thumb knob on the air kit that controls the air flow, so I have to hold it while it cuts or all the air comes out the side instead of the nozzle.
I have previously tried cutting at .1" DOC and 46inch/min and it wasn’t any better. What do I need to do here? Slow it down more? Would bits that are the same size as the holes I am trying to make be better? I’m a bit lost here.
I would take even less depth of cut say .01" and come down to 20 inches per minute feed rate but most important what is your plunge rate? I would keep that around 20 inches per minute as well. Also what are you using to create the toolpath? I use Vectric Aspire and Fusion 360, Vectric has a drilling toolpath and Fusion has one called Bore which is great. They ramp down slowly which is essential for both cut quality and endmill/spindle life. This is what you want when drilling a hole.
Loctite, Reduce DoC, climb mill, ramping 2deg, .01 DoC 24ipm plunge 120ipm feed 24k rpm. Great success with A9 relton cutting fluid and i had 1" stickout doing the same size holes to 3/8 depth. Chip evacuation as well.
Also once you are beyond the shoulder expect shoulder rub and other problems, I very rarely see a proper taper on shanks to accommodate.
Edit: you will be likely to get 50 holes maximum with cutting fluid out of this tool in terms of life for this cut at 4* diameter and thats if the shoulder rub isnt a bigger problem than i anticipate.
If you need more than 50 Id advise doing 30 then soaking the cutter in lye till the aluminum is gone then go for another 30 and repeat as necessary
Slow your RPM down and your feed you are getting to much heat build up. Harvey Tool General Machining Guidelines. Use this link to figure out your RPM and your feeds then reduce them by about 25% because you are running dry.
I am using carbide create and carbide motion. The holes are just big enough for the bit to travel in a circle within each, so I’m not drilling straight down
I can’t use loctite because the knob needs to be tightened and loosened to turn off/on air flow. I don’t think I can do ramping with the free carbide motion software.
Pink loctite aka low strength is intended for this. The low strength is used for things like grub screws etc on machine tools that are intended to be readjusted essentially when it cures you can still produce enough force to deform it but it takes up all the space between the threads because mating threads are never the same giving you a nice hold without being so tough that you couldnt adjust it with your fingers.
It’s counter intuitive, but feed faster…much faster. I rarely am less than 75-100 IPM in aluminum unless I’m doing a really light finishing pass. Chips are not ejecting because they are too small, and you’re right not carrying the heat away. Faster feedrates make bigger chips that carry the heat away. Especialy on the holes, get an air blast kit like the C3D Air Assist. That will really help eject the chips and with the heat.
with a 50/50 mix of IPA and distilled water. It’s not flammable but still evaporates almost instantly taking a ton of heat away. The air also blows the chips away too. I do recommend getting the plastic one instead:
The flexible metal one moves by a few millimeters after I aim it which is annoying. I have a 3D printed holder for it that I am happy to share the model for.
