HELP: Need to mill alu, brass & copper with single flute endmill

[Ferdo]

Hi,

Forwarning, I am not a machinist.

I need to mill very small parts in some 3mm thick alu, brass and copper with a 2mm single flute endmill. I have no idea what my feeds and speeds need to be. I am using Fusion 360 for my CAM and I have tried using different CNC speeds and feeds wizards with very poor results and constant tool breakage.

It's very hard to describe exactly what I need help with so I have provided some picture to help illustrate my point.

My cnc machine is a custom 500kg+ epoxy granite mill with a 24k 7kw single.

radius of the cut is 1.9mm

https://imgur.com/nCtqbFM

https://imgur.com/lmDIVGp

https://imgur.com/3OvSWKN

 

[mhajicek]

Hi,

Forwarning, I am not a machinist.

I need to mill very small parts in some 3mm thick alu, brass and copper with a 2mm single flute endmill. I have no idea what my feeds and speeds need to be.

Here's what you want:

Advanced CNC Speed And Feed Machinist Calculator - HSMAdvisor

HSMAdvisor is an Advanced Speed And Feed Calculator for Professional CNC Programmers and Machinists. It supports hundreds of combinations of cutting materials, tools and coatings!

hsmadvisor.com

 

[Ferdo]

Here's what you want:

Advanced CNC Speed And Feed Machinist Calculator - HSMAdvisor

HSMAdvisor is an Advanced Speed And Feed Calculator for Professional CNC Programmers and Machinists. It supports hundreds of combinations of cutting materials, tools and coatings!

hsmadvisor.com

Hi

Thanks for your response, but I have already tried this.

Kind regards,
Ferdo

 

[jaguar36]

The wizards are expecting a much more rigid machine. A professional milling machine is an order of magnitude stiffer than what you’ve got. Try reducing your depth of cut to like 1/20th of what they recommend. Also, for this type of machine you’re better off over on the cnczone, they ‘ll be much more helpful with DIY machines.

 

[Nmbmxer]

Check the runout on your cutter. You might be biting off more than you intend.

 

[memphisjed]

Air or coolant blasting at the cutting area? Any shadow spots of blast area?
Pre drill the entry point, those small helix have no where for chips to go.
Second nmbmxer. Runout with a single flute is amplified.

 

[50BMG DUDE]

I'd get rid of the single flute cutter. A 2mm 2 flute endmill has a core that will be much less prone to breakage. Also use some WD-40 as cutting fluid

 

[mhajicek]

Yeah, single flute cutters should only be used in plastic, and even then, I've gotten better results with two or three flute cutters. You want flood coolant, and the nature of your machine will necessitate lighter cuts than standard. Without flood coolant, the material will stick to the cutter and cause breakage. You can get away without flood coolant, by only misting with WD-40 or similar, but then you REALLY have to reduce your cutting parameters. If not using flood coolant, a proper, material specific, coated endmill will significantly help your chances.

 

[memphisjed]

add non-pm approved message. spe tools from amazon (and other places) are more machine and program forgiving cutters on these small sizes than name brand tooling. the surface finish is not the greatest.

 

[HenkaJ]

Use fusion's adapive roughing with a 1xD depth of cut, and 0.1xD optimal load. Try a 0.02mm to 0.045mm chip load and see if you're still gumming up the works. If you're milling aluminium, try MQL with ethanol.
If i'm not mistaken, that's a FS3MG machine frame which should be plenty rigid enough to run even larger end mills in alu & steels.

As others have already pointed out, measure the runout on the tip of your tool.

 

[Ferdo]

I appreciate all the advise fellas. I will try this tomorrow and get back to you with the results.

Cheers

 

[Ferdo]

Use fusion's adapive roughing with a 1xD depth of cut, and 0.1xD optimal load. Try a 0.02mm to 0.045mm chip load and see if you're still gumming up the works. If you're milling aluminium, try MQL with ethanol.
If i'm not mistaken, that's a FS3MG machine frame which should be plenty rigid enough to run even larger end mills in alu & steels.

As others have already pointed out, measure the runout on the tip of your tool.

Here is what I have come up with. Let me know if you can see where I can add any improvements.

https://imgur.com/a/7ToN05Q

https://imgur.com/o39SDF3

 

[HenkaJ]

Here is what I have come up with. Let me know if you can see where I can add any improvements.

https://imgur.com/a/7ToN05Q

https://imgur.com/o39SDF3

Increase your ramping feed rate if you're ramping down in to the material, and bring down the ramping RPMs. Try a 0,06mm chipload so 19200 1/min and 1228mm/min.
How deep are the pockets you need to cut? If the final depth is less than 2mm, i'd disable 'Multiple Depths' and just cut them in one pass.

What brand of tooling are you using? If you're using a name brand such as datron, look up their recommended speeds & feeds and go from there.

 

[HenkaJ]

Also one important thing to note.

Monitor the actual machine speeds when it's cutting. If the machine can't accelerate fast enough in tight spaces, you're actually taking a much smaller chip load than what you've programmed. So test out the program, see if the actual movement speed matches what you've programmed and adjust accordingly.

 

[Ferdo]

Increase your ramping feed rate if you're ramping down in to the material, and bring down the ramping RPMs. Try a 0,06mm chipload so 19200 1/min and 1228mm/min.
How deep are the pockets you need to cut? If the final depth is less than 2mm, i'd disable 'Multiple Depths' and just cut them in one pass.

What brand of tooling are you using? If you're using a name brand such as datron, look up their recommended speeds & feeds and go from there.

Pardon my ignorance, but I have no idea what you mean by "Increase your ramping feed rate if you're ramping down into the material, and bring down the ramping RPMs. Try a 0,06mm chipload so 19200 1/min and 1228mm/min".

You're going to have to speak to me like I am an alien with basically zero milling experience.

What should my feed rate during the ramp-down be?
What should my ramping RPMs be?
Is the chip load the same as the feed per tooth?
19200 1/min what?
1228mm/min what?

Again, apologies for my ignorance.

The pocket is 3mm deep. Should I go with a 1.5mm step-down?

I am using a DLC-coated balanced Crown Norge endmill. A very expensive mill I know, but everything I purchased from Aliexpress was breaking. I want to stop experimenting and get my feeds and speeds down before I start milling because I can't afford to replace these Crown Norge endmills. Hence, I appreciate everyone's input.

Link to the specific endmill: https://alvoen.se/alvoen/webbshop/k...elagd-balanced-d2-d6-l6-l50?GroupId=APG443180

The only information I could get from the reseller was as follows:
2mm tool:
RPM 24000
Feed 15-20mm/sec
1-2mm/pass