[zeox]

Hello,

My name's Martin, I'm new here.
I am new to CNC machining. I've been gradually learning to use a custom built CNC router for the past few months. The machine is pretty low-end. I am now struggling to adjust its gantry, because of non-paralelism.

Anyways, I now realised that I would need an indexable/face end mill.
The chinese spindle on the machine is 2.2kw with an ER20 collet. The largest chuck is for a 13mm shank tool.
I am still working only with MDF and Plywood, and for these materials I have a 16mm(8mm shank) 2 blade end mill, that does a pretty good work a quickly clearing large portions of material.

However, my goal is to machine aluminum (aluminum castings mostly). And I will need a large tool that can quickly face my parts.
Looking in aliexpress, I see that mose indexable mills use the same diameter for the cutting head and the shank.
So the only option (without altering) is a 13mm, single blade cutter. This one:
https://www.aliexpress.com/item/13-1...0-e1a3eb3a1c77

However I'be been thinking about some of the larger tools (20 or 30mm) like this one:
https://www.aliexpress.com/item/BAP3...0-161c5041bea9

And turning on a lathe to make the shank shorter, and reduce it to 13mm.

My question is, if this is a viable option, will the spindle be able to handle such a large tool etc.?
I've red a similar thread, where one guy was asking for the same but on an ER11 1.5kW spindle, and he was told to not go for a tool bigger than 1 inch. If I follow this logic, my 2.2kW spindle should easily handle a 20mm tool.
My Feeds and speeds calculator tells me that I should run such a tool at ~4700 rpm for a 1 or 2mm deep cut, which is within the limits of the spindle (3000 - 21800 rpm). It also tells me to use TiN/TiAlN coated inserts, however I can't seem to find those. Will standard carbide coated inserts do the job too?

[JQ_Quint]

Hello,

My name's Martin, I'm new here.
I am new to CNC machining. I've been gradually learning to use a custom built CNC router for the past few months. The machine is pretty low-end. I am now struggling to adjust its gantry, because of non-paralelism.

Anyways, I now realised that I would need an indexable/face end mill.
The chinese spindle on the machine is 2.2kw with an ER20 collet. The largest chuck is for a 13mm shank tool.
I am still working only with MDF and Plywood, and for these materials I have a 16mm(8mm shank) 2 blade end mill, that does a pretty good work a quickly clearing large portions of material.

However, my goal is to machine aluminum (aluminum castings mostly). And I will need a large tool that can quickly face my parts.
Looking in aliexpress, I see that mose indexable mills use the same diameter for the cutting head and the shank.
So the only option (without altering) is a 13mm, single blade cutter. This one:
https://www.aliexpress.com/item/13-1...0-e1a3eb3a1c77

However I'be been thinking about some of the larger tools (20 or 30mm) like this one:
https://www.aliexpress.com/item/BAP3...0-161c5041bea9

And turning on a lathe to make the shank shorter, and reduce it to 13mm.

My question is, if this is a viable option, will the spindle be able to handle such a large tool etc.?
I've red a similar thread, where one guy was asking for the same but on an ER11 1.5kW spindle, and he was told to not go for a tool bigger than 1 inch. If I follow this logic, my 2.2kW spindle should easily handle a 20mm tool.
My Feeds and speeds calculator tells me that I should run such a tool at ~4700 rpm for a 1 or 2mm deep cut, which is within the limits of the spindle (3000 - 21800 rpm). It also tells me to use TiN/TiAlN coated inserts, however I can't seem to find those. Will standard carbide coated inserts do the job too?

Hi Martin,

You say your machine is low end, are you sure its capable of machining alum? You may find at 2mm depth of cut it may struggle. However assuming it can cope I would advise to stay with solid carbide. I know you want larger diameter tooling but the indexable inserted tools like you listed will pull more load on the spindle as the carbide honed edges (on the inserts) just simply arent as keen as a nice sharp spiral endmill (uncoated). If I was going to tackle aluminium on my 6090 router (also with 2.2kw spindle) I would be going for a 12mm solid carbide endmill.

Another note - at 4700rpm the torque on these spindles is VERY low so again may struggle to cut at these low revs. I would be opting for higher revs, lighter cuts and push your feed rates bud.

Jamie

[zeox]

Hi Jamie,

Thanks for your reply. According to the guy who sold me the machine, it should handle aluminum if mist cooling is added (alternatively I could be spraying some oil by hand).
Anyways I have already ordered two mist sprayers, and I intend to use a standard compressor to supply them with air. In the future I intend to order one of those large aquarium pumps with 300L/min capacity.
Anyways the router I have is widely used for stone engraving (tombstones mostly), and handles 10-12 mm deep V-cuts in marble and granite.
Here is a picture of it from the site of the manufacturer:
http://www.cnczone.com/forums/attach...1&d=1485552567

Here's a pic of my current work
http://www.cnczone.com/forums/attach...1&d=1485554024

This is the upper part of a plywood mock up that will be used for sand casting aluminum. It already has filler applied and is ready to receive paint. So that large flat face on top (with the drill hole in it) will have to be flattened on the actual casting. That's the place where the riser will be. There are also two more faces on the other sides that have to be flattened, but this is the largest one.

As for the tool. Yes I was afraid it might be so. So I will have to stick to 12-13mm flat end mills
However my feeds and speeds calc (Gwizzards) gives me very low RPM even for carbide flat end mills. It says that for a 12mm, 3 flute carbide mill I should use 6500rpm for cuts from 0.1 to 1mm.
It's only when I reduce the diameter of the tool to 6mm, that it proposes higher rpm - 13000

So, do you think I should go for 12mm at 6500rpm, or should I use 6mm @13000 rpm?
At what RPM do you use the 12mm mill on your machine? And what feed and depth of cut?

Edit: I just found the YouTube channel of the guy who makes these machines.
There are videos of his machines engraving stone with water cooling, and aluminum with no cooling at all (I suppose he poured some diesel on the stock piece first).
https://www.youtube.com/watch?v=WNthVfFL_rc
https://www.youtube.com/watch?v=fmgtEOPEi8Q
https://www.youtube.com/watch?v=Fil273LWhto