milling copper


geoffrey pike
 

Is it any better to use a 2 flute mill instead of a 4 flute end mill to cut slots in copper plate
said slot is for LDMOS device to be soldered in,
cheers
Geoff
GI0GDP


Neil Smith G4DBN
 

I use a 2-flute polished (uncoated) slot drill. With a 10mm cutter, I run 1200rpm and 75mm/minute, with WD40 lubricant.  I have used a three-flute carbide end mill as well, but the fast-helix cutters designed for high-rate machining of aluminium work best for me.

Top trick though is to avoid C101 and use C111 (or C109 if you can find it). C111 machines with nice short chips, doesn't tear, isn't gummy and doesn't build up on the tool edge like 101.

Neil G4DBN

On 14/09/2019 22:12, geoffrey pike via Groups.Io wrote:
Is it any better to use a 2 flute mill instead of a 4 flute end mill to cut slots in copper plate
said slot is for LDMOS device to be soldered in,
cheers
Geoff
GI0GDP


Peter G3SMT
 

Hi Geoff,

Not sure which type is better but I have found that lubrication of the cutter with either kerosene or white spirit improves the cut and reduces the "stickiness" of the copper.

73

Peter    G3SMT


On 14/09/2019 22:12, geoffrey pike via Groups.Io wrote:
Is it any better to use a 2 flute mill instead of a 4 flute end mill to cut slots in copper plate
said slot is for LDMOS device to be soldered in,
cheers
Geoff
GI0GDP

--
Peter G3SMT


Mike Willis
 

Best solution, find someone else to do it who can do it properly. Otherwise you get a poor finish, or a tap breaking and getting stuck just as you tap the last of 20 holes.
--
Mike G0MJW


DougF VK4OE
 

Greetings to all.

My experience is that I have met my copper drilling/tapping/milling needs by way of purchase of drill bits, taps and milling cutters which are intended for use in cutting copper.  They do exist!  They also are great when trying to work with brass, some alloys of which are tough and likely to break whichever tool is in use.

FWIW.....

--Doug Friend, VK4OE.

On 15/09/2019 3:51 pm, Mike Willis wrote:
Best solution, find someone else to do it who can do it properly. Otherwise you get a poor finish, or a tap breaking and getting stuck just as you tap the last of 20 holes.
Mike G0MJW


geoffrey pike
 

Thanks all, i will give a 2 flute mill a try, this 4 flute is digging in, oh and more rpm
cheers
Geoff
GI0GDP

On Sunday, 15 September 2019, 07:47:07 BST, DougF <uwaves@...> wrote:


Greetings to all.

My experience is that I have met my copper drilling/tapping/milling
needs by way of purchase of drill bits, taps and milling cutters which
are intended for use in cutting copper.  They do exist!  They also are
great when trying to work with brass, some alloys of which are tough and
likely to break whichever tool is in use.

FWIW.....

--Doug Friend, VK4OE.

On 15/09/2019 3:51 pm, Mike Willis wrote:
> Best solution, find someone else to do it who can do it properly.
> Otherwise you get a poor finish, or a tap breaking and getting stuck
> just as you tap the last of 20 holes.
> Mike G0MJW



Neil Smith G4DBN
 

For really nasty copper, I have used a heavy spring to pre-load the table against the leadscrew and bolted huge lumps of lead to the table, and even in one case, made a 3kg collar for the collet holder to give lots more rotational inertia. That was trying to fly-cut at 3 inch radius though.  I gave up and used two passes with an 80mm shell mill with just two polished carbide neutral inserts with a chip-breaker and used paraffin spray mist coolant in a Noga-Cool Mini.  Then I ditched C101 and moved to C111 and use normal tools and speeds/feeds without problems.  Janky material makes for janky finishes. Using neutral or negative rake and lots of tool pressure is supposed to help, and in fact with drilling, it does.  I use spiral-point taps on through-holes bigger than M4, and thread-rolling taps with some brown waxy cutting compound for M4/3/2.5

In other news, I have two 6 x 7 inch slabs of 3/8th inch mill-finish C101 which I'm trying to face flat and parallel for some French half-kW SSPAs on 23cm. Totally horrible. Harmonics and wavy chatter are making this job very ugly.  I should have superglued it to an inch-thick ally slab right from the start. I am an idiot.

Neil G4DBN

On 15/09/2019 18:20, geoffrey pike via Groups.Io wrote:
Thanks all, i will give a 2 flute mill a try, this 4 flute is digging in, oh and more rpm
cheers
Geoff
GI0GDP

On Sunday, 15 September 2019, 07:47:07 BST, DougF <uwaves@...> wrote:


Greetings to all.

My experience is that I have met my copper drilling/tapping/milling
needs by way of purchase of drill bits, taps and milling cutters which
are intended for use in cutting copper.  They do exist!  They also are
great when trying to work with brass, some alloys of which are tough and
likely to break whichever tool is in use.

FWIW.....

--Doug Friend, VK4OE.

On 15/09/2019 3:51 pm, Mike Willis wrote:
> Best solution, find someone else to do it who can do it properly.
> Otherwise you get a poor finish, or a tap breaking and getting stuck
> just as you tap the last of 20 holes.
> Mike G0MJW