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Author Topic: Keen to learn mild steel with my CNC router!!  (Read 2048 times)

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Keen to learn mild steel with my CNC router!!
« on: May 27, 2016, 04:24:27 AM »
I have a very rigid gantry CNC Router with a 2.2KW variable speed spindle. I want to have a go at making some money cutting mild steel with it as it was offered today. Can I have some advice please on where to start with regards to cutters, air supply, misting etc. I am unable to wet the bed so misting or air would be the only option.

I have found I have no problem cutting alloy but the feeds and speeds needed to be perfect to avoid any tears from broken cutters lol

Has anyone had success doing this and wondering if it is a worthwhile project to pursue.

What about cutters? Any recommendations for dry cutting mill bits?

I hope to hear from someone I see a thread on another forum without any replies ha.

Regards from NZ
Boyd

Offline Davek0974

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Re: Keen to learn mild steel with my CNC router!!
« Reply #1 on: May 27, 2016, 05:17:47 AM »
Most likely looking at carbide two and four flute cutters, limited to <10mm dia.

Give us an idea of what sort of size tool and ill have a play with some figures.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Keen to learn mild steel with my CNC router!!
« Reply #2 on: May 29, 2016, 06:25:23 AM »
ROUTER + steel => tears, imho
Unless you use very small cutters and go quite gently.
Cheers
Roger

Offline dude1

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Re: Keen to learn mild steel with my CNC router!!
« Reply #3 on: May 29, 2016, 06:31:08 AM »
if you have a router spindle good luck

Regards From the Mainland 
Re: Keen to learn mild steel with my CNC router!!
« Reply #4 on: May 29, 2016, 12:17:48 PM »
i have never run a router, but ive run many machines of various rigidity over 40 years of machining, and this should apply.....run the cutter at or near recommended speeds, say 75% to start.  run the cutter at or near recommended feed rate per tooth, say 75%.  start with a very shallow depth of cut, say .005 inch.  if you find success there, increase the depth parameter slowly, say 50% at a time.  when you find you are breaking the points of the teeth, back off a little.  you may need to spoil a few cutters to find optimal results, and of course if you really want to get the best cutting rates you can similarly play with the feed and speed rates youre using.  imho, air is better than nothing, and mist is better than air.  if you use nothing or air, you may want cutters with TiAlN coating, these are designed to run dry and hot.  check your tool rep, there may be even better coatings available these days.  oh and ive always preferred cutters with a small nose radius, but these will be more pricey and generate more pressure.  but in a word or two, you will need to experiment a lil for your best results.  good luck!

Offline Davek0974

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Re: Keen to learn mild steel with my CNC router!!
« Reply #5 on: May 29, 2016, 01:11:06 PM »
Here's a for-instance...

Free-cutting mild steel,
6mm two-flute carbide tool
1.00mm depth of cut
Slot cutting
5138rpm
348mm/min feed rate

Now, the obvious issue with a router is the speed, my 2.2kw spindle is pretty useless below about 7-8000rpm which is too fast and will burn the tool.

Give it a go but i think steel is pretty much out for routers.

You could drop to a 3mm tool and gain rpm but loose possibilities in depth etc.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: Keen to learn mild steel with my CNC router!!
« Reply #6 on: May 31, 2016, 06:24:29 AM »
Hi there,
I have a 750W router spindle in a small homemade bedmill, cast iron beds
and a 3 inch by 3 inch solid steel column. Thought it would be rigid enuf for
steel and it is JUST.
The low torque of the spindle has made an effective limit of 3mm endmills.
You need to keep the federate up otherwise your tool does a lot of rubbing
but not much cutting and wont last 5 minutes. If you stall your spindle the
tool breaks almost instantly so federate/depth of cut are critical. Plunging
and slotting must also be carefully planned federate wise.
I had no real success until I adopted flood cooling, I wont be going back to
dry/mist/air anytime soon. I've made quite a few parts like this, slowly and
quite a few learning humps along the way....
The last few months I have been building a new spindle based on a 2.5kW
servo to get the torque required to mill steels. While servos are readily
available on Ebay pretty cheaply matching servo drives are not. Don't be fooled
by sensorless vector drives, I tried and was disappointed. I'm designing and building
my own servo drive, tourqe and speed loops only at this stage. This hobby has a way
of engaging you to learn lots of different things, in this instance programming 32 bit
microcontroller to enact 'field oriented control', what a mission! If success is measured
by what is learnt along the way I'm going great guns....

Craig
My wife left with my best friend...
     and I miss him!