« previous next »
Pages: [1]

Author Topic: CNC machines  (Read 944 times)

bedlamite

  • Hold my beer and watch this!
  • friend
  • Senior Member
  • ***
  • Posts: 9,925
  • Ack! PLBTTPHBT!
CNC machines
« on: September 03, 2013, 07:55:16 PM »
I know there's been some discussion about RepRap, but has anyone got a CNC mill up and running?

I just ordered motors, motor controllers, and a breakout board.

For Software, I've got LinuxCNC up an running on an older Sempron, and I've also got an older copy of AutoCAD I've been using for a few years. I'm looking at a few programs for toolpath generation: Freemill, PyCAM, and FreeCAD. Has anyone used any of these?
Report to moderator   Logged
A plan is just a list of things that doesn't happen.
Is defenestration possible through the overton window?

Boomhauer

  • Former Moderator, fired for embezzlement and abuse of power
  • friends
  • Senior Member
  • ***
  • Posts: 14,513
Re: CNC machines
« Reply #1 on: September 03, 2013, 08:02:37 PM »
Get on Practical Machinist forum.

Report to moderator   Logged
Quote from: Ben
Holy hell. It's like giving a loaded gun to a chimpanzee...

Quote from: bluestarlizzard
the last thing you need is rabies. You're already angry enough as it is.

OTOH, there wouldn't be a tweeker left in Georgia...

Quote from: Balog
BLOOD FOR THE BLOOD GOD! SKULLS FOR THE SKULL THRONE! AND THROW SOME STEAK ON THE GRILL!

DustinD

  • I have a title
  • friends
  • Senior Member
  • ***
  • Posts: 919
  • I have a personal text message
Re: CNC machines
« Reply #2 on: September 04, 2013, 08:54:31 PM »
That and www.cnczone.com are awesome resources.
Report to moderator   Logged
"I don't always shoot defenceless women in the face, but when I do, I prefer H-S Precision.

Stay bloodthirsty, my friends."

                       - Lon Horiuchi

Nick1911

  • Administrator
  • Senior Member
  • *****
  • Posts: 8,492
Re: CNC machines
« Reply #3 on: September 05, 2013, 10:53:18 AM »
I've thought about installing CNC on my mill, but never actually pulled the trigger.

What kind of mill are you using?

I'm curious how it turns out - please keep us updated with how the project goes.
Report to moderator   Logged

AZRedhawk44

  • friends
  • Senior Member
  • ***
  • Posts: 14,032
Re: CNC machines
« Reply #4 on: September 05, 2013, 10:56:13 AM »
Don't you need some sort of crazy-heavy platform for CNC milling?  Otherwise the vibrations knock your workpiece or even the whole platform around?
Report to moderator   Logged
"But whether the Constitution really be one thing, or another, this much is certain - that it has either authorized such a government as we have had, or has been powerless to prevent it. In either case, it is unfit to exist."
--Lysander Spooner

I reject your authoritah!

Nick1911

  • Administrator
  • Senior Member
  • *****
  • Posts: 8,492
Re: CNC machines
« Reply #5 on: September 05, 2013, 11:08:08 AM »
Quote from: AZRedhawk44 on September 05, 2013, 10:56:13 AM
Don't you need some sort of crazy-heavy platform for CNC milling?  Otherwise the vibrations knock your workpiece or even the whole platform around?

Generally you start with a manual mill, and add servos, limit switches, etc to that.
Report to moderator   Logged

bedlamite

  • Hold my beer and watch this!
  • friend
  • Senior Member
  • ***
  • Posts: 9,925
  • Ack! PLBTTPHBT!
Re: CNC machines
« Reply #6 on: September 05, 2013, 03:56:00 PM »
Mostly this is an exercise to learn how to do this. I'm building the frame from boxed 3/4" Sandeply, and it's moving on ABEC7 608RS bearings with 4140 precision ground square rails, and I'll be using a trim router. It'll have a fixed gantry and the x axis on a movable bed, y and z axis are similar to this.

It boils down to speed and precision cost money, and my goal is to keep the entire project under $500. Not ready for a Bridgeport, yet  ...
It should be able to cut wood, plastic, and soft metals, steel isn't going to happen. Part of me wants to make an AR15 lower out of walnut, just to bring to the arfcom roasted nuts shoot at some point.

Just got the tracking number for the motors and boards, UPS says they should be here Tuesday.
Report to moderator   Logged
A plan is just a list of things that doesn't happen.
Is defenestration possible through the overton window?

charby

  • Necromancer
  • Administrator
  • Senior Member
  • *****
  • Posts: 29,295
  • APS's Resident Sikh/Muslim
Re: CNC machines
« Reply #7 on: September 05, 2013, 04:08:24 PM »
Quote from: bedlamite on September 05, 2013, 03:56:00 PM
Part of me wants to make an AR15 lower out of walnut, just to bring to the arfcom roasted nuts shoot at some point.


A company not far from where I live is already doing that.
Report to moderator   Logged
Iowa- 88% more livable that the rest of the US

Uranus is a gas giant.

Team 444: Member# 536

Nick1911

  • Administrator
  • Senior Member
  • *****
  • Posts: 8,492
Re: CNC machines
« Reply #8 on: September 06, 2013, 02:37:12 AM »
In machining, rigidity is everything.  When the cutter hits the work-piece very high cutting forces occur - if the frame isn't strong enough it will deflect resulting in loss of dimensional accuracy. 

This isn't to discourage you from the project.  Lessons learned can easily be applied to $1000 benchtop mills that can cut metal.  But... don't expect too much of it.  Proper mills weigh as much as they do because that much cast iron truly is necessary if one intends to hold tolerances expected of machined parts.

Good luck and have fun playing with G codes!
Report to moderator   Logged
Pages: [1]
« previous next »