Since Coils is far from the first to ask and I am on my back from surgery and have time, I will try to detail my CNC conversion. This will be a work in progress and I will add to it/ change pics out as I get better ones.
My conversion is not the only way I am sure but it WORKS and works well.
CNC stands for
Computer
Numeric
Control. Basically you give the machine a series of numbers or "G" codes (more on this later) and the machine moves in one through 4 axis (yes there are more axis but for us this is it)
A basic explanation is this:
A g code is written or converted from CAD (Computer Aided Drawing)
by means of a thumb drive or CD this is put into the desktop computer.
You open your CAM (Computer Aided Machining) program and it checks the code automatically for basic errors (i.e. is the code in the right format)
You locate your zeros on your part (basically where the coordinates are x0,y0,z0,a0
Zero your program or enter the coordinates it is to start machining from.
Make sure your material is well clamped.
Hit start.
The CAM sends signals to the stepper controller which is powered by the power supply
The Stepper controller sends signals through the shielded cables to the steppers telling it how fast and how far it needs to turn. My controller can do all 4 axis at once.
The steppers either rotate the ballscrews or cogged pulleys attached to the ballscrews to move the table and head.
The steppers are also your measuring device, each rotation has hundreds of "steps" and each step is calibrated to a linear distance of the bed, you can use some scales to interface also if you have DRO (Digital Read Out) but the steppers work very well themselves UNLESS THEY SKIP.
Your part is machined.
You will need:
A mill drill, mini mill or knee mill.
A desktop computer running XP(for some reason beyond me many laptops are "clocked" different and?or lack the type of graphics card you need) ADD LINK HERE I use an old dell I bought from the local computer repair shop for $50
A power source for the stepper motors
CAM program
A stepper driver
Shielded cable (ADD TECHNICAL NAME HERE)
ADD LINK TO ebay
Cable connectors
Stepper motors (
YOU MUST SOLDER IN A RESISTER AS SPECIFIED OR BURN OUT YOUR SYSTEM)
Ball screws
Ball nuts or zero back lash ball nuts
Bearings (MUST SUPPORT AXIAL AND THRUST LOADS)
brackets (you make)
OPTIONAL PARTS
pulleys (to increase the power and holding ability of the steppers)
McMaster-Carr
belts
McMaster-Carr
My set up:
My CNC uses a X Axis stepper directly driving a ball screw
This is a direct drive coupler used to correct any misalignment.
It is hidden in here:
one end goes on the stepper shaft and the other goes on the ball screw
The stepper is
NEMA 23 Stepper Motor: KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 (Inductance 2.8 mH) Can be used for G540, G251, G250 or any other driver
381 oz In. Hybrid Motor
1.8° /200 Steps Per Rev.
3.5 Amps Current Per Phase
4-wire Bi-polar, NEMA 23 Frame
Found here:
Stepper Motor
Buy a stronger stepper for the mill drill, it should be fine for a smaller mill
The ball screw is
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc. $11.24 a foot
The ball screw nuts are (need 2)
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc.
Part Number: 19193 $26.23 each
Belleville washers (unknown number, maybe 6-8)
McMaster-Carr
0.630" 1.250" 0.040" 0.082" 0.021" 230 330 qty12 9712K82 $5.11
now I think these are right, I will measure some. They are 1.250" OD and the mount for zero backlash is only 1.00" wide. You will have to mill out room for them.
Heres a pic of the outside
My y axis was skipping (caused by not enough torque and resulting in a lost "zero") so it is geared down for power by using cogged xl pulleys, belt and idler bearing)
I designed a better bearing retainer here, look at the button head screw that over lapps the bearing.
The stepper is
NEMA 23 Stepper Motor: KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 (Inductance 2.8 mH) Can be used for G540, G251, G250 or any other driver
381 oz In. Hybrid Motor
1.8° /200 Steps Per Rev.
3.5 Amps Current Per Phase
4-wire Bi-polar, NEMA 23 Frame
Found here:
Stepper Motor
I would go with a stronger stepper here, but for a smaller mill it should be fine
The ball screw is
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc. $11.24 a foot
The ball screw nuts are (need 2)
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc.
Part Number: 19193 $26.23 each
Belleville washers (unknown number, maybe 6-8)
McMaster-Carr
0.630" 1.250" 0.040" 0.082" 0.021" 230 330 qty12 9712K82 $5.11
now I think these are right, I will measure some. They are 1.250" OD and the mount for zero backlash is only 1.00" wide. You will have to mill out room for them.
The Z axis seems to have a million solutions, this is mine. a XL belt, cogged pulleys and idler bearing. It drives the head up and down.
Video of z axis operating. Dont get dizzy ;>
The stepper is
NEMA 23 Stepper Motor: KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 (Inductance 2.8 mH) Can be used for G540, G251, G250 or any other driver
381 oz In. Hybrid Motor
1.8° /200 Steps Per Rev.
3.5 Amps Current Per Phase
4-wire Bi-polar, NEMA 23 Frame
Found here:
Stepper Motor
It is just right for my use
The ball screw is
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc. $11.24 a foot
The ball screw nuts are (need 2)
5/8 X .200 Right Hand Recirculating Lead Screws & Nuts for Power Transmission - Roton Products, Inc.
Part Number: 19193 $26.23 each
Belleville washers (unknown number, maybe 6-8)
McMaster-Carr
0.630" 1.250" 0.040" 0.082" 0.021" 230 330 qty12 9712K82 $5.11
now I think these are right, I will measure some. there is plenty of room here so no need to cut mount
The top of the assembly
The middle
The attachment point to the head. Please note the red wires go to a ton of LEDs glued in to light the work surface evenly
I added this spring to put constant tension on the head. It makes machining much easier to not have to loosen and tighten repeatedly.
I believe this is the spring
McMaster-Carr
9434K163 1 Pack Music Wire Precision Compression Spring, Zinc-plated, .750" Length, .12" Od, .016" Wire $4.65
my A axis (or 4axis or rotational axis) is run off a cogged set of XL pulleys and an XL belt, run to a dividing head.
The stepper is
NEMA 23 Stepper Motor: KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 (Inductance 2.8 mH) Can be used for G540, G251, G250 or any other driver
381 oz In. Hybrid Motor
1.8° /200 Steps Per Rev.
3.5 Amps Current Per Phase
4-wire Bi-polar, NEMA 23 Frame
Found here:
Stepper Motor
It is just right for my use or even too big
I did not buy ultra expensive zero backlash ball nuts, I made them.
homemade zero backlash nuts
The belleville washers are under significant pressure. The right nut is secured in the mount. The springs push against the left nut which is prevented from rotating but he sides and bottom of the mount but it is allowed to slide in the mount for wear adjustment. The springs MUST BE STRONG or the table will shudder and grab as the end mill cuts.
power supply
KL-350-48 48V/7.3A
110V/230V $49.95
Switching Power Supply
Stepper driver (Gecko)
GeckoDriver G540 4 Axis driver Current New Version with a
complete Motor Connector Set of four 9 pin modules,
Special $239.95,
Page Title
CNC CAM (Mach III)
$149
Mach3 - 45000Hz 6-Axis Controller for
Windows XP and 2000 $175
MACH 3 FEATURES
Converts a standard PC to a fully featured
CNC controller.
Up to 6 axis cnc control
Allows direct import of DXF BMP JPG and
HPGL.
Visual G-Code display
Generates G-code
CNC Software
Axial/thrust bearings
McMaster-Carr
Ballscrews are EXTREMELY hard be sure to anneal before turning and threading.
PRICE
$66 ballscrews
$170 ball nuts
$49 POWER SUPPLY
$50 DESK TOP COMPUTER
$239 Gecko driver
$149 CAM mach III
$200 bearings pulleys couples etc
TOTAL
under $1000 easy