259 lines
10 KiB
Markdown
Executable File
259 lines
10 KiB
Markdown
Executable File
# Type
|
||
|
||
<figure>
|
||
<img src="TAIG_CNC_Mill.JPG" title="TAIG_CNC_Mill.JPG" />
|
||
<figcaption>TAIG_CNC_Mill.JPG</figcaption>
|
||
</figure>
|
||
|
||
Our CNC mill is a [MicroMill DSLS
|
||
3000](http://www.microproto.com/MMDSLS.htm), a [Taig Manufactured CNC
|
||
Mill](http://www.taigtools.com/cmill.html).
|
||
|
||
This mill is generously on loan from the Smithsonian.
|
||
|
||
We are running [ArtSoft Mach3](http://www.machsupport.com/) for control
|
||
software.
|
||
|
||
# Terms
|
||
|
||
- Computer Numerical Control (CNC) - The ability to control a machine
|
||
using mathematical commands
|
||
- Computer Aided Design (CAD) - Software which generates a model which a
|
||
machine can translate into tooling commands for manufacturing.
|
||
- Computer Aided Manufacturing (CAM) - The actual process of production
|
||
from file to finished product.
|
||
- Tooling/tools - The bits used in a mill to actually
|
||
- Milling - The use of a spinning piece of metal to shape an object
|
||
through calculated removal of a media, normally via an X / Y / Z axis.
|
||
- Manual Data Input (MDI) - A method for doing manual milling with
|
||
precise control commands.
|
||
- Lathing - The use of a "static" piece of metal to shape an object
|
||
through calculated removal of a media which is in (usually) a circular
|
||
motion.
|
||
- [Mach3](http://www.machsupport.com/) - The software used to translate
|
||
G Code into electrical pulses which can be used by a mill.
|
||
|
||
# Getting Started
|
||
|
||
To initially get started with the CNC mill, it's helpful to have a basic
|
||
grasp of G Code. How better to get started with this than to begin
|
||
playing.
|
||
|
||
## Turning on the Mill
|
||
|
||
When turning on the mill there are three primary "light switch" style
|
||
switches which should be turned on. The first is on the back of the
|
||
black box labeled "MicroProto Systems, MicroMill DSLS 3000". This switch
|
||
is located on the back to the right side (imagine reaching around on the
|
||
rear right). Flipping the switch "up" should turn this on.
|
||
|
||
Next, turn on the main control to the spindle. This is achieved via the
|
||
light switch on the M3/M5 box. Turn this to the "on" position (flicking
|
||
it towards the label M3/M5).
|
||
|
||
Finally, turn on the spindle on the actual mill. This is in a blue
|
||
enameled box residing on the Z axis. Flip this switch "up". If the
|
||
spindle immediately starts spinning, this is because someone didn't send
|
||
the control command to stop it. This isn't a problem, but we will want
|
||
to stop it sooner than later. We will cover this in the next section.
|
||
|
||
To avoid unexpectedly turning on the spindle motor when powering on the
|
||
machine, wait to flip the power switch to the on position until after
|
||
EMC2 is running. This will ensure that the parallel port is in the
|
||
appropriate state according to the configuration file to keep all motors
|
||
off by default.
|
||
|
||
## Starting Mach3
|
||
|
||
This can be done by using the icon on the desktop.
|
||
|
||
## Spindle control and Emergency Stop
|
||
|
||
If the tooling is clear of all obstacles, you can press *F5* to toggle
|
||
the spindle motor on and off.
|
||
|
||
The switch on the right side of the mill, near the top will cut power to
|
||
the spindle. This is the best way to shut it down in an emergency... but
|
||
note that the axis can still move after the switch is thrown. Pressing
|
||
*Reset* in the interface will signal Mach3 to make an *Emergency Stop*.
|
||
You'll see the *Reset* button blink, and the status line at the bottom
|
||
will read "E-Stop Triggered, press reset...".
|
||
|
||
## Making our first motions
|
||
|
||
### Jog Controls
|
||
|
||
To start, we're going to use the "jog" functions to move the milling
|
||
cutter around and get a feel for what is "positive" and "negative" on
|
||
the X, Y, & Z axis.
|
||
|
||
Especially, when starting out, limit motion to the X and Y axis as this
|
||
has the least potential for damaging our tooling (aka, breaking a bit).
|
||
As you get a feel for what's positive and negative, we will start using
|
||
larger motions.
|
||
|
||
To start, hit the "tab" key to bring up the Jog controls. The main
|
||
settings on this panel are the *Jog mode*, which can be either
|
||
*continuous* or *step*. In continuous mode, holding down the motion keys
|
||
(described below) will make the axis move continuously, and quite a lot.
|
||
In step mode, pressing or holding the motion keys will move only a fixed
|
||
step per key-press. The step distance is also configurable on the Jog
|
||
control screen. You can hide the jog controls when not in use by
|
||
pressing the *Tab* key.
|
||
|
||
To start, select continuous mode in the jog controls and press the *Left
|
||
Arrow* and *Right Arrow*. Notice that the mill table moves left and
|
||
right. This is the X axis. Next, press the *Up arrow* and *Down Arrow*
|
||
keys briefly, notice that the mill table moves front to back. This is
|
||
the Y axis. Finally, press the *Page Up* and *Page Down* keys briefly;
|
||
notice that the spindle moves up and down. This is the Z axis. As you
|
||
were moving the milling cutter around, you'll notice that the
|
||
coordinates are displayed in the main window. This is where you can
|
||
quickly survey where your tooling is located.
|
||
|
||
### Obligatory Setup
|
||
|
||
Sometimes the *Reset* button in Mach3 will be flashing. This usually
|
||
means that you exceeded the movement limits or speed of the mill and the
|
||
controller has signaled Mach3 to stop. Often clicking reset is enough to
|
||
clear this error.
|
||
|
||
### Mill Controller Crash
|
||
|
||
Sometimes the controller will crash, this is usually evidenced by
|
||
*Reset* complaining that it cannot clear a limit. It will offer a button
|
||
that says "Fix this for me". "Fix this for me" actually redefines what
|
||
an error is in the software (e.g. if input low is defined as an error,
|
||
then it will redifine error as input high). Instead of clicking *Fix
|
||
this*, you should try turning off and on the mill controller using the
|
||
switch on the rear, lower-right side. Clicking *Reset* again should
|
||
clear the trouble.
|
||
|
||
### Advanced Manual Control - MDI (Manual Data Input)
|
||
|
||
Click on the MDI tab in the main Mach3 screen to the MDI Controls
|
||
section. Within this section (the line next to input) we can type in
|
||
actual G Code to move our tooling around. To start, we're going to use
|
||
simple "go to" commands. This will rapidly move the tool to the position
|
||
that we tell it to. Note, at any time, we can stop the execution of
|
||
these commands by hitting the "stop" button on the screen or typing
|
||
ALT-S on the keyboard. The first command we will use is "rapid go to" or
|
||
"g0". As an example: make sure the tooling is well clear of the table
|
||
using the jog controls and all axis are (roughly) centered. Reset all
|
||
axis (X, Y, Z) to zero using the *Zero Axis* button located to the left
|
||
of the current axis location. As you click zero axis, you should see the
|
||
axis change to -0.0000.
|
||
|
||
To make our first motion, let's move the X axis to position 0.5. To do
|
||
this, enter this command into the box marked *Input*:
|
||
|
||
` g0 x0.5`
|
||
|
||
The X axis should begin moving and it should stop 0.5" to the right of
|
||
it's initial position.
|
||
|
||
Additionally, we can give multiple coordinates at once. Now try the
|
||
command:
|
||
|
||
` g0 x0 y0`
|
||
|
||
This should send our tool back to the starting position. This can make
|
||
things go much, much faster for resetting back to the position that you
|
||
started with the mill at.
|
||
|
||
To have more fine grained control we can use the command "g1". There is
|
||
nothing that G0 does which G1 cannot. The only difference in syntax is
|
||
that we specify the feed rate of the motion as the first option. By
|
||
default the mill is set to operate in inches per minute. Thus, unless
|
||
you change this (via g code) it should be assumed that this will be the
|
||
unit of measure for your commands.
|
||
|
||
Lets slowly raise our Z axis up one inch:
|
||
|
||
` g1 f2 z1`
|
||
|
||
Note, since we were at a position approx 1 inch up and told the mill to
|
||
return to zero at a rate of F2 or 2 inches per minute, it will take
|
||
approximately 30 seconds for this command to complete. Slow movement of
|
||
the tool (especially when 'plunging' the z axis is a good idea as it
|
||
allows for time to hit the "esc" key if things start going horribly
|
||
wrong).
|
||
|
||
Now, let's build on some of these together:
|
||
|
||
` g1 f10 x1 y1 z1`
|
||
|
||
Whoops, back to zero:
|
||
|
||
` g1 f5 x0 y0 z0`
|
||
|
||
When moving back to zero you will see that the mill is moving half of
|
||
the original speed (5 inches per minute rather than 10 inches per
|
||
minute).
|
||
|
||
Let's really open this thing up and see what it can do. While watching
|
||
this command move notice the *feed rate* indicator in the preview MDI
|
||
tab. This will allow you to see the actual speed of the tool.
|
||
|
||
` g1 f50 x1 y1 z1`
|
||
|
||
Linear motion is great and all, but how about we dwell outside the
|
||
euclidean space for a minute. The next commands that we are going to
|
||
learn are G2/G3. G2 will make a clockwise arc while G3 will make a
|
||
counterclockwise arc. The command syntax is as follows:
|
||
|
||
`*G2 - Command`
|
||
`*Fx - Feedrate at X inches per minute`
|
||
`*Xv - Destination X coordinate (in this case end at v)`
|
||
`*Yw - Destination Y coordinate (in this case end at w)`
|
||
`*Ix - X axis center point offset`
|
||
`*Jy - Y axis center point offset`
|
||
`*Za - Interpolated Z axis coordinate (optional)`
|
||
|
||
To start, lets make a circle:
|
||
|
||
` g2 f5 x1 y0 i-0.5 j0`
|
||
|
||
Annnnd we fail. This is because we've given junk data to the mill. Lets
|
||
try that again making a circle. Of course, to make a circle, we will
|
||
want our beginning (1,1,1) to be the same as our destination (1,1,1)
|
||
only changing the X axis center point offset.
|
||
|
||
` g2 f5 x1 y1 i-0.5 j0`
|
||
|
||
Fun math bits... run that command again and note the "distance to go" or
|
||
"DTG" in the preview area. Note the distance at the immediate start of
|
||
plotting our 1 inch diameter circle (2 \* 0.5 X offset). This should be
|
||
a predictable [result](http://en.wikipedia.org/wiki/Pi)
|
||
|
||
# Tool Changing
|
||
|
||
Use a wrench to gently remove the chuck. Check the toolbox beneath the
|
||
mill for different bits and other things as required.
|
||
|
||
Little force should be required to tighten the chuck; it has been said
|
||
that finger-tight is often sufficient.
|
||
|
||
# When you're done
|
||
|
||
Please cleanup the mill area and place tooling back into the mill
|
||
toolbox under the bench.
|
||
|
||
Finally, turn off all three power switches noted above.
|
||
|
||
Thanks
|
||
|
||
# Caution
|
||
|
||
Please avoid doing these things, unless you can deal with the
|
||
consequences yourself.
|
||
|
||
- Don't run the mill too far off axis. The stepper motors will usually
|
||
make a harsh grinding sound when this happens.
|
||
- Don't leave the mill completely unattended. Be prepared to hit the
|
||
*Reset* key within at most a minute of hearing something go wrong.
|
||
- Obviously, don't put your hands in hazardous places.
|
||
|
||
Otherwise, the mill is robust and newbie friendly.
|
||
|
||
[Category:CNC_Mill](Category:CNC_Mill "wikilink") |