Tutorial for dummies

CNC USB Controller Software

Tutorial for dummies

Postby timoteo_mendes » 25 Oct 2013, 11:14

I am in the mood to create that manual since i have some troubles as well...

CNC–USB CONTROLLER SETTINGS AND LIMITS
A. REQUIREMENTS
1. Machine is a CNC router or mill type.
2. Standard axes X, Y and Z.
3. Limited switches installed and calibrated.
4. Fixed tool sensor and movable tool sensor (option).
5. Machine Steps/Unit correctly calibrated.
6. Machine is tested and functional with all above requirements.

B. MACHINE LIMITS
1. "Settings/Axes3/Limits/Limit Switch": Check X-, X+, Y-, Y+ and Z+. Uncheck other
check boxes.
2. "Settings/Axes3/Limits/Soft Limit" : Uncheck.
3. Lower machine jogging speed with speed override slider (bottom left corner of main
screen) to avoid hitting limit switch too fast. Use single-step jogging as needed.
4. Jog X- all the way until limit switch is hit, machine stops and machine position display
is red. Jog back a little until the limit switch is released and machine position display is
no longer red. This is machine absolute X- position (X0).
5. Please make sure “Machine/Set Position/Enable” is checked.
6. Execute “Machine/Offset/Zero” to zero working offset.
7. Execute “Machine/Tools/Zero Tool Offset” to zero tool offset.
8. Execute “Machine/Set Position/Zero Axes/X” to zero X position. X coordinate will now
have value zero.
9. Jog X+ all the way until limit switch is hit, machine stops and machine position display
is red. Jog back a little until the limit switch is released and machine position display is
no longer red. Write down coordinate X+. This is machine maximum X+ size.
10. Repeat procedure for Y- and Y+ axis.
11. Z is different because there is one limit switch Z+.
12. Mount your favorite tool into spindle. Then slowly lower Z axis so that the tip of tool bit
just touches the top of tool table. Use single-step jogging if needed to avoid crushing
tool bit into the machine table (hint: put a piece of paper between tool tip and table top.
Tool tip will press paper into table top. When the paper can no longer move then tool
tip is low enough).
13. Execute “Machine/Set Position/Zero Axes/Z” to zero Z position.
14. Jog Z+ until the limit switch is hit, machine stops and machine position display is red.
Jog back a little until the limit switch is released and machine position display is no
longer red. This is machine maximum Z+ size.
The machine absolute coordinate limits are now measured.

C. WORKING LIMITS
1. Jog machine to X, Y positions where you normally start cutting which is usually above
machine absolute X-, Y- limits (Just short distance away from X- and Y- limit switch).
The starting point can be anywhere else within the machine limits. Table center as
starting point is also quite common. Z is not important at this time.
2. Execute “Machine/Set Position/Zero Axes/X” to zero X position.
3. Execute “Machine/Set Position/Zero Axes/Y” to zero Y position.
4. Jog to X- until limit switch is hit, machine stops and machine position display is red.
Jog some distance back so that limit switch is released and machine position display is
no longer red. Write down X- position.
5. Jog to X+ until limit switch is hit, machine stops and machine position display is red.
Jog some distance back so that limit switch is released and machine position display is
no longer red. Write down X+ position.
6. Do the same for Y axis. Write down both Y- and Y+ positions.
7. "Settings/Axes 3/Limits/Limit-/X”: Input measured value of X- position.
8. “Settings/Axes 3/Limits/Limit+/X”: Input measured value of X+ position.
9. “Settings/Axes 3/Limits/Limit-/Y”: Input measured value of Y- position.
10. “Settings/Axes 3/Limits/Limit+/Y”: Input measured value of Y+ position.
11. “Settings/Axes 3/Limits/Limit-/Z”: Input zero value of Z- position.
12. “Settings/Axes 3/Limits/Limit+/Z”: Input measured value of Z+ position.
13. On 3D display window, the machine working area is now displayed as orange cube.
14. Enable “Settings/Axes 3/Limits/Soft Limits” and check if they are working. Be careful in
Z- direction. Tool can crash into machine table. If everything is correct, tool will make a
hard stop exactly at table top. Z- is only direction where soft limit makes hard stop. In
all other directions there is de-acceleration.
15. Be careful not to loose above steps when setting up machine absolute coordinates. If it
is changes, please repeat the above steps from beginning.
16. After the machine coordinates are set, the machine "Set Position" commands should
NOT use because they will change the machine absolute coordinates. It is best to
disable them by unchecking "Machine/Set Position/Enable".
17. If limit switch is hit before soft limit stops machine then your working area is too big and
you should adjust its limit value.
The machine working coordinate limits are now measured.

D. WORKING OFFSETS
If previous step was done correctly, at the 3D display screen, the orange box represents
machine X, Y, Z working area limits with yellow cone represents tool at X0, Y0 which is the
location where the cutting will start. Within this are limits, machine can move freely. If "Soft
Limits" are enabled then moving outside this box will cause motors to de-accelerate to a stop.
If "Set Position" commands are activated, they will change the machine absolute coordinates.
If that happens, CNCUSB controller will not know the correct positions of machine and
settings of soft limits, fixed tool sensor, tool change positions, etc. are useless. Therefore, it is
important that the machine limits and working limits are correct. That is why "Machine/Set
Position" command should be disable to avoid incidental changes to the limits.
What if X0, Y0 is not where I want to start cutting Z0 is to be at top surface of material ?. Here
is how to specify working offsets.
1. Place cutting material somewhere on machine table and jog X, Y axes to the position
where you want to start. Usually this is lower left corner or center of cutting material but
it can be anywhere.
2. Click "Offset - Current XY" or execute "Machine/Offset/Current XY". The machine X, Y
position displays are changed to X0, Y0 and "W" check-box is enabled. Enabled "W"
means that working offset is active. Checked "W" means that offset is applied to
coordinate display. If "W" offset is unchedked. The offsets will still be active. It is just
coordinate display that don't show it.
3. To clear offset, click "Offset - Zero" or execute "Machine/Offset/Zero".
4. The X,Y offsets are now set. Slowly jog Z axis down using single-step jogging until tip
of tool bit just touches the cutting material. Click "Offset - Current Z" or execute
"Machine/Offset/Current Z". Z0 working offset is now set. If Z0 is not on top of material
(i.e. at center or bottom of cutting material) then it can be set with the same procedure.
5. Now working offset is set for X, Y and Z. Load G-code and start cutting.
Recommend: Practice above procedures by placing different pieces on machine table and set
working offsets. This should become routine. Absolute coordinates are not required to use
working offsets.

E. HOMING
Machine absolute position can be corrected using Homing procedure just like we did it
manually in previous steps except that it is now done automatically.
At this point, you must know how to manually set machine absolute limits, working limits,
working offsets and you should NOT use any of "Set Position" commands.
Initial checks
– Check “Machine/Set Position/Enable”. We will need these commands.
– Uncheck “Machine/Soft Limits”. We will need to jog past soft limits.
– Clear working offset with “Machine/Offset/Zero”.
– Clear tool offset with “Machine/Tools/Zero Tool Offset”.
Measuring “Return Distance”.
1. Slowly jog machine X- until limit switch is hit, machine stops, and machine position
display is red.
2. Execute “Machine/Set Position/Zero”. Slowly jog the axis back until machine position
display is no longer red. The machine position display now shows how much we need
to return for switch to release. This value is usually between 0 and 5mm.
3. Write down this number and repeat procedure for all other switches (X+, Y-, Y+, Z+).
4. Take largest value, apply at least 2x safety factor and round it. This is “Return
Distance”. For example, if the largest value is 1.4mm then 1.4 x 2 = 2.4, use 3mm for
“Return Distance”. Value smaller than 1mm is not recommended.
5. Go to “Settings/Axes 3/Homing/Return Distance” and set "Return Distance" with the
calculated value.
6. Now jog to position where you want to have “HOME”. Usually this is at X0, Y0.
7. Zero all axes using “Machine/Set Position/Zero”.
8. Now jog Z up to a safe height. Roughly measure distance between tool tip and table
top with ruler or tape meter (i.e. 100mm). Round this number and use “Machine/Set
Position/User ...” to set Z value. The machine position displays should read X0, Y0,
Z100. Tool is at safe height.
9. Uncheck “Machine/Set Position/Enable”. You don't want to change absolute
coordinates any more.
10. Set “Settings/Axes 3/Homing/Go To” to this position (i.e. X0 Y0 Z100).
11. Set “Settings/Axes 3/Homing/Speed” to avoid fast return.
12. Usually you want to home Z first, then X and Y together. Set this with “Settings/Axes
3/Homing/Sequence” Z to 1, X and Y to 2.
13. You can home to positive or to negative side (Z is usually always positive). Set this with
“Settings/Axes 3/Homing/Direction”.
14. Now jog to X- until limit switch is hit. Read position display and add “Return distance”.
For example, if your display reads X-85 and your “Return Distance” is 3 then -82mm is
your value for “Settings/Axes 3/Homing/Set Position/X”.
15. Now jog to Y- until limit switch is hit. Read position display and add “Return distance”.
For example, if your display reads Y-50 and your “Return Distance” is 3 then -47mm is
your value for “Settings/Axes 3/Homing/Set Position/Y”.
16. Now jog to Z+ until limit switch is hit. Read position display and add “Return distance”.
For example, if your display reads Z120 and your “Return Distance” is 3 then 117mm is
your value for “Settings/Axes 3/Homing/Set Position/Z”.
The Idea behind this is the machine moves until switch is triggered. Then it moves back by
“Return distance” so that switch is released. This position is then used to set absolute
coordinate position to “Set Position” value. Machines then moves to “Go To” position.
Enable homing with “Settings/Axes 3/Homing/Enable”.
Now try homing with “Machine/Home”. Keep one hand on e-stop in case you did something wrong.
You will probably need to set machine limits again using these new values. Use slightly
smaller limits because soft limits need to de-accelerate machine to stop before limit switch is hit.
End of Settings and Limits

After this as been done will start to adding a fixed tool sensor.
And to decide were we would like to machine and set the 0 work offset.
timoteo_mendes
 
Posts: 10
Joined: 21 Oct 2013, 12:33
Controller: DIY Mk1

Re: Tutorial for dummies

Postby Andrej » 29 Oct 2013, 08:57

Great tutorial.
Discussion can continue here:
viewtopic.php?f=5&t=1064
Andrej
 
Posts: 2489
Joined: 10 Jan 2012, 16:09
Controller: Many controllers


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