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4 X 8 blackToe setup

4 X 8 blackToe setup

Postby keith » Sat Jan 30, 2010 5:37 pm

Patrick has kindly provided me with his basic machine MACH3 setup and asked me to post it on the forum. This should provide a great resource for us all. If anyone else wants to post a different setup, wouldn't that be the beginnings of a great resource we can all share!

So here it is direct from Patrick:

Method so you know:
Motor - 200 steps per revolution
Drivers for motors that will be moving via chain should be set to 1/16 microstepping
Actual steps per revolution - 200 * 16 = 3200

Now to find the steps per inch:
#40 sprockets are .5 inch pitch. At 9 teeth, you have 4.5 inches of travel for one revolution.
So, 3200 / 4.5 = 711.111111 steps per inch

There is your number to put into the step per.

If you are working in mm, try replacing the 4.5 inches with 114.3 mm.
So, 3200 / 114.3 = 27.997 steps per mm

For the screw, you have 2 turns per inch.

If you have 1/4 microstepping for the screw, here is the formula: 200 * 4 * 2 = 1600 steps per inch
for mm, there are 25.4 mm in one inch, or 12.7 mm in .5 inches. So, in one full revolution, there is 800 steps for 12.7 mm. Let's divide and see what we have... 800/12.7 = 62.99 steps per each mm.

The Titanic was built by professionals; the Ark was built by Amateurs..........
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4 X 8 blackToe setup

Postby mikeusnret » Fri Feb 05, 2010 6:29 am

why would one use 1/16th microstepping instead of 1/8th or 1/4? just curious here.

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4 X 8 blackToe setup

Postby PHoodDaniel » Fri Feb 05, 2010 8:13 am

1/16th microstepping increases the resolution. 200 steps per rev multiplied by 16 is 3200. If 1/8th is used, then you only have half the resolution. I would not suggest higher than 1/16th (i.e. 1/32, 1/64) as the motor torque will not be as high.

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4 X 8 blackToe setup

Postby george » Mon Mar 22, 2010 5:02 am

Here's my EMC2 Setup (AKA stepconf wizard responses):

=========================
Basic Machine Information
Machine Name: blacktoe
Axis: xyz
Machine units: inches

Driver: Keling 4030

=========================
Parallel Port Setup

Pin 1 ESTOP Out [ ]
Pin 2 X Step [X]
Pin 3 X Direction [X]
Pin 4 y Step [X]
Pin 5 y Direction [ ]
Pin 6 z Step [X]
Pin 7 z Direction [X]


=========================
X Axis Configuration

Motor steps per revolution: 200
Driver microstepping: 0.125
Pulley teeth: 1 : 1
Lead screw pitch: 28.4
Max vel: 10
Max acc: 20
Table travel: 0.0 ... 48.0
Home location: 0.0

=========================
Y Axis Configuration

Motor steps per revolution: 200
Driver microstepping: 0.125
Pulley teeth: 1 : 1
Lead screw pitch: 28.4
Max vel: 5
Max acc: 20
Table travel: 0.0 ... 24.0
Home location: 0.0

=========================
Z Axis Configuration

Motor steps per revolution: 200
Driver microstepping: 0.25
Pulley teeth: 1 : 1
Lead screw pitch: 32.6
Max vel: 1
Max acc: 20
Table travel: -0.240 ... 2.50
Home location: 0.0

=========================
Advanced Configuration Options

[X] Include Halui user interface component


=========================

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4 X 8 blackToe setup

Postby mikeusnret » Wed Apr 07, 2010 2:24 pm

What are the particulars for the Z-Axis lead screw for setting the steps per in Mach3?

I think the one patrick provides is a 1/2"-10 2 turn 5 start? or is it something different?

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Postby Awesomeness » Wed Apr 07, 2010 11:52 pm

Here's Patrick's description about setting the lead screw...

For the lead screw, I recommend 1/4 microstepping. So, 200 steps per inch multiplied by 4 steps (per full step) is 800 steps per revolution. With lead screws, the math is a bit reversed since the mechanism is actually increasing the resolution. The lead screw, as mentioned above, yields 2 turns per inch. Since we are going the other way and the mechanism is multiplying the resolution, we need to multiply the steps per revolution by the number of turns per inch (2). So, the product of 800 and 2 is 1600. Another way to think about this (similar to the roller chain math) is to divide 800 by the number of inches in one turn, which is 1/2 inch. so, 800 divide by .5 gives us the same answer, 1600 steps per inch. you can increase both the roller chain and lead screw numbers by increasing the microstepping. Make sure to understand the torque at higher settings.

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4 X 8 blackToe setup

Postby mikeusnret » Thu Apr 08, 2010 3:35 am

Got ya Guido.

I have always done it as 200 * screw tpi = X

X * microstepping = Y

Y / # of starts = Z (Steps Per)

Alot of the variables depend on whether one uses 1/4 or 1/8 microstepping, Size of the lead screw and it's inherant threads per inch ie 1/2"-10 or 1/2"-13. Also, is it a 5 turn 2 start or a 2 turn 5 starts lead screw.

Defaulting to a 1/2"-10 2 turn 5 start screw and drivers set for 1/4 microstepping we could apply

200 * 10 = 2000. 2000 * 4 = 8000 8000 / 5 = 1600 which is the same that you came up with :)

I'll go plug this value in as my Steps Per on the Z and measure the amount of travel in inches and then adjust up or down by 50 as needed so I'm dead on in travel.

I recall on my 20 x 40 table, I started out at 8000 steps per and to get an actual inch of travel, I ended up with something like 8026.

Thanks again for the info and the memory refresher :)

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Postby homebear » Thu Apr 08, 2010 4:36 pm

Hey all, just signed up for the forum. My three man fabrication company has had a blacktoe v2.2 up and running for about a month now.

Question, is there any disadvantage to just using the "set steps per unit" tool on the Mach3 settings screen rather than manually inputting the numbers discussed in this thread?

My method so far has been to mount a pair of digital calipers to stable block on the table, and run the steps per unit wizard using the distance the router mount pushes the caliper head (resolution of ".0001) for the "how far did the axis move?" prompt.

This has been a little frustrating in that I may get a fairly accurate reading once or twice after my initial setting, then randomly get one that is up to .025 off. I'm not sure if the discrepancy in repeatability is due to my putting full faith in the wizard, but I don't see how this could be failing I have had some proportional issues as a result of this in my attempts so far to route pcb boards.

I see that you were getting a ballpark from the math and using trial and error to calibrate your machine Michael, that seems like the next logical step I should take. Has anyone else had the kind repeatability issues I cited? Or could these be due to a mechanical error on my part? Not enough chain tension...

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Postby homebear » Mon Apr 12, 2010 5:48 am

Update. If anyone is following this, I switched my drivers to 1/16th micro step and things are looking up. I am able to get movements accurate to .0001 now. All by using the automated mach 3 unit test. I've been using a fairly expensive servo'ed TechnoCNC router at my school for a while now and it's no where near this accurate! PCB's here I come!

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Postby Awesomeness » Mon Apr 12, 2010 6:02 am

Good to hear!

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