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new at cnc
« on: September 24, 2016, 06:14:44 PM »
Tha Conductor here,
I build pretty nasty electric bicycles at the moment,
My version 2.1 is rear wheel 143v by 150a...
Does a 17.xx second quarter mile @ 85mph!
Im evilfz1 on youtube...

Just got a tiag tools servo driven cnc from micro proto systems...
Ive been 3d printing and laser cutting for years,
But obviously you all know how far behind he curve i am jus now getting into cnc...

One issue im having is im almost getting 2x scale of m input measurements vs how far the machine is acually moving...

Ive been manually jogging for a few days, and noticed it was telling me x was 24" wide when its only 12"
And what troubles me is that ive calibrated each axis as their setup book shows me values to input...

Today i ran the circle wizard, and once again confirmed of almost 2x scale...
Outer diameter of circle was going to be 1.75"
It turned out to be .909 as far as my digital mic read...
I know my cutter was .25 and was input correctly,

And as far as this particular circle wizard,
i didnt see anywhere were it differentiated what side of 1.75" i wanted to cut,
probably.bc it already knew i wanted 1.75" so itd have to cut he inside...

I am also very weary of how slow my A axis is rotating, and also what keys besides home and end keys, im using a hp laptop, will jog the A?

Thanks for any kind words, i hope to sooner than later publish some of these initial parts i purchased this mill to.make,


Offline Tweakie.CNC

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Re: new at cnc
« Reply #1 on: September 25, 2016, 01:42:05 AM »
On the Mach3 Settings screen use the Axis Calibration feature to set your Steps per Unit (use as large a dimension as you can) then see if your machine now moves the correct distances.

Re: new at cnc
« Reply #2 on: September 25, 2016, 11:31:29 AM »
Hey Tweakie,
Ha ks for the response,
I had played with those step values a lil prior to asking...

Upon reading your reply, i tried again,
And noticed just above the axis calibration button in the settings tab,
there is an reset Interp button,
Dont know what that did, but its reading correctly now,
and the given values for steps per are plenty accurate enough till i tune it next weekend...
Hopefully its smooth sailing from here, haha
Thanks again for the nudge...

Re: new at cnc
« Reply #3 on: September 25, 2016, 07:43:02 PM »
My suggestion is not to use the axis calibration function. It gets you close but is not accurate.
The calculations are quite simple and provide the correct values.

The Taig has a 20 turn per inch leadscrew.
You then need to take into account any mechanical gearing due to belts.

You then needs to work out the encoder resolution.

For example, if you have a 2:1 belt drive and a 250 ppr encoder, the calculations are;

tpi x belt gearing x encoder ppr

20 x 2 x 250 = 10,000 steps/inch

Alternatively, get the seller to tell you what it should be.


Homann Designs
email: peter at homanndesigns.com
Re: new at cnc
« Reply #4 on: September 25, 2016, 08:42:10 PM »
Yeah, all that was illustrated in their book, it was something other than how hey were calibrated,
altho they are all calibrated to as close as i can measure with my digi caliper, lol...

Im curious what the reset interp button did, is what i think set it straight.earlier...
Id imagine it stands for interpolitan?

i changed the units right there by the calibrate axis button,
From inches to mm and back to inches and then hit reset interp button,
Checked it and something had changed...

Its all good now!
I went on to fine tuning,
its dead on repeatably at 4" in all xy and z,
once again, as far as my digi caliper is concerned!

thanks again!
This is awesome!