[obie1]

I have a foamlynx cnc machine used for cutting foam, balsa, ect. Im using Mach2 software and cannot figure out how to keep the scaling correct so that 1" on the cad drawling = 1" on the piece being cut. Ive tuned my motors so that they run smooth @ 2000steps/unit, 10.65velocity, 61.75Acceleration rate. Are these settings the only way to keep the scale intact, or am i missing something? (chair)

Thanks in advance,
John

[High Seas]

There is a scale factor for each axis. On the Program run page you can make adjustments there if needed - be sure and hit the enter key. Kinda bit of a kludge - but maybe that will help.
Also, what have you set up for the minimum pulse width? I don't have your setup (system) but maybe there's the problem? Good luck - cheers - Jim

[obie1]

I've tried your suggestion but that seemed like a hack way of doing it. I wanted to get it set up correctly so anyone can use it, instead of just me.

My minimum pulse width is 2u sec and my direction prechange is 1u sec.

[ger21]

You're steps/ unit needs to account for screw lead and microstepping. Are you using microstepping? what screw lead? This should be the only thing that controls the distance moved.

[obie1]

Here is the specs on my machine:

CNC router table - for Dremilpad
3/4" stainless Steel rods provide a stable and reliable movement.
Comes with all motors electronics and cables. All you need to do is add the Dremil and the software.
1/2-10 ACME screws and nuts with full step / Half step / 1/8th step and 1/16th step board configuration provide up to 16,000 steps per inch.
X: 36" - effective travel - 20".
Y: 36" - effective travel - 22".


I was incorrect about my motor tuning parameters above, i loaded the wrong mach2 profile. The correct ones are below.

500 steps / unit
Velocity 2 units / sec
Acceleration 7 units / sec^2

So how exactily do i tell if im using micro-stepping?

[ger21]

Which step units is your drive using? If 1/8 step, than 8 times 200 steps per turn for your motor times 10 turns per inch for your screw = 16,000 steps/ unit.

[obie1]

Ahh, ok....So thats probally a setting in my controller box?

I need to ask the manufacture because this system came with absolutely no paper work.

:cheers:

[ger21]

So how exactily do i tell if im using micro-stepping?

What are your drives set to?

If 1/8 step, steps per unit = 8 * 200 * 10 = 16,000 steps/ unit.

[obie1]

My drives are 1.8 degrees. 360/1.8 = 200 So that means 200 steps per turn? Is that what im lookin for?

Thanks,
John

[obie1]

I found in another manual where it shows jumpers on the controller board for this setting. I emailed the company for the default.

Then i use your formula
1/8 - steps per unit = 8 * 200 * 10 = 16,000 steps/ unit.
Half - steps per unit = 2 * 200 * 10 = 4000 steps/ unit
Full - steps per unit = 1 * 200 * 10 = 2000 steps/ unit

Then i have 1 unit / inch? Am i on the right track now?

Thanks!!

[ger21]

The unit is 1 inch, yes. Those numbers should work. And 1/8 steps would probably be the way to go.

[AdamH]

I'm looking for information on cutting blue foam with cnc. Could anyone point me in the right direction. What is the best machine, how much do they cost, how big pieces can they cut etc?

thanks in advance

[High Seas]

Hot Wire - or router cut?
Just about any of the router machines you'll find in the photo gallery will do blue foam - there maybe a few Hot Wire machines there as I recall though.
Hot Wire (DIY) seem pretty inexpensive, but then are a bit purpose built and limited to that job. (Don't know how well the wire works with blue foam - I've wanted to do some Hot Wire but haven't started that one yet) Cheers - Jim