Topics

1

General Mach Discussion / Axis length movement profiling / mapping ?

« on: October 11, 2010, 07:26:06 PM »

Hi,

I am in the build phase of a DIY wood router.
- Sized for 4 x 8 sheet
- model airplane wings
- sheet plywood
- Various other hobby things.

This is for hobby use for routing wood and foam. I have an idea to also use it to improve my drilling results as it also incorporates a drill in the Z axis. (not a spindle, a hand drill, so not perfection use, just better than I am by hand)

Drive Method
- Tried to do them all the same, but in the end, they might all end up different, but most likely belt and rack and pinion.

Motors
- At this point, steppers running open loop. I have some linistepper driver kits already, but am open to options if other methods are significantly better, and I have the budget.


Question

Regardless of what method is used, there are always imperfections and non - linear areas of a drive mechanism. For example, even high end ball screws have a rating for "accuracy per foot or meter", and a belt has even larger errors, most likely, not consistent over a 8 foot distance.

I read the mach III manual again last night (yes, I am a beginner) and found a setting to "fine tune" a local section of motion for a movement distance, but I wondered if there is a method to "fine tune" sections of the axis. Example, if I can manage to borrow a very accurate meter, can I somehow profile the axis for these imperfections continuously, or over say 10 regions of the axis ?

I realize that my work may or may not need this, it is partially for my own learning.

I am sure this has been asked before, I just could not find it in the many  pages of threads or the manual.

Feel free to just point me to the right section of the manual or an existing thread.

Thanks a lot

Harry

2

Feature Requests / More axis for master / slave control

« on: December 28, 2007, 01:14:02 PM »

Hi, I posted this in the Quantum area, but today saw that this is the correct place for feature requests.  Sorry for double posting.

I am designing / building a DIY router.   As planned, I am running up against the need for more than 6 axis for driving steppers.
- X = master / slave = 2
- Y = master / slave = 2
- Z = 2 (or more) independent Z spindles with independent Z motion = 2
- I would really like to use a stepper motor for one of the spindles = 1 or 2
- 4th axis - not yet needed, but I would really like to be able to add in the future = 1

All would be driven off of parallel ports.

Thanks

3

G-Code, CAD, and CAM discussions / Going from Rhino 3D cad to G code for Mach III question

« on: October 31, 2007, 03:58:46 PM »

Hi

I am building up a DIY CNC router which will be run from Mach III.  I do not have ANY CAD programs or experience, and am not ready to take this part on right now.  I am also new to G code.  Wow - sounds pretty lame when I spell it all out.

Anyway, a guy I know would like to take his 3D Rhino (cad ?) drawings (true 3D shapes, not 2.5) and have me cut them out in foam.  I told him that he should buy a copy of Mach III as well, import the CAD file to Mach III, and send the resulting G code to me to run on my cnc router.  I assumed I can provide a copy of my tool configuration information to him, and his exported G code would work on my router.

Now that I am reading a bit more about it, I am thinking that this advice is not sufficient - perhaps wrong.  After searching through the topics here and on cnczone, it seems that the steps are really more like:

a) Draw in Rhino CAD
b) Convert from CAD to CAM using Rhino CAM or similar
c) Post processor - no idea what that is ?
d) Have him import into Mach III at his site
e) Email the file to me for running
f) Run on my machine using Mach III

Is this right ?

It seems like perhaps Meshcam is easier ?


I tried searching and reading about this topic, but I am still unsure of how to go from drawing to part.

Thanks

HarryN