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Author Topic: Fusion 360 and issues with Mach 4 G-Code  (Read 2419 times)

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Re: Fusion 360 and issues with Mach 4 G-Code
« Reply #10 on: January 03, 2021, 11:45:07 PM »
Hi,
are you going to use index homing?

I never bothered and with good quality roller plunger snap action microswitches I can get 0.02mm repeatability from session to
session without index homing, and 0.02mm is close enough for me.

If you don't want index homing, just don't enable it. If you do then you'll have to assign pins, input assignments....all the usual stuff for
inputs but for three new index inputs.

Craig
Gotcha, Yeah I might do it down the road, but as of right now, my method is pretty accurate.  I'm assessing everything right now.  I'm perfectly square, but I need to do some minor motor tuning.  I programmed a 4"x4" square, and my Y axis cut 4.003" and X axis cut 4.016".  My X axis has up to 4 thou of slop, so i know I can still dial that down.  That's about 4 thou per inch that I'm off.... 

Here's an odd question outside of G code now.  I've used a dial indicator to measure and tune the motors using .5 and 1 inch increments.  When I tested a large distance like 12 inches, I would be nearly a 1/32" off when using are reliable straight edge (wood pecker brand) and I used a knife edge of a bit, so a flat profile bit with a sharp edge, to make my measurement.

I'm not sure why this is, but I trusted the overall measurement more than my dial indicator.  I'm kind of lost why fine tuning in 1 inch increments would scew 1/32 of an inch over 12 inches.  After tuning with the straight edge, I then checked with the dial indicator.  My Y axis is off by about .003 over half an inch and my X is .0001 over half an inch. 

You know as I checked those just now, I realized my gantry has .010" of slop (due to plywood compression).  This would probably account for the .016 of being off

For woodworking this is more than close enough.  I cut a 12x12 square out, and you couldn't tell on a measuring tape that it was off by few thou here and there. 

I guess what's important is when I command my axises to move back and forth, they do it reliably and accurately to .002 and .003.


Now the question is, will this be enough to machine aluminum?  Primarily boring out holes so I can upgrade this thing down the road!  I would love to replace the gantry with a 3x6 80/20 product, and make custom uprights so they are stiffer than the plywood setup I have now.  Also, I would like to upgrade how I've mounted the ball screw on the gantry.   All future projects, but for now, I need to learn some more CAD, CAM and G-Code.

If anyone has answers to why soft limits act the way they do running G-Code, please comment. 

If anyone is interested you can check out my build, I've attached pics.
Re: Fusion 360 and issues with Mach 4 G-Code
« Reply #11 on: January 04, 2021, 02:02:46 AM »
when i start i also did not use index homing ,but i got many problem ,specheli with z axiss(0.2mm  +-)
we change all our machines to use the index from encoder
,now its much better, i suggest use home index
Re: Fusion 360 and issues with Mach 4 G-Code
« Reply #12 on: January 07, 2021, 05:36:21 AM »
Hi Strikermed,
"Now the question is, will this be enough to machine aluminum?  Primarily boring out holes so I can upgrade this thing down the road!  I would love to replace the gantry with a 3x6 80/20 product, and make custom uprights so they are stiffer than the plywood setup I have now.  Also, I would like to upgrade how I've mounted the ball screw on the gantry.   All future projects, but for now, I need to learn some more CAD, CAM and G-Code."

To increase the stiffness of the X axis, you can add a piece or two of plywood 90 degrees to the current uprights. It looks like you have enough room in the pictures. It should be widest near the linear bearing and can taper to almost nothing at the top. Right now you are flexing the plywood across it smallest dimension (3/4") and the new stiffener will be 2" minimum.
HTH
Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: Fusion 360 and issues with Mach 4 G-Code
« Reply #13 on: January 07, 2021, 08:56:54 PM »
Hi Strikermed,
"Now the question is, will this be enough to machine aluminum?  Primarily boring out holes so I can upgrade this thing down the road!  I would love to replace the gantry with a 3x6 80/20 product, and make custom uprights so they are stiffer than the plywood setup I have now.  Also, I would like to upgrade how I've mounted the ball screw on the gantry.   All future projects, but for now, I need to learn some more CAD, CAM and G-Code."

To increase the stiffness of the X axis, you can add a piece or two of plywood 90 degrees to the current uprights. It looks like you have enough room in the pictures. It should be widest near the linear bearing and can taper to almost nothing at the top. Right now you are flexing the plywood across it smallest dimension (3/4") and the new stiffener will be 2" minimum.
HTH
Mike

Thanks for the suggestion!  I had thought about gussets as well.  I thought by adding a strip of plywood I would be doing that very thing, but I think I need to give it a triangular gusset to stiffen it up.  Down the line I hope to update my gantry with 80/20, and build some custom brackets out of 1/2-3/4 aluminum plate to replace the plywood.  Hence the aluminum requirement.