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Author Topic: G40, G41 and G42 have no effect.  (Read 18323 times)

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Re: G40, G41 and G42 have no effect.
« Reply #10 on: August 07, 2011, 02:04:13 PM »
OOps! P.S.
The gear needs to be cut using compensation for the cutter diameter which is one eighth inch.

Thanks again

jim agray

Offline Tweakie.CNC

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Re: G40, G41 and G42 have no effect.
« Reply #11 on: August 08, 2011, 01:25:54 AM »
Hi Jim,

Before I started using Gearotic Motion I used Gear Generator for the profile then the free version of CamBam to create the offset toolpath (tool radius offset). This then ran just fine with Mach without using the three G's.

Tweakie.
PEACE
Re: G40, G41 and G42 have no effect.
« Reply #12 on: August 08, 2011, 04:25:54 PM »
Tweakie, Thanks for the information. I'm ordering Gearotic Motion right now. I guess that should solve my remaining misunderstanding about this project plus allow me to do a whole lot more later.

Thanks,
Jim Gray

Offline RICH

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Re: G40, G41 and G42 have no effect.
« Reply #13 on: August 08, 2011, 05:14:58 PM »
Jim,
Quote
But now I'm running out of time.
Quote
the gcode file must, please, have been run before and tested.
Really now........your time problem is not ours......... >:D

Quote
but offsetting for cutting is my problem
I generated a dxf file for the gear from two different programs and LC choked when trying to do an offset for either of them.
What happens is that a lot of gear programs generate the profile for one tooth and then you rotate / create an array for the others.
LC dosen't like that. Additionaly the programs create manny short line sgments instead of arcs and the gear profile can be made up of arcs and reduce the code significantly if drawn. I used CamBam and it also choked on the files also ( probably my doing   :D ). Didn't have time to fool with the files but think I know what you meant about offsetting them.
RICH
Re: G40, G41 and G42 have no effect.
« Reply #14 on: August 08, 2011, 06:57:40 PM »
Rich, I wasn't critcizing nor placing any burden on you guys, I was trying to get you to sympathize with me and my being nagged on by my  wife!

I don't lay claim to any of your time nor effort, I was just trying to let you guys know I was in a pickle and needed  unusual help if there was someone who wanted to volunteer helping. The problem is definitely mine.

You mentioned that you tried to create the gear using two different programs, thank you. But you say you don't know if they were using an array to duplicate the teeth after the first?

I mentioned testing it because I always seem to leave something out of my first of anything, and find out only when I test.

Please be kind enough to let me know anything you find out, if you so desire.

When I try my best but can't get something done, I have no choice but to give up or ask for help.

Thank you,
Jim Gray

Offline RICH

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Re: G40, G41 and G42 have no effect.
« Reply #15 on: August 08, 2011, 07:38:04 PM »
Post the dxf file generated by your program and will have a look at it in CAD and LC.
RICH

Offline BR549

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Re: G40, G41 and G42 have no effect.
« Reply #16 on: August 08, 2011, 09:14:39 PM »
As Rich said please post the DXF of the part your need. One of us will figure it out. 

(;-) TP

Offline RICH

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Re: G40, G41 and G42 have no effect.
« Reply #17 on: August 08, 2011, 10:48:59 PM »
The pic below shows the results of cleaning up the gear drawing in CAD before importing into LC.
I quickly made all the segments of the gear out of arcs in the drawing. The one on the right could not be offset in LC and as you can see
there are numerous rapids created after it was cleaned. When something won't offset, manny times it's due to parts of the profile
not being connected and quickly shows up when you try to pocket it or create offsets.

The one on the left side was cleaned up in CAD by doing a zero fillet to all adjoining pieces of the profile. It is continous and there are no overlapping of elements or breaks between the elements. Notice there is only one rapid. No problem doing offsets to the profile.

The cleaner the drawing is for LC the less trouble you will have.
I drew over the numerous small straight line segments with arcs and created a different profile to be exported for use in LC.

I have found that most of the programs  that just create the actual profile of gears and allow you to DXF them out create  a poor
profile. By that I am meaning that there are no arcs used and the dxf leaves something to be desired.

I don't do manny gears and in the past drew all my gears out in CAD. I have a spread sheet that gives you all the dim's for any  spur gear
so it can be drawn quickly . Once a tooth is accurately drawn a radial matrix is done on it to provide the others in the drawing. I remember
some time ago comparing drawn gears to the gears done by some programs and although the programs created the profile manny times the profiles where not accurate. Not out by a lot but still not an accurate gear.

I have Gearotica but just can;t seem to egt around to fooling with it. It is a slick program.

So should you hear me echo that the dxf is something to be desired and is a culprit to problems remember the attached pic.

Please note that  i don't want something drawn by etch a sketch programs to check.......

But still interested in yours Jim,

RICH

Offline BR549

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Re: G40, G41 and G42 have no effect.
« Reply #18 on: August 08, 2011, 11:52:09 PM »
Also note the the shape of the ROOT will be different. You cannot cut a inside square edge with a round tool. It will always leave a minimum radius the size of the tool. Depending on the application whether this is a problem or not with tooth clearance.

This is the 2.5d method of CNC gear cutting. Some Gear generation programs  may use the 4th axis method to Machine the gears. Check before you buy to make sure it matches the method you have to make the gears.

Just a thought, (;-) TP

Offline Tweakie.CNC

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Re: G40, G41 and G42 have no effect.
« Reply #19 on: August 09, 2011, 02:01:59 AM »
Tweakie, Thanks for the information. I'm ordering Gearotic Motion right now. I guess that should solve my remaining misunderstanding about this project plus allow me to do a whole lot more later.

Thanks,
Jim Gray


Hi Jim,

You won't be disappointed, Gearotic Motion is brilliant and it just keeps getting better (Thank you Art).

Tweakie.
PEACE