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Author Topic: Simple radius cutting - isn't !  (Read 599 times)

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Offline JG

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Re: Simple radius cutting - isn't !
« Reply #10 on: July 20, 2020, 10:26:41 AM »
Thanks for that re-assurance Tweakie  -  even though the concept may be old, it shouldn't make it obsolete surely ?

To me it seems a very obvious way to simply draw the component 'at size', code accordingly and simply use G41 or G42 with a suitable Cutter offset to cut either a 'Pocket' or a component to fit that pocket.

It seems that currently (hand coding) I have to deal with the offset manually - it's no great shakes really but copying a few blocks of code and then going through it to apply the offset is prone to potential error -- I am only human and therefore inherently error prone  ;D

Offline Tweakie.CNC

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Re: Simple radius cutting - isn't !
« Reply #11 on: July 21, 2020, 01:15:18 AM »
I started using Mach when it was Mach2 and by then CAD / CAM was the way to go. From then and up to the time development on Mach3 ceased there had always been issues, reported on the forum, with cutter radius comp. From memory the usual problem was insufficient clearance at the lead-in but over the years many revisions were made regarding G41 / G42.
As mentioned earlier CAD / CAM calculation incorporating the tool radius to adjust the toolpath not only made life easier for the likes of me but it also relieved Mach of the additional calculation when creating the trajectory. Everything worked better.
I would not want to go back to driving a truck without power steering and I would not want to go back to using G41 / G42 although, as you say, they are not actually obsolete - it is just that I have moved on.

Tweakie.
KEEP SAFE !

Offline JG

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Re: Simple radius cutting - isn't !
« Reply #12 on: July 21, 2020, 03:13:43 AM »
That's a very useful analogy Tweakie -- I agree that Power Steering is utterly indispensable   :)

If you look at my profile you'll see that I also 'Looked at' Mach2 in 2007 but I didn't have a machine at that time and I'd even forgotten about it until I tried to register on the forum last week so naturally was not aware of the history.

Essentially the 'arithmetic'   -  not even 'Maths'  -  involved in calculating the tool-paths for shapes that can be easily determined by hand-coding is quite trivial. It would be a different matter if I was trying to plot NURBS curves by hand!

I might get as far as plotting a Reuleaux Pentagon (as in my Avatar) but that could be a bit challenging.

My real concern was that the errors I am finding might be down to a fault in my S/H Denford MicroRouter and the reason for it being sold on.  I've already found that the vertical alignment of the motor was compromised (now corrected) but it's good to know that my fears are mis-placed.
« Last Edit: July 21, 2020, 03:19:48 AM by JG »

Offline Graham Waterworth

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Re: Simple radius cutting - isn't !
« Reply #13 on: July 21, 2020, 06:54:22 PM »
G41 P2.49 X20. Y-5. F200.

Try changing this line to this
Without engineers the world stops

Offline JG

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Re: Simple radius cutting - isn't !
« Reply #14 on: July 21, 2020, 08:16:40 PM »
That sorted it Graham, well, at least as far as letting me run a simulation --- and I can see how a 90ยบ arc would be a gentle lead-in to avoid a 'slam-dunk' into the pocket giving a better finish.

I'll see if I can do something similar on my workshop machine in the morning by getting it to draw the path but I'll naturally have to modify the Z figures since that machine has Z0 to Z-100 as the soft limits.