Trochoidal Pocket & Profile MOPs plugin (HSM)

[jk]

Helix spiral lead-in aka spiral drill may be obtained easily with a tangent lead-in - use tangent radius < cutter diameter and small spiral angle (ramp angle) - say, 5 degrees

[jk]

Updated first post with v1.3.1
* fixes for some complicated shapes

test shapes are these (medial axes were wrong due to the Voronoi generator go crazy):

[annuello]

Your plugin is inspiring me to prioritise my ballscrew upgrade on my mill.  Just saying...

Annuello.

[kvom]

Used the plugin in anger today, that is cutting metal instead of electrons and pixels.  Success was had!  

Here's the pocket:



.24" DOC, 10% stepover, 4000 RPM, 11 IPM, .25" 2-flute carbide endmill.

The CB file is attached in case anyone is interested.

Couple of comments:

1) Why a chord feedrate?  Seems a rapid would be normal

2) While the pocket wall finish isn't terrible, I assume most users would use a rouging clearance and then a finish profile for the walls.

[jk]

Nice ! I must wait a few more days before finally trying it on real metal )

Maybe a rapid would be ok for chords, but CB will insert Z retract if G0 distance > max crossover distance, the thing I want to avoid. So I use G1 with a different feedrate for chords. Anyway, it's easy to crank up chord feedrate to match rapid.

PS
I saw the minimum cutter stepover is set to 0.1 in your file. I guess you want to set it 0.8-0.9,
since it is a percentage from the normal cut stepover, not a stepover as is.

[kvom]

Problem is I have no idea what that field does.   

[jk]

It's a bit of magic, let me try to explain )

Plugin places slices one-after-one keeping the specified stepover all the time (10 % in you case). If the next slice can't be placed to satisfy specifed stepover, it may be either still emitted or ignored.
If min stepover setting is 0.5, it means 10% * 0.5 = 5% stepover is ok too, keep this slice, otherwise drop it.
It works this way for stepover undershoot.  Stepover overshoot is never allowed, new cutters cost money )

0.8-0.9 seems to be ok most of the times.
For some complicated shapes plugin may stop producing slices half-way, setting should be lowered to help him get thru.
For some shapes setting may affect profile accuracy in the corners (see attachment 0 and 1).
Unnecessary low value allows plugin to produce very thin slices here and there (see attachment 2 and 3)

In other words, leave it default and lower only in case of the problems :-)

[kvom]

Good explanation.  In this case it was irrelevant since the pocketing was just needed for fast removal of material.

WRT to the chord rate, I'm guessing from your answer that the plugin just generates toolpaths and passes them to CB for actual translation to g-code.

Is it possible to calculate the estimated machine time since you could certainly calculate the lengths of every move?  I generally run all my code through Cutviewer which gives me it's estimate, but an estimate by CB would be useful.

[jk]

kvom,

Yes, it's CB duty to generate g-code, accounting for the used preprocessor, work offsets, arc modes and much more. I just supply toolpaths and feedrates.

Rough time estimate is possible and, I'll include it in the next non-bugfix version.

[Bubba]

Hi 'jk'.

Just used the Trochoidal MOP plugin and must say it is the best pocketing MOP for machining metal in CB as far I'm concerned. One suggestion I have if is not to much trouble to incorporate cleanup/profile type pass at full depth, just so the sides wont look as rough. Some pockets when dimentionally necessary one can use profile MOP, but in my case the pockets were for bolt head clearance only so rough sides were good enough.
Again, Thanks for this very practical plugin.

[kvom]

The cleanup profile pass may not be a good idea, unless it's just an option.  Some reasons:

1) Pocket may have roughing clearance, so a pass on the same clearance is probably useless

2) Pocket may have been incomplete because of tool clearance, and those areas may need a separate MOP

3) Feeds and speeds for said finishing profile are likely different than for the pocket itself.

My .02

[Bubba]

The cleanup profile pass may not be a good idea, unless it's just an option.
***************
I guess you got a point there, I haven't think of all that. An option for profile pass would work because I try to use cutter that does not create clearance problems for me..

[jk]

No, cleanup profile won't be added - there is a great profile MOP already in CB, no reason to duplicate it.
There is a lot of code inside the profile MOP !

Select pocket mop, click 'profile' to inherit same primitives, copy and paste format if required to inherit depths etc. - easy :-)

[Bubba]

No, cleanup profile won't be added - there is a great profile MOP already in CB, no reason to duplicate it.
There is a lot of code inside the profile MOP !

Select pocket mop, click 'profile' to inherit same primitives, copy and paste format if required to inherit depths etc. - easy :-)

Not a problem! I know how to use MOP's in CB!

[Dragonfly]

@jk
I'm doing some test cuts in MDF to verify a complex part and decided to give a try to the plugin.
No error messages and no messages at all in the message window (Diagnostic level 3) but the tool path generation misses a part - the lower 'leaf' - of the area defined by the geometry.
Tried changing some values - step over, tool diameter but no effect.
Attaching a simplified .cb file. Everything left to default except DOC and tool 0 selected with 6mm diameter.