Rigid Tapping Not Working - Summary <resolved, works great with photos> >

[RJS100]

Uwe... You out did yourself today. Not only did you get this thing up and running, but you did it fast enough that I was still able to cancel the new encoder I ordered last night!

Even better, I tapped these three holes at 800 rpm. The threads look perfect.

Thanks again... Richard

[Muzzer]

So, to clarify, does the Fusion post processor output G84 with F or Q for the thread pitch? It looked as if most Fusion posts including Centroid set the spindle speed and then convert the pitch into a downfeed, F.

Uwe talked about creating a modified post to take advantage of Centroid's G84 that allows for pitch to be specified directly as Q, rather like the Intercon output - but it doesn't seem that was required in the end.

[RJS100]

Actually, , the post was modified to output the Q value that Centroid is looking for by Andrew Laas on the Fusion CAM Forum (https://forums.autodesk.com/t5/fusion-m ... 88#M158955). Uwe was kind enough to copy and paste the modified code into a the Swissi PP.

Thanks... Richard

[Muzzer]

Aha that's interesting, although I don't have a spindle encoder on my mill. My lathe does - but the concept of "G84 rigid tapping" doesn't apply in that application. I may take a look at the changes to see how it was done. The Fusion forum link is very helpful.

The default Fusion output for most PPs (not just Centroid) assumes a constant spindle speed and then sets the feedrate F that is appropriate for the required thread pitch. I believe the Q parameter that Centroid use uses the spindle encoder (spindle angle) to determine the Z position, which feels technically more robust. That suggests that once issued, the G84 Q... command gears the spindle to the Z axis so you should be able to manually rotate the spindle and observe the Z position move in coordination. I can't try that myself as I have no encoder but it would be interesting to see if that is how it works.

[RJS100]

I wish I could give it a try for you, but I am away for a few weeks. I will give it a whirl when I get back. I think your description is correct. Yes, the folks on the Fusion CAM forum have been extremely helpful to me over the past year or so. Andrew Laas on the forum appears to be quite familiar with Centroid. He made a point of demonstrating exactly how he modified the post.

I never touched a milling machine, CAD program or even knew what "g-code" meant before I started playing with this stuff about 2 years ago. I love this hobby and would be lost without the awesome folks on the Centroid and Fusion CAM forums.

Best... Richard

[suntravel]

Aha that's interesting, although I don't have a spindle encoder on my mill. My lathe does - but the concept of "G84 rigid tapping" doesn't apply in that application. I may take a look at the changes to see how it was done. The Fusion forum link is very helpful.

The default Fusion output for most PPs (not just Centroid) assumes a constant spindle speed and then sets the feedrate F that is appropriate for the required thread pitch. I believe the Q parameter that Centroid use uses the spindle encoder (spindle angle) to determine the Z position, which feels technically more robust. That suggests that once issued, the G84 Q... command gears the spindle to the Z axis so you should be able to manually rotate the spindle and observe the Z position move in coordination. I can't try that myself as I have no encoder but it would be interesting to see if that is how it works.

exactly, the Z axis is electronic geared to the spindle. Turning the spindle and the Z axis will move just like on a manual lathe with the lead screw.

Uwe

[RJS100]

One more question... Earlier on this post, Uwe mentioned that you can tap the same hole more than once, I tried it and it worked great. Just curious... How does Centroid register the tap to start in the same place each time?

[suntravel]

Encoder Z impulse

Uwe

[RJS100]

Thanks... Pretty cool software!

[cnckeith]

once per rev there is an index pulse from the encoder that CNC12 automagically uses to line back up with the existing threads enabling deep hole tapping, peck tapping and the ability to retap the same hole over and over again.