3D Finish Strange Results

The c2d files are over 8,000 KB and couldn’t upload. I thought the simplified test files would be smaller but the first one is over 10,000 KB. Trid saving as V-6 and that’s 12,000 KB!

Put them on a Google drive and post the link?

Link to Oval - X.c2d (Used for 135° cut)

Link to Oval - 3.c2d (Used for 45° cut)

Slim differences between the two files.

I tried experimenting with this for a bit, but couldn’t arrive at a meaningful conclusion — my suggestion would be to try using a slightly larger tool and adjusting the stepover and making some test cuts until you arrive at settings which are workable for your needs.

I just ran a couple of scaled down tests. Made the basic shapes about half of what I originally did. Also chopped the moose down so the only thing left was the body: minus antlers, head and legs. Ran with .030 stepover and 1/8" ball nose. One test ran Finish passes at 0° and 90°. The other ran at 45° and 135°. Both neat - no glitches.

Tomorrow will try 45/135 but with a .031 stepover. Anxious to see what happens.

I see. I dont see any issues with my relief carvings because my finishing toolpath follows a spiral (in a box) The result is that the head of the cutter never touches the same place on the workpiece twice. The toolpath describes a circle, increasing in diameter from the centre outwards, so there are never any of the adjacent furrows that are an artifact often seen with a raster finishing toolpath.

Done Testing. I quit looking for things that didn’t work. Ran original c2d with same 1/8" round nose but stepover of .013". Set Z about .02 deeper and ran the same 45° and 135°.

Shine small light across and all looks good. I’m happy, at least until I try this for real.

Not sure what wood I’ll use. Actually I kind of like the Southern Pine that I picked up at Lowes. It cuts pretty well and didn’t cost a bloody fortune.

Appreciate all the advice and thoughts.

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Interesting, what are you using to generate that tool path? It will be on my list of things to try

Carveco Maker… the lowest level of this software. You cannot buy a perpetual licence and own this cheapest version but can purchase the more complex versions. The Maker version is $18 per month. I have been using it for around three years and it gets frequent updates. The design language of the interface is readily understandable.

samples.

Very short video clip - turn down sound first:

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Like the looks of it and I’ve already got the cutter.

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Back to Frustated again.

Yesterday, I took slightly updated Moose (Oval - 6.c2d), re-created the 3D Rough ( Oval - 6 - 11 - 3D Rough Interior.nc) and 3D Finish Toolpaths (Oval - 6 - 12 - 3D Fine 00°.nc and Oval - 6 - 14 - 3D Fine 90°.nc). Since I hadn’t experienced bad things with Toolpath Angle of 0°, 1/8 ballnose, and a stepover of .012" I figured that was a good starting point.

I ran the Rough and it looked reasonable, taking around 1.5 hours to complete. Then Ran the Finish at 0° and was thrilled at the result shown here:

A few feathers but nothing at all bad. Approximately 700 parallel lines of varying depths clearly defining the bowl background, moose and the stars on the surrounding rim. Exactly what I hoped for. Still in need of another Finish pass from 90° before minor sanding.

Incidentally, running router at about 26,000 RPM. Everything at default feed rates.

This morning, I turned my Shapeoko Pro loose on the 90° Finish toolpath. Utterly @#$%^&*()_.
See picture:

Machine was not bumped during run, not even touched.

Screen shot of the Toolpath Simulation for the three toolpaths shows this:

What is going on?

Here’s a link to the updated c2d file:

I would guess that your cutter did not maintain its correct zero height. Those deep gouges suggest very strongly that the cutter was not where you asked it to be during the cutting process. Was it adequately tight in the collet? Please remind me if you using a trim router or a spindle.

In any event, the collets should be cleaned so that no cut debris or dust remains after use. If it is a trim router, remove the collet after the cutter has been used and strong suction plus brushing so the collet is clean. The taper that the collet fits into should also be cleaned after every use. Blown clean or use a vacuum and brush to remove every scrap of dust and debris.

Are your collets worn and not holding correctly or are you not tightening them sufficiently? Have you marked the cutter shank and ensured that it is at the same height at the start as when the cut has finished? If you can be certain that collets and cutter are not responsible, then it may be worth looking at Z starting height and how consitent the carriage remains at the chosen height during the cut.

Cutter has for sure gone deeper than I wanted!

I’m using the Carbide’s ER-11 Router. The 1/8 ball nose cutter is in freshly cleaned collet and is tight. It does seem like I could definitely over-tighten the small collet but I tighten it pretty hard. The 1/4" collet seems to hit the “tight enough” point very clearly.

Don’t know how I could mark the shank to be sure it hasn’t shifted at all during a run.

This was Finish Pass #2, so the cutter barely had anything to cut. By my figuring using CAD, the ridges are just slightly over 0.001163, based on a .012 stepover. In the bowl area to the left of the moose, some places were barely touched by the cutter on the 2nd Finish pass. I have to look pretty hard to see which way the ridges run. And for each of the 3D passes, I’ve re-initialized the machine before starting. I’ve avoided even touching the collet since starting on the Finish passes. And then the moose gets zapped in the belly and back.

I can watch the reported Z height when it hits the rim with the stars. Consistent. Even on the rim, Z moves as it hops over the stars. “Z” at the rim is supposed to be 0.2500 and the star-hopping appears to take it to as high as 0.1285 before stepping back down to 0.25. At least according to the nc files.

You suggest “looking at Z starting height and how consistent the carriage remains at the chosen height during the cut.” How do I do that? The only place where I see that I can judge that is on the rim and so far that seems pretty good. It seems to only get screwed up when it encounters the moose.

Use a dry wipe marker and draw a line completely around the shank where it meets the collet. If the bit has moved, you will see gap on the shank, next to the collet, where there is no circumferential marker evident.

Marking your Z carriage with a dry wipe marker and the rails that it moves on is one way to detect any differences. There are also clocks that can be used as digital height guages but they are expensive and possibly overkill to discover what is happening with your set up. Is the router collar being held tight enough in the router mount?

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If the cutter was slipping down, everything after the slip would be too low.
The gouges in the moose don’t have corresponding gouges in the bowl.
This suggests the misalignment is lateral/horizontal, not vertical. Is there any slop in your Y axis?

To fix this particular job, I would lower the Z zero by the depth of the grooves & rerun the 0° path that looked good.

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As you note, the bad stuff seems to be entirely on the moose. When I ran the D Finish at 0°, I saw absolutely nothing wobbly, the East-West lines ran straight, and I couldn’t see any sign of skipping or stalling.

Running North-South, I can’t recognize any wobble, only the obvious cuts to the belly / back and antler. The single scar above the moose suggested to me that at some point the Y travel might have been delayed but of course I have no idea whether it was cutting North- or South-bound at that point.

Since this piece has become another test piece, I kind of filled the scars with wood filler. I’ve also created an abbreviated NC file which will only cut from about the should to the tail. Hopefully will try running that in the afternoon. First however, I’ll take the bit out, thoroughly clean the collet and the router shaft. Could it be that the Z movement just isn’t happening fast enough?

I’ve been using this lightly for the past two years. I’m primarily used to a router table with a Bosch 1617EVS with 1/2" collet and two wrenches. I think I use as much tightening pressure with the 1/4" ER collet as I do on the Bosch, but couldn’t swear to that. But tightening the 1/8" collet seems to be different - a bit softer perhaps?

After looking at your pics and thinking way too long I believe your statement “Could it be that the Z movement just isn’t happening fast enough?” points where I would be looking to resolve the last issue of N-S lines mainly on the moose. It seems like an intermittent lag in upward Z movement most pronounced when the rate of change in Z is greatest. Why?, no clue. For testing purposes you might be able to reproduce it with a simple relatively small diameter 3d hemisphere 0.5 inch tall, running the finish path at 90 degree. I would run the test hemisphere (hopefully showing the issue) then clean, lubricate the HDZ, and run the test again. Hopefully identifying something that improves the cut. Maybe contact support.

A rough guide which may assist you. It is recommended by REGO-FIX (inventors of the ER collet in 1972) that ordinary ER collets over 6.35mm (1/4") in size are tightened to a torque of 80Nm (59 ft-lbs). Between 1.5mm (0.059") and 6.35mm (1/4") a torque of 32Nm (23.6 ft-lbs) is used. Collets under 1.5mm (0.059") require a torque of 16Nm (11.8ft-lbs)

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Good idea. I’ll try that this afternoon. After thoroughly cleaning shaft and collet.