Testing some stars for flags.... having issues

CNC Machines Shapeoko
1

I’ve got an odd problem carving stars…… getting kinda uneven results.

Like a lot of people, I figured I would try to do a US flag. I downloaded the star pattern at:

https://community.carbide3d.com/uploads/default/original/2X/d/d49f9fcc6fc6822379f55a0a4cdc0b289e03c858.c2d

And then I wanted to test and see how the different bits I have work for making stars, and which one I like best.

So I resized the download above to (“Lowes premium”) pine I have to test with, and set up a test with 2 different sizes of stars I want to do (for a smaller, and later larger flag.)

I divided the job up into 3 parts – one for each bit I wanted to test. I set the touch-probe the lower left, probed x/y/z using #201, then I changed bits, re-probed Z, and ran job 1. Then I changed bits, re-probed Z, and ran the next job. Repeat that for the 3rd.

All 3 jobs are V-carve jobs. I’ll upload my Carbide Create file if I can to show people.

The jobs were:

Job 1: Top 4 stars

Job 2: Next 4 down

Job 3: Last 2 on the bottom

But my output was inconsistent.

[Album] Imgur

Bits used and feeds and speeds:

Job 1: #302. 14,000rpm, 30 feed ratre, 14 plunge rate

Job 2: https://www.amanatool.com/rc-1145-cnc-insert-v-groove-45-deg-x-13-16-dia-x-63-64-x-1-4-inch-shank-router-bit.html , 12,000rpm, 20 feed rate, 10 plunge rate

Job 3: https://www.amanatool.com/45771-k-solid-carbide-30-degree-engraving-0-005-tip-width-x-1-4-inch-shank-signmaking-spektratm-extreme-tool-life-coated-router-bit.html , 18,000rpm, 20 feed rate, 10 plunge rate

Job 1: The smaller stars are mis-shaped and curved on the left. The larger ones are also mis-shaped… almost turned counter-clockwise. Lots going wrong here

Job 2: Shaped better, but still inconsistencies in the lower left, and lots of tear-out with the right arm comes in. Also, these stars come down to a certain point and stop vertically (Z axis). Unlike the others, these have flat bottoms, not points at the bottom (although that may just be the max bit depth it will use for a 45-degree bit.)

Job 3: Bit of both problems combined. Lower left issues, tear-out in the center, and just inconsistent lines.

Any help/ideas on getting these to look would be greatly appreciated. I’ve still got the test board attached to my machine, so I can make changes and re-run things.v testing stars.c2d (66.6 KB)

2

You may want to go to this site below and try to build your own set of stars and compare those to what you’ve been using. Complicated in a way, but, if it gets you what you need it should be worth the time. Found on the Carbide site.

How to draw a star --- Carbide Create,

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I figured it out! I thought it was the stars pattern, or maybe some version problem between the older stars file and a newer Carbide Create program…

But nope. An eccentric nut to the top left of the router had rotated, creating some “slop” where the router could lean forward. This was causing the cutting angle to change depending on the direction and force applied.

I rotated that nut so the v-groove wheel was tight against the rail again, and re-ran the test the exact same way. Came out looking great.

[Album] Imgur
2 Likes
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Nice, but stars on the flag have sharp points. Good job figuring out that problem.

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Yeah, no clue why the stars don’t have sharp points. I’m setting Z using the touch probe, and the file I attached before shows sharp points for the stars.

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I would do a quick test with paper method of setting the z zero, it sort of looks off by a bit

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