Needing some carving help!

[ntraub01]

Time to dip into the wealth of knowledge to help me with the finer points of 2.5D carving with the SB.

Software: PW3D
What: An internment box for my father-in-law
Material: Cherry
Size: Finished size aprox 8x10x10
How:
Roughing Path - 1/4" downcut @ 16000 rpm & 3 in/sec, with direction of wood grain - Went well and took only about 20 minutes to complete roughing.

Finishing Path - 1st Attempt - 1/8" endmill @ 12000 rpm & 2 in/sec, 90 degrees against wood grain - Failed misserably, little to no detail and all kinds of fuzzies...not acceptable in any shape or form.

Finishing Path - 2nd Attempt - 1/32" tapered ballnose @ 12000 rpm & 1 in/sec, 40% stepover, with direction of wood grain, aprox carve time 2 hours - Still getting fuzzies and noticing that as the bit returns as a climb cut it does little to no actual cutting but does most cutting on the conventional direction of travel.

The 2nd Attempt for the finishing path had great detail but also had carving marks (water lines) throughout the area which I would love to get rid of. (See picture)

I'm not sure if I need to reduce the stepover, change bits, change travel speeds, I would love to figure out how not to use a "raster" approach to eliminate the ineffective climb cut...

I know you all have much more experience with carving than I do so please feel free to contribute as all constructive criticism will be greatly appreciated. The only thing I can't change is the wood selection and what is actually being carved.

Thanks in advance!!

Nicholas

2458724588

[Kyle Stapleton]

Your roughing is good, rpm are a little high but ok.
Your final is way off, you need about a 3-5% step over with an 1/8-1/16" if you want to limit sanding and get a much better detail.

If you look at the preview in the software it will give you a very good look at what the final will look like.

Look up cowboy1296 (Rick Ashwood) he does really nice 3d work.

[scottp55]

Nick,
Stepover is culprit like Kyle said.
Also agree with Kyle that a 16'th will probably give you what you need for detail.
I'd change to about 15-17K for rpm though for the finishing toolpath. Smaller bit Usually higher RPM.
Only done a dozen or so small ones though, but had good luck if leaving.015 to .02" on roughing pass at 1.5,1.5 in Sugar Maple using tapered .0625".
Hope someone who knows more kicks in.
scott

[srwtlc]

Not knowing what your finished layout or intent is (applique, inset, or whole side of a box), I can't say if you needed to work with any boundary offsets or not and if you could have used thinner material to start with, but...

Roughing pass is ok. Would maybe run around 12K-13K, 0.25"-0.375" per pass, 0.40" allowance, and I prefer across the grain for roughing to eliminate long splinters that can clog the dust collection and possibly peel off material that shouldn't be.

That first attempt finishing pass...complete waste of time...forget it. You won't get the needed detail or finish quality for a finish pass with an standard end mill. Erase that one from memory. :)

For your finish pass, by the looks of the size and detail of your scene, you would be best off to use a 0.0625" tapered ballnose (maybe even a 0.125" one if the detail is less) and use 8% -10% stepover. I prefer 8%, but you trade a little more time for a smoother finish. At 10%, you can start to see some fine score lines.

I'm guessing that your "ineffective climb cut" was due to bit deflection from too high of a stepover which both contributed to the scoring lines and fuzz. Rastering with the grain is the correct way to do your finish pass. Although, sometimes it's beneficial to run the finish pass cross grain to eliminate fuzzies with woods that are stringy like butternut, but you can end up with visible cross grain score marks.

Depending on your model thickness (shown in your software), and the thickness of your material, you may be able to re-run this with a different ballnose to clean it up. You may be able to lower the model in the material setup to be a bit further down or just nudge (MN) your Z axis down a bit after zeroing the new tool or your 1/32" ballnose. If you use a different tool, don't forget to recalculate the tool path for the different tool. Never-the-less, if you are going to re-run it with the 1/32" ballnose, you need to recalculate the finish toolpath so that you have a smaller stepover (try 8%).

[cowboy1296]

Thanks Kyle for the comments. Since I use Scott for mentoring from time to time I would follow his advice.

One proven way to determine which which ball nose to use with 3-d carvings. I primarily use 1/8 or 1/16 ball nose and dont own a 1/32. But calculate your finishing tool path with the larger bit, in my case 1/8 and preview your tool path. IMPORTANT: Leave that preview visible. Then recalculate it with the smaller bit, in my case the 1/16. Now watch your screen closely and then click preview. You should notice a change in the quality. If the change is minor stay with larger bit in my case the 1/8 but if you notice a major change go with the smaller bit, in my case the 1/16.

I am working on my second cup this morning and hope that all made sense. If you get in a bind and need someone to look over your work you can always email me your file and i will take a look at it. IMPORTANT NOTE: you can only email files that are not copywrited.

Here is one that i am working on and it is in the first stage of finishing. I used a quarter inch ball nose end mill for the roughing. During roughing i used a shadow depth of cut set at .07, a 40% step over with a feed rate of 3.0 inch per second. Perhaps i could cut deeper during roughing but that is just my preference. I leave a machining allowance of .035. you could leave a little more or even less but that is just what i use. I initially thought that i was going to have to use a 1/16, but i used the above mentioned test to determine that a 1/8 was what i needed. My plunge rate and feed rate are set close together, 2.6 inch per sec for feed and 2.4 for plunge. This carving is 30 inches long and took 6 hours to do the finishing tool path.

Something that i learned on here, set your hooks on 16 inch centers. that way your screws securing it to the wall will be covered up.

Scott please weigh in on suggestions here if you see any needed.http://www.talkshopbot.com/forum/attachment.php?attachmentid=24589&stc=1

[Joe Porter]

Along with what Cowboy said about comparing previews with one tool path over another, A tip from Tim Merrill suggested that your give a contrasting color to each finish tool path and that will give you an indication of weather the .0625 ball nose is worth the extra time....joe

[srwtlc]

You pretty much covered it Rick. Good tip on the double preview, I use that as well, but forgot about it.

Also, for anyone getting into 3D work, it's essential that you delve into learning how to tweak your ramp settings to suit and saving out those settings for future use. This has been discussed in depth here in other threads.

[cowboy1296]

finished. this is really the first time that i have worked with wormy maple, i like it but black walnut is still my favorite. The hooks are not screwed in yet, they are just sitting there
http://www.talkshopbot.com/forum/attachment.php?attachmentid=24610&stc=1

[ntraub01]

Thank you all for the great advice. I would honestly have even less hair than I currently do if I had not reached out to you all, thank you again!!

Things are progressing well and I have 2 of the four sides carved, BUT when I attempt to mirror the existing file I run into issues.

Everything progresses as expected through the entire setup process until I proof the roughing and finishing paths.

Calculate the roughing path then hit next to move forward.
Calculate the finishing path then hit next to move forward.
Pass on the cutout path and hit next to move forward.

When I run the preview machining, the model flips back to the original orientation AND the resulting cut files are also back to the original orientation regardless.

If I don't run the preview machining and save the files without previewing, then go to she SB control software and use the preview option there, the resulting cut files are back to the original orientation.

SOOO, now what?!?!

Ideas please and thank you!!

[cowboy1296]

NICHOLAS, I sent you an email, did you receive it.