Cutout path - Pierced - or Deep Recess?

[keninar]

No intent to “reinvent the wheel” but have a project that I am working on that has me stumped with regards to the “best” way to accomplish the goal.
As per the pic, the project is a simple task of an solid letter circumscribed in a circle. 66078

My initial approach was to create the pattern, outline the pattern, delete the pattern, and assign a cutout to the remaining pattern. This did seem to accomplish the goal, but using the 3/16” bit for the cutout (I still wince when doing a cutout with the 1/8” bit) was a bit tight in some of the internal curves.66076 (Ignore the artifact on the left -forgot to erase a line in the pre-processing steps).

Then I considered placing a circle over the letter area and assigning a full depth carve region (.76 or better) and getting the material removed that way. Seems to be sort of a left-handed piercing approach. 6607766079

Three questions:
1. Will the full depth carve region approach work without problems?
2. Is the original approach (multiple cutouts) a better option?
3. Am I missing the obvious methodology to get to the end result?
Thanks for any and all input. (I have obviously been away from the “project approach” thought process too long!)


ken

[mtylerfl]

Hi Ken,

You'll want to use the 1/8" bit due to the tight areas in the example project you posted. No reason to be skittish about the 1/8" Cutting Bit, it works fine (based on my nearly seven years of experience with it on the CW machines and I also use the same bit on my ShopBot - the bit works like a champ). Especially since Designer ver. 1.131 introduced the ability to set a Max. Pass for the bit, that feature virtually eliminated any issues with bit breakage when performing cutouts.

Personally, I would not take the pierced carve region approach using the 1/16" tapered carving bit because the taper of the bit will distort the letter and will likely make the "skinny parts" too skinny as well. Unfortunately, the preview does not take into account the 7-degree angled geometry of the 1/16" tapered carving bit when the preview is generated...in other words, the preview makes it appear you are using a straight bit, not the tapered one. Now, the exception could be if you own the 1/8" ballnose Carving Bit. If you do own that particular bit, then you could indeed take the pierced carve approach without fear of distortion of the internal carved areas since that bit is straight (and in that case, the preview would be accurate). If you have the 1/8" ballnose Carving Bit, just remember you need to select that bit as the "Pattern Bit" in your Board Settings menu.

[mtylerfl]

Without seeing the actual MPC, I'm not sure about the comment I made regarding the distortion of the letter using the 1/16" tapered Carving Bit. I looked at your screenshots again, and it appears you may have applied a Draft to the letter. If you also used Bit Optimization: BEST, then perhaps the angle of the bit won't encroach on the letter as much as one would normally think. Perhaps, a real-world test run is the only way to tell for sure.

[liquidguitars]

I think the 1/16" tapered carving bit makes for a nice cutout bit option especially if your pattern is carved first.

you can even bypass the cutout and just "Pierce" through the board a extra .100"

[keninar]

Thank you for your response, Michael.

I'll take another stab at the cutout approach (there IS a significant time difference - carving vs cutting!) Perhaps I'll broaden the tight areas a bit to assist.

The apparent feathering was due, I think, to the fact that I imported a blurred image to create the pattern. Kinda liked the appearance, but the client (my wife -who doesn't really know what she wants.......................but knows what she doesn't, usually after the fact!) has fairly vertical edges in her mind. That tends to support the cutout option.

And as they say: "The customer is ALWAYS right!"

Have used the minimum pass option when using the 1/8" bit to cutout (normally .125, but that sure takes a long time to cut through .75 material). In your experience, what should I use for this parameter, using big box pine or MDF for this project? (Note: it will be painted).

Again, Thanks!!

ken

[mtylerfl]

...
Have used the minimum pass option when using the 1/8" bit to cutout (normally .125, but that sure takes a long time to cut through .75 material). In your experience, what should I use for this parameter, using big box pine or MDF for this project? (Note: it will be painted).

Again, Thanks!!

ken

Hi Ken,

It would take "forever" to cut at a .125" Max Pass. I think it would be pretty rare to have to go that shallow (extremely hard wood might need that conservative amount). For Pine or MDF a Max Pass of 0.3" is perfectly safe (that's what I set all the POM Cutpaths at). I also specify a minimum of 4 tabs, 2 tabs per foot and tab thickness of 3/16".

[keninar]

Ha! I've lived the "forever" timeline - ever since I got my machine. Never thought to ask the vets for guidance.

This will make carving even more enjoyable!!!

Will take your advice and up the ante. Thanks!

Film at 11.

ken