Hi,

I tried a 3d cut today, one of a crocodile swimming. 

I  found it to be an interesting exercise working out quicker cut types on PixwlCNC.

Firstly I did a rough parallel cut with 1/4 inch flat to remove a lot of wood and following the canvas contour. Then I did another with  a 2.5 mm ball nose lengthwise followed by another parallel cut, cross wise. This cleaned up a lot of the hanging hairs and smoothed out the finish.

I cut it out then finished with a path carving using a 90degree v-bit to chamfer the outside edge.

The finish quality was good except I did have to do some manual sanding as this exercise demonstrated:

1.  My Z-Axis has a little bit of slop in the up down movement.  It left random artefacts of cross lines which I had to sand off. Not large, just visible and annoyingly visible.  They were possibly 100ths of a millimetre in height, just visible and easily sanded.

At least I should be patting myself as it is a home made CNC.

2. I assume I could hide the issue by doing a cross Parallel cut first then a longitudinal one last following the wood grain.  There would be less Z axis movement and cuts. 

3. Setting the Z retract height needs more of my attention as I had the Z retracing way above the canvas contour wasting cut time. I've to work on the what the optimum heights should be to keep Z-axis retraction minimised.

Here is a photo:

Russ

Hi Russ,

That looks great! Definitely the sort of project that PixelCNC was geared for :]

What kind of wood did you use? Is that red oak?

 - Charlie

 A bit off topic....  I've been using these for awhile , been great for sanding after cutting. Come in different grits they work well. Alligator looks great.

Thanks valhallaCNC.

Also re your suggestion of the rotary brushes for smoothing. I’ve be hesitant in using them as I’m concerned the bristles would gouge out the softer wood between the grains. Do you find that occurs or is it just technique?

The ones I have they are made of nylon and very flexible, with the different grits some are pretty gentle. Even with softer woods and using a lighter touch I haven't found them to be harsh. I've used them for detailed carving with great results. You have to follow the cuts not across them, but can go against the grain just fine. I think it's mostly the pressure you apply, but pretty simple to use.

I appreciate the advice on that as I’m thinking my next carving would be of flowers and that’s not going to be easy cleaning with sand paper. I’ve seen a Dremel section in our hardware store with wheels like you’ve shown for fine work. I’ll have another look. 👍

Don't know about Dremel they have a much higher RPM, nylon fingers will be a lot shorter I'm using 3" diameter wheels on  cordless variable speed drill.