Ok, with my first successful cut under my belt and a second more complicated one going, I would like to speed up the process.
Thank you all for getting me here.
Where does one look? I am currently using the settings from Ryan’s milling basics page.
Do I start with online calculators? To I just start cutting and vary the settings until the steppers studded, the dial it back?
Most of my work centers around my culinary woodworking. My side gig rehandleing kitchen knives has paid for the mpcnc along with other shop upgrades. I plan on using domestic and exotic hardwoods, along with rough cutting soft metals for handle parts.
I am at that stage of wanting to tweak things to improve speed, but knowing that testing will take time. I default to what works for when I have been using, even if it may be slower, I know it gives a great finish. When I have tried to push it, something invariably goes wrong. I did linear pocketing for a large slip fit box. It turned out fine and had a nice surface on the face of the pocket. But the way the operation went, I kept getting these long strands that clogged up the dust collection. It was a mess. It was birch. Don’t have that problem with walnut and oak. It’s back to peal even though it is longer. I’m still trying to get my head around all these things.
I dialed in my settings using first foam to get the tool paths. Then MDF to test accuracy on something denser. Then in wood for a final test. This was a small version of my part. Then I went to the full size. It’s a large investment of time though to get through these tests.
This cut is a set of custom knife handle scales. I am carving a giraffe pattern into stabilized spalted maple. I will cast the newly carved pockets with resin. This 1.5inch x 6 inch carve 1 inch deep will take 6 hrs. You can see the 3D printed version and today’s progress below.
Those are pretty tiny pockets, but the tip is mostly for things like a box where you want tall sides, and a bottom. Instead of milling a pocket in the middle, if you just use two pieces of wood, you can cut a hole to make the sides and then glue it to the bottom. If you are using pockets for those, that is still probably overkill. I am assuming you are actually using holes.
Not sure why it took me 12 + hrs to Completely understand what you wrote. I am blaming lack of sleep due to the kids.
I was intentionally trying a pocket. I was hoping to cast resin in the pocket with wood on the bottom to eliminate leakage, then I can slice the bottom off and slice the cast in two for perfect matched pairs.
It sounds like that’s just an inefficient strategy and I should cut everything, first, then cast the sliced hollow scales.
The holes aren’t that big, so it may not make much difference, compared to the time it takes to seal the bottoms. If they were larger holes, then yeah, it takes a while to clear out that material. On some jobs, literally 99% of the time can be spent on the pocket.
Imagine a scenario where you wanted 5mm deep letters in 10mm thick material. You can get a 5mm sheet, cut the letters out as holes, and glue it to another 5mm sheet.
I think your feeds and speeds are just way way too slow…
Get a scrap piece of wood and do just one pocket. Try that pocket at different speeds and depths until you get grinding on the steppers. Then back off to about 80% that speed and or DOC.
I do this every time I get a new bit or try a new type of wood.
Also, are you doing adaptive milling or are you just cutting back and forth?
For reference, I did the following part out of Iroko. I used a 1/4" end mill at 10mm DOC and a 450 mm/min Feed rate. I did adaptive milling with a 1mm stepover. The entire box took ~ 2 hours to mill. The pocket on the right is ~4"x4" and 1.25" deep. The burning on the lower passes is from sawdust buildup and an older bit that’s been abused. I really need to get some compressed air on the machine to blow sawdust into the dust collection and out of my pockets.
I made the pocket on the bottom left about 6 times in scrap wood to find a speed and DOC that didn’t chatter.
I will say that I was in your same boat when I first built the machine. I was watching videos of other people cutting and was upset that my machine seemed to cut very very slow compared to theirs.
