Just playing around learning how to use this Shapeoko 5. I made this simply catch all. Problem is, it took over 3.5 hours to make. It’s 6.5” x 9” and the bottom where the logo is, is .65” deep.
The roughing pass took over 1.5 hours using default settings with a 1/4” #201 all the settings were left at default. I was going to use a 7/16” bowl bit thinking it would be a good application for this…but apparently not? Because of the feeds and speeds people recommended using were so much slower the estimate for the bowl bit was like 280min!
What is the purpose of the bowl bit if not to hog out a bunch of material in a bowl? In my case using those settings it’s 2x slower than just using a straight flat endmill.
Besides cranking up the feeds and speeds, what options are there for reducing the time to make this?
The speed and feeds are limited by how much power you can put down to swing the bit, and in your case you are limited by the power your spindle can put out.
I use a Bowling Bit to make the bottom curves rounded.
Here is something you can do to speed up the process.
Do an offset inside your vector and clear that with a .25 EM. The offset should be big enough so you don’t mess up the round over at the bottom from your bowl bit.
I do lots of dish carve (bowl bit) stuff and after a bit of playing with F&S here’s what I ended up with (Makita router):
NOTE: I use a larger bit than you have so most of this needs a bit of adjustment. I do think you are running it too shallow though. Cut deeper for the roughing paths and then shallow for the finishing path.
Finishing pass (last 0.5, only)
RPM 8000 (I use a lot of white oak and much fast seems to burn when hitting the end)
DOC 0.5mm / 0.2"
Finish pass feed 2000mm / 78"
Step over 2mm / 0.08" (raster pattern in the grain direction only)
I’ve found that the VFD can’t handle the roughing paths in the same way with this size bit so I run those at 16,000 RPM then drop to 8,000 for the finishing path to prevent burning.
I was under the impression that bowl bits are intended to provide the desired fillet/contour between horizontal and vertical surfaces rather than rapid hogging, but perhaps I’m mistaken. ¯\(ツ)/¯
The CNC is a great tool but not the only tool. The SO5 is a pretty rugged machine but so is wood. The 0.02" depth of cut seems a little light but the 7/16" bit is taking a pretty good bite. There is a lot of mass in that bit compared to a 1/4" bit. Some folks are really pushing the SO5 but unless you in production a good outcome is better than fast. The CNC machining is a constant learning process. So if you learned something the exercise was valuable. Everyone here on the forum had to learn to crawl before they were able to walk and eventually run. So chalk up your experience as a learning event and move on to the next adventure.
One more thing you can do in Carbide Motion is if the job is progressing smoothly then increase the speed at 10% intervals. When you start hearing and/or seeing stress back down 10-20%.
