Hey everyone,
I've more or less converted a cheap Chinese machine into a decent small scale CNC router with a Makita RT0701C. I've got it clamped to the z truck with plywood clamps that do a great job.
Lately I've had requests for signs/plaques, so I've done a few from Home Depot poplar. I realize poplar doesn't machine very well, but it's cheap and good to test designs with. The problem I'm running into lately with the cuts I'm making is that they don't end up with sharp corners. They're stringy and fibrous...not really fuzzy like a lot of people complain about. It's just a rough edge, so when the job is finished I have to go back over each corner edge and sand off the junk to get a clean edge.
What I'm not sure of is if the poplar is the issue or if the bit is dull, because I also have the same problem with Home Depot birch. Maybe Home Depot wood isn't the best wood to use..? Quick rundown of how I'm running the jobs:
Feedrate: 1500mm/min (I can probably push it a little harder but I don't want to overtax my machine.)
RPM: 15-20K (I hover around the 3-4 setting on the Makita)
Depth of cut: 2-3mm (if I do 2mm, I plunge, if I do 3mm I ramp)
1/4" straight router bit (2 flute, HSS I think)
I'm not getting burns, and my cuts are clean on the endgrain (I believe that's the correct term) but the corners come out rough.
I realize it's hard to tell without pictures, but I've already sanded everything. But what do you guys think? Bad wood or bad bit?