If you are using Mach 3 or 4 I would start by halving your motors acceleration in motor tuning and set the motion to constant velocity not exact stop.
I’m using Mach4. I’m still learning it so I’ll need to figure out where these settings are.
I was experiencing “skips” of some sort (certainly loss of x/y zeros) when executing rapid moves. In the end it turned out to be that I had not set my limit switch indicators correctly. My machine is not perfectly square and I had set the limit switch indicators to be the same distance from the front of the bed. This caused the gantry to torque somewhat when zeroing. The torque made it much harder to move the gantry. When I adjusted the limit switch indicators by lengthening one so that it met it’s switch at the same time as the other side, it removed the torque and I haven’t had rapid move skips since.
I don’t know if anyone else has had/will have this issue, but thought I’d throw it out in case to save someone else some time.
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Also, on the pro models, make sure the tension on the pinion gear is correct. Too low and it might skip (has happened to me), too high and it might bind (also has happened to me)
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Ok while the stop butten is active go to the to of the home screen you’ll see a configuration tab, second on the left from memory. In that tab you should see controller, select that then you will see motor tuning. As you select each motor you will see an acceleration box.
I think you can set CV in the setup tab from the home screen.
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Looks like you have a ton of feedback but I will throw in my 2 bits.
I have NEMA23 and agree that depth of cut in particular is hefty, esp for MDF.
I never cut deeper than 2mm even roughing softer wood. Most commonly I will rough with depths of 1 or 1.5mm at speeds of 1000-1500mm/min
Steve
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This is a little concerning. The depth isn’t a problem but at those speeds I’m afraid I’ll be burning the MDF. My spindle has a min speed of 6k rpm.
Just want to say I appreciate all the input. I’m taking it all in and will be trying all the suggestions.
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My Porter Cable router has a single speed of 21,000 RPM and I can cut pretty slowly before burning anything - have you experimented to find what feed rate does cause burning? Also, you can switch to a smaller bit to reduce the effective SFM - a 1/4" bit instead of a 1/2" bit, even if only for the finish pass. And make sure your bit is sharp - wood is fairly abrasive and dulls bits quickly.
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I haven’t tried with the .5" EM but I did with my 2" surfacing bit. I was running at 100 ipm and irrc 9k rpm. I was cleaning what appeared to be burnt resin off of it afterward. This was before I understood feeds & speeds and also what made me go learn about them. Not a 1 for 1 example but it still left me a little gun shy.
two bits more…
reading through the whole thread here it dawns on me how little attention I pay to charts for cutting wood. I really only consult charts occasionally if cutting metal or using fine bits on stone, etc.
For (hard) wood I do it all pretty much by “feel”.
I generally start conservatively and commonly dial up the travel speed if it feels good.
When I say “feel” I mean minimal vibration, no earth shaking corners, nice chips, no burning, and just the “happy” sound of a machine not struggling. In short, the machine is not laboring but not “spinning its wheels” (burning) either.
Most of my cutting (excluding fine finishing) involves DOCs of 0.5-1.5mm and stepovers of 25%-50% of the end mill diameter. linear speeds usually 1000-2500mm/min. I imagine some folks will consider this slow - but I don’t burn endmills or wood and I rarely lose steps. In my experience if you push (bog down or jerk around) the NEMA23 you will lose steps (which in guitar work can really suck)
Ive cut a ton of wood (guitars mainly) and I think you will gravitate to this “feely” approach over time.
I will say again, and others may differ, but in my hands with the NEMA23, 3+ mm depths in hard wood doesnt work - unless of course you are using very small stepovers (like shaving) which I would only be doing in the course of finishing passes or some profiling cuts.
(Also, I use a spindle now. The old Bosch router really got tiresome. Just bogs down too easily).
Spindle waaaaay better though I had to spring support the thing due to its weight.
Steve
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The standard I’d found online was depth of cut equal to the diameter of the bit which is why I thought .15" was a very light cut with the .5" bit. Having had no success finding information for the NEMA 23 and having no experience to go on otherwise I assumed that was OK.
Someone mentioned earlier that I shouldn’t take on a big project so soon but I think I’ve learned a ton more from my missteps than I would have from a smaller project. I hate making mistakes but I do learn well from them.
So, that said, the project I’m doing is Shaker style cabinet doors. The .15 DOC is the big pocket in the middle of the back of the door. The front pocket is deeper but haven’t gotten there yet. I’m cutting pockets for 7 doors and a drawer in this one sheet of MDF. I’ve already drilled the holes for all the hinges and handles which worked perfectly. The big pocket is the last thing on this side.
Cutting time for the pockets with the settings I mentioned was like 2 hours. One of the things I noticed was how hot the stepper motors were getting. Was that because I was making them work too hard or do they always get that hot. Like hot water bottle temperature… if I had to guess, maybe ~120° or so.
And if I do make a shallower cut we’re talking 4 hours or more. Can these motors handle that kind of work?
The bigger projects just cost more when they go sideways. Smaller project are quicker to set up so you get more of them in a shorter amount of time.
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Ive never used doc equal to diameter of endmill.
Thats a mighty chunk. My machine would not tolerate it at all and my delicate guitar necks would routinely shatter. An exception would be for like minimal (<0.5mm) profile cleanups where I might go to depths of 1 or 2 inches in a pass (this removes the “bathtub ring” profile cutting marks. )
Aaah, time! I imagine a lot of us were a little disappointed in finding how long these operations can take. I had visions of cranking out guitars in an hour. I would guess that all the milling for a guitar, neck, fretboard, etc runs maybe 12 hours plus a ton of setup time. ‘Course thats 10% what it would take w/o CNC (if I could even pull it off -which I couldn’t).
My typical contoured guitar top takes about 4-5 hours I think. Initial roughing is close to 2 hours.
Then a lot of time in Z and planar finishing with tiny stepovers. Planar could in theory go a lot faster since very little wood is coming off but I’m limited by the turnarounds. If sudden turns are jolting losing steps is a risk, not to mention general hardware abuse.
All this said, Cabinetry is somewhat different I imagine. I have seen video of milling wood more aggressively than I do but I suspect a lot has to do with the power and precision built into those machines. Also, probably less likely to explode MDF or wood where cutting is mainly pocketing and profiling. Also their hold downs must be mighty.
At the end of the day, it’s just really fun
Steve
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You’re not wrong. I look at it as a time vs cost and I’m always in a hurry. My day job doesn’t leave me much time unfortunately.
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You should have a look at Gwizard for speeds and feeds, https://www.cnccookbook.com/. They have alot of info on CNC and I have used them for maybe 10 years now.
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I signed up when someone first posted it above but haven’t had time to dig into it yet. It’s definitely on my to-do’s.
Yes they can handle the work. I ran Nema 23 motors for years on other machines and rarely missed steps. In the old days the general rule of them was if you could touch the motor for 5 seconds it wasn’t getting too hot. The steppers are going to get hot on long runs and even uncomfortable to the touch. 1/2 the bit diameter is the rule of thumb for depth of cut. At the right speed 0.15 DOC should be fine. Just as an FYI I have NEMA 34 package now and I still only run somewhere between 100-200 ipm even tho AVID says it can boogie faster. If you are missing steps cutting 0.15" deep there is some else wrong with your set up.
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Mach has a speed and feed calc built in fyi
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Thanks. That’s helps a lot.