What makes a good CNC router? The person who runs it.
One that makes lots of dollars. Buckets full that is.What makes a good CNC router?
Not true @JOAT. My intention was to do the same thing at work, make signs.My vote would be one that can do what you bought it for.
Good points, Kit. But I think you meant NEMA 23 motors.Mike,
A good start for a beginner's guide but there are plenty of worms in the can! As someone who has built and upgraded his own machine, with a tight budget being a critical part of the design decisions, I would make the following comments regarding budget, amateur level machines before donning my tin hat and ducking below the parapet...
The rigidity of the frame and linear rails is critical. The rigidity of the gantry especially so (according to a Brazilian manufacturer one of my friends visited recently). Sheer weight will reduce vibration but likely add cost and reduce speed from a given size of motor. Careful design is important here to maximise the capability of the materials used.
Stepper motors are cheap and effective. As long as the motors and their drivers are rated and adjusted correctly and you run your machine within sensible limits they work. You will suffer some missed steps (along with some broken tools) as part of the learning process regarding feeds and speeds but the value of timber ruined is unlikely to exceed the extra expense of using servo motors instead.
Most machines use NEMA32 sized steppers having 200 steps/rev, these are by far the most common type of stepper and are widely available. One of these motors on a 2mm/rev lead-screw gives 0.01mm resolution. Micro-stepping (a function of the driver not the motor) increases the resolution at the possible cost of reduced speed.
Stepper drivers, breakout boards for computers, external controllers and the bits that go with them vary in cost enormously. Personal experience tells me that you can assemble the electronics for a working 3-axis machine using an old junk PC and the cheapo bits available from China for about $80 the lot. For maximum speed plus minimum noise, vibration and heat plus customer support from the manufacturer add another nought.
ACME lead screws are way cheaper than ball-screws but both require careful construction and installation of the thrust bearing to avoid backlash. I'm about to upgrade my machine to use new ACME screws with DIY thrust bearings and delrin nuts, both of which will be adjustable to reduce backlash and to take up wear over time. Watch this space!
That's probably enough for now.
I have no info on the motors you speak about I am far from an expert I laid out my basic knowledge to try and help others in a constructive discussion is what I was hoping for thank you for your responses. I agree the operator makes a big difference but that was not what this was about it was strictly a discussion on the different attributes of machines for sale.One that makes lots of dollars. Buckets full that is.
Not true @JOAT. My intention was to do the same thing at work, make signs.
Yet, realizing there's much more to be made. So much more that ideas are endless.
I'm more into making the things that make things work better. I dig jig building.
Hell, maybe one day I might make a fortune making underwear hangers.
I've seen a few machines that now carry brushless (micro?) steppers. Any insights to those?
Or is it basically same concept just they last longer.
I seen it over at TechnoCNC, here:...
I've never heard of a stepper motor with brushes, are you possibly thinking about spindle motors? Traditional mains powered, hand operated routers will have an induction motor using carbon brushes as part of the mechanical commutator. Modern 'Brushless' motors use transistor based switching to perform the commutation function and tend to be less noisy as a result but usualy require an external controller and power supply. Stepper motors, as I understand them, are a form of brushless motor.
Liking the helical gear rack a lot , but not liking direct drive steppers . I’d like to know what there rated back lash is.Ronnie,
That's one serious machine! Way out of my league. I think there's a bit of sales hype in them saying "The Techno HD Series CNC Router utilizes brushless microstepper motors" as this is true of all stepper motors in practice, even the ones in my humble machine.
On another point mentioned earlier in the thread: I think one of the reasons for using racks instead of leadscrews, especially on bigger machines, is that a long leadscrew would be prone to whip when spinning at high speed as it is unsuported along it's whole length. It may be cheaper to manufacture as well as a rack can be made in sections. The helical design as shown on the machine Ronnie linked to should be nice and smooth running.
Lol... thats a good one. I was back & forth w/ Brandon @ sabre only to learn that Techno is 9 miles away....
When I bought my machine I looked at the Techno but I thought the machine I bought to be better.
I also looked at the Freedom machines they are also very nice.
You can do it in a number of different ways. I chose to go simple, with well documented components, and didn’t have any problems.I'd like to build a small machine but I dont have the electrical component experience.
Where would a person like I start out from scratch not knowing the setup? I'm talking
connecting all the electrical parts. Leave out the physical parts build, extrusions etc.
Im sure there's others that are stumped.
Hah! Thanx Balloon & 4D.... Sorry David, I had forgotten about your build....
@difalkner did a beautiful job wiring his somewhat more involved electronics, documented in his build log. His shows what is involved when using separate stepper drivers for each stepper, and he controls power to his VFD, water pump and a few other items using relays. He installed proximity limit switches at each end of each axis. He also has 2 separate power supplies to power his Nema 34 sized steppers. While not the most complicated DIY I’ve seen, it is certainly more sophisticated than my approach and should be seen as covering just about everything one might want.
65K for a 4X4 , that’s a little expensive. It probably has every whistle and bell ,like multi tool change and vacuum table on it though .Hah! Thanx Balloon & 4D.... Sorry David, I had forgotten about your build.
I'll check into this and see what comes about.
After finding out the Techno HDS 4x4 is $65k... :nerd: Lol we'll see.
Palpitations..... mellloooooo melllloooooo ok