NX scares me. We have to use its little brother, Solid Edge, at uni and that's frustrating enough. Especially as they never actually teach us properly, so you end up having to work stuff out by yourself and invariably this leads to learning to do things the wrong way, or leaving big gaps in your knowledge.
I am teaching NX8.5 to our engineers next week. Having proper training makes huge difference.
I'll give that a watch tomorrow.
I am getting ready to do this as well. I am using an old table as my starting point. It's about 4' x 4', I want a decent size working area. I'm going to be using a Dremel as the cutting tool and an Arduino as the controller.
I have a lot of the parts I need already, but I'm only in the hunting, gathering phase right now. I have two stepper motors but I don't know if they will work yet. I have a parts list started and am getting ready to start buying/making the needed things and get this project going! I am going to do a time lapse of the project if I can get my camera to cooperate.
How is yours coming along?
No progress, the real world has been getting in the way. Still waiting for my motor drivers to turn up. Still. Need to order my linear rails. Still need to grind my shirty welds off. Still need to finish designing the y and z axes.
That's what keeps happening to me. Sounds like a Matchbox 20 song.
Well today is the last day of the 'expected delivery' time frame on ebay for my stepper drivers. Shame they only got dispatched at 3am. From Hong Kong.
That sucks. I have a digital soldering station I'm waiting on but I'd say with the weather it won't arrive today.
Is there a place that suggests what steppers to use? I have two from printers or something, I think they will work for this project but I'm not sure.
I highly doubt that steppers harvested from printers will have enough grunt to run a CNC mill. They'd probably manage a laser cutter gantry, as long as it was light weight.
I've also found (although this might be because the printers I nicked mine from are /old/) that printer steppers are relatively low resolution, at 7.2 degrees/step. The printers tend to use a gearbox to increase resolution, but for a CNC extra gearing means extra backlash and should ideally be avoided (Backlash can be compensated for in software to an extend, but if you want decent repeatability it's best to minimise it from the outset) .
General rule of thumb (can't remember where I got this or how valid it is...) is you want at least 1Nm to be able to use a dremel effectively to cut wood. The motors I've just received are 3.1 Nm, cost about £30 each and they need a hefty 5 amp driver.
In terms of how much torque you need: to cut a straight line in the X axis, you need enough grunt to both move the y/z gantry and enough left over to push the tool through the material. Additionally, your y/z motors need enough torque to prevent the tool deviating in either of those two directions. It soon mounts up to needing quite a bit of force.
Furthermore, when you look at a stepper motor torque rating what you get given is the holding torque - i.e. how much torque it has to hold its position. As the RPM of the motor increases, the torque decreases. If you use microstepping you can also reduce the available torque by a large chunk.
Also also, there is seemingly no properly reliable way to calculate a linear force from a screw torque. Due to the number of variables in a setup (particularly the friction between your screw and nut), the normal formulas used can be out by 25% or more. Some US building code I saw says that if a particular clamping force is required, you must measure it directly with a strain gauge rather than using a formula to find out how much torque to put on a bolt.
If you don't mind and have time can you point me to some of the guides you consider the better ones for this project? And link me to the motors you ended up buying?