Worth a Thousand Words

[Chunky]

CNC Diagram I don't remember exactly where it is. But somewhere you have a fully functional diagram demonstrating electrical flow through diodes, capacitors, AC versus DC, etc. It's absolutely wonderful, helped me a lot. I wish you would expand on that and put up a diagram showing the workings of a typical hobbyist CNC router. I have made a rough stab at it (see link above), but some of the info is missing. Why? Because I'm a newby and don't know where those wires go or what's in that box. Such a diagram would help me a lot in knowing what to buy next and where it goes. After a while you could describe typical values for the components. For example you could note next to the stepper "a popular size for this kind of application is the___ and costs about ___." I'd love to be a part of such a project. A committee organized for the purpose of helping the ignorant should include one ignoramus. I'm your man.

[CNCadmin]

Here you go- http://www.cnczone.com/gallery/showphoto.php?photo=251

[skippy]

On the note of helping, I'm temporarily in forced retirement because even though I've had legal right to work here since day one (my wife of 14 years being an EU national), and even though we did all the preparation work at the Spanish Embassy before coming here, you still have to wait for them to actually give you the piece of paper saying it´s ok to work.

Just this week I received a letter saying they have now given me a date for an interview for 28 December 2005. That means I will have waited ONE AND A HALF YEARS for the interview! So in the meantime I find myself with plenty of time on my hands. I've been wanting to be a donation member to this site since I joined but due to not working that´s temporarily out.

One of the thoughts I've had is to make a database of the type that, starting at the beginning you have HARDWARE, software. (I'm using upper case to show what I chose) This takes you to the subs of mill, ROUTER, edm or whatever. From there to links to written articles (both cnczone and outside), frames, router motors, spindles, LINEAR SUPPORT, accessories, drive motors, etc. From there to TSK, Thomsen, home made, etc. From there to written articles, links to suppliers, etc. about TSK products.

I find the search system very good here at cnczone but sometimes you don´t know where to search and this is particularly the case for newbys. That way newbys could be directed to first do all their reading and if they're still stuck, come back and ask. I think it was Einar that posted a great link to a stepper motor article not long ago and this database would facilitate finding the many articles of that calibre as well as photos, suppliers, specs, etc. I imagine it would be an opensource, work-in-progress kind of thing but I'm happy to do a lot of the slug work. Maybe something like this already exists here and I just haven´'t seen it yet. This database idea is just an extension of Chunky's idea above.

EDIT: I wrote the above before I´d actually clicked on Chunky's link above and I think I prefer his idea to mine as it's more visual. However I would just include a few more levels such as starting off at software, hardware then level 2 would be what type of machine and so on. Chunky, count me in as hack number 2 if we can raise enough interest in this project.

What's everyone's thoughts?

[fyffe555]

Skippy, good ideas. The search here is pretty good, once you figure out what to search on, given that Paul is constrained by what the forum software can reasonably provide without burning up his bandwidth or cycles..

Benny and others did a lot of good stuff a while back on FAQ's along these lines. The problem is that it takes a lot of sustained effort by the contributors both to produce and keep updated. And opinions differ.

Paul, Maybe something along the lines of Wikipedia would work? No idea what that would take...

Skippy; Immigration is a pain. try doing it the other way. It took me 3 years to get a social and right to work here in the US. Despite the fact that I already had a current work visa and that my Home country has both Work Visa and visa waiver agreements. The US expects to operate to the limits of the agreements elsewhere but doesn't follow it themselves - just like the rest of the world I guess. Interestingly everyone I met or spoke to in the process up until the final interviews wasn't a native of the US or even a native English speaker. I was once asked ' why can't I speak english proper?' this to a Brit with an Eng. Lit BA... An interesting if frustrating experience...

Andrew

[Chunky]

Andrew, Skippy: Been to England and Alicante. Thanks for the offers to help. CNCAdmin was apparently not interested in pursuing this. He referred me to some action graphics which were cool but did not address my needs. I still want to do it. I need to do it so I can get a better understanding (especially of the hardware). So I'll welcome help from either of you or anyone else.
I could've told you-- if you want optimal benefits as an immigrant you need to sneak over the Mexican border. Then proclaim yourself as illegal. There's all kinds of programs currently available and the promise of more to come. I was born here and I think I might try it myself.

[Chunky]

Let's start with that yellow box in my diagram (see link in first post). What all's in there? Keep in mind that it's my scenario, my machine, and I'm telling you it's a simple 3 axis router. It's got a 1/4" Porter Cable router on it. I want it to be reasonably fast but speed's not a big factor. Reliability is. I bought 3 stepper motors on Ebay (not really, just in this scenario) and the seller said they were average motors with lots of life left. What's in the box. I want to know exactly what's in that box. Don't assume anything if you want to help me.

[JavaDog]

The "Yellow Box" in your link would have:

1) Breakout Board - Par interface between PC and Drivers.
2) Drivers (Gecko Drives, Xylotex, Etc...) - Parses information to Servos/Steppers.
3) Power Supply - For both your Servos/Steppers and your Drivers.

[ViperTX]

Fans, heatsinks, wire, parallel cable receptacle, AC input module (AC receptacle,switch & fuse), terminal blocks for DC distribution, DC fuses for each axis, connectors for input (encoder, limit switches, emergency stop) and output (to steppers/servos). A metal box that's not yellow, filter for the fan, AC cord. Screws, nuts, lockwashers, tie wraps, heat shrink tubing....

[fyffe555]

Chunky, I'll have a go, no pretty pictures thou'.

What's in the yellow box? quite a lot if you assume it contains everything needed that's not either on the PC or the machine itself. The components themselves will vary depending on your choice of vendors, type of motors, whether you have 'extras' like home, limit switches and spindle, cooling or vacuum controls. At the least the yellow box(s) will contain;

An interface to the PC. Physically the connector the other end of the parallel port cable attaches to. It breaks out the seperate signal wires to connections suitable to match the other parts in the yellow box. Logically it takes the signals generated/needed by the PC driver software like Step/Direction, home switch, limit switch, enable to each motor driver, microstep setting. Often its a seperate board, aka breakout board, or may be part of an all in one board including the motor drivers.

The Motor Driver(s). Each motor needs a dedicated driver that (usually) takes the step and direction signal from the PC and converts it into the neccessary sequence of coil energizing, or switching on and off the power as needed to each motor coil to produce the movement requested by the step and direction signal. Different drivers are needed for Unipolar or bipolar wiring schemes. Some steppers motors and drivers are uni polar, some , bi and some can be both. Some commercial drivers are one driver per motor, some have several drivers combined on the same board and usually include the breakout function. Some drivers include home switches some don't. Some include enable functions and microstepping functions, some don't. Some drivers are chopper (or pwm) type drivers where the driver manages the amperage provided to the motor. Some drivers cannot directly control the amperage and so need resistors in series resistors to limit the current. Without current control the motors would burn. The yellow box will contain three drivers, one per axis, either seperate devices or all on the same board to drive your three stepper motors. Depending on driver type there may also be some substantial current limiting resistors.

Power supply(s). Usually several. One will provide power for the breakout board (where neccessary) and the logic in the drivers. Usually 5vdc, 12vdc or both. The Motor drivers need a supply sufficient to power the motors, usually a very large transformer, bridge and capacitor. This is usually rated at the rated amps of the motor(s) and 10-20 x the face plate voltage. 48vdc and 4a isn't unusual per motor. Some choose to have a seperate PS per motor, some combine the capacity into one supply and drive all drivers from the one supply. Advantages are that, depending on driver vendor/type, the supply can often be smaller than the total max of all the motors combined because, 1/ usually not all three motors are running at full capacity at the same time, 2/ there is some degree of power generated (back emf) by decelerating motors that the driver (usually) can send back to the PS. Note that a linear (trans/bdrige/cap) supply is usually prefered over a switching PS for this reason.

Relays; If you're switching anciliaries like spindle, cooling vacuum etc then these are usually 110vac and can be switched by a relay controlled from signals from the PC via the breakout board.

Wiring; not so obvious is that there's a lot of different signals of various strengths wizzing around and so its usual to isolate and shield signal wiring, home/limit and motor wiring. The yellow box will have connectors for the four to eigth connecters per motor, for each axis home and limits switches, and where used power out for anciliaries.

Indicators; Usually its useful to know when power is on and where featured if the drivers have faulted, are enabled, or what ever else you want to see..

Fusing; usually the AC, DC supplies and drivers will be slow blow fused to protect the various components.

Cooling; Drivers get hot, as do power resistors where used, so usually some passive or active cooling is required.

hth

Andrew

[Chunky]

Originally Posted by JavaDog The "Yellow Box" in your link would have: 1) Breakout Board - Par interface between PC and Drivers. 2) Drivers (Gecko Drives, Xylotex, Etc...) - Parses information to Servos/Steppers. 3) Power Supply - For both your Servos/Steppers and your Drivers.

There's no way this is going to be painless. What's a par interface? And what do you mean by "parses info"?

[Chunky]

Originally Posted by ViperTX Fans, heatsinks, wire, parallel cable receptacle, AC input module (AC receptacle,switch & fuse), terminal blocks for DC distribution, DC fuses for each axis, connectors for input (encoder, limit switches, emergency stop) and output (to steppers/servos). A metal box that's not yellow, filter for the fan, AC cord. Screws, nuts, lockwashers, tie wraps, heat shrink tubing....

I was just about to get comfortable with this stuff. Where to start?

[ViperTX]

Chunky, parallel interface for step & direction controllers.