Would it have to be PC-driven?
I've been thinking a lot about the via pins and working on a basic design;
possibly using a soldering iron, solder wire feeder and a stamp/anvil to
'squish' the solder flat (for multi-layer boards). The thing with all these
operations is that they require specific coding:
- select a diameter for vias on a LCD input screen.
- holes of matching diameter in the DRILL file will be treated as vias.
- via process:
∗ drill.
∗ stamp a small circle of the via pad on both sides, to make a depression
around the hole, or maybe use a wide V pattern.
∗ fill hole with solder.
∗ stamp solder mound with a top flat stamp and bottom anvil (a simple
solenoid should make a great stamp, maybe spring-loaded to reduce the
vibration on impact).
I'm trying to find a flexible way of making vias, without chemicals, that
would allow me to use multiple layers one day. I might be content making
2-sided prototypes for now, but I'd like to be ready for the future.
I don't really care to have your code controlling the motor control.
Ideally, I'd like to be able to control the pulses, and have a black box
that makes the motors work. Look at the Gecko system, it is a similar
two-part system if I read the stuff right: a single controller and
individual drivers for each motor.
If you incorporate the 'controller' aspect within your driver board, I lose
all flexibility to add customized tools in the future. Maybe if you make a
PIC that we would pass parameters including all g-code data required to make
both arcs and lines. This PIC would then communicate with the drivers and
have protected software just like the drivers.
I figure a modular approach would be the best. I know it makes for a pain
since you are trying to use a single circuit, but separating the processes
permits you to protect the parts you want to keep for possible future
marketting. We also get to add a variety of tools and interrupt the process
between operations.
Robert
:)
-----Message d'origine-----
De :
Homebrew_PCBs@yahoogroups.com [mailto:
Homebrew_PCBs@yahoogroups.com] De
la part de Alan King
Envoyé : juin 6 2005 12:58
À :
Homebrew_PCBs@yahoogroups.comObjet : Re: [Homebrew_PCBs] Stepper motor drivers
Robert Hedan wrote:
> All I'd need would be the assembled PCB driver boards, since you
> appear to have quite a lot of inventory on hand. :) I can take care
> of fabricating a box. I guess I'd start with 3 axis, and get that
> working first. All I'd need to know is exactly what input the drivers
> expect, and I should be able to feed it something, somehow, someday,
> from a PIC.
>
Got my board up and running tonight, it's been probably more than a year
since I stopped drilling and have done almost completely top side boards for
testing. So I'm now remembering a few more changes to make..
50% or even 25% blind chopping on hold. Right now it just sits there baking
the
motors, since I only used it intermittently I never cared. 100% torque
stationary is overkill since you don't have that much moving.
Blind chopping for everything. If you have say a 5V supply and 3V motors,
this
would let you set it to 3/5ths duty and assume you're getting around the
right
current. Since it's usually the heat that kills this should be ok even if
it's
sloppy.
Microstepping. Right now it's just dead half stepping. Lots of resonating
and
vibration if you're not at a good speed. Even just an 8 or 16 progressive
transfer instead of full on/off would give a tremendous improvement. A good
acceleration profile and not running at speeds that vibrate badly would also
be
ok and easy to do. May just have it do full or half steps, and the micro is
just internal for smoothness, but really the supported range is rather high,
would be easy enough to give full access to say 16 position microstepping
and
use 4 bits.
IR remote. I have good IR code already built up, very easy to add. Instant
keyboard input, for manual jogging and more for and only a single pin, and
not
stuck in one place.
There are a few other things I'm not thinking of right now no doubt.
While
there's nothing too special besides the IR and math code parts, I'm not sure
I
actually want to give out the source. May just make it easily available as
a
programmed chip and send it with the board etc, which may be easier anyway
since
it's going to need the SMT version. Won't be a real limitation since it's
made
as dumb as it can be made, only goes point to point etc, with the real code
work
being all on the PC side.
Was really just designed to be a basic motor running unit. While it
could be
made into something very advanced without too much effort I don't think most
people would need much beyond these improvements. I'd be willing to stick
about
anything anyone wants in, but it'd be on a fairly long timetable for things
beyond this. Proper feedback based chopping is about the only other thing
I'd
use so it too may go in eventually.
Alan
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