Recently acuired components, any advice?

[Halfdone]

I recently came across some Stepper motors, drives, and power supplies for free (rescued from scrap). I am anxious to build a 3 or 4 axis CNC machine (Possibly joe2000chevy's great new Machine).

So are any of these parts useful or should I just try to sell them to get the funds to build my project (controlled with HobbyCNC or Gecko). If so any ideas how much they would be worth?

Of course like most people in this forum I am trying to build this project without spending anything out of pocket. I hope to spend less than $500 for the drive controller, steppers, and materials.

See the attached pictures for the parts in question. If these parts would make a good machine (I realize they would be overkill for a starter machine) where would I start to get these components working? I would need to control them via PC somehow.

Thanks in advance for any and all advice.

[candle]

if used wisely you could do virtually any size machine for copper/aluminium alloy, and even for steel, just get two more microstepping drives, they are self powered, so no worries here, you don't really need that bulk 5V supply, as any at-style psu will do it without all those radiators
try to find some info on J3 connector, or you will stuck right at start

[Halfdone]

I found the manual for the driver and the diagram is posted below. Could the "indexer" be a Computer running CNC software? I have 4 motors total all simular (1 is only 3 stacks, 3 have 4 stacks). I guess I could use the 3 stack motor for the Z axis.

Now I guess I will have to find at least two more drivers. This may be hard to do considering I saw one online selling for more than $1000.00. Perhaps it would be better to sell these parts and go with more hobby sized parts, since that is what I will be doing primarily. Although cutting metal parts sounds intriguing............

.........But I would have to find a way to offset the cost of buying more (and expensive) components.

[candle]

how good you are with electronics?
indexer can be indeed pc running mach3 software, but you need a way to convert ttl signal into diffrential ones
there is a chip from texas instruments sn75176, it can transmit and recive so you would need 5 (one per line) to get it working
why bother with diffrential inputs?
well.. cabling may be extremally long and cheap - you need cat5 computer cable (as for network adapter) or any other twisted pair cable
and whats the most important - it exceptionally well protected against EMI radiation and noise pickup - no false steps, no need for optoisolation

[derekj308]

Hi Guys
I checked the manual (http://www.micromech.co.uk/dir_produ...acsci/5630.pdf) and I would think that this drive can be run from an simple parallel port interface board and Mach. The inputs for the drive can't be driven directly from the parallel port. I experienced this when playing around with industrial stepper drives and I built a simple pull up circuit to supply the drive with 5V and 20mA. I then bought a parallel port interface card and was able to control the drive. Buy a cheap parallel port interface card and have some fun getting one of your motors to turn. The evaluation version of Mach is free and will allow you to execute under 1000 lines of G code.

Don't get rid of the 5V 25A supply. You never know when you will need to run 1250 LED's in unison lol.

Cheers

Derek

[candle]

anyway, if i were you, i would never, never ever sell this microstepping driver - just put it on shelve and wait until next pop up
it costed you next to nothing i suppose, and if you're willing to wait a bit for next to come (year, two - who knows, doesn't matter really) then after some time you will have all you need for pro machine
meantime - you can use simple drivers for few $ (20 at most) and get those steppers spinning - they will be underpowered for sure, but it doesn't matter for start
consider this long term investment
if you want i could draw you schematics for interface board between your driver and parallel port

[Halfdone]

Thank you all for the advice,

I am competent with electronics and have evan made my own PCB's, I just need schematics to go off of.

Candle, I like your advice about holding onto the driver, that makes absolute sense to me. I would greatly appreciate if you could provide me with a schematic for the interface. Do you have any cheap drivers in mind that would get me started with these large steppers? I was looking into building one that I found here http://pminmo.com/ but I don't know enough yet to pick a good one. If I found some ok drivers online for cheap I could go that route as well.

I have read discussions about using "G-code" for machine control, I have decent skills with AutoCAD but have no idea how to go from .dwg files to G-code. Can someone advise me on this as well.

I guess I am actually asking for a crash course in how to build my own CNC and operate it. I have been reading alot of the forums but sometimes its hard to gleem the right information that I need from them.

Mark

[chuckknigh]

How is your background with mechanics? It's actually pretty simple to build the mechanical systems -- to do it well is slightly harder.

Go to your kitchen. Pull out a drawer...slowly. That's your X axis. Seriously!

The cabinet itself is staying still. Between it and the drawer will usually be 2 glides, one on either side. The drawer moves in and out, and only in 1 plane. The motive force is your hand pulling it out...in the middle. Notice, now, that there is probably some "wiggle" present in the drawer, from side to side. In a machine tool we want to get rid of that wiggle.

Building something comparable in the shop, is just as easy. You start with a platform onto which you place your moving parts. This could be anything, including bed rails -- but it needs to be strong and absolutely flat. On top of this, you build a platform. Rollers, often called linear bearings, allow that platform to roll back and forth, just like the drawer in your kitchen. Since it's built with more precision than your kitchen drawer, there's no wiggling from side to side, during the rolling.

Now, you have a single axis. If you attach a drive screw to this, probably in the middle, you have the fundamental basis for a CNC machine. You need only build 3 of them...X, Y, and Z...and stack them on top of each other, to have the mechanical part of your router finished.

Now that you have a better understanding of what's going on, mechanically, take a look around this site. It contains an amazing depth of knowledge, and the members are among the most helpful I've ever had the good fortune to come across.

This is a picture from this site (don't remember the name...sorry!) that shows the sliding platform and stationary base. This one slides on what appear to be plastic bushings...simpler yet. It looks to be a good design, overall.

-- Chuck Knight

[candle]

for those on pminmo webside picstep would be the most apriotiate - it has still less than reqiured 5A per phase, but since it has current limiter then this is no problem - just your drives won't get enought juice to get to their rated torque characteristics
i don't know about the price though
generally speaking you need bipolar driver rated at at least 2A for any torque of those steppers you have - it should you get close to 1.2-1.5Nm - this seems to be more than enough for most diy applications
(schematics comming soon - that is after won battle with windows on other machine)

[candle]

as promised
let me know if you build it
schematics


ps. how to upload attachments??

[ger21]

Originally Posted by mark95621 I have read discussions about using "G-code" for machine control, I have decent skills with AutoCAD but have no idea how to go from .dwg files to G-code. Can someone advise me on this as well.

If you use AutoCAD 2002 or newer, I wrote a macro to create g-code from within AutoCAD.
AutoCAD 2 G-Code macro

[Halfdone]

Thank you Candle for the schematic, I will try to find the parts and build it when I get the time. Just one question, is J2 connected the the Parallel port on my computer and J3 connected to the driver?

After looking at building the Picstep driver it is looking pretty expensive to build 4 of them, I figured I might as well build all 4 right off, so I may look into some off the shelf drivers and controller. How about this setup? http://hobbycnc.com/hcncpro.php

Would the steppers pictured above be considered 4 wire with a ground or could I consider them 5 wire?

Gerry, the Macro you made looks great, I can't wait to use it (I just finished reading your entire thread). Looks like I will have to start thinking more about how I draft in AutoCAD to get the paths going in the correct direction. I can't wait to read the tutorials that you said you hoped to make.

Now I just need to find time to start tinkering.