questions to the "old hands" about the 1.2 stepper driver

Hi

I've been looking into the old 1.2 stepper driver, as it seems to have some advantages over the 2.3 version.

The biggest advantage I can see is:

• it is easier to source the parts globally
• it is 100% through the hole soldering
• it can be mounted on a stripboard

Questions:

1. Besides the heatsink and lack of ability to have finer stepping resolutions than hafstep, what were the issues causing the development of generation 2 steppers?

I've got 3 of these running an early rapman. They get *very* hot - I mounted old cpu heatsinks to replace the 'standard' ones. I did have some problems with overheating and the steppers buzzing and moving on their own, but the heatsinks fixed that.

There is quite a bit of work in building them, and apparently the SMD build is a lot easier. Also, it's more designed for professional production (like MakerBot)

The connectors are more standardised and better than the bare wire connections to the 1.2 board.

In short, they still work fine and should still work in a gen2 (or probably gen3) setup.

p.s. I'm currently playing with a single-sided SMD version of the 2.3 board, which I can build at home.
[renoirsrants.blogspot.com]
Mainly because I want to try SMD and the MakerBot bare PCBs are out of stock. Although they do have some 1.2 boards left!

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

Mine get far too hot without a huge fan cooling them down, but my 2.3's are only warm to the touch. I'm also using a stepper controller that does 1/8th stepping which is much smoother. If you're looking to buy a controller, I can't recommend [www.diycnc.co.uk] enough. 18 pounds is probably almost as cheap as the parts, and they solder the smd for you.

Wow .. thanks, yet another link I'll store for later reference.

I love the fact that the board is rated for 2.5 amps, that extra 1/2 amp was one of my reasons for investigating alternatives for the 2.3 drivers.

The 2.3 version has a safety thermal shutdown which will prevent the chip from damaging itself. I ruined one 1.2 board before I learned that the standard heatsink was not enough.

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Darwin clone, Gen 2 electronics, Arduino Duemilanove w/ AtMega328, 5D Firmware, Pinchwheel extruder
[www.codeerrors.com]

The 1.2 and 1.1 steppers are great as long as you have active cooling on them.
I basically choped up some old CPU heat sinks and added fans.

You might want to consider using the enable line to switch the motors off while not inuse. This helps keep everything cool.

Note Switching the enable lines off and on while printing ie switch the Z off while the x and y are working causes in accuracies in the prints.

Stephen

I have just ordered one of http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180476693873&isIU=1]these[/url],
I will let you know if its any good when I have tested it out.

sorry screwed up the link, this should work

4 axis stepper drive board

Since I had the camera out, I took a picture of the v1.2 board I made a few weeks back.

I still have not tested it, so the main chip is out. When I took the BOM to the store it said large heat sink. So I got the largest one that would fit.

I think they used these heatsinks to make spaceship models in starwars type films, It has two large fins that come out over the side.



-julie

Nice.

However I found my very large CPU heat sink (I ama afraid much bigger than yours) was not enough and had to attach a fan as well. CPU fans are a good way to go.

If you don't want to go down the route of a fan a stepper I have seen people use a computer case to house the electronics and a single large fan (which is usually the same cost as a little fan) to keep everything cool.

Good luck

Stephen

Ironically it was replacing the fans in my existing CNC controller that got me active here. The new ones glow blue when turned on. Makes it look interesting inside. The blue fans were 1/2 the price of the plain black ones.

Perhaps Henry Ford knew something we did not.

-julie

In case anyone is interested, the 4 axis drive board arrived, took about 9 days, packaging good and all parts present, the board look neat and tidy with a professional finish, when I get it wired up I will post the results

Wired up the board over the weekend, works a dream and does what it says on the tin,
powered by an old computer power supply this solution saves a lot of messing about.

Does anyone know where to get SMD v1.2 PCBs?

Makerbot is out of stock on them, and they probably won't be restocking them. The only other place that has them is Reprapsource but it's in Europe. I'm using them because my motors pull about 2.5A and the chips are easily heatsinked. I doubt that v2.3 will work with this current.

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Vitaly
[contraptor.org]