[Lab] Marauder project (around 400 bucks and counting)

[John Nicol]

Hi Darcy,

 

The CNCZone forum listed is specifically that board you have in the photo,
not Chinese CNC controllers in general.  It applies to the three and four
axis controllers based on the TB6560.   I have the same three axis one that
you show in the photo purchased of eBay about two months ago.  I am honestly
surprised that it works for you, the design means that the motors share a
ground with your LPT port, so there is no isolation between your PC and the
motors, but as long as the voltages are kept low you shouldn't blow the PC
up.  That is an option though.  Never run it over ~34 V or you will blow the
stepper drivers and risk the LPT port.  The opto-isolators are also wired
wrong in this design and there is significant noise on the stepper driver IC
clock that means a loss of steps for most people.   I run it at 24V.

 

I have analysed the design as well (being an electronics tech in a previous
life) and can say that I would not recommend that design.  I also tried to
contact the company I bought it off eBay from and they have yet to respond.
There are a few companies in Hong Kong and China that seem to deal in these
boards.  The fixes that are listed in the CNCZone forum will work up to a
point and a few have reported good progress.  I have found that I am losing
too many steps and lots of hair to continue with that board.   I might try
one more suggested fix, which is to bypass the opto-isolator on the clock
and go straight from the LPT pin to try to get a clean signal.

 

I have seen some newer boards out on eBay that might address these issues,
so looking forward to some reviews on CNCZone before jumping that way again.
Probably just go with HobbyCNC for now.  

 

The big caveat with the above is that if it works for you, then it works and
that is a good thing. 

 

I am just missing electrical, everything else is done and now shopping
around for alternate controllers.

 

John

 

 

 

 

 

From: darcy.whyte at gmail.com [mailto:darcy.whyte at gmail.com] On Behalf Of
Darcy Whyte
Sent: June-06-11 5:11 PM
To: John Nicol
Cc: lab at artengine.ca
Subject: Marauder project (around 400 bucks and counting)

 


The cnc controllers work great and the price is right. I doubt the issue
people spoke about on cnczone is about all chinese cnc controllers. There
will have been an incident or incidents with a specific one. I had problems
the the cnc controllr on a mill I bought in china but they replaced the
electronics. But that's a different piece of hardware. 

 

Eventually there will be a bill of materials with lots of different options.
People can spend as much as they want on controllers.

 

What are you missing for your CNC project? Just electrical?

 

 

 

On Mon, Jun 6, 2011 at 5:02 PM, John Nicol <john_nicol at hotmail.com> wrote:

Today's Topics:

  1. Marauder project (around 400 bucks and counting) (Darcy Whyte)

=====

Hi Darcy,

Nice to meet your virtual acquaintance!  First time posting in the mailing
list so hopefully I don't screw it up too badly.

I went to your website briefly and saw the electronics proposed.  I would
stay away from that particular Chinese design and manufacturer.  I purchased
a 3-axis board + NEMA 17 motors off eBay and have had nothing but problems.
There is even a forum discussion on CNCZone about these.  The design is
flawed.

http://www.cnczone.com/forums/general_electronics_discussion/110986-how_i_fi
<http://www.cnczone.com/forums/general_electronics_discussion/110986-how_i_f
i%0d%0axed_my_chinese.html> 
xed_my_chinese.html

There are suggested fixes in the forum discussion and I have applied these
(and learnt how to solder SMD at the same time, so it was worthwhile from
that point of view), but although it improves the noise, it is missing steps
all over the place.  A piece of crap.  I made the CNC described in
Instructables here:

http://www.instructables.com/id/How-to-Make-a-Three-Axis-CNC-Machine-Cheaply
<http://www.instructables.com/id/How-to-Make-a-Three-Axis-CNC-Machine-Cheapl
y%0d%0a-and-/> 
-and-/

I have a picture of what I have made and can email separately.  All up, I
guess it cost me $600 so far.  It would work quite well I am guessing if I
had a "real" controller board.  I am thinking of getting a kit from hobbyCNC
and buying some 6 wire Nema motors from eBay to make it all work.  Currently
I have a dremel, but will upgrade that to a trim router.

Regards,
John




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