Mostly Printed CNC

[innkeeper]

Work in progress.

mostly printed cnc - mpcnc - work in progress

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[Mark the Greater]

Very cool! What board are you going with?

[innkeeper]

a smoothieboard clone called mks sbase it can drive 2.5A per stepper.

[Mark the Greater]

Very cool. I've been meaning to put something like this together but haven't made it a priority. I grabbed a Smoothieboard so I will end up going with external drivers. Keep posting!

[innkeeper]

You may not need to go outboard for drivers..i think smoothie can handle 2a per stepper.

I've seen some 84 oz steppers at 2a that are made by OMC.
and i've been hearing some good things about OMC steppers cost/performance.

I've been considering them myself as a potential upgrade to what i have now.
I happened to have some 65oz nema 17 stepeprs on hand so i'm starting with those.

Considering you would probably run those at 1.8a with the smoothie board for a safety margin, you would be at 75 oz holding or 150oz per x and y axsis, i think that is a little overkill for this design (i like overkill)

(edit: corrected stepper motor manufacturer name from osm to OMC)

[jsc]

What are you going to use for a spindle? I'm interested to see your first test cuts.

[innkeeper]

for a spindle i am going to start with an old Chinese zip saw i have on hand it came with 1/4 and 1/8 collets and a vacuum attachment. its very similar to the DW660 in size. in fact i am using the DW660 mount for the upper mount and a slightly modified dw660 mount for the lower part.

[i'll post pic of it here when i get a chance]

i'm using a harbor freight router speed controller, also that i had on hand.

i'm pretty much going with whatever parts i have already. i'm probably less then 250 out of pocket including plastic.

if it doesnt work out and i buy one, id likely go for the dw660 which i've seen for 52 bucks on amazon.

if i end up using it a lot i'll swap it out for a chinese ER11 spindle of ebay, which is much quieter but more expensive and has the potential of controlling the spindle speed from gcode.

[Mark the Greater]

I am going to have to look in to those steppers. I got an ER20 spindle w/ VFD inverter though and that's a lot of weight. We'll see what happens!

[Rovida]

Dear all, I finished today the mounting of a Mostly Printed Cnc.

I have no a Ramps but I have a Sanguino available....any suggestion for using this board? Someone of you already did?

Thanks a lot

Roberto

[innkeeper]

it should work, no reason it shouldn't as far as I know.
if you have it, no harm in tyring it.. i'm all for doing things with what you have on hand.

the 32 micro step drivers they recommend on the site isn't really necessary unless you need the additional drive current.... since most steppers have a +-5% accuracy so the whole idea of going to 32 micro steps for accuracy is kind of silly... since the accuracy of most steppers to support that just isn't there if that's your goal.

Worst case you end up buying a ramps if it dosn't work out.

I can only tell you what i'm doing... but haven't wired it yet... but plan to do that this weekend (slow going with limited free time)

I'm going to use a smoothieboard clone called a mks sbase, it has drv8825 drivers just as they recommend on the MPCNC site so it is good for 2.5a of stepper current and can do 16 or 32 micosteps.
google seach the board to learn more also see the smoothiewear / smoothieboard threads on this forum.

I used the MKS SBASE this replace my 'bad from the factory' Rambo board on my m2, so I am mostly using it because I am familiar with it and like it so far.it has a lot of additional features, the drv8825's also I can plug a 12864 grapic lcd (reprap) to it directly with no adapters ... also, just like the real smoothieboard, it comes with Ethernet interface as well as usb and serial.

on the flip side it dosn't run marlin, it runs smoothiewear. which is good and bad... good because no recompile to change things, but bad as your mostly on your own as to using it on a MPCNC.

frankly, from a cost perspective though, using the electronics as spec'ed on the MPCNC site would likely be cheaper....
my way is closer to 70. - 90 if you include the glcd .. which I did.

that's my 2 cents...