RAMPS board and NEMA23s

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skantron
Posts: 23
Joined: Tue Apr 01, 2014 8:59 pm

RAMPS board and NEMA23s

Post by skantron » Tue May 06, 2014 6:02 pm

I'm looking to make a RepStrap type mod to my Shapeoko (and for a while to just use *as is* as a 3d printer to get familiar with it and help decide what sort of RepStrap I may want to build), but I was wondering what controller board and extruder to get. My SHapeoko uses NEMA 23s on the X/Y and a 17 on the Z. Will the standard RAMPs board be able to drive that well enough, or should I look at another controller board?

I was also looking at extruders and saw two complete kits, one a Wades type extruder and another direct drive (I also like this these were complete kits, rather then just the hardware, or just the printed parts, seems like it's hard to find a place that sells both)
http://www.makergeeks.com/waexrefukitr.html wades extruder and hotend full kit
OR
http://www.makergeeks.com/siexretopr.html Direct Drive Extruder and Hotend

Then there is mounting the printing head to the Shapeoko, but I figure once I have the parts gathered up I can make something for that.

So, all in all I would need, to get started
RAMPs Board
End Switches
POwer Supply for RAMPs
Extruder
Stepper motor for extruder
Hotend and Thermosister
Glass Plate
Heater Pad
Various Wiring
Mounting of some sort for printing head.
Printer Filament

Is there anything I am overlooking at this point?
- Shapeoko2 #4557, NEMA 23

cvoinescu
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Location: Camberley, UK
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Re: RAMPS board and NEMA23s

Post by cvoinescu » Tue May 06, 2014 10:07 pm

Your link to that Wade extruder kit includes a photo that clearly shows a counterfeit J-Head. The J-Head is an open-source design, so anyone could make one or improve on it; however, the license covers only the design, not the name. The name should be used only with permission. Many of the fake J-Heads are built to a much worse standard than the original, and deceptively passed as the real thing by their (mostly Chinese) sellers. It goes without saying that Reifsnyder, its designer, doesn't get any money from those people. Because of this, I would stay away from MakerGeeks.

(MakerGeeks: if, by any chance, the photo is out of date and you actually sell the real J-Head hot end now, I take this back -- but please update your product image, it puts people off.)

You can buy the real J-Head at hotends.com and a few authorized resellers, and I can not recommend it enough. It's trouble-free and very forgiving.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

akhlut
Posts: 304
Joined: Wed Mar 27, 2013 1:16 am

Re: RAMPS board and NEMA23s

Post by akhlut » Tue May 06, 2014 10:18 pm

RAMPS will be fine. Its just an interface. The stepper drivers are what matters.

What power supply do you have now? It might be sufficient.

Everything else seems ok.

As cvoinescu points out, get a jhead from hotends.com. I have 4 and have never had an issue (other than my own stupidity).

Shapeoko or s2? I could probably design the mount for you and print it and a wades off for you.



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skantron
Posts: 23
Joined: Tue Apr 01, 2014 8:59 pm

Re: RAMPS board and NEMA23s

Post by skantron » Wed May 07, 2014 12:59 am

Thanks guys, I had no idea those were Counterfeit Hotends, I emailed the vender and will see if anything has changed... what's the easiest way to identify them? They had a RAMPS kit with stepper drivers for 110.00 but I may stay away from them all together, as I am sure the low cost reflects a similar situation with teh RAMPS and Arduino board. In regards to the stepper drivers, most venders seem to offer or bundle Pololu stepper drivers rated at 2 amps per coil...

It can be pretty overwhelming the different choices of extruder and vendor, esp. when you may have to go from place to place to get everything you need... Any recommendations for places in the US with decent prices and shipping?

So, If I get a Jhead, I was thinking 1.75 Filament (though haven't seen anything one way or another strongly supporting which way to go with that), and have no idea what size oriface I should consider. Most hot ends are sold with the appropriate thermosister now, correct?

I have a couple older computer power supplies and various 12V power supplies in the 5-20A range.

Is a heated bed for PLA that necessary starting out?

Akhult, thanks for the offer! it's a Shapeoko2, I thought I would mill something out, but something printed may be a better choice. I will PM you if I get to the point where I can take you up on that.

Thanks!
- Shapeoko2 #4557, NEMA 23

cvoinescu
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Re: RAMPS board and NEMA23s

Post by cvoinescu » Wed May 07, 2014 1:45 pm

One sure way to know your J-Head is counterfeit is that it comes with a 1.75 mm "conversion kit". Other ways to tell:
  • Hot end material: MK V-B and MK V-BV (the current version) are made of brass (yellow). Many clones are what looks like aluminum (white).
  • Nozzle shape: the J-Head does not have a nipple; many clones do.
  • Nozzle shape: the conical part of the nozzle has cylindrical neck that's less than a millimeter tall; in many clones, the neck is much longer and the nozzle stands out further from the heater block.
  • Heater block size: the J-Head has a small heater block, no wider than the PEEK part -- only as big as the heater resistor. Clones often have a wider block.
  • Heater type: the J-Head uses a resistor as the heater element; many clones come with heater cartridges.
  • Heater attachment: many clones have a set screw to retain the heater cartridge; the original doesn't have a set screw.
  • PEEK part shape: the J-Head MK V-B and -BV have five sets of grooves in the PEEK part. Many clones have only four.
  • PEEK machining: the J-Head is machined neatly and cleanly. Many clones have very visible tool marks.
  • Version: the current version of the J-Head is MK V-BV. MK IV J-Heads haven't been made in years, so if you see a new hot end being described as MK IV, it's almost certainly a fake.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

skantron
Posts: 23
Joined: Tue Apr 01, 2014 8:59 pm

Re: RAMPS board and NEMA23s

Post by skantron » Wed May 07, 2014 2:26 pm

cvoinescu wrote:One sure way to know your J-Head is counterfeit is that it comes with a 1.75 mm "conversion kit". Other ways to tell:
  • Hot end material: MK V-B and MK V-BV (the current version) are made of brass (yellow). Many clones are what looks like aluminum (white).
  • Nozzle shape: the J-Head does not have a nipple; many clones do.
  • Nozzle shape: the conical part of the nozzle has cylindrical neck that's less than a millimeter tall; in many clones, the neck is much longer and the nozzle stands out further from the heater block.
  • Heater block size: the J-Head has a small heater block, no wider than the PEEK part -- only as big as the heater resistor. Clones often have a wider block.
  • Heater type: the J-Head uses a resistor as the heater element; many clones come with heater cartridges.
  • Heater attachment: many clones have a set screw to retain the heater cartridge; the original doesn't have a set screw.
  • PEEK part shape: the J-Head MK V-B and -BV have five sets of grooves in the PEEK part. Many clones have only four.
  • PEEK machining: the J-Head is machined neatly and cleanly. Many clones have very visible tool marks.
  • Version: the current version of the J-Head is MK V-BV. MK IV J-Heads haven't been made in years, so if you see a new hot end being described as MK IV, it's almost certainly a fake.
Thanks cvoinescu! I will probably buy directly from Hotends,com or a dealer listed in the reprap wiki. So, if I go with a J-Head what size nozzle do you recommend for starting out, and which kind of filament size? my current thinking is 1.75 and .35, but I'm not really basing this on anything other then it seems to be the most common.

I think I will get one directly from
- Shapeoko2 #4557, NEMA 23

cvoinescu
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Re: RAMPS board and NEMA23s

Post by cvoinescu » Wed May 07, 2014 2:37 pm

The 3 mm filament J-Head is more common, and it works very well with a Wade-type extruder. For a direct-drive extruder, both 1.75 mm and 3 mm will work, but some people think that a direct-drive extruder may have trouble pushing 3 mm filament. It depends on the extruder design and on the hot end. The J-Head is one of the best, if not the best from this point of view, so you should be fine with either size of filament.

As for the orifice size, 0.4 mm is sort of standard. I'd avoid the smallest orifice for a 3 mm direct-drive extruder, just because it needs the most force to push the filament through, but other than that, any combination should work, so it's down to the cost and availability of filament, the time it takes to print, and the print detail. IMO, there's no significant difference in the quality of the print between 0.35 mm and 0.4 mm orifices, but with a 0.4 mm orifice you can print faster. The 0.5 mm orifice allows even faster prints, but at the expense of some detail.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

skipmcdonald
Posts: 22
Joined: Fri Oct 25, 2013 2:31 pm
Location: Dallas/Fort Worth Area, Texas, USA

Re: RAMPS board and NEMA23s

Post by skipmcdonald » Wed May 07, 2014 6:31 pm

Over the years I have built 5 different 3d printer designs and rebuilt a couple of those into improved models.
If you are using relatively small (lower amperage) nema23's and a ramps 1.4 you can get marginal performance with the 4988 drivers and a 12v 400+watt PC power supply printing PLA at 185C onto an un-heated bed using 3M blue painters tape.

Large nema23's will demand too much amperage overwhelm that setup and you will probably have a poor experience, you may get the motors to move individually but under the load of 5 motors going plus the hot end you may have glitches you can't explain. Check your voltage during a print and if it drops significantly then you are drawing too much amperage for the power supply to handle. That is a dangerous thing to do.

The 4988 drivers are "chopper" type and you can adjust up the current using the pot on each board. You will want to make sure the drivers have heat sinks (the little aluminum extrusions glued to each chip) and consider putting a fan near them to enhance cooling because you will probably be driving them at near their maximum depending on the amperage requirements of your nema 23's. You should set them at near the minimum setting you can and still not miss any steps.
If you set them higher than that you will probably get some thermal shutdown and the motors will just stop temperarily mid job and ruin the print. With the nema23's set right you should not feel significant motor heating (not too hot to touch) They can run hotter than your drivers can stand (or that you can comfortably touch) but again that will lead to a thermal shutdown where a motor will just stop or perhaps cycle between stop / go / stop / go when it should have smooth motion.

If you have a higher voltage / higher amperage power supply you might consider higher powered drivers like the 8825 drivers that are pin compatible with the 4988 but can drive up to 2A, and perhaps you can also drive a heated bed as well add up the amperages, motors, hot end, and heated bed and make sure you have a little room for error.

I have had very good luck with nema17 powered Wade's style extruders with a number of different hot ends. The secret is a nicely hobbed bolt.

My favorite hot ends have all been 1.75mm filament .35mm nozzle combinations.
3mm filament .5mm nozzle is a good combination for a repstrap if accuracy isn't as important because the only thing you intend to print are calibration parts and then just the parts for your first dedicated printer. Those parts have to be mechanically sound but not necessarily pretty. 3mm filament is also probably a better choice for a bowden style extruder / hot end combination in my limited experience with them.

Good luck, and let us know how your experience goes.

Skip
Shapeoko 2 #3181, Protoneer Arduino CNC Shield, Step-Stick 4988s, GRBL 9b+, All Aluminum Bed - Misumi HFSQN4-15250 extrusions, Dewalt DW611, Precision Think & Thinker, Collets.

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