Multi-Extruder setup fail

[mikefazz]

I have had my RoStock for a few months and have been working towards dual and eventually a triple extruder setup. I have all the mechanics in place but lately I keep having issues with my setup which I believe come from the stiffness of the bowden tubes. I print with 3mm filament and use 1/8" ID 1/4" OD teflon tube. I like the setup of the filament being under the table and that is why I kept the original style with the extruders off to the side ... but having 3 stiff tubes pushing against the carriage I believe results in the loss of steps I am seeing.

I am currently using a RUMBA board and I recently upgraded is XYZ stepper drivers to the higer power A4988 drivers leaving the stepper at 1/16 microstepping. I am considering dropping them to 1/8 or 1/4 microstepping but I am not sure if that will fix my issues.

I also noticed all the setups are moving to mounting the extruders on the top with the bowden tube coming out at angles. This would allow the extruders to be equally spaced (radially) and more evenly push on the carriage. I am a bit resistant to this mostly because I don't want to abandon my design;(

If interested I am using a water-cooled setup where I have a single water block which holds my hot ends in place and provides cooling to prevent the little PLA melt zone creep. I am also using my own hot end and extuder design because why buy what you can spend many hours of trail and error to create;)

I would love to post a picture but that doesn't seem to work for me at the moment.

[geneb]

I've never heard of a successful rostock design that used 3mm filament.

Why not re-tool to use 1.75?

g.

[Nylocke]

I ran a Rostock mini with a 3mm buda, but I had loads of problems. 3mm isn't that great for Deltas unfortunately.

[MSURunner]

With multiple 3mm bowdens, I think the only way you would be able to get that to work would be to mount the extruders at the top. I have a 3mm setup on mine with an E3D and the extruder top mounted. I like this much better than off to the side for a couple of reasons. First, that space at the top is wasted inside the build volume, why not take advantage of it? Second, the bowden acts as more of a top loaded spring then, as opposed to the side loaded spring that you are encountering. I would probably have stuck with a 1.75 setup if I didn't already have a well functioning 3mm printer as well, though, especially if I were doing multiple extruders...

[mikefazz]

Hmm well I was afraid of this (3mm vs 1.75mm) as I have invested in lots of 3mm filament;( Wish I had asked questions earlier;) I have noticed RoStocks seem to always use 1.75mm and I do recall richrap mentioning 3mm not being a good idea for deltas but I just forged ahead...

My extruder design is geared and seems plenty strong for pushing 3mm but for 1.75mm has there been any experience with slipping with direct drive setups since it takes much less force?

So I think I'll try top mounting the extruders for now but also begin the conversion to 1.75mm

[geneb]

The EZStruder shipped with the Rostock MAX and Orion is a direct-drive extruder. No problems with it slipping.

g.

[mikefazz]

Hmm I may go to the direct drive for simplicity in the future.

For now is there a reason the top mount extruder has the bowden tube angled outward instead of inward? With my extruder design angling the tubes inward would be best. I suppose the tubes could hit each other but I doubt that would be a big deal.

[geneb]

The top mounted extruder that SeeMeCNC sells aims the bowden straight down. The one that Trick Laser sells aims the bowden in toward the center of the machine at an angle.

g.

[mikefazz]

The Trick laser one: http://www.tricklaser.com/EZmount-KIT-f ... NT-KIT.htm shows the extruder mounted with the filament coming angled out from the center of the machine... I am hoping to go the opposite direction.

[geneb]

No it doesn't. The photo doesn't show it well, but it's actually facing toward the center of the machine.

Here's a better picture:
http://www.geneb.org/rostock-max/blue-max-done.jpg

g.

[Eaglezsoar]

No it doesn't. The photo doesn't show it well, but it's actually facing toward the center of the machine.

Here's a better picture:
http://www.geneb.org/rostock-max/blue-max-done.jpg

g.

Is that a bed probe I see hanging there? It would be great if you got that working, think of the thousands of kits!

[geneb]

Yeah, that was taken when I was still fiddling with it.

Until some great strides are made with regard to delta auto-calibration, the bed probe is a waste of time.


g.

[mikefazz]

So both pictures show the same thing which is the exit of the extruder points down and radially outward... Anyways I tried a setup with the tube pointed inward and I think with multiple extruders this could cause an issue... So I'll point mine outward like the TrickLaser one.

Thanks

[geneb]

Yeah, I totally misunderstood what you were talking about. *laughs*

The angle of the bowden tube presents zero issues.

g.

[artexmg]

I have had my RoStock for a few months and have been working towards dual and eventually a triple extruder setup. I have all the mechanics in place but lately I keep having issues with my setup which I believe come from the stiffness of the bowden tubes. I print with 3mm filament and use 1/8" ID 1/4" OD teflon tube. I like the setup of the filament being under the table and that is why I kept the original style with the extruders off to the side ... but having 3 stiff tubes pushing against the carriage I believe results in the loss of steps I am seeing.

I am currently using a RUMBA board and I recently upgraded is XYZ stepper drivers to the higer power A4988 drivers leaving the stepper at 1/16 microstepping. I am considering dropping them to 1/8 or 1/4 microstepping but I am not sure if that will fix my issues.

I also noticed all the setups are moving to mounting the extruders on the top with the bowden tube coming out at angles. This would allow the extruders to be equally spaced (radially) and more evenly push on the carriage. I am a bit resistant to this mostly because I don't want to abandon my design;(

If interested I am using a water-cooled setup where I have a single water block which holds my hot ends in place and provides cooling to prevent the little PLA melt zone creep. I am also using my own hot end and extuder design because why buy what you can spend many hours of trail and error to create;)

I would love to post a picture but that doesn't seem to work for me at the moment.

Your setup sounds really interesting! any chance you share a picture??

[mikefazz]

I'd love to show a pic but can't seem to add attachments to the forum. Unfortunately, after spending quite some time on that setup I accepted it is no good and have switched to 1.75mm filament and mounted extruders from above. When I get a setup that seems reliable I plan to put it up on thingiverse. My current design allows me to put 3 extruders and 3 spools at the top... kinda top heavy now but seems to be a simpler and more elegant setup than I previously had.

[artexmg]

I'd love to show a pic but can't seem to add attachments to the forum. Unfortunately, after spending quite some time on that setup I accepted it is no good and have switched to 1.75mm filament and mounted extruders from above. When I get a setup that seems reliable I plan to put it up on thingiverse. My current design allows me to put 3 extruders and 3 spools at the top... kinda top heavy now but seems to be a simpler and more elegant setup than I previously had.

3 Extruders? sweet! what PCBoard are you currently using then?

[mikefazz]

I figured out how to upload some pics...

So here are a couple pics of the old setup:

While I could have tried 1.75mm all from the side I think having the extruders radially spaced around is much better.

Here is what I am working on now:

I really think this setup has much more potential.

3 Extruders? sweet! what PCBoard are you currently using then?

Using Rumba which I like for the most part... had to add a relay for the heated bed... When I tried switching with its under-powered MOSFET it got so hot that it de-soldered itself and fell off;( For now I am hoping for dual extrusion with a setup that can support 3 for the future. I don't know if triple extruding firmware is very common yet...

I also am using a big server PS I got from my local PC recycler $3 for like 36A of 12VDC

[artexmg]

I figured out how to upload some pics...

So here are a couple pics of the old setup:

DSCN1375_sm.jpg

DSCN1378_sm.JPG

While I could have tried 1.75mm all from the side I think having the extruders radially spaced around is much better.

Here is what I am working on now:

AboveBelow2.jpg

I really think this setup has much more potential.

3 Extruders? sweet! what PCBoard are you currently using then?

Using Rumba which I like for the most part... had to add a relay for the heated bed... When I tried switching with its under-powered MOSFET it got so hot that it de-soldered itself and fell off;( For now I am hoping for dual extrusion with a setup that can support 3 for the future. I don't know if triple extruding firmware is very common yet...

I also am using a big server PS I got from my local PC recycler $3 for like 36A of 12VDC

Men, this is impressive!

Did you already finish your build?