EZstruder "micro skipping" musings

[mhackney]

I printed mine in PLA just because I had it loaded. But in retrospect, my extruder stepper gets a little warm so PLA might be a problem. I don't if ABS would fare much better, it would depend on how hot your stepper runs.

[mhackney]

Well, the jury is in...

I've been running the geared stepper (5.18:1 ratio) with the ezStruder for a few weeks now on my Rostock Max and a mini kossel. The issue I observed with the carbon fiber PLA has been completely eliminated (see the 1st post in this thread)! I can actually see and feel the difference in the way the filament comes out of the nozzle - no pulsing and nice and smooth. It has a positive effect on print quality too. I am completely convinced that low steps/mm on the extruder is not optimal. Increased microsteps help somewhat but with that comes reduced holding torque, which at low extrusion speeds can be problematic. I highly recommend a geared stepper motor on the ezStruder.

[KAS]

So I don't typically pre-load with filament coming out of the nozzle before starting a print. I get these little dots forming around the skirt until the filament is flowing out smoothly. Those dots seem to correlate with the extruder steps and can be felt with the through the manual filament loading knob.

With the geared reduction do you feel those steps or is it smooth through the knob at the extruder? I'm starting to wonder if that has any correlation with the vertical banding issue some of us are having.

[mhackney]

KAS, that is exactly the point - with the geared stepper you do not feel the steps at all, a very smooth, continuous flow. Your observation is exactly the same as mine with a standard stepper motor on the ezStruder.

I've seen the vertical banding myself and even with the Smoothieboard they are there. I don't see any (significant) change with respect to the banding but I DO see a significant improvement in the smoothness of the perimeter surface, they are almost slick they are so smooth. I've tried photographing this but it is not really possible to capture.

[Nylocke]

I ordered a HobbBoblin for use with testing my new extruder design I'm going to be working on. The goals for this one are for it to be easily made for those who have a Greg/Wade's extruder or EZstruder (so it can use a Mk7 style drive gear or a hobbed bolt (thats what the HobbGoblin is for)), it will be geared, with options for either a belt driven system or a printed gear system, and it will be compatible with EZ-style mounting (its meant for Bowden), and of course it will be useable with flexibles. The goal is to be able to take an existing EZFlexstruder and modify it to be geared with minimal changes. Hopefully I'll be able to use the arm design I've been using in the end. I have no clue how it will end up looking, but it will probably be pretty interesting. It should end up being cheaper to make for those who already have an existing Greg/Wade's or EZ/EZflex extruder design than to buy a geared stepper. Hopefully

[KAS]

Well darn, I was hoping for one last hell-marry before installing a few upgrades this weekend. Since I'm waiting on the official GLCD, I'll order the 5:1.1 and do it all at once.


ebay, is blocked at work. That link above still the correct geared stepper I should be looking for?

[gestalt73]

Hey mhackney,

I've stumbled across a way to light and photographic printed parts in the most cruelly unforgiving way possible.
I've been using it to compare print quality as I try to get my Cyclops dialed in.

Brightly overlit at a slight angle. Here's a shot of the setup and what the pics look like.
(The two on the left are examples of some of my best prints, but even those look less than perfect when lit this way.)

I'd be very interested in seeing the difference in surface quality if you have some test parts you could light in a similar way and share.

I also ordered a geared stepper yesterday to play with and to see what all the fuss is about.

http://i.imgur.com/MJiHpiO.jpg
[img]http://i.imgur.com/MJiHpiO.jpg[/img]

http://i.imgur.com/Ma4h0lT.jpg
[img]http://i.imgur.com/Ma4h0lT.jpg[/img]

[Earthbound]

Well, the jury is in...

I've been running the geared stepper (5.18:1 ratio) with the ezStruder for a few weeks now on my Rostock Max and a mini kossel. The issue I observed with the carbon fiber PLA has been completely eliminated (see the 1st post in this thread)! I can actually see and feel the difference in the way the filament comes out of the nozzle - no pulsing and nice and smooth. It has a positive effect on print quality too. I am completely convinced that low steps/mm on the extruder is not optimal. Increased microsteps help somewhat but with that comes reduced holding torque, which at low extrusion speeds can be problematic. I highly recommend a geared stepper motor on the ezStruder.

Michael,

Did you machine an adapter plate or use something you printed? If printed, could you share or link the .stl?

[KAS]

Is this the correct one?

http://www.amazon.com/Geared-Stepper-Mo ... +17+geared

[mhackney]

I designed my own since I had a couple of special things I needed to do. Here is the basic adapter:

Nema_17_Geared_Stepper_Mount.stl

(144.32 KiB) Downloaded 374 times

And yes, that is the stepper motor. I ordered off eBay from the same vendor.

[Earthbound]

I designed my own since I had a couple of special things I needed to do. Here is the basic adapter:

Thank you.

[geneb]

Nylocke, will your design allow using the original hobbed gear that is supplied with the EZStruder?

g.

[Nylocke]

Yes, you may have to buy some 5mm or 3/16" rod but that's the plan. Going to be working on the design tonight and tomorrow, I'll start a new thread for the progress.

[Tonkabot]

Of course I only find this thread after I buy a Kysan 5.2:1 geared stepper [ because I thought it would work better on the extruder].

I still have to put together an EZstruder or something, I'll look at the things posted in this thread.

But, I have another idea that I think might help with the extruders: a larger diameter hobbed pinch roller seems like it would make more surface area contact the filament.
It would 'gear' it down a little because of the larger diameter, but with the 5.2 ratio we should still be more steps/mm on the filament.

Have people tried a bigger gear hob and pinch roller? [ which seem like it might not work so well with direct drive - not so a geared stepper]

I also wonder if people have tried servos* instead of steppers on either the delta arms or the extruders (or both)?

* A real servo is not a model airplane servo, it has a DC motor (coreless brushed or brushless) with a gear box and an encoder.

On the extruder I would expect that you could maybe get away with a small enough servo that maybe it could mount on the head (like Mr. Trick Laser's Nema 11 idea)
(Mr Trick Laser cause I can't spell bviendeos - sorry)

[Eaglezsoar]

Thanks for the .stl file for the geared stepper adapter plate Michael.
At this link: http://www.thingiverse.com/thing:744759
I found a printable ezstruder that accepts the geared stepper and flexible filaments, the description reads:

A remix of Nylocke's EZFlex extruder, which is a direct replacement for Seemecnc's Ezstruder, but modified to work with a planetary geared motor.
The bowden tube runs all the way to the hobbed gear, allowing this to be used with flexible filaments.