Changing the Extruder

I have a PRUSA i3, most of it quite standard, I have a problem with the extruder mechanics.

The setup I have is a typical Gregg Wades type, but I am looking to replace it with something a little more tougher. I have looked at some metal ones but they all seem to be for 1.75mm and I would like to stick to 3mm as I have tons of it.


Any suggestions?

Dave

Hi Dave,

First of all, may i ask what kind of problems you are experiencing and what hot end doe you use?

About the metal extruder, the only option you have for 3mm is with a planetery gearbox motor if you go direct drive.

I have a Direct drive bulldog xl extruder myself, because i also use 3mm, in combination with my e3d v6 it works fine.


Ps: This is an example of the bulldog on a prusa i3 [www.thingiverse.com]

Picture added is the bulldog on my printer

Edited 3 time(s). Last edit at 09/04/2016 12:57PM by Govahnator.

Hi,

Thanks for the response.

I have a e3d v6 as well, so the same setup.

The problems I am getting is always feed problems. The only way I have been able to get it feeding OK is to tighten up the tension so the filament is really tight on the hobbed bolt, but this is giving more issues now as it just chews up the filament and then have to clean out the serrations on the bolt and this normally does this half way through a print, very annoying.

The Bulldog is a good looking bit of kit, but that is quite a price tag....

Dave

What kind of motor are you using currently on your extruder, is it a rather small nema 17? Also it is quite possible that there is a problem with the assembly of your extruder/hot end, did it ever work well?

The original one is quite expensive, the one i bought is half the price, the one from robotdigg it's 72 dollar at the moment excl shipping.
It is a bit harder to reassemble when needed, but i dont care, it also comes assembled.

Edited 2 time(s). Last edit at 09/04/2016 05:03PM by Govahnator.

I have had the printer almost two years now and in that time, most of the time it prints just fine. I first had issues and found by increasing the tension all my problems went away. This eventually caused part of the frame of the extruder coming away where one of the bolts went for the tension. I got a 2nd extruder, just a standard Greg Wade type, which I had to buy as I could not print it myself, this has been working well for months, now the frame on this has snapped in half, so now I am thinking its time for an upgrade.

Yes the steppers are the 17 nema size,

When people print stuf and sell they dont use 100 procent infill, claiming it is not necessary, wich is bs for mechanical objects ofcourse.

Well, i would advice you to go for the robotdigg one for sure if you are on a budget.

Works fine with me i did it for the same reason as you.

Excellent, I will do.

I am assuming you changed the stepper to a larger one?

Also, what other changes did you need to make, are there changes to the firmware for the different gearing?

I didn't change the stepper, i bought the bulldog xl extruder in a whole.

Yes it needs to do less steps, you have to recalibrate the extruder . I use 930 steps/mm with 32x microstepping, but this will be a bit different for each motor.

Edited 1 time(s). Last edit at 09/04/2016 06:29PM by Govahnator.

Aliexpress have some nice clones for about 18 dollars, and the adapter for 12. So if you cannot afford the original you have other choice.

Quote
ggherbaz
Aliexpress have some nice clones for about 18 dollars, and the adapter for 12. So if you cannot afford the original you have other choice.

That's why i adviced him the robot digg bulldog xl, even if you source all the parts for the cheapest, it will match the bulldog price (72 usd), but you won't be sure everything fit's and works.

Dave,
what type of hobbed bolt you using ? a wade with a v6 should be happy times, the first upgrade I made was to an adjustable hobbed bolt like the e3d hobb-goblin " you can fine tune the bite to the path of filament"

Quote
govahnator
people print stuff and sell they dont use 100 percent infill, claiming it is not necessary, which is bs for mechanical objects of course

printed many parts for printers with 35% and two perimeters with a .4 nozzle does just fine 100% a waste of time and plastic.

Quote
jinx
Dave,
what type of hobbed bolt you using ? a wade with a v6 should be happy times, the first upgrade I made was to an adjustable hobbed bolt like the e3d hobb-goblin " you can fine tune the bite to the path of filament"

Now that looks like a solution, my bolt is very rough, I am sure it must damage the filament.

I now have one on order, lets see if that resolves it along with a new wade unit.

I have repaired mine just enough to allow me to print out a new extruder, fingers crossed it will last long enough.

Dave

Just a note, my Chinese replacement nema 17 had shaft flex problems under presure. Put the old one back on. No flex.