Upgrading my Prusa i3 extruder/hotend - Recommendations

Hi Everyone my name is Andy and this is my first post after spending a few weeks reading all the great info here. I built my first printer(i3) and have been struggling to get a finished print to date.
My source materials are one of the more expensive acrylic kits from AliExpress. Overall, I feel like its built quite well but when it came time to print it appears I have run into the downsides of the generic kit. All printing has been done with 1.75 PLA

Problems I've encountered:
- Filiment not feeding
- extruder motor 'ticking' (related to the first issue)
- print feed stops after 10 minutes of perfect printing..(I got so excited when it printed for 10 minutes... sigh)

Estimated Causes:
- head temperature is inaccurate
- heat creep due to generic J-Head style(no heat sink) hotend
- underpowered stepper
- non-ideal extruder gear
- inability to adjust tension on the extruder

After reading dozens of posts on the topic I'm convinced the best thing to do is replace the extruder/hotend so I know what I'm working with as opposed to guessing on generic parts.

Would anyone have a couple recommendations on a good extruder/hotend combo to purchase? I think replacing the stepper with a Nema17 is a no-brainer..
What should i know about mounting the new extruder/setup on my x-axis, will I need to change out that mount?

I've attached a couple pictures of my x axis/mount setup as well as the original setup.

Thanks so much for all the great information and I look forward to chatting with you all!

Hi Andy. Maybe there's multiple problems in one. First, ticking means the motor don't have enough power to drive the filament. 1. check that the pololu's output power matches the motor's specifications, especialy if your motor is cold or too warm to the touch. 2. it's mabe because the hotend is clogging at a thime, the heatsink of the hotend gets too hot (it must remains cool), so the PTFE tube inside expands or shrink and that clamps the filament, or maybe at a time the filament fuse too high into the hotend and jams. Try to cool down the heatsink, it must stays cold to the touch anytime. Some rubbish extruders don't have any heatbreak, so it's impossible to keep simulteaneously the heatsink cold and the nozzle hot.

I also bought a cheap prusa i3 kit. I wasn't able to get a nice print until I changed for an E3D hotend. It could be managable with PLA, but I print in ABS only which is more hazardous. I also changed for a more powerful motor for the extruder. It's a direct drive extruder, and you need enough power to drive the filament properly. Keep in mind you have a chinese thermistor, that means the temperature you read may not be the real temperature. With an external thermometer, I measure 95°C on the bed when Marlin records 116°C. A huge difference. On the nozzle, I also have the same gap but on the other side, The nozzle is hotter than recorded. So you'll have to don't trust the recorded values and make your own trys. Good luck !

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Thanks much, the ticking has been inconsistent which leads me to believe it's a heat issue.... I asked for a new multimeter with temperature for Christmas so I'll be able to check the sensor. On the topic of hot ends, the e3d seems to be the one everyone raves about, did you have any trouble mounting it to your extruded or did you change your extruded as well? It seems that the top extrudes are the Wades and the direct drive variants. For 1.75 filiment I've read that the wades may create too much torque plus I suspect staying with the direct drive will be a better fit to my x axis.

Thanks!

I changed all fron the X carriage to the nozzle. All was some great improvements. I reworked all because I wanted something compact. Wade's is a geared extruder. More torque is good, but IMHO it's necessary for 3mm filament only. The direct drive is more compact. I re-used the parts of my existing extruder : a 38 tooth drive gear and a v623zz bearing. Through, the carriage gives some gain a bit on the Z printing area, and allow Igus bearings to avoid wobble. I can post the files if you're interessed. Note : it's for E3D v5.0, the v6.0 is a bit shorter.

Edited 2 time(s). Last edit at 12/20/2014 02:26PM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Thanks for advice, I bought the e3d nozzle and cooling fan upgrade, along with a better geared bolt for my extruder motor. I'm pretty sure heat creep up the hot end was the problem I was having so we'll start there and hopefully that will get me through a completed print. I did like the look of the Bulldog Lite extruder though... Pricey but looks a bit more durable than all the printed plastic.

Here's the link to the kit I started with.. I know people say the acrylic frames aren't awesome and I'm sure I'll learn that first hand but it's a start. Overall the kit went together cleanly, and the kit arrived to the U.S. In less than 8 days. If doing this over I would have picked up an extra 30mm fan for the hot end shaft right away and I think things would have printed no problem. Also of note I did not install the repetier host version that came with the printer, I just downloaded the latest from their website. I've since learned that the install that came with the printer had preconfigured settings for this printer ... I may go back and try this perhaps slower feed rate or something I missed would have helped.

[www.aliexpress.com]

Guess that's why this is a hobby... Thanks for your help!

Hi Zav,

May I ask a question, We have the Aurora Z605, and have similar situation you helped athemier with.

As the product had challenging documentation, we are not able to clearly determine which Thermal Resistor we have on the Extruder Hot end.

We use Marlin on the Arduino IDE, and are presented a List of possible Ohm values and manufacturers in Configuration.H

We trial an error detrained that the number 8 worked for the heating bed, but am still struggling with the Extruder as we can not get the actual values of the extruder to match the software settings in REPEITER.

We are using a sears IR sensor to measure the hot end of the extruder and can only get 120 C, while the reading in REPEITER software says much higher. This is attributed to us not having the right Firmware selection of the Thermal Resistor.

The Printer is new from Ho Ho Ho,and all other aspects work great. we are able to print well in PLA but need to correct the temp issue to use abs.

Thank you for any help and I hope we can all follow your leadership to help each other..

Best regards,

Nick

HI Athe,

Did you try adjusting the tension on the roller which pushes the filament against the Stepper motor friction gear.

IF it is clicking it may just be too tight.

Best regards,

Nick

Hi Nick, sorry I was out some days. Some IR guns cannot measure properly on metallic and/or glass surfaces, because signal is reflected or difracted. Regular reprap resistors and heat cartridges are fixed 4.7ohm. You can measure the exact value with a simple multimeter if you like, but IMHO that small variations are not realy a factor. Otherhand, chinese thermistors measurement may vary +-10%. So the same filament may be properly extruded at 180°C on a printer, and at 200°C on another printer. You may print a heat test part for each new filament on the machine which is going to use it. Even into a same brand, your extrusion temperature may vary from colours to colours. Sometimes a small gap of temperature may produce different quality.

ABS is another world. To get perfect printouts with ABS is realy difficult. Some people never reach that goal and go back to PLA. I print with ABS only, and I wasn't able to print anything properly until I installed an E3D hotend. I had to replace the chinese heatbed's thermistor because it did not survived to +110°C. Maybe it's wise to calibrate the printer with PLA only, and when you'll be experienced enough with FDM technology and your printer, then try some ABS. But be prepared with hard times ^^)

Edited 2 time(s). Last edit at 01/06/2015 11:15AM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

HI Zav,

Thank you for the direction.

We will try this out...

Best regards,

Nick

Hi Zav,

we got the heating issue resolved can print with ABS.. working on feed and speed of material into extruder....trying to get the software in marlin code to correct values, as sometimes we chew up the line with the motor to feed into the extruder.

thanks for all your help

Nick

you're welcome

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Quote
nick001
Hi Zav,

we got the heating issue resolved can print with ABS.. working on feed and speed of material into extruder....trying to get the software in marlin code to correct values, as sometimes we chew up the line with the motor to feed into the extruder.

thanks for all your help

Nick

Nick

Just for the benefit of others can you detail what the problem was?

Doug