Extruder Problem

I am getting near the end of my build on the 3D printer. Got all the axis working fine and now having a problem with the extruder. It appears to me that it not getting as hot as indicated. I am using ABS, the temp reads 240 but the flow is slow and not fluid at all. I purchased a extruder ass’y with a thermocouple, I did remove the thermocouple and replaced it with the thermister that came with the kit that was purchased from Sain Smart it measured 100K (there were no specs on the thermister from Sain Smart). I have installed the 3 jumpers under the driver for the axis and extruder.
The configuration is as follows
Baud Rate 250000
Define Temp_Sensor _ 0 1
_1 1
_2 0
_3 0

Default_Axis_steps_Per_Unit 101.669, 101.669, 101.669, 87
Default_Max_Feed_Rate 200, 200, 3 ,300
Default_Max_Acceleration 3000, 3000, 100, 10000

Need more information:
Direct or geared?
1.75 or 3mm?
J head, all metal?
When you extrude 10mm, the filament moves 10mm?
Does the filament curls as soon as comes out of the nozzle or comes out straight?
Fluid as "smooth" or fluid as "melted"?
Does the extruder clicks when operates?

Does it hurts when touched....... Just joking.
( but it does).

Feed rate for extruder probably too high but depends on type of extruder? Acceleration it's fine, steps per mm? If when you ask an axis to move 10mm and it does it, then they are right.

But the most important questions:

Have you tried other thermistor settings?
Have you contacted your seller and asked what kind of thermistor they sold you?

Edited 1 time(s). Last edit at 10/28/2014 11:01PM by ggherbaz.

Thanks for the many suggestions. I have one important thing to add, I checked the temp with a digital multimeter with a temp option and a K-Type thermocouple to measure temp, I was able to slide the thermocouple inside the hot end and fount the temp was 5 to 10 higher than the display on the printer said.

It is a direct drive ( A grooved gear on the stepper motor shaft with a pressure wheel)
It is a 1.75 mm extruder.

The extruder is all metal ( I am very new to the 3d world and not sure about J head)

The filament does curl as soon as it comes out

It does not seem to be very hot to the touch as just coming out on a 240 C extruder

It does not appear to be smooth or melted

I have not tried other thermister settings since I now feel the temp in correct

A further update:

The pressure wheel was loose

If the feed rate is increased the filament comes out in a steady stream and is fluid

What I am now working on is the filament has a hard time getting started

Also having a problem getting the extruded filament to stick to the bed

If with "hard time starting " you mean: takes some time to come out of the nozzle? Then, that's a normal thing that we all deal with, for that you just set a little skirt around your part in the slicer and that takes care of the problem, if you mean something else let me know. Regarding the filament sticking to the bed it is really simple, but need to do it right, if you have a heater bed, set it at 110 for ABS, I assume you have a glass sheet? If not go and get one (cheap lowes glass cut to size works just fine, don't mention for what you are going to use it because they would not sell it to you ) don't waste your money with kapton tape or any other tape "you don't need it " get PURPLE PVA glue stick from Elmer "PURPLE" again PURPLE, understand? Now preheat your bed and nozzle to working temperature, once ready run the calibration instruction in your printer, with a filler gauge using a 0.10 blade, adjust your nozzle distance in all the point required, the blade just needs to slide with some little pressure in between the bed and the nozzle. Once you are used to that one time is plenty, but just to be sure, run it twice. After that just apply few layers in different direction of the PVA glue, once changed from purple to white you are ready to print, and your part will stick to the bed until you let it cool down, at which poit it will pop by itself (PLA will require some freezer time or force to come off) .

I am almost there with getting my first print, I will get the Purple tape tomorrow ( it is in stock at my local Staples). Again I am very new to the world of 3D printing I am not sure what you mean by "calibration instruction in your printer"

also is there a was to increase the layer size to get more filament with each pass. I tried Layer height is Slic3r but I must be doing something wrong.

Thanks again for your patients

ed

Since I don't know what kind of printer you have, I have to generalize, some printers with lcd display and the firmware settings done allow you to run a calibration script, the nozzle proceed to an specific point and goes down untill Z endstop is activated, at which point you proceed to calibrate the distance between the nozzle and the built plate, then you hit (next) and the nozzle moves to the next position and the cycle repeats untill your calibration is done. If your printer is not set this way, you will have to home Z and then slide the nozzle "usually" through the 4 corners and center of your plate and calibrate manually, yet some other printer have some servos or sensors to do Auto-bed leveling (which I don't think yours is like that) printers without lcd display can be done through the slicer software which most of them also have this calibration feature.
What you set in the slicer is your layer height and have nothing to do with the printer calibration, it has to do with quality.
It is not tape, it is glue, stick glue by Elmer and it is purple when you apply it and the turns white.
Extrusion multiplier will allow you to increment the amount of filament layered but you need to be careful with it, if you are not putting enough filament might be more related to the steps per mm settings in the firmware. Like I said, layer height determines how high the layer is going to be (0.1 0.2 0.3) etc. It will establish the quality and details level of the printed part.

I have tried your suggestions but still have same problems. I still think it has something to do with low filament flow. It is time to walk away for a day or so, the last thing I want to see my printer go air born. Thanks for your help ggherbaz check your private messages folder.

I am still having extruder problems. I thing the main problem is the tip does not get hot enough to keep the filament fluid. The extruder is trying to expel filament when I print but it appear to be clogged. This happens with both PLA & ABS.

I am using Ponterface and Slic3r. The printer is a DIY made from mostly PVC pipe.

I would like to replace the hotend and attach to the existing extruder, can anyone recommend a hotend to attach or any other suggestions.

The extruder was purchase on line as a complete assy. ( it came with a thermocouple, I remover the thermocouple and installed a thermister.) The temperature was checked with a external meter and found to be within 10 Degrees C of the reading set. ( I was able to get the thermocouple of the external meter into the head of the extruder next to the thermister ). The orange wire in the picture on the extruder is the thermocouple to the external meter

its a dirty tip (at least thats what i think)
there is a procedure to swap between ABS and PLA or there are cleaning filaments

the bottom line is: take ABS drop the temp to about 230 (i think 240 is to much and than you said its around 10 degrees more so its around 250 and thats a temp to print nylon)
push at least 30cm of the material through extruder that should get rid of the remaining PLA residue

it is advised to have separate extruder for every material type (ie. ABS,PLA,Nylon) though almost no one does it

a good quality PLA should print at 180 when you get it to 250 it burns and clogs the tip it is the same with ABS to Nylon change of material
when after printing with ABS(at 230 c) you want to go PLA (at 180 c) than the leftovers of ABS dont melt and effect is the same

in the worst case scenario take out the tip, and put it into small acetone safe bottle with just a bit of acetone, than shake for a few minutes (Acetone will not disolve PLA but it will make it soft)
than take it out and blow out the remaining bits with compressed air (Common sense required )

I had that proble few month ago, a true WTF moments when you can see it printing on very very slow speeds and no amount of temp increse would help to print faster if any thing it would make things worse

Thank you for your input on my problem Faktuu. I think the heat was to high. in any event I got past my first layer.
Lets say my first print does look like a box and leave it at that.

ed

Edward,

Sorry I have my own problems and forgot about you.

Few thing to try to resolve your problems:
1 take apart you extruder and specifically take a look at the stainless steel pipe, look inside and see if it have a PTFE liner (plastic pipe) , if it does, check for signs of melting, if it doesn't there it is one of your problems. If it is present, pull it out carefully and check for any crushing at the ends, if you think that you can damaged it, just slide a piece of filament and be sure it moves freely.
Next is your heater block, did you removed all the original silicone seal ? I'm thinking that your thermistor is not staying in place or it is moving. Get all that sealer off and be sure you secure the thermistor properly (if you want to you can sealed with plumbers silicone tape) sold everywhere.
Firmware issues: are you using both minimum and maximum switches? If not need to disable one of them, all your homing is in minimum so disable the max ones.
Z homing: when you home z, where is your home top of printer or built plate? Couldn't see the switch nowhere.
One design concern I have: your z works with belts, belts works great with deltas because they dont pause too often and they are using 3 steppers and 3 drivers to do it, you most likely are using the z stepper driver to control the 2 steppers for z, that by using belts they have to hold what it looks to be a "heavy" carriage, you might be putting to much stress into the motors but specially to the driver, you might be loosening print quality by using this method, (I don't know for sure) but will Definitely recommend you to redirect one of you unused extruder drivers to the second z stepper.

Thanks for reply and suggestions, I did remove the orange silicone ring around the heater. The thermister in not moving around it is held in place with tape (Kapton).

Limit switches and homing don’t appear to be a problem, ( homing in lower left and Z is at the table) all 3 axis are working very smoothly, I have built a number of CNC machines is the past and going to 3D printing was the next step. The Z axis is very smooth and the weight of the carriage is not a problem.

I did take apart the stainless steel pipe, there is no PTFE liner.???

I had very limited success in getting a box to print adjusting settings in Slic3r, I will continue this to see if I can get the flow it increase. I feel this is my main problem but don’t know is causing it.

ed

Ok perfect, you just found the problem. If truly there is no PTFE liner inside the stainless steel tube, that is the reason of not extruding right. Your filament will swell quick inside the plain metal tube and will plug, this type of extruders need the PTFE liner to operate properly. You might succed printing with ABS but definitely not with PLA.

You can purchase a ss pipe with an opening for the PTFE liner and the PTFE tube at eBay or my preferred one Aliexpress. If you have access to cnc machinery then just drill the ss pipe "almost" all the way from the bottom up with a 4mm drill and purchase a PTFE tubing with a 2mm ID 4mm OD and insert it.

Edited 1 time(s). Last edit at 11/07/2014 04:33PM by ggherbaz.