Printer wont extrude filament.

Hello!

I am fairly new to RepRap 3D printers and have recently purchased and assembled a Senhai Prusa I3 SH802M printer, along with 1 kg of re1.75mm A.B.S filament.

All the motors and cooling fans seem to work and the thermistors show the heat bed and extruder as being at the right temperatures (235 degrees Celsius for the extruder and 100 degrees for the heat bed). They also feel hot when I put my hand near them.

However, I have noticed that whilst I can control the extruder position using the LCD display on the printer itself, and it feeds the filament when I do so, trying to use the manual controls on the Repitier software does not make the extruder position move or feed the filament at all. Furthermore, when I try to print, the extruder looks like it is trying to feed the filament, but gets to a point where it stops and starts clicking. No filament material comes out of the extruder at all. Pulling the filament out shows that it has little marks where the motor cog is pushing into it as it turns.

Does anybody know what the problem could be and how I could attempt to solve it please?

Your help will be greatly appreciated!

Thanks all, Billy.

The clicking is the extruder trying to push filament and not having enough torque to do so. This can be caused by your steps per mm on your extruder to be calibrated wrong, your idler spring set too tight or not enough voltage to the stepper itself. There are many guides on calibrating extruder steps per mm, but to start you may try halving your current value.

A thought occurs to me, do you have microstepping enabled? It's a simple matter of ground pins under the stepper drivers

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If you need some help, or don't understand what I just said, feel free to send me a PM anytime

Printer: Prusa i3, 2 E3D v6 Hotends, Arduino + RAMPS 1.4 with a Bypassed 5V Regulator, 400w Insignia ATX PSU, Custom Designed Bowden Extruders

Hi there,

Thanks for getting back to me. I'm afraid that I am not so up on this at the moment, so some terms are a bit unfamiliar to me.

How do I change my steps per mm or disable microstepping?

Thanks again and sorry for my ignorance!

Bill.

Edited 1 time(s). Last edit at 04/06/2016 09:09AM by Billythakid.

Are you sure the thermistor is set right ? Do you have a way to verified the temps inside the nozzle with a multimeter with temp measurement ?

I had the same problem kind of , it turn out the thermistor was way off and while I was printing at 200C , it turn out to be around 175C so the force require was way too much for the extruder and that make it skip ( clicking) or grind the filament if I had the current a little on the high side.

IR thermistor pistol wont work for that.

With the nozzle hot, and with one hand holding the extruder open so that you can feed filament in with the other hand, are you able to push filament into the extruder so that it squirts out the nozzle?

It will take a bit of force to do so, but you should get molten filament flowing out the nozzle.

Only extrude when the hot end is at temperature. Seems you can do that using the LCD controls so the temperatures must be OK.
In repetier ensure you have the extruder at temperature. When printing ensure you have a gap between the extruder nozzle and the bed.
If the motor is clicking it implies you have insufficient current to the motor. If the filament jams the motor usually keeps going and you get grinding away of the filament. Teeth marks on the filament are OK. I don't know what control board you have but look for info on setting the motor current. Usually done by adjusting a small potentiometer on the board while taking a reading of the voltage at the potentiometer.
Why it doesn't extrude when printing or from Repetier is unclear but you may have the speed setting to fast. Repetiers manual extrusion rate can be easily adjusted. I suggest you don't bother trying to print until you get the manual control sorted.
There is always the chance there is an issue with the extruder, Chinese copies are notorious. I have not had an issue and im not clear what is wrong with them as the extruders are very simple. Some things to look for:- The Teflon tube inside the threaded heat break has the correct size hole for your filament, It should finish at the end of the threaded tube not inside. The nozzle with the small hole must contact the end of the threaded heat break when assembled. The hole in the inside of the nozzle (filament size) should align with the Teflon tube - not sure how to check that - may be remove the nozzle, screw the heat break in and use a drill or some filament pocking out to check its in the centre of the nozzle threaded hole, then do the reverse to check the hole in the nozzle is in the centre of the heatbreak hole.. The threaded heat break must be visible between the top of the hot end block and the carriage/heatsink . Don't wind the threaded heat break so far into the carriage /heatsink that it contacts the drive gear/tensioner. Tighten the locking nut so it doesn't move.

Thank you all for your messages; you're very kind for helping out.

The latest is that I have reduced the tension on the idler spring and ensured that the extruder is warmed up to 240 degrees and kept there for 10 minutes.

The manual controls for the extruder on Repitier now seem to work and I am able to extrude filament, which comes out of the nozzle in a thin, bendy strand. Albeit, I have noticed that when I have attempted to print, the filament is coming out all curly and has been sticking to and around the nozzle. I figured that this might be down to the height of the Z-axis being calibrated incorrectly, and so have tried to fine tweak it so that it homes in at a piece of paper's thickness from the heatbed. I have also used some hairspray as some adhesive to see if the filament will stick to it.

Not sure if that will help, but I am going to try and print another object tonight and will report back with the results.

Thanks again, Billy.

Hello all,

Hope you're doing well.

I have come a good way since my last post. I bought some Kapton tape and applied it to the alluminium heat bed.

The extruder is extruding ABS plastic now and with the help of a 10mm brim and support material, it is sticking well and I have been able to print a few objects with a degree of success.

The only questions I have if somebody would be so kind as to answer for me, are:

* What is the best way of applying Kapton tape to the bed and then removing a finished object from Kapton tape without damaging the tape itself?
* I noticed that when I try to slice some bigger, more complex objects, Sli3er takes a good while to export the G-code, especially taking a long time 3 quarters of the way through the process. Are there any tips on how to decrease the time taken?
* Are there tips for decreasing print time in general. I notice that some objects can take many hours, so I'm guessing that this is the norm sadly?

It's all quite challenging at the moment, and even stressful on times, but I find that I'm learning it quickly and I am enjoying it on the whole!

Thanks again, Billy.

Use the soapy water method to apply the kapton tape. The soapy water allows you to position the tape, then squeegy it down. Either let it dry overnight or warm up to bed to dry it.

Wait until the bed cools to room temperature and the objects will either self release or can be removed with a little pressure. Expect the tape to pull up on things that are really stuck on. I've used a hammer to tap the side of the object to pop it off. I use a purple glue stick on the glass or aluminum to get things to stick.

One place you can speed up the print, without affecting the exterior too much, is to increase the infill speed and use the rectilinear pattern.

Slic3r: make sure the 'avoid crossing perimeters' is unchecked unless you really need it. If you do turn that on, it can take hours to complete.