Extruder blocked because of the filament

I have been enjoying the new Prusa i3, which is my first 3D printer arrived a couple of weeks ago.
I did a few reinforcements to square out the X/Y/Z. Printed a few nice items, no big issues.
Now I am getting into more details and asking for better printing results.

The first thing I noticed is the extruder motor sometimes loses its steps. I thought the torque wasn't big enough until the block happened.
I pulled the Bowden tube off the extruder, pulled the filament out. I found a bump in the filament. I attached a picture of the bump.

Is this a manufacturer defect or caused by other reasons.



Thanks

Edited 2 time(s). Last edit at 09/27/2015 10:13PM by bonmotwang.

One more question:
Isn't the tube too big for 1.75mm filament?
OD 4.18mm, ID 3.00mm

4x2 tubing will get you better prints and is what is usually used for 1,75 filament. The extra bends on the filament from the lager tube will make the extruder work a lot harder. My guess on the bump is insufficient cooling on the heat brake. It is also an indication that you might be feeding the hot end more then it can extrude.

Quote
SlowFoot
4x2 tubing will get you better prints and is what is usually used for 1,75 filament. The extra bends on the filament from the lager tube will make the extruder work a lot harder. My guess on the bump is insufficient cooling on the heat brake. It is also an indication that you might be feeding the hot end more then it can extrude.

I ordered 2mm tube.
So you don't think bump is from manufacture defects?

Edited 1 time(s). Last edit at 09/27/2015 07:19AM by bonmotwang.

Just designed a cooling duct for the heatsink.
It should increase the airflow to bring away more heat.


Edited 1 time(s). Last edit at 09/27/2015 10:12PM by bonmotwang.

New part printed. Will report the result.


This is the very first "userful" part I got from my 3D printer. :-D

Edited 1 time(s). Last edit at 09/28/2015 10:21AM by bonmotwang.

Hi,

Are you shure you're not trying to print 1.75mm filament
on a 3mm filament machine ?

++JM

Quote
J-Max
Hi,

Are you shure you're not trying to print 1.75mm filament
on a 3mm filament machine ?

++JM

I don't think so. If it is a 3mm filament setup, that small bump would be able to pass.
I have never used 3mm setup before, but I thought 1.75mm will never work on a 3mm.

Just ordered a 1.8mm ID, 4.0mm OD PTFE tube. It should fit perfectly, I hope it won't be too tight

you're hoping that the 0.002" difference in ID to filament is enough??

I had that on a direct drive and filament jammed within the tube.
It wasn't' immediate, but some random time later, when a batch of filament had a varying diameter.

in this picture, you can actually see the diameter difference.
This was not cheap china crap, and when I sent the image to the supplier, he sent me a replacement roll for the troubles.

my last McMaster Carr purchase was for 3mm ID, but again, direct drive not bowden.

Quote
davew_tx
you're hoping that the 0.002" difference in ID to filament is enough??

I had that on a direct drive and filament jammed within the tube.
It wasn't' immediate, but some random time later, when a batch of filament had a varying diameter.

in this picture, you can actually see the diameter difference.
This was not cheap china crap, and when I sent the image to the supplier, he sent me a replacement roll for the troubles.

my last McMaster Carr purchase was for 3mm ID, but again, direct drive not bowden.

I am experimenting the ID of Bowden tubing too. I know 2mm is "standard" and on order too. 1.8mm will give me some test result on what I am interested to know.

Just a kind reminder for you: don't be a fool, those business men know well about the well known "cheap China crap" rumor from you guys and make you pay extra for so called none-made-in-China. Your blue stuff in the picture is a good example. It shouldn't happen right?
You just need to be smarter to get good stuff, but not overpriced.

Ok. I fixed the problem by simply dialing up the extruded motor current. From 200mA to about 400mA.

I added heatsinks to all step motor drivers. I didn't know what are those little heatsink blocks for.
Also added a fan to cool down the drivers.

Now it is printing at 180C. No more skipping!

I kind of agree with you about patriotism marketing, for pride and quality and all of that. I see that.
I can also accept being a fool and not smart. Thanks for picking on me.

Glad you got the extruder to work with the amperage tweak.

Quote
bonmotwang
I have been enjoying the new Prusa i3, which is my first 3D printer arrived a couple of weeks ago.
I did a few reinforcements to square out the X/Y/Z. Printed a few nice items, no big issues.
Now I am getting into more details and asking for better printing results.

The first thing I noticed is the extruder motor sometimes loses its steps. I thought the torque wasn't big enough until the block happened.
I pulled the Bowden tube off the extruder, pulled the filament out. I found a bump in the filament. I attached a picture of the bump.

Is this a manufacturer defect or caused by other reasons.

Thanks

Defect. I had 1out of 8 spools of Inland filament like that, swapped it, and was fine. There are diameter specs for the stuff, and that won't meet them . . .

- Tim

Quote
davew_tx
I kind of agree with you about patriotism marketing, for pride and quality and all of that. I see that.
I can also accept being a fool and not smart. Thanks for picking on me.

Glad you got the extruder to work with the amperage tweak.

Hey Dave. My apologies if there was any offence.
Wasn't personal. Just a kind reminder when we source stuff from China or anywhere, because of sharing information globally, too many low cost and low quality stuff come up on your screen, and hard to make the judgement. They even got good comments from those inexperienced DIYer's.
Those north american middle men do have good source/vendor's from China, but they don't get to jack the price high by 3 times.
But if you cannot find a good vendor, well, then go for the price they set up.

I am in R&D plus manufacturing business. I have seen too many made in USA product only have final assembly, packaging and labeling kept in the states.

I think the "rumor" is tied to consumers driving the price down, the quality down and bitching when their item breaks and is disposable.

With almost everything being made in China, I think it's safe to say most everyone has come across "cheap china crap".

Two years ago prices were different, and there was less selection, and I paid only a few dollars over the budget stuff.
Today, their products are $30/lb, and 3x the going rate of cheap stuff, and 1.5x that of good enough stuff.