Extruder gear eats trough filament Rep 2X

[Jaime]

Hi all,

I have a Replictaor 2X brand new, at firts we didnt have any trouble with the printer but last week we notice the the extruders started to eat trough filament making jobs stops mind print becasue there is no filament coming out of the nozzle. I have no idea idea why this is happening.

We have already checked the extruders and they seem to be fine, no dust or filament residues, also stock temperature seems fine (we use 230 and 110 for bed) the print job starts fine but after 1 hour or so it wtops extruding filament, we are not sure why. When we remove the filament we notice small dents on the filament (we are using makerbot stock filament)

Do you have any advice on why this is happening?

best.

Jaime

[Jetguy]

It's a replicator 2X- that's why

#1 filament feeder/drive section is known to break and not put enough pressure pushing the filament into the drive gear. That leads to the drive gear grinding a half moon into the filament. Bottom line, if you grab the filament and stop it from going into the extruder during filament loading, the extruder MUST thump or click. If it just grinds the filament without noise- the feeder system is failed in some way

#2 the thermal design of the hotend strayed from previous proven designs. Bottom line is parts that should be cold are hotter in the 2X than previous designs. This leads to filament melting early and resulting jams in the hot end section.

#1 and #2 caused 3rd party companies to manufacture upgrades such as David's 3 in 1 extruder upgrade and Carl's entire hotend setup.

http://devilsinthedetails.ca/   http://shop.raffle.ch/shop/alu-dual-cooling-block/  http://shop.raffle.ch/shop/hot_end/

[Jaime]

Thanks for the reply

#1 We have tested this, it does make a clicking sound.Looks like the gear and extruder setup is too tight, is there a way to release some tension?

#2 Is there a way to see if this is happening? like identifying parts that are melting but should not be?

[Jim Fouch]

I have found if you're slipping and not clicking while filament is not being fed, then your gear may be too loose. There is an head set screw that is used to set the about of torque on the gear drive. I think you need to release the lock before adjusting this. You may need to adjust a few times. After adjustment, try to stop the filament with your fingers in the feed side and when it stops, you should hear a clicking. If not, then you have it set too lose.

Also be aware that you can over tighten the set screw, so be careful.  

[Jaime]

Hi Jim, thanks for the feedback,

Like u said to JetGuy, it does make a clicking sound we we try and hold the filament, but i dont know if the torque is set wrong. I have no idea where that screw hole is.

Where can i find it?

Best.

[Jim Fouch]

I have a 3-in-1 as my right extruder, so please ignore that. I have a stock R2X as my left extruder. I have an arrow pointing to the set screw.

[Jaime]

Thanks a lot for the picture Jim,

This means i need to use the hex wrench that comes with the printer to loose this screw a litle and then make some test?

Best

[Jetguy]

No, this is a bunch of bad advice.

You want the stepper to never be able to slip ever. It's a ball bearing idler pushing the filament into the drive gear and and very little friction.

Your problem is the hot end and we are barking up the wrong tree. All adjusting the screw tension is going to do is make the drive gear slip and that worse, not better.

Solve the problem- you have a jammed clogged hot end.

[Jim Fouch]

once you tighten the set screw (while the handle is lose) when you go to relock the handle it will be harder. If you loosen the screw the lever will be loser.

This is just a hunch. Everything that Jetguy said may also be in play.

I know when I got my 2X, I had to adjust the set screw a few times.

I mostly print with my right extruder. I had about 300 hours on the stock extruder with maybe 4 air prints. After upgrading to the 3-in-1 (40 hours so far) I've probably had 10-15 jams. I've also played with the adjustment screw on there and still have not got it 100% dialed in.

Another thing you can look at is the filament after you have unloaded it. You want to see some decent teeth marks from the gear. If you're just seeing small indents, then you probably need it tighter. If they are major indents or the stepper clicks/skips steps w/o you trying to stop the filament, then you have it set too tight.

On Tuesday, December 16, 2014 6:10:18 PM UTC-5, Jaime wrote:

[Jim Fouch]

Oh, I was under the impression that he was having slipping problems AFTER he was printing for some time. If he's not able to extrude at ALL, then yes he needs to track down the hot end first and make sure it's clear.

But, I have see problems with my 2X stock extruder when the tension screw was not tight enough. I have also seen mine set too tight where the friction over powered the motor.

[Ryan Carlyle]

Failures that happen after a while are usually heat-related due to thermal management issues, not drive gear issues.

[Jaime]

Thanks everyone for the replies.

Yes, I am having troubles after some printing time, when I stop the print and unload the filament to see whats going on, I notice that the extruder gear makes a half moon on the filament and of course it wont let the stuff pass trough the hot end.

Like Jim said, i have a hunch that maybe the drive gear is too tight. So today i will run some test, if that not works I will be looking for heat related issues and post the results.

Thanks a lot again.

Best.

Jaime

On Tuesday, December 16, 2014 4:04:47 PM UTC-5, Jaime wrote:

[Ryan Carlyle]

"Too tight" doesn't chew a hole in the filament. When you have good gear tooth bite depth, there's enough meat bitten that the extruder doesn't have enough power to break the grip and start stripping. Usually a divot means the drive gear is too loose.

One possibility is that the stepper heating up is causing the superstruder to thermally expand/warp. It's a pretty marginal extruder design so a moderate amount of thermal warping could take some pressure off the idler. Injection molded parts like this do tend to do warp at high temp. 

[Jaime]

Hi Ryan thanks for the reply,

Is there something we can do about it? should I contact makerbot support?

Best

[Scott Booker]

The first step would be to check to make sure that the pre-load has been set correctly on the filament feed system.  MBI had a habit of setting them "too loose" and not using Loctite or a similar mechanism to retain the setting.

Per the instructions, tighten the pre-load set screw in 1/4 turn increments until you can't get the release lever to toggle over.  Then back off 1/4 turn.  Pre-heat and use the "Load filament" option to extrude some filament.  Grab onto the filament as it enters the extruder.  If you can "stall" the stepper motor (hearing/feeling the "clicks") then the feeder is working "OK".  If the stepper doesn't stall and the drive wheel starts digging a crescent into the filament.... then you have a drive system problem.

The problem may be due to a section of undersized filament (the MBI "superstruder" doesn't tolerate undersized (OD) filament)... or there is a bind/problem in the drive.  As Ryan mentioned, it is a craptastic design.  It can be improved and "remedied" through disassembly and some creative clearancing with jewelers files..... but if you have a "new" R2X you should probably just contact MBI for a replacement under warranty. 

[Jaime]

Hi Scott,

Thanks for the pointers.

i will try and do that today. If nothing works I will write to MBI to see what we can do.

Best.

Jaime

[Ryan Carlyle]

You can also print yourself a typical spring-arm type replacement extruder drive system. Many people go that route. Personally I strongly prefer metal extruder components for the R2x because you want the chamber to get warm for good ABS results.

[Scott Booker]

Don't waste your time sending a support EMAIL to MBI.  You will probably never hear back from them.

The only real way to get tech support from MBI is to call.  Sad, but true.