Ok, HELP! Plastistruder makes lousy Top Roman noodles....

Summary:

Plastistruder not operating as expected.

Ok, HELP! Plastistruder makes lousy Top Roman noodles....

dataman 27 Jun 2010 07:11

Noobs in Las Vegas on Day 3 of buld..

I think we've hit a major snag. Our pilastistruder just isn't cutting it.

First there were a lot of issues with the feed mechanism. Seems like the feed path is a real pain in the tail. Am I right, or is this is a square peg round hold problem. The exit path of the pinch when is square and larger than the entrance to the extruder head. Seems to be some resistance even manually pushing floss into this entrance. If you can get it that far, it stops when it hits the brass piece. Ok, so far so good.

We've gotten some nasty looking crispy noodles by taking it up to 255. Rebuild the head with the nichrome bundled on the first 4 threads near the nozzle. That's a bust. Let it heat to 225, feed rate 225, made sure its in the extruder head, and the pully just stalls… reverse out the floss, wait 5 minutes, forwards back in, try again, no beans.

So what the hell?

We've followed the directions. Used 2 multimeters. Found we're about 5.6ohms on the Nichrome. Everything else looks to spec.

I've been able to push manually to produce floss before we rebuild the head. We need some specific help to finish this build. We're really stuck. 2 days blown on this now.

What have we done wrong?

Feed apparently works…

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

dataman 27 Jun 2010 08:43

I thought an image might help…

Thats my third attempt to get it workkng, and Im really frustrated. The bot is assembled and good to go but for this one piiece… Of course. And damn, I'd like to fab a few missing pieces if it was running!

Anyhow, heres a look at the chinese noodes its printed…

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

dataman 27 Jun 2010 08:44

If some poor soul would call me, let me call them, or skype me through this insane setup, I'd really appreacited it. It cant be that hard.

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

cakeller98 27 Jun 2010 09:14

the idler wheel and the heater barrel are the two weakest links (imo)

I was NEVER able to get it working as designed - but then many have… but a lot have had to pick up second sets of parts just to get a first set working.

so - what I'm saying here is - don't give up - this isn't "easy" it's just possible.

if you can swing it the MK5 pinch wheel is, um - 100% better than the MK4… so get that if you can.

I redesigned idler wheel so I have a piece of PTFE pressing on the filament - similar to the PAXTRUDER - OMG! SOOOO much better. I haven't had to adjust the tension (knocking on wood) for ~40-50 prints, including filament changes etc… so that design direction is AWESOME! if you haven't seen the paxtruder - check it out (google it if you can't find it here)

I never got the heater barrel to work as designed - but to be honest - that's the thing I'm still working out. mine works, but it's got some kinks…

sounds like you're running it a bit too hot (255 if true, is WAY too hot)

for testing purposes, disconnect your heater barrel from the plastruder and push the filament through by hand - as a test anyway it shouldn't be difficult. if it is, then there's something wrong. the stock plastruder pinch-wheel mechanism can't overcome a lot of friction/hangups/etc… so gotta make sure your path is good.

FWIW I rebuilt my plastruder assembly 5 or 6 times, and the heated end ~5 times (separately from the assembly rebuilds)… when it finally works - it is a rather satisfying feeling.

good luck.

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

passim 27 Jun 2010 15:41

The stock design works fine, but there are certainly points that can be improved. I've got 2 bots and both of them have hundreds of hours of prints on them now with stock setups before being worked on.

First - don't run the feed rate at anything less than 255 until you're setup well. If you're consistently stripping the filament there are three things that can be causing it:

- your temps are too low
- you've got the nozzle too close to the build platform, making the pressure too high
- your idler wheel isn't adjusted correctly.

If you can run some filament through and post a photo of it we can tell you if you're adjusted too tight or too loose, but that'd be my first guess. I think you've got it too tight. In that case you squish the filament too much then it won't fit into the insulator well.

If you have resistance when just pushing plastic through the PTFE / barrel combo, then chances are you've got the barrel tightened too far into the PTFE. If you overtighten it you'll cause a little lip in the PTFE that filament can snag on.

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

lampmaker 27 Jun 2010 17:50

The stock design certainly has some points of improvement (I personally believe that to be an understatement).
For some, it seems to work just fine, many others seem to have perpetual problems. The margins of operation are just too tight. I never got the stock design to work, here are some of the improvements I made that did the trick for me:

- get the new MK5 driver pulley.
- A new idler wheel, with the same thickness as the bearing. I always had some misalignment between the idler wheel and the filament. The new, thicker idler wheel is much more forgiving. A small V-groove in the center of the wheel keeps things aligned nicely. You'll need a lathe to make this.

I also completely changed the hot end, but that will take a little more time to document nicely.

If you want to know if it's the driving end (pinch wheel & idler wheel) or the hot end that is causing your troubles, try to measure how much force is required to push the filament through the hot end manually. (there is another post about that" Poll: how much pressure does your extruder need?"). My extruder needed about 2 kg of force at 220 degC with ABS. if you need much more, your hot end is causing the troubles.

get some spare parts from makerbot so you can rebuild the hot end a few times and play with different parameters.

good luck!

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

dataman 28 Jun 2010 08:14

Guys, I'd like to start by thanking you for all your help. The kind encouragement and replies I received from this posting helped a great deal.

Here's what worked:

We took apart the extruder and could not even pass the metal test rod through the PTFE. Scanning the unofficial build videos on the web, we were able to glean that drilling out the PTFE with a 1/8" drill bit was what was needed. After that, it was easy to pass by hand into the rebuild extruder and produce floss. Should be part of the standard build instruction. If you can't get past the PTFE you can't get into the barrel!

Next, the pinch wheel was slipping trying to get material into the barrel. Almost, but not enough. I had been tightening against the plastic itself, and remembered that the build instructions wanted us to use that crazy metal rod. Well, now we tightened against the crazy metal rod. The pinch wheel now grabbed the material, and straight into the extruder it went. When we backed out, it had the signature bite marks, but not terribly deformed. Produced floss for 5 minutes with no hesitation.

Our first cube attempt was very strange, went through all the documented steps, ReplicatorG started up, ready to produce the 5mm cube, and promptly dove into -10mm INTO the platfom! What the hell! Oh man, damn cables must be backwards!

/BEGIN FLAME
And here I need to slam Makerbot, documentation, and the whole process. Documentation here is beyond terrible. There is NO documentation on the damn ribbon cables. Nor is there a damn freaking word anywhere on INVERT THE FRACKN Z AXIS! Did I miss something? Is this some right of passage? A lousy bug in Replicator 16/Linux? Anyhow, I drove 30 miles to get new Molex connectors, only to figure it it was software settings.
END FLAME/

Long story story, we printed the test box…damn nice looking box..

Then I noticed that the X and Y axis were switched. No problem, easy to swap the Servo Motor controller wires. DUH!!!! I know, I know. Live circuit. Killed one controller board. (Any advice on this? Completely dead X board, motherboard OK, X path tests good on Y board, X controller dead. Is it (hopefully) the 7805 that usually goes? Or more likely that frackin logic circuit) Anyhow, I've been around electronics long enough to know that you don't hop swap motors circuits. New Boards (2 - 1 spare) en route. But if there is a know quick fix, would love to hear it.

Anyhow, I will become active in this community and help noob documentation on PTE, Controller boards, and FRACKN ribbon cables.

RIBBON CABLE: Both connectors, Same Side of Cable, Nubs (pin 1) Face Same Directiion, <—-< See? How hard was that?

Re: Ok, HELP! Plastistruder makes lousy Top Roman noodles....

passim 28 Jun 2010 11:44

Glad you made some progress! The z-axis inversion is mentioned here, did you go through the calibration steps?

http://wiki.makerbot.com/cupcake-cnc-10:cupcake-calibration

Re: Ok, HELP! Plastistruder makes lousy Top Ramen noodles....

ddurant 28 Jun 2010 14:35

It seems like every other person who builds a cupcake misses the reversed axis bits - I know I did.. I think a better name for this would be "Absolutely do this stuff before you start!!!!" instead of "Calibration."

It's not that things aren't documented; it's more like there's so much documentation that it's easy to miss important bits.

Re: Ok, HELP! Plastistruder makes lousy Top Ramen noodles....

dataman 28 Jun 2010 15:35

Damn it, Damn it, Damn it.
I see it now.

Ok, the reason we are missing it is due to the incomplete nature of that page.
We're so burnt out on the instructions at this point,
That we're scanning configuration instructions.
When we get to this page, and it's incomplete at the at the bottom,
We discounting most of the page.

I know I pretty much glanced past it after the pastistruder ordeal.

Gentlemen, thank you for pointing out my error.
I do appologize.

But please, if anyone can update the ribbon cable instruction, please do.
I added a discussion note to that page in hopes it will help someone

I also added a discussion note on the how to print page about z problem.
I'll amend with a note on the calibration check.