Filament Spool Holder Wars

J

Just when you think you have everything figured out and you have the ultimate Filament Spool Holder, something in the universe changes enough to throw a wrench into the works.

In my case, I think it was my PLA spool running low on filament and so getting more prone to getting stuck. I need a spool holder that is above the machine and doesn't track back and forth when the head moves. That tracking is getting the filament stuck (I think).

But how can you print a spool holder when your spool holder isn't working?

(I know, I could use something NOT printed for the spool holder. Especially if I had my tinker toys, but that seems so Un-Meta).

My answer is to use a different spool that is still full. In fact I used one that is still full of a different sort of filament. Instead of the PLA I am using the Flexible Tough series from M3D. This stuff is much softer and stickier. It is easier to work with AS LONG AS you are not using supports or a raft. The supports and raft are so tough that you can't break them off of the model.

Better get some common terms out there:

SKIRT: a border of material printed before the actual print. This goes around the outside of the furthest boundary of the actual model. The main purpose of the skirt is to clean the print head and get it flowing good before you start the real print. If you monitor the quality of the skirt, it will give you a good clue as to how well the printer is working and if you should abort the print early (perhaps to clean the hot end nozzle).

RAFT:  a flat piece of filament sort of loosely woven. It is bigger than your model and is meant to provide better adhesion to the base of the printer. Some prints will un-adhere, otherwise, and just go sliding across the mat during printing. The raft is designed (by the print software) to be weak and come apart from the main model (unless you are using the Flexible Tough stuff, above.)

some practice towers sitting on a common Raft with Skirt

SUPPORT: little stacks of filament that are auto-printed by the software when it deems that a model overhang is to much to support itself during printing. The supports are very thin and designed to break away from the model on completion. You can use "MAT to MODEL" supports and/or "MODEL to MODEL" supports. The main difference in these two things is apparently how hard they are to get to to remove. "Model to Model" could end up being interior to the model someplace that is hard to get to.

Hulk Torso (badly printed) with Supports (and Raft)
(Hulk from Thingiverse)

I probably should get a few different print heads also and use a different one for each type of filament. Why? Because the different types have different melting temperatures. This means that you could get a wad of high temperature filament stuck in your gun and not be able to push it out with the molten lower temperature filament. That might be what was happening when I was switching back and forth between the PLA and the Flexible Tough. Doing some more experiments.

So my new overhead spool holder I had to make out of the flexible tough. It looks cool, but it is a little bit too flexible. I am hoping that having it printed, however, will allow me to print a new holder out of PLA (or perhaps some new and stronger filament that I am about to order).

A little too Flexible

New ways for things to go wrong: Feedback

Sometimes it is almost like a forensic lab. Trying to figure out what possibly could have happened that made the print screw up in a certain manner. My little M3D micro is a low end (perhaps the lowest end) printer. Many refer to it as a toy. That is why I got it, it was cheap enough that I thought I could do some experimentation to see if 3D printing was right for me. What did I find? When everything goes right (and I do mean everything: Model Design, filament delivery, printing, adhesion) then you can print some very nice little objects. Exactly what I wanted to be doing. 

However, when any little things goes wrong, you end up with a pretty colored Mare's Nest.

The main generic problem seems to be: Feedback. There is None. These cheap little printers are made pretty exclusively out of digital stepper motors and a heater. I can find only 2 feedback elements. There seems to be a little switch in the head of the extruder that gets depressed when the head pushes against the table. This lets the thing reset its height (Z) count and not push itself descructvely through the table base. The other is the heater element. It has a thermometer integrated into it so the machine can set a precise temperature in the extruder nozzle to properly melt (but not burn) the specific material of filament that you are using (PLA has a lower melting temperature than ABS, for instance). I do not believe there are any other feedback elements.

So, how does the machine reset X and Y coordinates? It goes a long way X and then a long way Y. During this run it hits the X and Y stops and just clicks a lot at the stops. Presumably this is non-destructructive since it does this pretty much at the beginning of any operation (like a print). 

How does it know when the extruder nozzle is clogged? It doesn't. So when the extruder nozzle does get clogged or partially clogged (that seems to happen fairly often, at least with PLA) strange things can happen. The most typical thing is that your model just doesn't have enough plastic in it and ends up being a weak colored string-art in the same basic shape as the model you want but that will pull apart in your hands when you pick it up. A well printed model is extremely difficult to break (with your hands). The other thing that can happen is that the ink shoots back up into the extruder head casing and makes a big wad of plastic in there. Not sure how bad this is. I think it may block air flow and further contribute to clogging. It is hard to get out because once into the head it hardens whilst wrapped around the electrical wires and such. I had to leave some of it in there because it just seemed to risky (to the printer) to remove.

Blue PLA filament backed up into the housing. This after 75% was removed.
Note that it is wrapped around the electrical wiring. Imagine the entire base filled with Blue Gunk.

What if the model becomes unstuck from the table pad? This is an adhesion problem. PLA seems to have this fairly often especially if you try to print something that is small but tall (like a cylinder going straight up). If the Model pulls off the bed and gets knocked over, then suddenly the printer is printing while hanging in the air. It doesn't know that it does this and is perfectly happy to spend the next hour or so injecting little tiny mile long hairs of filament all over the space of your printer. This is what I call the Mare's Nest.

(Small) Mare's Next in Tough Filament. This one probably caused by not having the right supports.

A better recent Fiasco.

Here is another good one. Halfway through a print, the control cable that attaches to the print head got snagged by the external filament spool holder. This essentially prevented the head from moving forward in the Y direction. So when it tried, it did the same thing as when it tries to reset to 0 and the gears slipped (hopefully non-desctructionly). This made the Y direction be wrong. So now the printer is still printing but the model  is shifted by about half the Y size as the model in the Y direction. Once again the printer is printing in the open air, but only half the time. The other half is over the first part of the model. So you get this shifted object halfway up. Still useless, mind you, but weird looking. Took me a while to figure out what had happened since the control cable had freed itself sometime during the rest of the print. Well, truth is that I am just guessing what happened. But it had to be something that could cause the printer to lose track of its Y direction, and I think that would required some sort of physical intervention (probably not just software).

Example of the head shifting. The upper part of this Hulk print got shifted
a couple of times, a little to the Right. See how the Neck is spread a little to the right.

In this one, the spool was almost empty and the spring of the last few winds was so
strong that it actually pulled the head backwards and made the offset you can see
on the model on the right.

I wish I had pictures of all of these things... but I would hate to have to try and replicate a disaster just to have a picture. (Or Would I?)(Perhaps I can just wait and update this entry with future disasters)

More Spool Holder Wars.

Half way to all PLA

ARGH. The new overhead spool holder is OK, but the spool isn't quite high enough, and it occasionally gets hung up on the slender center rod because the spool can get turned a little. There is just too much play between the large spool center hole (a couple of inches) and the little spin rod (about like a metal clothes hanger size). The solution? Design a center piece that clips into the spool and has a small guide hole for the metal rod. Simple, No? Well. Almost.

Big Hole, Little Rod. Non Ideal.

It is education time again. I am printing this spool thing and it just ins't as strong as I think it should be. I have what is essentially a cylinder on top of another cylinder and the connection between the two is pretty weak. In fact, the bottom cylinder (more of a disk) is flimsy. Why is that? My epiphany comes from a memory of this structure (see picture below)  that I downloaded from the net. Why is the center part of this arm a hole? Why not solid? Here is my thinking: You cannot control very well the center of a solid object (at least not with the software I am using for slicing). So a solid object really isn't that solid. It has little threads crisscrossing through it (see other picture) but not a real strong structure (Well, you could make it solid. But that uses a lot of filament).  The strong structures are the Sides of an object. So by creating more sides, I can create more (and targeted) strength. So putting a hole in a flat arm essentially creates more sides and so more strength. As an additional feature, using holes uses less plastic.

Why is that hole there?

A Solid Pipe?

This is what a solid looks like. Not so Solid

So, a couple of iterations and I have a strong enough and flexible enough center spool. It fits into my filament spools and makes a great addition to my Mega Spool setup.

Yes, I designed this.

Look how cute it looks !!

Time to try something different. I order some ABS filament. ABS is touted as being stronger than PLA and used for professional builds but a little harder to work with. It is apparently more sticky and adheres better but it can't be used for high resolution prints. Fair enough.

On the Spool, it turns out it is much more springy than PLA. So springy, in fact, that it springs right off the spool during printing and mucks everything up. Drat. I need some sort of guide. Something that sits with the spool and keeps some mild tension on the filament so it can't go springing off when I am not watching. So I designed this thing below. Not the holes in the arms to make it stronger !! It Works GREAT !!!

Now I have the ultimate Spool holder system. I even started posting some of these designs up to Thingiverse as my own things!! (Link to Thing 1 here). I have used this system quite a bit now and it seems to work great with ABS and PLA.

At Last, my spool Holder is FINISHED !!

Hmmm, in the picture to the left, is that metal bar about to slip out of the holder? Going to have to design something to stop that.

UPDATE:

1) Left side tower kept falling slipping off the M3D frame: Fixed with reprint in red ABS
2) Filament Guide too wiggly: Fixed with longer housing/hole for rod.
3) Rod keeps slipping left or right off of the holder: Fixed with Though Flexible holder buttons.
4) Center Spool was a little off. Reprint with slightly modified design in Tough Flexible.

Getting Started with 3D printing

How hard can it be?

Buy a 3D printer, download some free software. Maybe grab a couple of test designs (which are called "Models"). And away you go.
Unleash the Inner Inventor in us all. If nothing else, print your own lego bricks.

Buying A Printer

I admit that this was my first barrier. Last time I looked around, a basic (but non-kit) printer setup was like $500 And that was over my threshold for "let's go see what this baby will do".

Well, a couple of things happened that pushed me over the top.

First, I have this OTHER project trying to get computer controlled LED lights on my LGB Trains for my Xmas setup. That was going fine until I realized that I just didn't have any good clean way of putting the lights onto the cars. Hot Glue was a bad idea. I needed flat surfaces to start with. I tried wood. And soldering. And more wood. And I ruined a lot of lights. And I just couldn't make it look "nice". I needed something more customizable.

Then, On a facebook ad, of all places, I saw a cool looking little 3D printer being advertised for Xmas for under $200. My partner got it for me for Christmas. This is  a M3D Micro. It has a printing area of about 100mm on a side. So fine for small things. I figure I could hook some things to gather to make my mount surfaces for my lights.

M3D

M3D Mini with Mark I external filament holder.

Now M3D is an interesting company. They were a quick starter company and are pretty much just getting going. I am still not sure what I think about them. First, my printer was broken right out of the box. Would only track X back and forth about 20mm. I tried customer support. This was very slow during the Xmas to New Years week, and I don't blame them for that. The advice they gave me sounded good, at first. "Gee, sounds like you have set a soft stop in your software, send this Q-command that should free it up" (No go). Couple other things (also no Go). Finally, they send me to this page with directions on how to fix a broken something or other.

Directions read something like: "Remove bunch of screws. Remove Cover. Gently remove Important thingee to reveal unseated thingee. Reseat. Apply Super Glue. Put back together."

Apply Super Glue?

Why not just say "Please Void Warranty at this time".

Anyway, I applied for a return.

Took a week to reply to me saying they would accept my return but I had to pay shipping.

Took a week after I paid the shipping for them to email me a shipping label.

Took a week for the shipment to get to them.

Took a week for the New one to get back to me.

I was pretty mad by then.

But the new one works !!

Well. Sort of.

You know what the 3 most common things are that can make a model print poorly?

1. At initial start, filament doesn't stick to the table. Caused by:
1. Reel not feeding easily.
2. Height not aligned properly.
3. Tray too cold.
2. During print. Spool doesn't feed well. Caused by:
1. Reel not feeding easily.
2. Filament getting unwrapped and tangled.
3. God.
3. Clogged hot nozzle. Caused by:
1. Reel not feeding easily.
2. Incorrectly set temperature controls.
3. using the printer.

As you see. The Reel not feeding easily is a problem. You can also see that one problem, like reel not feeding, can cause the other problems , like Nozzle Clogging. The M3D comes with an internal integrated spool holder and feeder. The first thing you need to do is replace that baby with an external feeder. The second thing you need to do is figure out that you need a even better feeder and print that one. And the third thing you need to do may be to buy a feeder from someone...

 

 

 

For the last couple of days I have been plagued by bad prints. They look sort of like good prints, but they can come apart in your hands. Sort of more like a birds nest than a lego brick. As far as I can tell, it all because me spool just isn't feeding well enough, and I think this cause the nozzle to get clogged. 

It is also unclear to me, at this time, what the resolution and solidness settings I can use. Models are, by default, hollow with pretty thin walls. You can make them more and more solid at the expense of longer print time and the use of more print filament.

and that leads to the next 3D printer issue:

Print Time

You know how long it takes to print 1 of 3 of the pieces I need to make my new Print Spooler? About 2 hours a print. Now perhaps I am using the wrong settings. Might be able to get that down to 1 hour. Still, one hour a piece for things is going to take a long time to get my light holders made. That that 1 or 2 hours assumes that I didn't make a mistake in my creation of the 3D model (using TinkerCad, at this point) and that the 3D model didn't have some internal problem (like holes are not holes) that you can't tell from the CAD software, and that it didn't just all go bad because of the spooler. You know what happens when the spool gets held up a bit? The filament stops adhering to the previously printed model. When that happens, the printer continues on printing right up in the air. And you get little tiny threads of plastic in great big Bird's Nests all over the printing space of your printer. At least my Partner finds them amusing.

I find it very difficult to walk away from a print and let it on its own. So I can apparently waste a lot time just watching plastic melt and the little servo arms running around drawing the model layer by layer. See, if I am watching, then I can abort as soon as something goes wrong. Instead of waking up in the morning, after allowing an 8 hour print to run all night, to find that things blew up half way through and I now have a Mare's Nest in my office.