Just Another RepRap

[ AGAIN, BE SURE TO READ THE BIT AT THE END ABOUT MAKERFAIRE 2012 ]

Right on the heels of a blog post earlier this week, another post!

This is going to be a long one.. but with lots of pretty pictures.

Ok! In the last blog post things finally got awesome – I printed a money clip that looked absolutely flawless, out of PLA, on my RepRap. (As I type this it’s September 23rd, so I’m around 11 months behind, as I’m blogging about events from the end of October 2011).

I probably had my expectations cautiously dialed back (expecting something else to go wrong, so it wouldn’t be so bad when it did), but nope – there was a whole lot of smooth sailing from that point on. Feast your eyes on some of these prints.

For years I’ve worn two gears on the lanyard that holds my badge for work. They’re printed out of ABS on the Makerbot Cupcake that I printed my RepRap’s actual parts on (specifically they’re the z-driven pulleys from the original Sells Mendel). I finally printed one out of PLA and put it on my badge between them, making a cool gear sandwich.

..and here it it on my badge between the ABS ones:

It was getting near winter, so next I printed out this snowflake ornament:

It is so cool watching this snowflake print:

You print two and slide them together:

Next I went to an item I remember seeing from a long time ago – a toothpaste tube squeezer. Let’s just say that if there was some innuendo I was supposed to pick up on from the description, I didn’t quite notice it until it printed out (or maybe I’ve just got an active imagination). While it was a great quality print, it didn’t actually help much with the toothpaste.

I ran out of plastic and switched over to old old plastic (I’d been using 4042, then I switched to 4032, which isn’t used anymore). I used it to print out a Hello Kitty for Alicia:

And then I moved on to an unbelievably great print.. The castle..
First, there was a slight failure, as I started getting slips on an axis.. (I believe it was the Y axis and I remember that giving me problems for a while). This made me slow down the speed of my prints.

I adjusted the speed, printed, and got this:

This first pic has a bit more perspective, then on the next I must have zoomed in:

Just to prove to myself that that wasn’t a fluke, I printed another.

Next.. can you guess what this is? (cover your ears)

(those of you who know what that is appreciate that, I’m sure)

Then I printed another (better quality) filament spindle holder (which I believe was my third?)

Then I tried printing a simple soap dish, which curled up and broke my extruder again.

It was at that time that I decided to switch to a heated bed. Part of me still pines for those old days because I loved that little plastic purge slot in the front, which I wouldn’t be able to use with the standard Prusa heatbed. But, the tradeoff was worth it.

I once again tore apart my printer:

Prusa’s heated bed wasn’t designed for a Sells (original) Mendel – it was designed for his Prusa Mendel redesign. But I wanted to use it on my Sells Mendel. This posed a few problems for me to overcome (as well as an inconvenience – the purge area that I loved, which allowed completely automated prints, would now be inaccessible). Even mounting it though had issues.

Here was my plan for the heated bed:

As I said in the video, I was worried about heat going down from the heatbed through the bed adjustment screws I had going down into PLA, so I decided to make some PTFE washers (I thought I’d made them out of old ruined PTFE insulators, but the video shows I made them from the raw PTFE rod that I make insulators from).

I know I’m repeating myself from the last post here, but what I say in this next video was worth saying again:

Here is the headbed set up, almost done:

Here’s my first print onto a headed bed (although it was with a damaged PTFE insulator that I knew would fail).. No tape needed – just printed straight onto glass.

Then another print of it, this time with a rebuilt PTFE insulator:

I had a temperature problem during that print (video not worth showing), which I apparently fixed.
Then I tried the soap dish again:

Then the Y-axis skipping that I mentioned above reared its ugly head again:

By this point my friend Chris Connelly (who had built the original Makerbot with me that I used to print the parts for my RepRap) had decided (wisely, and with my encouragement) to stop waiting for me to get printing well enough to actually print him parts. He purchased printed parts for a Prusa Mendel (Iteration 1), and had been coming over for printing days where we’d work on the printers in the basement. Here is video I took of his first print:

There’s something to be said for a room filled with the sound of multiple 3D printers printing at the same time.

Next up: an extruder that supports holding up a PEEK block for an Adrian-styled extruder nozzle. Even though I was doing it out of PLA (a bad idea), I figured what the hell, and tried printing a Greg’s Accessible extruder from PLA (configured to support rods that hold up the PEEK block):

The result:

…and the large gear for that:

…and the idler:

All of it:

Small gear no good? No problem:

Perfect:

It’s amazing how when some part of something works so well, that you can end up ignoring other parts that don’t work. I kept forgetting about the Y-axis skipping problem I was having (or maybe after 11 months I’m just forgetting that I always remembered it but just didn’t know what to do about it). So even though the soap dish gave me problems, I tried designing an iPhone tray for me to rest my iPhone on while I slept (so it didn’t vibrate off of the table in the morning when the alarm went off). I designed holes at the bottom for Sugru, and it was basically going to just have a rim (like the soap dish) with a slot near the bottom.

It failed, and the failure is worth showing (because even the failed object was still amazing to hold in your hand).

and.. failure:

Time to stop here I think (even on a failure). Now the blog is caught up to November 26, 2011 (today is September 26th, 2012) – so I’m still 11 months behind. Next up in the next post: it was time to try the new extruder.

As I said last post, in one week I’m heading down to Makerfaire NY 2012 to show off my RepRap (I’ve attended for the past two years but this is the first time I dragged my RepRap down there to exhibit). I’m booth #8736 in the 3D printing village. If you’re in the area, come on down! It’s September 29th and 30th. Makerfaire NY 2012.

[ BE SURE TO READ THE BIT AT THE END ABOUT MAKERFAIRE 2012 ]

I think I’m actually going to have all of my credit cards paid off before I catch up on my RepRap blog. [Edit: I wrote that months ago. It turns out, I actually did! Credit cards all paid off. ] Here’s another update – at the end of the last post I was caught up to September 25th, 2011. That means that I’m starting this post out about twelve months behind. (When I first typed that sentence, it said seven months behind. Procrastination = bad)

Here’s where things finally started to get good. My friend Chris was now building a Prusa RepRap, and purchased RAMPS 1.4 and a PCB heatbed. That motivated me to finally get around to upgrading my electronics – I was still using the old Gen 3 Makerbot electronics (which only barely did microstepping, and didn’t have a standard way to drive a heatbed). So I too purchased the RAMPS 1.4 electronics and Prusa’s PCB heatbed.

Here’s the last video of my RepRap before I tore it apart:

For those who aren’t familiar with RAMPS, RAMPS stands for RepRap Arduino Mega Pololu Shield. It’s a shield that plugs onto an Arduino Mega, it has Pololu stepper drivers plug into it, and it can support a heatbed and up to two extruders. Here’s what it looked like when it arrived.

I tore all of the original electronics off (actually I left the stepper drivers underneath on the back unused), cut a new piece of MDF, and mounted RAMPS to that. Then I rewired everything up (which was considerably easier since almost everything is on the same board).

This change thankfully also pushed me to make three others:

1. I decided to try using Sprinter firmware instead of the RepRap 5D firmware I’d been using.
2. I tried out pronterface instead of RepRap Host for control software
3. I tried slicing with SFact (a simplified Skeinforge) instead of using the built-in slicing that RepRap Host used to do for me. I’d used Skeinforge before with the Makerbot to make my original RepRap parts, but I’d read that SFact automated lots of the redundant settings and made calibration easier.

Using Sprinter and pronterface, here I am successfully demonstrating working X Y and Z axes:

(Note: After this point my wife and I finally upgraded our phones from older iPhone 3GSes to iPhone 4Ses, so from this point on my pictures will all be higher res and hopefully the video will be more stable.)

Here are a few pics of the new electronics taken with the new phone:

This next video is where I started to really get excited. The excitement was a sliiiight bit premature because I didn’t realize yet that my Z-axis wasn’t going up enough (I needed to slow down the Z speed to accommodate my RepRap which can’t move that fast in Z), so I ended up canceling this print, but I was happy nevertheless:

It turns out I didn’t have my Z speed limit set properly, so it was trying to go up too fast and wasn’t moving. In setting that I also had to fill in other settings, such as layer height. I decided to print some hollow calibration cubes to try to get that right.

(If I add a fan to my x-carriage that should actually let me print at far smaller layer heights, I think)

I tried going smaller. 0.2 looked great until it didn’t:

The back of 0.2 didn’t come out well though:

But still that layer height looks so small..

Then during this print:

the extruder barrel pushed out of the PTFE:

Even though the heater barrel pushed out of the PTFE insulator (a problem that always caused me headaches), I remember not minding at all this time, because things were going so well.

I realized one thing that helps out a lot when fixing your RepRap is actually putting it ON a lazy susan:

So.. I rebuilt the hot-end (twice, as it failed almost immediately the first time), and printed more of the calibration cubes. Here’s the result:

With that progress made, I went back to trying to print a money clip. Here was my nervous mid-print video:

and even further along:

Behold! Apologies for there being so many pictures of this, but this was a huge moment for me. Check out the quality of this money clip:

Watch this video:

And this was even worth a second summary video:

Can you tell I was excited?

I have so much more to post, but I need to cut it here. There are a lot of really great quality print pictures coming up in the next blog post!

Today is September 23rd, 2012. I just got you all caught up to October 29th, 2011 (about 11 months ago).

In one week I’m heading down to Makerfaire NY 2012 to show off my RepRap (I’ve attended for the past two years but this is the first time I dragged my RepRap down there to exhibit). I’m booth #8736 in the 3D printing village. If you’re in the area, come on down! It’s September 29th and 30th. Makerfaire NY 2012.

(At this rate, you won’t see pictures of that for a year. )

I’m catching up! I’m not as far behind as I was before. Hopefully with just a few more blog posts I can catch you all up to my current state of RepRap (which, again, is far ahead of what I’m currently blogging about – April of last year (2011)!

Ok, so where was I.. At the end of the last post, I had just recovered from a catastrophic failure – I replaced my old melted X-carriage with a brand new OpenX carriage and had started printing. I was having extrusion problems again (resulting in rice-krispie consistency), but at least I was printing again.

This seems like a good place to post something I often talk about regarding having printing problems and not knowing what to do about it. When doing RepRap printing, there seem to be times where something isn’t working and you have no idea what exactly is causing it. The problem is that there are so many things that potentially could be a problem that you have no idea which one needs fixing. I liken it to being lost inside a cave or mountain in the game Minecraft. For those of you who aren’t familiar with Minecraft, all you need to know right now is that it’s a blocky cube-based video game with a custom world for you, with hills, valleys, caves, mines, and you can dig and climb. Sometimes with RepRap it feels like you’re inside a mountain in Minecraft, and you’re lost, and you just want to dig your way out. When you’re lost in a mountain in Minecraft, for all you know, you’re right up against an outside wall, and if you just dug West by one block you’d be outside, but instead you arbitrarily decide to dig East instead, and dig yourself deeper into the mountain, still lost. (leave aside Minecraft tips like digging upwards in this scenario!).

It feels like that with RepRap sometimes. Hey, this print is awful.. should I adjust the tension on this belt? Or maybe a variable in the firmware about my rate of extrusion is wrong? What if I got a heated bed? The extruder! Maybe I need a new extruder!

That. That problem where there are so many dimensions of variables that it’s tough to know what to do to improve your situation. Maybe all you needed to get back to working was adjust the tension on that one screw on the extruder idler (just half a turn!), but you instead decide to take apart your extruder to floss the hobbed bolt. That’s how I felt for a long time. It’s not entirely how I feel now, which is good, but I’m blogging about back then. So if you’re reading this and you’re like “YES! THAT’S HOW I FEEL!”, you’re not alone – you at least have the last-year-version-of-me in your camp too.

Looking back on my pictures, the next dimension that I tried tackling was the extruder. I arbitrarily picked East.

One extruder that I wanted to build (which, spoiler alert, I still haven’t yet built) is the RepRap Universal Mini Extruder (also here on Thingiverse). That extruder uses 1.75mm filament.

So I started with its heater barrel. I needed to make this on my lathe.

First I figured out the angle for the cone at the tip.

After turning the cone, I had something that looked like this:

I then cut the brass for the heater block for it:

Here’s a better view of the barrel at this point:

Then I drilled out the back, with progressively larger drill bits.

The way this barrel will work is that a PEEK section will actually rest inside the brass, and inside both of those will be a PTFE tube. Here’s the PTFE tube inside just the heater barrel for show:

To have the PEEK rest inside the barrel nicely, the big hole in the heater barrel is a flat counterbore (as seen in the hot end drawings), not drilled with a standard drill bit. I purchased a 6mm end mill from mcmaster to flaten out that hole:

A few weeks later (after unrelated quadcopter, telescope, and pool opening fun) I then got on to the PEEK part:

..and for fun, here’s a 3D view of that (let your eyes drift until both images overlap on top of each other):

That was all around the May/June timeframe. That’s the last RepRap photo I took until August 21st (now I’m only around 7 months behind in blogging again!). Then I seemed to lose track for a while of the new extruder barrel, and instead just tried printing again. The next pictures I have of are a hobbed bolt:

… a horrible octopus attempt:

(which wasn’t quite as bad after cleanup):

… and then the Minecraft pickaxe I printed. :

The Minecraft pickaxe print did not go without incident. At one point I paused, triggering a bug I’d seen in either the RepRap Host software or the 5D firmware where it would print at incredibly slow speeds:

Despite that, I ended up with my deliberately-heavily-pixelated pickaxe:

Maybe I could use this pickaxe to dig West.

Then sometime in August, I saw a Google+ post by Forrest Higgs saying how he finally bought a proper crimping tool and was now making harness cables about ten times faster. Ever since the time that I’d initially found header housings/pins on mouser and shuddered at the crazy crimper price I saw there ($267.45 on mouser.com! AAGH!), I’d dreamed of being able to crimp correctly (but I wasn’t spending that crazy money on some professional crimper). It turns out an excellent crimper can be found for about a tenth of the price. He pointed me at these URLs:

Crimping Tool: 0.08-0.5 mm² Capacity, 20-28 AWG
http://www.pololu.com/catalog/product/1929
($29.95)

Female Crimp Pins for 0.1″ Housings 100-Pack
http://www.pololu.com/catalog/product/1930
($5.95 for 100)

0.1″ (2.54mm) Crimp Connector Housing: 1×2-Pin 25-Pack
http://www.pololu.com/catalog/product/1901
($0.69 for 25)

(and there are 1×3, 1×4, and 1×1 housings too).

These changed everything. They took crimping headers from a painful headache experience to something easy and satisfying. You’re insane if you don’t go buy one of those crimpers now. It ratchets, tightens everything exactly as tight as it needs to be, and the pins just slide perfectly into those housings and make that satisfying “click”.

Here is the crimper that arrived at my house:

Here was video that Forrest pointed me to as well that shows how to properly use one of these crimpers:

The only things about that video that aren’t as good as they could be are:
1) The crimper shown is one of the cheap horrible kinds that don’t even ratchet.
2) It seems like he’s skipping a step. I, at least, first crimp the clip around the insulation, then I crimp the inner piece around the wire. To crimp the clip around the insulation, I usually hold the female pin on the wire and use regular pliers to make a temporary crimp against the insulation, then I crimp the insulation part, then I crimp the smaller conductive wire part with another sized notch in the crimper.

More pictures of the crimper:

Ok so I moved my RepRap back down into my basement, and put it on the lazy susan that I used to use for filament. I know, it seems like that would react to the vibrations while printing, but it didn’t. What it DID do is give me easy access to all sides of the printer, by simply unplugging the power and USB. It’s like my RepRap is a car up on the lift at a mechanic’s station!

It certainly felt like it needed to be at a mechanic’s station. Here was a horrible horrible calibration print I did right after moving downstairs:

I’ll end it there. Things are about to get a lot better. A lot better.