Playing With Glass

The build surface of a 3D printer is critical for producing good prints. There are a few things that can go bad during a print or may prevent one from even starting printing.

The main issue is adhesion. You haven’t felt frustration until a 20 hour print gets loose at the last few layers. Other important issues are flatness and warping which might not be as important for some people with certain types of prints, but can also affect adhesion and are very important to me.
There are many techniques to get the job done, I haven’t tried all of them but through trial and error i found the method that works for me.
At first, I tried to print directly on top of the hot-bed. That’s not a good idea, not only is the hot-bed flexible and not flat, it can easily be damaged by the hot-end or a print that’s stuck too well. Applying masking tape, painter’s tape (basically the same thing) or Kapton tape (thick nylon-like tape that can withstand extreme temperatures) can protect the bed from the hot end or stuck prints and some say help with adhesion, but I saw no improvement and it does not help with the hot-bed’s flexibility.
Some use commercial products like BuildTak, but I haven’t tried it yet.
Aluminium seems like a rather popular option, but it has a few drawbacks. While having good thermal conductivity, aluminium tends to warp in high temperatures. It’s relatively soft so it gets easily scratched and damaged if not handled with care. I think a better option would be copper, which has similar mechanical properties but better thermal conductivity. (to date, I haven’t seen anyone use copper)
I guess THE best surface would be made of diamond, it has the best combination of thermal conductivity and strength, but that would be a little over budget..
It was obvious to me that glass is the way to go. It’s hard, flat, can withstand a little beating if a print is stuck and it’s cheap. I actually got mine free.

20150125_223530

I tried a few types of glass sheets, 3mm, 4mm and 6mm thick, smooth and sandblasted.
Thickness was very important because i’m using a heated bed. The 6mm and 4mm needed a lot of time and energy to warm up to the temperature i wanted, the 3mm still serves me and it’s doing a fine job.
I thought about going 2mm but that’s harder to find and i’m afraid it might be too fragile.
The 6mm glass was actually a shelf from my bathroom. It wasn’t the right size and it was a hassle fixing it to the bed.
The 4mm had a sandblasted side and a smooth side. I thought the sandblasted side would help with adhesion but i saw no difference. I got if from a glazier who cut it form a scrap piece and gave it to me free.
The 3mm was taken from a broken all-in-one printer’s scanner bed. I cut it to shape myself with a glass cutter and to maximize the printing area, I cut the corners to make room for the bolt heads and washers holding the bed.

20141122_152118Sometimes a flat and hard surface isn’t enough to make the print stick, sometimes it needs a little help.
For ABS there’s a neat trick, I use ABS Juice, that’s ABS dissolved in acetone. Once applied, the acetone evaporates and leaves a thin layer of ABS on the bed for the print to stick to.
For PLA, I use UHU stic glue (like the one in the top photo). A thin layer is enough for a number of prints and it’s removed easily with hot water.
As mentioned above, some use different tapes on top of the surface, but they didn’t really work for me.

Advertisements

Building The 3D Printer

Well, I didn’t document the whole building process because there are A LOT of guides and documentations out there. Plus, it would have slowed me down considerably.
This is written after the fact, obviously.

This project is not completely finished and it might never be. I see it as an evolving project, I constantly add features and change stuff.

Most of the parts were ordered off eBay.
The frame is Dibond Aluminum. That’s plastic with aluminum layers on both sides, it’s supposed to be light and strong – it is.
All plastic parts are 3D printed and came with the frame (the whole idea of the RepRap project is self-replicating 3D printers, well not fully, just the plastic parts – the goal is to get a better printed to non-printed parts ratio)
The hot end is an E3D v6 all aluminum hot end.
The motors are Nema 17 stepper motors, they are a little less powerful that the “standard” 0.4Nm ones, but they work perfectly fine.
The controller is an Arduino Mega 2560 paired with a RAMPS 1.4 driver board.
I’m using a standard 500W computer ATX power supply.

The initial build took about about 3 days. It took place during the last summer at my house with a few of my friends who wanted to help and see the wander.
The build itself wasn’t special, just a marathon of wrenching, drilling, measuring, soldering and calibrating. Oh, and pizza. lots of pizza.

I think the most exciting moment was seeing the code and motors work together. It’s not something I haven’t done before, nor was it an advanced part of the build, but seeing the pile of metal and plastic turn into something that follows commands other that the trivial “stay” was just beautiful and a sign that the hardware is fine and we are on the right track.

After 2 and a half days we had a kind-of-working 3D printer. a diamond in the rough, one might say.
It extruded plastic and moved in the right direction, but it needed calibration and lots of it.

On the evening of the 3rd day I did some work alone and kept having the same problem – I could print fine at first, but after letting the printer rest it would not extrude more plastic, every time I had to disassemble the hot end and drill out the stuck plastic.
It’s too long of a story for this post (maybe I’ll post another one with the fully detailed comedy) but I’ll give you the recap of what I learnt – Computer thermal compound is not intended for these temperatures and if your hot end came with a little fan – use it.
I ended up breaking my hot end in so many places I had to buy a new one.

The new hot end took a little time to arrive and when it did, the semester had already begun and this one was brutal, papers and assignments every week in every course. I never thought I’d wish for midterms to come sooner, Argh..
I could only invest a few hours a week for fiddling with the printer but slowly and surely, it’s up and running.

3D Printer

Yeah, so I built a 3D Printer.

I have been fascinated by 3D printers for a while now, I’ve always wanted to build one. The notion that you can think of ANYTHING and make it a reality AT YOUR DESK with not that much of an effort – if any, blew my mind.
I read a lot and followed some really cool project only to be overwhelmed by the complexity and scale of the project (which turned out not to be that complicated), thinking that if I start I might get bored or worse, stuck, and leave it half finished.

So what made me go through with it?
One day, I was sitting at a friend-of-a-friend’s house talking about projects and DIY. I mentioned how I always wanted to build a 3D printer or a CNC machine and Gal, the one who lives there, said he built one a few years back and missed it. We decided to build mine together.
He also mentioned he wanted to get into programming with Arduino, with which I was quite familiar, so he helped me choose components for the printer and I helped him build an Arduino starter-kit. Win-Win.

Here I will share my journey, thoughts, lessons and updates revolving around building, maintaining and operating my 3D printer. Enjoy.