Print Bed Surfaces: “More than Moore” Edition

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Try this for yourself. Pick up some polished silicon wafers and support our makerspace here: The MakerHive Store

There are two beautiful aspects of the internet.

1. At some point in time bsolutely everything has been / is / will be for sale online for a really good price

2. Thanks to awesome communities on forums and on Twitter the best stuff tends to bubble up so that I actually hear about it before it’s gone.

Such was the case with a case of 8″ silicon wafers from Electric Goldmine. A friend mentioned that these things are so cheap and interesting that they just had to be useful. And he was definitely right.

Round wafer on a very Cartesian printer

Round wafer on a very Cartesian printer

These wafers are an excellent print bed for several reasons, and they’re perfect for me for a few more reasons.

1. Planarity – lithography at sub 20 nm nodes probably doesn’t work so well if a wafer isn’t perfectly flat

2. Heat Transfer – the combination of excellent thermal conductivity (compared to glass) and rigidity in a relatively thin wafer (these are 0.7 mm) allows for quick heat up and cool down and elimination of hot/cold spots on the print surface.

3. (just for me) Copper plated on one side – My Printrbot Simple Metal’s inductive probe looks for metal to tell how far away it is from the bed. Straight silicon doesn’t cut it. But one side of the wafer appears to be copper plated and polished. That creates a really nice surface for my auto-leveling probe to detect.

So how well does it work?

Pretty much like glass. I retried everything the internet told me to do when printing on glass, and ended up using purple glue stick again with really good results, just like on my previous glass bed.

Another huge advantage is that I’m not clamping the wafer to the print bed in any way. It is only resting on the silicone baking sheet which is clamped to the print bed. This way a wafer can be swapped out after a print for a fresh one, without waiting for the entire bed to cool down. I used to tell myself that 10 minutes to heat up here and 15 minutes to cool down there didn’t matter that much, but it does. What other lies am I telling myself?

Scribing wafers without a diamond scribe is a bad idea. At least Maverick is still giving me the thumbs-up

Scribing wafers without a diamond scribe is a bad idea. At least Maverick is still giving me the thumbs-up

1 wafer post-print, another wafer loaded and waiting

1 wafer post-print, another wafer loaded and waiting

Bat Owl rises from the silicon...

Bat Owl rises from the silicon…

To make this a bit more functional on my printer, I had to raise the print bed by about 1 cm. Already having a 3D printer, making standoffs to accomplish this was a breeze. The stack up is shown below.

Lifting the bed

Lifting the bed

Aluminum Bed

Aluminum Bed

Silicone baking mat for high-friction & thermal conductivity

Silicone baking mat for high-friction & thermal conductivity

Binder clips and fragment of silicon for the home position

Binder clips and fragment of silicon for the home position

Wafer on the bed, smothered in purple glue stick and ready to print!

Wafer on the bed, smothered in purple glue stick and ready to print!

 

This effort was much more rewarding than I anticipated, both in sheer fun and in functionality. I’ve expended much more effort for much less improvement in the past.

10/10 – Would buy & build again.

 

Now if anyone has a lead on 12″ wafers at a reasonable price…

Third Steps in 3D Printing – Print Bed Surfaces

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In the short time I’ve owned a 3D printer I have called it many things. A 3D printer is “the best reason to own a 3D printer” or “the most fun optimization problem I’ve ever faced.” It may have also been called some other things but I don’t like to gossip. In the spirit of perpetual optimization, I was tempted to improve my print surface and willing to try anything.

All those fancy Ultimakers and Rostocks printing on glass. It was obviously a superior bed surface to my bubbly Kapton and it wouldn’t need to be replaced (at least for a long time). Plus the internet said it was easy (if this adorable kid can do it, so can I!).

First let’s take a look at past print surfaces:

Original Printrbot Simple Metal print bed of blue masking tape

Original Printrbot Simple Metal print bed of blue masking tape

Heated Bed with Kapton Tape and gluestick

Heated Bed with Kapton Tape and gluestick

Both tape (blue masking and Kapton) worked fine. But it was difficult to remove parts and the tape got scuffed up and in some case tore off. Glass was definitely a more elegant solution.

I picked up 3 mm thick glass from a picture frame and needed to make one cut to get it down to size. After several failed cuts I finally got something that was functional and minimally dangerous. As I went to apply the glass to the bed I quickly found another problem. The auto-leveling inductive probe would only sense the aluminum bed at about 2.5 mm away. The probe was more sensitive to ferrous metals so I took a magnet and went looking for large flat pieces of metal around the lab. What I found was the back of a breadboard. After removing the binding posts and cleaning it up a bit added it to my growing sandwich of a print bed. The final piece was some silicone baking sheets (like these) in between the metal and glass to prevent any slippage. The final product is shown below.

Glass bed stackup

Glass bed stackup

Once this was all clipped into place it actually worked pretty well. I should mention, don’t overconstrain the glass. I was using four binder clips which produced significant warpage in the glass. Once I removed one of the clips my glass plate magically leveled out again. Mathematical.

It takes a long time to warm up, but it does work. And you wouldn’t believe how well it holds heat…

 

See it in action, from multiple angles!

Second Steps in 3D Printing – Heated Bed

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As soon as I got the Simple Metal printer working, I wanted to take it apart and make it work better. A heated bed was the most functional upgrade as it allowed me to ditch the blue masking tape and move to glass or kapton tape and remove my PLA shackles, allowing me to print in theoretically any plastic (realistically ABS). The heated bed upgrade from Printrbot was very easy to install and worked pretty well up to about 80 C. I did use thermal grease between the PCB heater and the aluminum bed because the finish was really rough. It might have been too rough for the thermal grease to help but it ended up working. I added some cardboard and a mousepad underneath the PCB heater to help guide the heat up to the print bed instead of down to my Printrboard. With those modifications I was able to reach 100 C in about 20 minutes. Not great, but functional.

Heated Bed with makeshift insulation

Heated Bed with makeshift insulation

Pipe insulation - Not as functional as cardboard, but looks better.

Pipe insulation – Not as functional as cardboard, but looks better.

Fan shroud in "traffic-cone-orange" ABS

Fan shroud in “traffic-cone-orange” ABS

Initially I used the square of Kapton tape provided as my print bed surface. Covering the tape with purple glue stick worked very well for ABS and PLA. But I did not give the Kapton the respect and consideration it demands and ended up with some nasty bubbles.

The heated bed upgrade was not without flaws though. As the makeshift insulation might suggest, there are some design elements lacking here. Some issues that should be resolved for more satisfying prints include:

1. Insulation underneath the heater PCB

Solution: Cardboard, Mousepads, Pipe insulation, anything else that will help keep the heat in. I ended up using lots of binder clips to clamp it all together

2. Heat sinking from the black metal wings that connect to the x-axis belt

Solution: Just print some standoffs! You’ll lose some z-height but the bed will reach higher temperatures and do it more quickly

3. No space under the bed for insulation in the original configuration

Solution: Mount the heated bed on top of the wings. I know it’s designed to be mounted underneath to end up with a flush surface that looks really nice, but form over function is not to my taste.

 

Overall, the heated bed upgrade was an expensive solution for mediocre performance. But it can easily be hacked to resolve some design issues and result in a very functional print bed.

First Steps in 3D Printing

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Every Thursday Adafruit runs “3D Printing Thursday” on their blog posting “All the news that’s fit to 3D print.” And every Thursday my lack of a 3D printer grew into a bigger and bigger void deep in my soul. The combination of a small budget and strong desire not to spend money on a piece of junk  left me with an empty space on my workbench.

Enter the Printrbot Simple Metal.

I still don’t see anything on the market at the ~$500 price point with such a high-quality frame and solid print quality. It was (and still is) the perfect entry into 3D printing. I bought mine already assembled and had little trouble following the online instructions to get it up and running. This is still far from a mass-market product, but for anybody with some technical inclination, a willingness to learn and a bit of enthusiasm it the perfect way to spend all those hours you should be sleeping. Watching every printrbot YouTube video before getting the printer doesn’t hurt either. (See bottom of post for the most useful videos)

Stock Printrbot Simple Metal with open source filament holder (beer bottle on a screwdriver)

Stock Printrbot Simple Metal with open source filament holder (beer bottle on a screwdriver)

I was pleased with the amount of PLA filament they included. It was certainly enough to print a few fan shrouds and owls. It took me some time to get used to the idea of slicing an STL file, saving the g-code and telling the printer to run the g-code. Running Repetier Host with Silc3r was probably the right way to start out. Although separating my slicer from my printer host is a much nicer solution. I’m now running OctoPrint on a RaspberryPi to control the printer and just slicing on a separate computer.

My first print was the fan shroud seen in the picture above. That g-code was downloaded directly from the Printrbot website and the print quality was decent. For my second print I downloaded the owl I saw in Cam Watt’s video (linked below). I sent that through Slic3r with a 0.1mm layer height and started printing. I came back a few hours later to find PLA spaghetti all over the printer and half of an owl was laying on the bench (my unspooled filament had gotten tangled up, emphasizing the need for highly engineered filament spool & spool holder). After my initial shock and disappointment I looked at the half-owl that did print and I was blown away by the quality. It was at least as good as any 3D print I had seen online. I immediately scaled down the owl model and starting printing again.

1.5" tall owl in natural PLA at 0.1mm layer height.

1.5″ tall owl in natural PLA at 0.1mm layer height.

I finally had a functional, good-quality 3D printer. That was just the beginning of the adventure. I quickly decided I didn’t like the feel of PLA and needed some upgrades to print ABS. (I might have mistakenly ordered 2kg of ABS filament instead of PLA as well which helped push me towards the heated bed.)

Now 3D Printing Thursday is the best day of the week!

 

 

Useful Videos:

Tested Review

Tom’s Honest Review

Cam Watt’s multi-printer test

Printrbot Simple Metal: First Moves

Printrbot Simple Metal: Calibrating the Auto-Leveling Probe