The Emperor Wears No Kapton

March 8, 2013

The MakerBot 2X was just released, and I’m a little disappointed to see that MakerBot Industries hasn’t gotten rid of the Kapton tape part of the printing process yet. It’s easily the most frustrating part of working with the printer, and in a lot of cases it’s completely unnecessary.

For non-3D printer people who have stumbled across this blog post, Kapton tape is a space-age amber adhesive tape that one lays down on a build platform to help prints stick while printing. Kapton tends to bunch up and self-adhere, making the process of affixing it to the platform a real exercise in patience.

Without some adhesive assistance, prints slide all over the platform and you get a big bag of fail.

I haven’t had the opportunity to use a 2X yet, but I’ve been printing on a Replicator 1 for about a year and I’ve found a few workarounds that let me concentrate on designing stuff rather than getting my prints to stick to the first layer. Presumably these tips will apply to your shiny new 2X, too.

The models in all of the following photos were printed on a Replicator 1 using ABS of various colors, using the original Replicator firmware. I’m using ReplicatorG to slice.

HBP 110°
extruder 240°
layer height: .25 to .27
feedrate: 45
travel feedrate: 65
ReplicatorG 037
Skeinforge 50

I’m generally printing small models onto painter’s tape. The base on this squirrel is maybe 5 centimeters in radius.

squirrel token with NUNCHUCKS!

I get at least a 95% success rate printing these. (I need a lot of them because the kids and I use them as tokens in Magic: The Gathering.)

If you’d like a nunchuck squirrel of your own, download the STL here. Unarmed squirrel tokens also exist.

I was having such success printing tokens of all kinds on painters’ tape that for a while I was thinking Kapton was completely unnecessary until I tried to print a Dungeons and Dragons dice plinth.

painters tape plinth

See that circled gobbet of filament? That’s caused by not covering the entire platform with tape. The plastic won’t stick to bare aluminum, so when the extruder does its pre-print nozzle clearing it takes the extruded plastic along for the ride.

These gobbets can mess with your print if they get caught up in the print area, so it makes sense to cover the extruder path with a strip of tape.

Note where the edges of the dice plinth curled up from the platform. My understanding is that as layers of plastic cool, they contract and pull the lower layers of the print upwards. If you want to avoid this pulling, the first layer really has to stick to the platform.

The Sharpie marks around the print help me to make sure the build platform is locally level in the print area. I hardly bother with MakerBot’s platform leveling script anymore. I don’t see the point of having level platform corners if I’m not printing that far out, and getting level corners is a second exercise in patience that I just don’t have time for.

So. I lay down a small piece of Kapton in the build area only. Don’t bother trying to cover the whole build platform if you don’t need to. It’s much easier to work with that way.

I spread a liberal application of ABSynthe in the build area and then hit the print button again. Success. Those bubbles in the kapton are usually a problem, but with enough ABSynthe anything will stick to the HBP.

plinth with absynthe

Take a look at the difference between these two prints from the side. Painters’ tape on the left, Kapton with ABSynthe on the right.

plinth comparison

But, there’s a small downside to using ABSynthe: look at the bottoms of these prints:

underside

The ABSynthe I have at the workbench is a noisome slumgullion of every ABS filament color I have, which leaves a murky film on the bottom of the print. Note to self: make mono-colored ABSynthe for higher-quality prints.

Why not use ABSynthe on painter’s tape? I’ve tried it. The ABSynthe fuses with the tape and it can’t be removed from the bottom of the print without a lot of sanding.

Advertisements

Sweet ABSynthe

January 1, 2012

ABSynthe is a simple brew of filament scraps and acetone. Brush it on your build platform and your ABS prints will be a lot more likely to hold fast for the duration of a print.

You’ve probably got some ABS filament ramen or failed prints scattered around your workspace. Chop them up and drop them into a jar of acetone. Feel like Walt from Breaking Bad disposing of the evidence.

Don’t overthink it, just add enough acetone to make a thin syrup. Huff not the ABSynthe.

I mix my ABSynthe in an (empty) 3.6 ounce jar of Proraso Pre-shave Cream. It’s a convenient size and the plastic top won’t dissolve from the acetone fumes. Plus, it’s imported from Italy.

ABSynthe

She’s-a-make-a-you print-a stick-a-real nice-a.

Dip a paper towel in the ABSynthe and smear it across your HBP.

Getting ABS prints to stick to a heated build platform can be an art. I’ve had excellent results with some ABS spools, where they melt just enough to stick throughout the duration of a print, but some plastics just don’t like my kapton tape. They end up going for a ride around the platform and I’m left with a big bag of fail.

Note that I’ve pretty much given up covering my entire HBP with kapton. I realized I was mostly printing fairly small things, and it didn’t make sense to spend the time ironing out all the bubbles and rending my garments when the kapton bunched up.

So I just lay one strip down the center of the HBP and I’m a much more relaxed person now.

IMG_1180

That schmutz on the kapton is the ABSynthe. I haven’t had a print slip off the platform since I started doing this. I’m generally printing ABS at 120°C.