A close look at the first few layers of some recent objects shows why I’m willing to put up with all the hassle described over the last few weeks.
For small objects, take a look at my build of coasterman’s calibration set:
Microscope LED ring light (two pieces glued on the obvious line):
Fan adapter plate:
Companion cube, with a slightly warped right corner:
Now, those objects may have other problems, but two things work really well:
- The first layer sticks like it was glued to the ABS film
- The side walls build perfectly straight, without bulges or shrinkage
What’s important to me: this is dependable and repeatable.
It’s not yet a simple routine, because these objects were built while I was hacking away at the HBP + aluminum plate platform, some are on the old ABP + aluminum plate arrangement, and they’re not all first-attempt parts. However, given a proper setup, It. Just. Works.
Part of the process involves a very slow first-layer feed: about 10 mm/s. At that pace the molten ABS has enough time to bond with the layer on the plate, even around corners; much faster and it can pull free.
The Extruder runs at 210 °C, the HBP at 120 °C, feed is 40 mm/s, and traverse is around 50 mm/s.
It is yet to be seen if this lashup will remain stable, but the first indications seem pretty good.
The Smell of Molten Projects in the Morning 
I’ve been following your ToM writings since the beginning – I think I received my kit shortly before you did – and I love them. You seem to find the time to explore all of the topics that I am interested in. Sadly, my ToM is still mostly stock, but I hope to begin upgrading it soon.
On that note, how are the cartridge heaters working out?
Which, apart from the heater resistors, isn’t entirely a bad thing: you just concentrate on printing, not futzing with the printer!
The cartridge heaters Just Worked, which is pretty much the whole point. I’m hoping MBI comes out with a decent-priced upgrade, so folks can get off the waiting-for-disaster treadmill…
Dear Ed
I really like your mods. I notice in the prints above, you have a printed outline and then no raft underneath. I guess you print the outline in order to get the plastic flowing. How do you do this. In code?
Michael
The outline comes from the Skeinforge Outline or Skirt plugins, depending on which version you’re using. In addition to getting the extruder stabilized before starting the object, that thread also provides a way to monitor the first layer’s thickness and width.
The first layer of my objects is essentially the same as all the other layers. I’ve settled on 10 to 15 mm/s for that layer and 30 mm/s for the remainder, with corresponding changes to the filament drive speed.
FWIW, I now use Kapton tape on the aluminum plate and ABS sticks just as well as to the ABS film. In fact, I sometimes must use a wood chisel to pry the parts off the tape! The key part of that is printing the first layer slowly (for good adhesion) at precisely the correct height (for correct sizes), which required adding the Z-minimum height switch.
Thanks for the good words; it’s been an interesting adventure…