Archive for August, 2009

new acrylic front plate!

08/22/2009

I went to town on our new Universal Laser Systems VLS6.60 laser cutter and made a new front for my makerbot:

I made the opening larger and took away the big M in the center so I would have easier access to the inside of the machine. The lower section is engraved with a bunch of diagonal lines and three makerbot Ms with patterns inside.

It was cut from 1/8th inch acrylic.

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Makerbot Vs. Dimension SST 1200es

08/20/2009

The Industrial Design department at the University of the Arts in Philadelphia (of which I am a part) just moved to a new building with brand new facilities, including a new shop. I guess it was time for an upgrade because almost every tool in the shop is brand new and we now have a Universal Laser Systems laser cutter (new favorite) and a Dimension SST 1200es 3D printer.

This particular Dimension printer happens to utilize fused deposition modeling and it prints with ABS plastic… So of course, having recently completed my Makerbot, I had to do a little comparison. I printed two objects (both of which can be found on thingiverse.com); a stormtrooper head and a dodecahedron. One thing to keep in mind when reading this is that my particular Makerbot is not up to the highest printing quality yet, so there is definitely room for improvement. First, the prints (click pictures for ultra large versions):

QUALITY
Obviously the Dimension wins this round. Printing at 0.245mm (0.01 inches) per layer, it trumped my 0.35mm per layer Makerbot prints. The XY resolution is definitely higher on the Dimension, and the plastic extrusion in general is more controlled and precise. If you are looking for tolerances rivaling what the human eye can perceive, the Dimension is what you are looking to print with.

The big difference is that the Dimension prints support material in addition to the ABS plastic. This means that crazy overhangs, objects within objects, etc. can be achieved. (The folks at Makerbot designed their printer to be compatible with multiple print heads, so some time in the future the Makerbot will be printing support material too)

TIME
The stormtrooper and the dodecahedron were printed at the same time in the Dimension; they took roughly 1 hour and 40 minutes to complete. The Makerbot had the stormtrooper done in 25 minutes and the dodecahedron done in about 16. Add an extra 5 minutes or so for setup between prints (which is a pretty conservative estimate) and you’re still talking less than half the print time (~46 minutes).

But wait! The Dimension prints support material as well, so the storm trooper and dodecahedron must go in a vat of solution for an additional hour. Bringing the print times to:
Dimension – 2 hours 40 minutes (assuming you didn’t have to wait for the solution to get up to 150 degrees and you grabbed the prints out of the printer as SOON as they were done– an idealized situation).
Makerbot – 46 minutes.

EASE
Those of you familiar with the Makerbot know how many settings there are to tweak just to get the bot to print something decently coherent. Skeinforge is not the user-friendliest software package ever made, and it takes some getting used to. The Dimension comes ready to party and, spare a few simplified parameters you might need to change, you can hit ‘Open File’, select your file, and hit ‘Print’.

The physical preparation is similar for both; the Dimension has a plastic tray you must snap into place, while the Makerbot has a build platform you must snap into place.

The Dimension is the easier of the two to use, however…

TWEAKABILITY
After learning the ins and outs of the Makerbot, I was taught how to print something on the Dimension. There is a drop-down menu for the density of the object you are printing; the options are something like ‘Sparse’, ‘Dense’, ‘Minimum’, and ‘Maximum’. To which I replied: you can’t even set the object density as a percentage from 0-100?

The Makerbot lets you tweak EVERY little detail, while the Dimension gives you almost no options. You don’t even have the ability to turn the support material off!

Things you might not realize can be tweaked on the Makerbot: layer thickness (.01 inches and .013 inches are your only options on the Dimension), feedrate (speed), flowrate (extruder speed), object density, wall thickness…

PRICE

Dimension SST 1200es: ~$30,000 (for just the printer, excluding plastic, support material, and build trays)
Makerbot: $750
Dimension obviously capitalizes on every opportunity to charge money; the plastic (which is almost identical to that used in the Makerbot) as well as the support material is housed inside a case that slides into a slot on the printer. Though I don’t know the price of a case off the top of my head, I know that it works out to about $5 for every cubic inch of plastic. A 5lb reel of ABS plastic for the Makerbot costs $50 or $60 (depending on the color)  and will last you at LEAST a few months of printing regularly.

Do keep in mind that you are paying $30,000 for the ability to hit the ‘Print’ button and walk away. This is crucial in many work environments (because it eliminates the need for a dedicated staff of technicians, which some printing technologies require).

WHAT THE INDUSTRIAL DESIGN STUDENT THINKS

Speed wins out over quality most of the time when designing things. 0.35mm per layer means that you can see how an object feels in your hand; ultra fine detail is not always necessary. 46 minutes versus 2 hours and 40 minutes is a HUGE difference!

The Dimension would be clutch in the engineering field because of the tolerances necessary, but as far as designing goes… I’ll take my $29,250 and sacrifice a few fractions of a millimeter.

No offense to Dimension, though. You make nice printers.

The Makerbot Process

08/11/2009

I wanted to write up this post for two reasons; one, to explain a do-it-yourself 3d printing platform to those new/curious, and two, to provide a solid explanation for those interested in purchasing a makerbot (a pretty hefty investment for most). Forgive me if some of this is rudimentary… I wanted to paint as complete a picture as possible.

SO. The Makerbot is a fused deposition modeling (FDM) printer (follow the link for more information on the process). All you need to know right now is that it prints plastic in a layer-by-layer process.

The printing process can be broken down into two major steps: computer software pre-processing and actual physical printing. I will limit this explanation to the Makerbot specifically.

First, a 3d model is designed in pretty much any 3d modeling software program. When it is finished, the model has to be processed before the 3d printer will understand it. Since the Makerbot prints layer-by-layer, the model needs to get sliced up (among many other things). The software run by most Makerbot users is currently Skeinforge, which happens to be totally free and open-source.

Skeinforge contains all of the settings for the user’s particular Makerbot– from speed, layer thickness, and extrusion temperature down to the exact distance the plastic extruder turns on before laying down a path (in fractions of a millimeter). These settings can (and must) be edited to get the most out of the printer. The 3d model is chopped up into thin layers by Skeinforge, and the output is a set of instructions that a machine can understand and use to build the model. The instructions are in a language called GCode. Since Skeinforge knows the details of the particular Makerbot, it tailors the build instructions to get the most out of the printer. When the instructions are compiled it lets you view them layer by layer. It uses lines and arrows to show you precisely what the printer will be laying down. Here is an example window from a build I did:
skeinview

GCode is a simple language used by computers to control machinery. Most lines in a GCode program are literally just “move here” and then “move there” and then “move back here.” It controls other aspects of the machinery as well; a CNC router, for example, has a milling bit and the GCode might tell the bit how fast to spin. In the case of the Makerbot, the GCode controls the position of the build and the speed and temperature of the plastic extruder.

The prepared GCode is loaded into a program which will communicate with the Makerbot. The program Makerbotters use is called ReplicatorG. ReplicatorG specializes in reading GCode and translating it into Makerbot language. The Makerbot itself has its own program on it which specializes in turning ReplicatorG-Makerbot-language into physical movements.

Setting up the Makerbot to print is very easy. You have to put either foamcore or acrylic on top of the build platform, which snaps into place on the bot. Once ReplicatorG is open, you can jog the X, Y, and Z axes so that the print head is positioned a fraction of a millimeter above the center of the platform. When all is ready you hit the “Build” button!

So to give a brief overview, the process can be summed up like this: 3d modeling -> conversion to GCode (Skeinforge) -> printer setup (ReplicatorG) -> print!

From a designer’s point of view, the process is quick and virtually painless… When iterating and prototyping a design, the first thing you notice is how little time you actually spend designing. Having access to a machine like this is invaluable.

it prints!

08/07/2009

So the makerbot is finished and it works. I will be posting a bunch in the near future on how it works, etc.