3D Printing Concepts

SLICING

Slicing is the process of turning your 3D model into a toolpath for your 3D printer. We call it slicing because the first thing the slicing engine does is cut your 3D model into thin horizontal layers. MakerBot uses a few different slicing engines in our software, and all of them let you change settings that affect the way they generate a toolpath for your model. If you’re having trouble getting your objects to come out the way you want them, the answer may be somewhere in these settings. Here’s an overview of some common concepts in 3D printing and what your options are.

SLICERS

MakerBot Slicer. The MakerBot Slicer is MakerBot’s own slicing engine. It’s super fast, and we’re adding improvements all the time. MakerBot Slicer is the slicer used for the three default profiles in MakerWare, and it’s also available in ReplicatorG 0037 and later.

Skeinforge. Skeinforge is an extremely customizable slicing engine that has given most of us our best prints but it’s also slow and has a steep learning curve. Skeinforge is the primary slicer in ReplicatorG.

Slic3r. Slic3r is a slicing engine created by the open source community. It’s never been optimized for use with MakerBots, but we’ve made it available for experimentation in the most recent versions of ReplicatorG.

LAYER HEIGHT

Layer height is basically equivalent to vertical resolution in 3D printed objects. It’s like pixels in a digital image, or thread count in sheets. The thinner the layer, the more layers per millimeter and the smoother the texture of your built object. The only problem with small layers is that they make you build take longer — for every layer you print at a layer height of .3 mm, you have to print three layers, each one taking just as much time, at a layer height of .1 mm.

The standard nozzle size on recent MakerBots is .4 mm. That’s about the diameter of the plastic noodle that emerges from your extruder, and, theoretically, .4 mm is the highest layer height you can print with this nozzle. But at that layer height, each extruded noodle of plastic would just barely touch the top of the previous layer, making for a weak object. We generally don’t try to build things with layer heights higher than .34 mm with a .4 mm nozzle.

The other end of the layer height spectrum is also complicated. By making adjustments to slicing settings, some MakerBot users have achieved layer heights well under .1 mm, but fairly low layer heights should be achievable out of the box. Start with a .15 mm layer height on The Replicator or Replicator 2X, or .1 mm on Replicator 2 and work your way down from there.

BUILD SPEED

Build speed is a combination of a couple of different things: The feed rate is the speed at which your extruder is moving. The flow rate is the rate at which plastic is extruding. With stepper motor extruders — a category that includes all MakerBot extruders since the MK6 Stepstruder — it’s generally best to set these both to the same speed, so when you set your Feedrate in ReplicatorG or your Speed While Extruding in MakerWare, you are editing both of those rates.

The tradeoff with build speed is between fast build times and high object quality. Very fast build times can cause rough textures and breaks in the extruded noodle of plastic.

TEMPERATURE

Extrusion temperature is the temperature the extruder heats to during your build. It depends on a few other variables, mainly the properties of the plastic filament and your build speed.

Different plastics melt at different temperatures — and in different ways. PLA makes a solid to liquid transition, like that of ice to water, and melts at extrusion temperatures from about 180C up. It also gets shinier and, with translucent colors, clearer when it’s extruded at higher temperatures. ABS makes a more gradual transition, and softens enough to be extruded somewhere around 215C.

Higher build speeds require higher extrusion temperatures. That’s because our plastics take time to melt, as well as high temperatures. The faster the plastic is being pulled through the extruder, the higher the extrusion temperature needs to be to melt it quickly enough. We use a temperature of 220C for ABS and PLA at speeds of 40 mm/s and lower, and 230C at speeds up to about 100 mm/s. These temperatures are optimized for use with both kinds of plastic, but PLA can often extrude at much lower temperatures.

You can also adjust your build plate temperature if you’re using a bot with a heated build plate. ABS really needs to be printed on a heated surface, and should stick well to Kapton tape over heated aluminum between temperatures of 100C and 120C. PLA sticks to non-heated surfaces, but larger PLA objects print well on plates heated to between 40C and 60C.

SHELLS AND INFILL

Each layer of a given object is going to be divided into two parts: shells and infill. The shells, also known as perimeters, are extruded outlines defining the shape of the layer. Extra shells strengthen objects. Infill is what happens in the space left over. It’s usually extruded in some kind of pattern — the MakerBot Slicer and Skeinforge both use a hexagonal pattern for infill by default. The main setting you’re dealing with here, though, is infill percentage. More infill will make an object stronger. Less will make it lighter and quicker to build. Before you build something, think about how much infill it will actually need. Objects for display often won’t need more than 10% infill, while even objects that are going to see hard use rarely need more than 80% infill. Not using more infill than necessary will help you save time and plastic.

Source: http://www.makerbot.com/support/guides/design/

Dual Extrusion for Objects

  • Extruder settings1.1
  • Object Information menu1.2

Setting things to build using two extruders is super simple in MakerWare. All you have to do is place your STLs or OBJs in the configuration in which you want them to build, and assign each one to the extruder you want to build it.

You might want to start by setting colors for your two extruders. Open the Edit menu at the top of the screen and choose Settings. The Settings menu will let you choose a color to represent each extruder. 1.1

Click on the drop-down menu for an extruder to see what colors are available. You can choose colors just to help you differentiate between objects in the MakerWare window, or you can match the extruder colors to the actual filament you will be building things with.

To assign an object to an extruder, click on it to select it. Then click the Object Information button at the lower left of the MakerWare screen or use the O key to open the Object Information menu. If you don’t see the Object Information button, check the MakerBots menu at the top of your screen; the button will not appear unless a bot with dual extruders is selected under Type of MakerBot.

Use the drop-down in the Object Information menu to select which extruder you want to build the selected object. 1.2

Once items on the plate are assigned to separate extruders, you will see a message warning you that the Thing you’re printing uses dual extrusion. If you get this message when building on a bot with a single extruder, you will need to convert your plate to print on a single extruder before Making the file. When every individual piece on the plate has been assigned to the extruder you want it to build from, click the Make It button.

DUAL EXTRUSION SLICING OPTIONS

  • Make dialog for dual extrusion2.1

When you open the Make dialog, you will see a few special options for dealing with dual extrusion prints. 1.3 First, choose which material is loaded into each extruder. Different materials will require different settings.

Next, choose whether you want your object to print with rafts or supports. With dual extrusion, you have more raft and support options than just turning them on and off. Use the Raft and Support drop-down boxes to choose from these options:

  • Choose Off to turn off the raft or supports.
  • Choose Left Extruder or Right Extruder to have the raft or supports printed only using the left or right extruder.
  • Choose Color-Matched to have the materials of your rafts and supports determined automatically. If you are printing a single-material object, the raft and supports will automatically be printed with the same extruder. If you are printing a dual material object, the raft and supports will be built from both materials so that each portion of your object will only touch raft or support structures of the same color.

Choose a profile and edit the other settings as you normally would. Then Make or Export your file. Your two extruders will work together to build your object.

DUAL EXTRUSION EXAMPLES

  • Dual color print with overhangs3.1
  • Dual color print with no overhangs3.2
  • Single color print with no overhangs3.3

Which dual extrusion settings you use will depend on what you are printing. Here are a few examples of how you might optimize your raft and support settings for different kinds of prints.

  • A dual color print with overhangs.Use the Object information menu to assign each object on the build plate to the correct extruder. When each object on the plate is assigned to the extruder you want it to be printed by, click the Make button.

    Set both Raft and Supports to Color-Match. Then make your other settings changes and print or export your file. MakerWare will automatically arrange your raft and support structures so that any given part of your object will only touch raft or supports of the same color. 3.1

  • A dual color print with no overhangs.Use the Object information menu to assign each object on the build plate to the correct extruder. When each object on the plate is assigned to the extruder you want it to be printed by, click the Make button.

    Set Raft to Color-Match and Supports to Off. Then make your other settings changes and print or export your file. MakerWare will automatically arrange your raft so that any given part of your object will only touch raft of the same color. 3.2

  • A single color print.Use the Object Information menu to assign the object on the build plate to whichever extruder you like. Then click the Make Button.

    Set Raft to Color-Match. If your object does not have overhangs, set Supports to Off. If it does, set Supports to Color-Match.Then make your other settings changes and print or export your file. MakerWare will automatically print your raft and, if you’re using them, your support structures in the same material as your object. 3.3.

Source: http://www.makerbot.com/support/makerware/documentation/dual/

Rectangular Prisms gone wild.

20140219_162317

 

What could be mistaken as a fossil or a dog bone depending on if the glass if half full or half empty.

The shape that originally started this model off was rectangular prisms believe it or not. Developed through Autodesk Maya with simple commands such as smooth geometry and bridging between faces has created this organic form.

Material: ABS

Time: 60 mins