These are important tips for designing your part in CAD that must be considered when designing a part to be printed with the DreamVendor
Max width (X): 3.125 inches, max depth (Y): 3.125 inches, max height (Z): 3.875 inches
Your part must fit within the build volume of the MakerBot: 3.125 inches in width and depth and 3.875” in height. If your part exceeds these dimensions, you will need to scale your part (using ReplicatorG) to fit within these constraints, else you will damage the MakerBot.
Minimum possible feature size: 0.80mm, minimum recommended feature size: 1.0mm
Your part should not have any features thinner or smaller than 0.80 mm. This value is equal to twice the diameter of the 3D printers' nozzles and is therefore the minimum size the MakerBot can print. Generally, it is best to keep features larger than 1mm since 1mm features are shells and tend to be very weak.
.STL units are important and should be in millimeters
Pay attention to your part’s dimensional units. ReplicatorG assumes that your .STL was exported in millimeters. Keep in mind that .STL units do not relate to the units you designed the part in; you can design a part in inches, then export the file in millimeters and ReplicatorG interpret it correctly. Inventor defaults to exporting in centimeters and must be changed to millimeters with the “Options” button available during .STL export before you click “Save”. If you do use Inventor to export the .STL in centimeters, then you can also scale the file in ReplicatorG by a factor of 10. Solidworks has similar options.
Include additional clearances
Design additional clearance for sections of your part that will interface with other parts. The MakerBot errs on the side of adding extra material rather than too little material. This means that external features (pegs) will be slightly larger than in the CAD model and internal features (holes) will be slightly smaller than in the CAD model.
These are tips for orienting, placing and adjusting settings for your part before you generate GCode in ReplicatorG that you should keep in mind to improve the quality/functionality of your part. Most parts will not be able to apply every design rule simultaneously, so compromises will need to be made. It is most effective to keep these rules in mind when originally designing the part.
In general, the rate-limiting step in 3D printing is adjusting the z-position of the part. As such, you want to minimize the height of your build. To do so, orient that part such that its largest dimension is in the XY plane. You can rotate the model with the commands under the “rotate” tab located on the right side of the ReplicatorG window.
Place delicate/intricate features so that each layer is drawn on the XY plane; beware of bottom features
To protect delicate features and/or critical surfaces, rotate your part such that these surfaces are facing upward. The bottom surface of your part will often have the poorest quality as it will be in contact with support structure and the raft. Removing these will materials may lead to flaws on the bottom surface and it may be difficult to remove these materials if the bottom surface is intricate.
Place curves so that each layer is drawn on the XY plane
Curves are best reproduced in the XY plane. If there are any important curved surfaces, such as a cylinder, the curves will be most accurately reproduced if the cylinder is upright rather than lying on its side. Curves in the XZ or YZ planes will have a stair step effect because of the layer-by-layer process the machine uses to create objects which approximates the curve.
Avoid tall, thin features; they will likely fall
Avoid orienting high-aspect ratio structures (i.e., long, thin ribs) vertically. These may fall over during the build due to the lateral force exerted on the part by the moving nozzle. It is best to lay such structures on their side.
Avoid printing a part that will need to undergo tensile forces along the Z-axis
If part strength is important, be sure to align the part such that applied tensile forces are aligned with the part’s horizontal placement (along the XY plane). Parts are weakest in the Z-direction as layers will delaminate when tensile forces are applied.
Always “Center” and “Put on platform” before generating GCode
After you load your model, it is always good to center the model and to ensure the bottom surface lines up with the platform. Do this by hitting the “center” and “put on platform” buttons under the “move” tab on the right of ReplicatorG. If you fail to do this, the MakerBot may attempt to start the build at a height lower than the build platform, which causes the extruder nozzle to nosedive into the build platform, severely damaging the MakerBot.
Always use a raft and full support
When setting up the build, always use a raft and full support. These options will appear after you click the “Generate GCode” button. Also verify that the “Print-O-Matic” and “Automatically generate when building.” boxes are NOT checked.
These tips can help solve printing issues or just improving the appearance of the print.
Cleaning up the print
After printing, the part will be attached to a raft that helps it adhere to the platform surface. To easily remove this raft, wait until the part is fully cooled and then pull off the raft in the direction of the largest ribs (the very first layer). To remove any support structure, again wait until the part is cool and then carefully remove the structures by hand or with a knife.
Sometimes rotating a part can solve print issues
If the part became offset during the print (similar to a splicing effect) along the XY plane then the problem may be solved by rotating the part about the Z-axis 90°, if possible. The orientation of certain features can sometimes cause the GCode Generator to generate a toolpath glitch during the part.
CAD File Error-checking with netfabb Studio
If your part did not print properly then one possible cause is that the .STL file used to generate the GCode for your part contained errors. To check this, please download the netfabb Studio Basic program from our downloads page and proceed through the following instructions.
1. Open the downloaded netfabb .zip file, extract the contents, then run the .exe file to install netfabb Studio Basic with the default settings.
2. Open netfabb Studio
3. Register the program (for free), or select “Later”
4. Go to Project > Open and select your .STL file
5. If the .STL file image is colored green, this indicates that your part is error free and not in need of repair.
6. If it is not green, click on the part to select it
7. If it is still not green, this indicates that there is an error in your .STL file (e.g., there are "holes" in your part, there is a bad surface, etc.). Go to the menu bar: “Repair -> Automatic Repair -> execute default repair” This will repair most common errors in the .STL file conversion process. If your part is not repaired (i.e., not displayed as green), then you might need to revisit your original CAD model and ensure that your part is completely solid (i.e., "water tight").
8. Go to "Part > Export Part > As .STL" to resave the repaired file (if repairs were needed). Then proceed through regenerating the GCode in ReplicatorG. Be sure to use the repaired file for printing and not the original version!