3D Printed Cannon on Thingiverse. Source: WhiteClouds
3D Printed Cannon on Thingiverse. Source: WhiteClouds

At some point, you’ll want to use your MakerBot Replicator 2 to print an object with multiple parts or multiple objects at the same time. This is possible to do and can shorten build times. However, there are some things you should take into consideration when printing multiple items at one time.

We printed a desktop cannon with multiple parts that are different shapes. You can find the 3D printable cannon on Thingiverse.com. When you download this project, it comes with all of the parts in one file, and each part as separate files.

We originally added the file with all of the parts to MakerWare and tried to print the parts at one time. There are some advantages and disadvantages to doing this. The advantages are the parts are well organized on the build platform and, in theory; everything should print in one print making it faster and easier.

However, there are some significant disadvantages to printing multiple things at one time—especially things that vary in size and shape. If one part fails, it can impact the other parts and you may lose all of the parts instead of 1 or 2 parts. Additionally, some parts may print better on a raft, while other parts don’t require a raft. You don’t have the option to print some pieces on a raft and some pieces without a raft in a single print.      

As we printed the cannon on the MakerBot 3D printer, one of the cannon ball halves and the plunger knob separated from the build plate during the print. The MakerBot continued to print as if the parts were still there creating tangles of filament. This ultimately resulted in canceling the build and wasting a lot of time.

We ended up grouping the parts and doing 3 separate prints. We grouped the parts based on similarity, whether or not the parts required a raft, and how the parts were oriented on the build plate.  For example, we used rafts on the cannon barrel and the plunger and rotated the cannon ball halves so the openings were down. We had much better results by grouping and printing similar parts versus printing everything in one print.

The only part we were unable to print was the plunger holder. We couldn’t get it to stick to the build plate, even with a raft. We altered the design of the plunger holder and made it square in order to print the part successfully. We also reprinted the plunger with a UV-cured resin 3D printer. The original plunger and spring printed successfully, but the PLA material was brittle and didn’t flex like we hoped it would for the spring.

In the end, the desktop cannon successfully shot a cannonball, but don’t expect to shoot your coworkers unless they sit within 2 or 3 feet of you. We liked the looks of the cannon, but it still needs some design work to make it function well.

Nevertheless, we learned some important lessons on 3D printing projects with multiple parts and hope these tips help you as well.