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(For more resources related to this topic, see here.)

Function

The software starts by taking a .stl or .obj file along, with all our settings, and converts it into GCode. Think of the GCode like an instruction set to our printer, which includes where to move, how fast to move, whether or not to extrude material, extruder temperature, lower platform, and so on. The following screenshot shows an example of GCode produced by the ReplicatorG slicing engine Skeinforge at the start of a print:

Start of GCode

The slicing engine is what tells your printer what to make and exactly how to make it. The algorithm involved directly relates to print quality, and thus gets the most attention from developers. It’s at this stage we can see the tradeoff between software and hardware: maybe the printer has the capability to print with greater resolution but current software might only break the model down so far? Or perhaps it’s the opposite, where the software can break down the model finer than the hardware is capable of producing? It turns out this is a major factor in what separates personal and commercial printers, and even a $200 and $2,000 printer—precision.

More precision costs more money in both hardware and software development. The hardware must be able to handle the precision calculated in software, and where it cannot, and then software solutions must be implemented in circumvention. It’s these reasons why algorithms improve by leaps and bounds with every software update, and why newer released printers outperform their predecessors.

To make it easier on the microcontroller, in the printer the GCode is converted into the .s3g or .x3g code, which is essentially just optimized GCode. From here it is used to generate motor steps and direction pulses, which are sent to the motor controller and then to the motors. It’s at this stage we realize that the process of 3D printing is just a handful of motors moving in a set pattern combined with a heater to melt the plastic material. The magic of 3D printing happens behind the scenes inside the slicing algorithm in order to create those explicit patterns.

MakerWare

You may be thinking, “This software is made by MakerBot and is intended to use with MakerBot printers that sounds like the best option”; well, you are mostly correct. MakerWare is currently still in beta, but is released for general use. The software is always in revision, and has made major improvements in a very short period time.

Logically, it would make sense to use the software explicitly designed for use with your printer, but up until MakerWare v2.2, the ReplicatorG software had been superior. With all the improvements made in MakerWare’s latest release v2.3.1, I would argue that the MakerWare software surpasses the ReplicatorG for use with a MakerBot 3D printer. This is one of the joys of being involved with MakerBot and the 3D printing environment- The products are always evolving and always improving. In a period of five years, MakerBot went from an idea to being acquired by Stratasys for $403 million. This speaks for how fast the industry is moving, and how fast the technology is advancing.

For those interested, visit http://www.makerbot.com/blog/category/makerbot-software-updates/ to see a detailed description (lots of pictures) of the improvements in each MakerWare update.

ReplicatorG

You might be wondering why we would even consider the ReplicatorG software. The simple answer is with the release of MakerWare v2.3.1 and the purchase of a MakerBot, we wouldn’t. The ReplicatorG software undoubtedly served as a building block for many of the features in MakerWare, and was the leading software for personal/hobbyist 3D printing for many years. The MakerWare software will meet all the needs for our designs, but if you are interested in learning more about open source 3D printing, I would suggest checking out this software.

We have chosen to use MakerWare (v2.3.1) for the examples in the article, as this software is most tailored to our needs. Visit http://www.makerbot.com/makerware/ to download your own beta copy.

MakerWare options and settings

The first step after opening MakerWare is to add a model to the build platform by clicking on the Add button. Let’s add Mr Jaws (by navigating to File | Examples | Mr_Jaws.stl) to our build platform. Once the model has been added, it needs to be selected by left-clicking it. This should highlight the model in yellow as shown in the following screenshot:

Mr Jaws is selected

Notice the buttons on the left-hand side, which are intuitively labeled Look, Move, Turn, and Scale. Clicking these buttons allows us to orient our model. Let’s move Mr Jaws to the top-right corner, spin him 180 degrees in the Z-plane, and scale him to 110 percent. The result can be seen in the following screenshot:

Mr Jaws is moved, rotated, and scaled

Once we are satisfied with the orientation, click on Make located at the top of the screen to open up the print options.

Ensure that your model is sitting on the platform by hitting the On Platform button (by navigating to Move | On Platform); else, you will print many layers of supporting material before finally reaching your part (if your part is floating above the platform), or you will damage your nozzle and platform (if your part is floating below the platform).

Print options

The default options are fairly straightforward, and will modify all the advanced options automatically. We will use the following table to describe each of the default options:

Option

Description

I want to:

This gives the option where to save the file or to send it directly to your MakerBot, if its plugged in by USB.

Export For:

This helps you select your MakerBot.

Material:

This helps you select the PLA that is recommended.

Resolution:

MakerWare has 3 quick set profiles which are Low, Standard, and High. These profiles reference the desired print resolution and directly control the Z-layer height. Remember that higher resolution requires longer print times.

Raft:

A raft is a surface slightly larger than the part which is built between the bottom of the part and the build platform. Rafts help reduce warping by having more surface area adhered to the build platform. Once a part has been printed, the raft is easily broken away. We will always be using rafts to help reduce errors in our models brought about by poor adhesion and warping.

Supports:

Supports are used to support sharp overhangs. We will always have the support box checked, as the software will determine when and where to use supports and will not print them if they are not needed. This ensures we will never run into errors from floating layers.

By evaluating the advanced options, we are able to observe the result from changing the default options and gain a little more insight into settings that influence our print. The following is a table describing these advanced options:

Advanced options

Description

Profile:

Profiles handle all the settings of a print. Profiles are a grouping of preselected options. By default, there are 4 profiles: Low, Standard, and High but you can create your own custom profiles.

Slicer:

The options are between MakerBot Slicer and Skeinforge slicer, and can be changed by creating a new profile. It is recommended that we use the MakerBot slicing engine because it has been optimized for use with MakerBot printers as mentioned earlier.

Quality | Infill:

Infill is the density of the object measured by a percentage. By default, the amount of infill is low (less than 20 percent) to save both time and material. The slicing engine will automatically create a pattern for the infill (most commonly honeycomb).

Quality | Number of Shells:

The number of shells will represent the perimeter thickness of your model. One shell corresponds to one layer (which is approximately 0.4 mm the width of the nozzle opening in XY, and will depend on the next property, Quality | Layer Height, for the Z thickness). All the profiles default to two shells. If strength is a concern for your model, it is suggested to increase the number of shells rather than infill. Adding shells will also increase print times.

Quality | Layer Height:

Layer height is the height of each individual cross-sectional layer. MakerBot Replicator 2 is capable of heights as low as 0.1 mm. This corresponds to 10 layers for a model of 1 mm in height. Lowering the height will increase print times.

Temperature | Extruders:

The temperature for the extruder by default sets to 230 C. Greater temperatures can improve adhesion but may require slower printing. Every individual has their own “magic number” for temperature, which they feel works best but its best to say within +/- 10 C range of the default. For our models we will be using the default 230 C.

Temperature | Build Plate

A heated build plate is only required if we are printing in ABS, in order to reduce warping. The default is 110 C, and slightly higher temperatures will improve adhesion but also risk greater warping upon cooling.

Speed | Speed while Extruding:

Extruder speed and temperature are directly linked to one another; the speed needs to be slow enough to allow the layer currently being extruded to bond with the layer underneath. Greater speeds have the potential to reduce accuracy but will decrease print time. Be extremely cautious while modifying this parameter, as it takes experience to match increased speed and temperatures properly.

Speed | Speed while Travelling:

When not extruding, the extruder head is capable of faster travel. It is recommended to leave this parameter as set.

Preview before printing

This is an amazing tool and you should check it off every time. Preview before printing allows you to see an approximate material use and time estimate to print the given model.

Summary

This article thus explained some basic steps to build a 3D model in MakerBot and to get it ready for 3D printing.

Resources for Article:

Further resources on this subject:

Packt

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