The Bantam Tools Desktop Milling Machine Software’s SVG (scalable vector graphic) file support is useful for milling two-dimensional or 2.5D shapes. It’s also great for quickly adding engravings to a project. Whether you’re in the early stages of prototyping or still learning how to program CAM, using SVGs is a great way to get started on your Bantam Tools Desktop CNC Milling Machine.
The Bantam Tools software can interpret SVG files in two ways: basic and advanced SVG handling. Basic SVG handling reads fills as engravings and strokes as cutouts. Advanced SVG handling allows you to do multiple cutout operations in one file using color coding. The Bantam Tools software combines the resulting shape with the tools you’ve selected, as well as the scaling, placement, and any other settings you specify. It then calculates the toolpaths that the Desktop CNC Milling Machine will follow.
Note: Both the basic and advanced SVG support are intended for closed paths. Any paths in your design with unjoined ends will be joined by our software as part of its pre-processing. Check to make sure all paths are joined as intended before importing the design into the software.
To help you create SVGs in your preferred design software, we’ve put together an SVG Quick Guide that you can download and print.
We begin by outlining one easy way to create an SVG, and then we dive into basic and advanced SVG handling in the Bantam Tools software. If you already know how to create an SVG, feel free to skip this next section.
Designing Your SVG
There are a couple of ways to create SVG designs:
- Create them from scratch in a design program. Some of our favorite programs are Inkscape, Adobe Illustrator, and Sketch.
- Save an image or clip art and format it as an SVG. Simple, black-and-white images work best.
In this support guide, we’ll focus on creating your designs from scratch in Inkscape.
Step 1: Lay out your design in Inkscape.
Download Inkscape and open the program. A new document will automatically be created. When you save this document, Inkscape’s default is to save it as an SVG file, which is great since this is the file type you want.
Before you start designing, manually set your canvas dimensions:
- Go to File > Document Properties.
- In the Custom Size window, change the units to inches (in).
- Set the width to the dimensions of your choosing.
- Save your file.
We like to set our dimensions according to the size of either our stock or part.
Once you’ve set your dimensions, then pull in your artwork. If you’re using a photo of a drawing or clipart:
- Bring your design into Inkscape by clicking File > Import.
- Use the Select and Transform tool to select, move, and scale objects, and use the Text Tool to add text.
Step 2: Turn your bitmap design into a vector path.
Next, you’ll need to turn your bitmap design into vector paths so that the Desktop CNC Milling Machine will be able to mill it. To convert photos of drawings or clipart into paths, click on the image, then select Path > Trace Bitmap.
In the pop-up window, check the box next to Live Preview and adjust the Threshold settings until the design contains the level of detail you’d like. Click OK and close the window to continue designing.
Using the Edit Paths By Nodes tool, click on the vector path to confirm it’s now a collection of vector paths. You should see lots of little gray squares that represent nodes of the vector. If you don’t see these little gray squares, something went wrong, and you should go back and try using the Trace Bitmap option again. The vector path you just created with the Trace Bitmap feature will now be in front of the original image. Delete the original image.
If your design contains text that you made in Inkscape––like we did for our Pocket Machinist Rule getting started project––you’ll need to convert it to vector paths, as well.
- Highlight the text.
- Click Text > Put on Path.
- Click Path > Object to Path.
Step 3: Fine-tune your layout.
Adjust the size and layout of your design until you like the way it looks. To adjust the size, click on the Select & Transform tool (the black arrow), then click on one of the arrows that surround the object you want to shrink or enlarge. If you hold down the Control key, the proportions will stay locked as you change the object’s size.
Basic SVG Workflow
Step 1: Create your SVG file.
By themselves, SVGs are just 2D drawings that the Bantam Tools software can interpret and generate toolpaths for. Any object in an SVG file with a border or fill will be machined. We refer to the inside shapes as fills and the outside shapes as strokes. The Bantam Tools software looks at strokes and fills to determine the inside and outside of shapes in a design.
If you’re designing more complex SVG designs, you should export separate files with each of your strokes. For example, when designing our 2.5D Delrin rooster puzzle, we exported three files: one for the body, another for the legs, and one for the eye.
Step 2: Set up your SVG file in the Bantam Tools software.
After creating and saving your SVG in the design program of your choice, connect the Desktop CNC Milling Machine to your computer and launch the Bantam Tools software. Navigate to the Initial Setup tab and import the SVG file you wish to mill. Follow these steps to set up your file.
1. Under Milling Tools, select up to three end mills to machine your SVG file. If the tools you’ve selected are too big to mill your design, the preview will display red markings. To fix this, either select smaller tooling or adjust your SVG design.
2. Under Toolpaths, select/deselect Engraving and Cutout accordingly.
a. If Engraving is selected, the software will mill filled areas and strokes to the depth specified in the Engraving Depth setting.
b. If Cutout is selected, the software will use the outermost shape as the outline for your project and mill all the way around it, all the way through the material, using the thickness (Z) that has been set for the material.
3. Specify the Engraving Depth you wish to machine at. We typically like to engrave at 0.003”, but this may vary depending on your design. This setting doesn't affect Cutout toolpaths. The shallowest engraving depth that can be set is 0.001” (0.025 mm).
In addition to the settings above, you also have the options to invert, select the cutout placement of your file, and indicate where you’d like your file to be scaled from.
For the Engraving toolpath, the Invert setting makes it possible to mill the unfilled SVG file instead of the filled areas. This can be useful for projects, like stamps, where the milled part should be the opposite of the design.
Invert has three options:
- No: The filled areas will be engraved. This is the default.
- Yes, within cutout: The unfilled areas inside of the outer cutout shape will be milled. The filled areas will not be milled.
- Yes, everywhere: All unfilled areas on the material will be milled, including areas outside the cutout. The filled areas will not be milled.
The Cutout toolpath will cut the outermost shape all the way through the entire thickness of your material. It can make a big difference if you cut on the inside of the line, the outside of the line, or right down the middle of the line. With this setting, you can choose exactly where the Cutout toolpath will be milled.
Cutout Placement has three settings:
- Outside: The toolpath will mill outside the line that defines the outermost shape in your design. This is the default.
- Center: The toolpath will mill on top of the line that defines the outermost shape in your design.
- Inside: The toolpath will mill along the inside of the line that defines the outermost shape in your design.
Step 3: Scale and place your plan.
After setting up your file, fixture your stock to the T-slot bed and locate your material. Then navigate to the Plan Placement tab. If you’d like to adjust your plan’s placement on the material, you can use a plan placement probing routine or opt to manually place your plan. You’ll also have the option to Rotate and Scale your plan.
Rotate: Change the value in the Rotate field to turn the SVG file to a different angle. The rotation field rotates the SVG file counterclockwise with respect to the center of the SVG.
Scale: Change the value in the Scale field to enlarge or shrink the SVG file relative to the material. If the file is larger than the material, the software will automatically shrink SVG files to fit within the size of your material.
Advanced SVG Workflow
With the subscription package of the Bantam Tools software, you’ll have access to color-coded SVG handling. This advanced feature enables you to create even more complex SVG designs and have more control over how the Bantam Tools software interprets strokes and fills, and in turn, mills your designs. Our software uses the colors red, green, and blue to interpret what cuts need to be machined.
- Red = Internal Cutout
- Green = External Cutout
- Blue = Engraving
Step 1: Color-code your SVG design.
Using the advanced SVG workflow will require a little bit more setup on the design end, but it will ultimately give you more control over your design. Color-code your SVG design, and when you’re finished, save your SVG file.
Step 2: Import and set up your file in the Bantam Tools software.
Hook up the Desktop CNC Milling Machine to your computer and launch the Bantam Tools software. Import your color-coded SVG file into the software and follow these steps to set up your file.
- In the Milling Tools dropdown menu, select the tools you plan to use. Click on the gear icon next to the tools you’ve selected to open the Tool Library if you want to enter custom speeds and feeds.
- Then, under Toolpaths, change your Engraving Depth. We typically set our depth to 0.003”, but this may vary depending on your design.
- Scroll down to the Advanced SVG dropdown menu. Select “Use Advanced SVG Handling”. This tells the Bantam Tools software to read the colors in our SVG and use them to determine how the Desktop CNC Milling Machine will mill the fills and strokes.
Additional Tips & Tricks
Utilize the Custom Tool Library
When working with SVGs, use the built-in Tool Library to customize feeds and speeds for your preferred tools, based on previous experiences and tool testing. To learn more about working with the Custom Tool Library and utilizing the Bantam Tools software’s 2.5D AutoCAM, refer to our dedicated guide.
A Note on Milling Tools
It’s also important to note that if you select multiple tools under File > Milling Tools, when it’s time to machine your design, the software will start with the smallest tool, milling details before milling with the larger tools. The software always uses the largest tool for the cutout, so this ordering reduces the number of tool changes required when using both the engraving and cutout toolpaths.
Stroke Sizing for Engraving
Another important design aspect to consider when working with either the basic or advanced SVG workflows is the size of your strokes. The width of your strokes will depend on the tooling you plan to use. We recommend setting your stroke width slightly wider (+0.001) than the diameter of your tool.
Note: In Illustrator, you can enter the stroke weight size in inches by replacing the “pt” suffix with “in”.
Consider Document Size and Scale
One important factor to consider when using SVG files is your document size. Sometimes called “page size” or “artboard size,” document size refers to the dimensions of the virtual canvas in the SVG file that contains your design. The “Scale from” setting in the software allows you to control whether the software takes the document size into consideration when placing and scaling your SVG file.
- Document contents: If you choose this option, the software will place the contents of the SVG file (the lines and shapes in the file) in the lower-left corner of the material. If the contents of the SVG file are larger than the material you have set in the software, the SVG will be scaled down to fit your material. The document size will be disregarded.
- Document size: The software will place the lower-left corner of the SVG document in the lower-left corner of the material. If your design is offset from the edge of your document, it will be offset from the edge of material in the software by the same amount. If the document size of your SVG is larger than the material you have set in the software, the entire document will be scaled down to fit.
Note: When the Document Size option is selected in the software, you can create SVG files that have the same dimensions as the material you want to mill your design into. When you match the document size of your SVG to the dimensions of your material, you can precisely locate