Use SVG Files to Mill Basic Parts Without Learning CAD and CAM

2018-09-25 | By Bantam Tools

License: See Original Project

Courtesy of Bantam Tools

Using SVG files to create 2D parts is fun and easy, plus it's really accessible for those new to milling, especially students in K-12 classrooms, hobbyists, and folks in makerspaces. Conveniently, the versatile, reliable, and easy-to-use Bantam Tools Desktop PCB Milling Machine supports importing SVG files like a champ. Here's a guide to the Bantam Tools Desktop Milling Machine Software's SVG workflow. We give you the basics and then explain advanced SVG setting and share tips for exporting SVG files from popular design software. Before you know it, you'll be milling your own custom designs with ease.

Also, be sure to check out our full Engraving Dog Tags tutorial for a complete step-by-step walkthrough.

What's an SVG file?

Scalable vector graphics (.svg) is a common vector image file format. Unlike raster image files (like .jpg, .gif, and .png) that store images in grids of colored pixels, SVG files store image information as lines and shapes. As such, they can be scaled to any size and still look perfectly sharp, unlike raster images, which may look fuzzy and pixelated when scaled.

More importantly, because SVG files store shapes instead of pixels, the software can turn the shapes into toolpaths, which you can then mill on the Bantam Tools Desktop PCB Milling Machine.

Why is this useful?

Simple vector drawings like SVG files are a great starting point for learning how to mill basic parts on the milling machine without learning CAD and CAM. Bantam Tools Desktop Milling Machine Software's SVG file support is useful for milling two-dimensional shapes for jewelry, stencils, and other design elements, milling multi-level shapes for 2.5D projects like chocolate molds, and making simple mechanical parts.

Many common graphic design and CAD programs can edit and save SVG files. These programs are often easy to learn, and many are available for free or at a low cost. Some of our favorite programs for SVG editing are Inkscape, Adobe Illustrator, and Sketch. There are also many free SVG files available on the web.

How the Software Converts SVG Files to Toolpaths

By themselves, SVG files are just 2D drawings, so the software needs to do some work before they're ready to mill. First, the software follows a simple rule to determine where to mill: any object in an SVG file with a border or fill will be milled. Then, the software combines the resulting shape with the tools you've selected, as well as the scaling, placement, and any advanced settings. Finally, it calculates the toolpaths that the milling machine will follow. Because SVG files require a bit of configuration, you'll want to spend some time to learn the software's settings. Read on for all the details.

Create Your SVG File

Start by downloading an SVG file from the web or designing the file in your design software. In order to make an SVG file that the software can use, you may first need to do a small amount of formatting in the design software.

The software looks at lines and filled areas to determine the inside and the outside of a shape. The software will mill within fills by default. The software will recognize fills of any color, including white. Make sure to check that empty areas are filled or made transparent the way you want them. Sometimes it can be helpful to set the background color in your design software to something other than white to clarify which areas are transparent and which are filled.

It will render in the software like this:

This gear has a border on the outside, but the inside of the gear is transparent.

Here's how it loads in the software:

Note: The red lines in both screenshots are Unmillable Area Warnings indicating regions where the milling tools won't be able to reach. In the case of the second image, the warning is shown because the border of the shape is too thin to be milled with the selected tools.

Another important thing to think about as you're creating your SVG is stroke (line) thickness. Since you'll be milling a physical object, using a stroke thickness that corresponds to the width of the tool you want to use is important. If the stroke thickness of your lines or borders are thinner than the diameter of your tool, the software will not be able to mill those lines.

In Inkscape, for example, go to Object > Fill and Stroke, and select the Stroke Paint tag. Make sure the Stroke Paint is set to Flat. Then, go to the next tab, Stroke Style, and set the width of your stroke to slightly wider (say, 0.001'‘) than the diameter of the tool you want to use. In the case of an engraving bit, the default stroke width works fine, but produces fine lines. If you'd like the lines to be thicker, set your stroke width accordingly. This is a nice opportunity to experiment with different tools to get the results you'd like.

Finally, if your design contains text, you'll want to make sure to convert the text to paths. This conversion means that the text in your design will be converted to shapes that the software can open. In general, text is a reference to a font and is not a path that the software can follow. Graphics tools usually have an easy way to convert text to paths; for example, in Inkscape, it's Path > Object to Path or Path > Stroke to Path. In Illustrator, you can convert text to outlines when you're saving the SVG file.

Once your design is ready, save it as an SVG file.

Basic SVG File Setup in the Software

To open an SVG file in the software, click File > Open or the Open Files button. When the file loads, a new plan configuration panel will appear on the right side of the software window. In the configuration panel, you'll see a number of options:

Placement

Expand the Placement panel and modify the X, Y, and Z values to manually shift your SVG within or on your material. 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.

Parts to Mill

The software offers two different toolpath options when milling SVG files:

If Engraving is selected, the software will mill filled areas and strokes to the depth specified in the Engraving Depth setting (see below).
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.

Engraving Depth

If Engraving is selected (see above), this value is the depth to which the SVG will be milled. This setting doesn't affect Cutout toolpaths. The shallowest engraving depth that can be set is 0.001" (0.025 mm).

Milling Tools

Select up to three tools to be used when milling the SVG file. With multiple tools selected, 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.

Milling SVG files will use the speeds and feeds defined for the tool. If you're milling a material other than FR-1, you'll need to define custom feeds and speeds for best results.

Advanced SVG File Setup in the Software

In addition to the settings above, clicking Advanced will display a few additional options:

Invert

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.

Cutout Placement

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 where exactly the Cutout toolpath will be milled. Cutout Placement has three settings (see illustration below):

Outside: The Cutout toolpath will mill outside the line that defines the of the outermost shape in your design. This is the default.
Center: The Cutout toolpath will mill on top of the line that defines the outermost shape in your design.
Inside: The Cutout toolpath will mill along the inside of the line that defines the outermost shape in your design.

In this diagram, the gray box represents the design. The three circles show where the tool would mill depending on the cutout placement setting:

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 when it gets imported.

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 your design within the SVG and import into the software without having to make any adjustments to your imported design before milling.

Tips and Tricks

The software makes it easy to adjust your files on the fly. You can adjust the SVG in your design program, and then click the Refresh button on the plan panel to update the software with your changes.

Refresh Button

In order to cut out shapes within shapes, use a filled shape and what's known as a Boolean operation in your graphics program to join the two shapes and remove fill where they overlap. For example, in Inkscape, create a filled shape with your desired cutout (here we used a filled gear with a circle in the middle with no fill). We then used the Path > Combine tool to make the gear one combined shape.

Notice that once FilledCombinedGearSVG is imported, we inverted it, then selected both "Engraving" and "Cutout" to the outline shape and the inside cutout to render, so it cuts the whole gear shape. The center of the gear will be engraved out, rather than cut as an outline.

If you wish to mill from a design in a .jpg or .png image, you'll need to convert it to a vector image first. To do this, use the image trace feature in your design software.

Tips for Specific Vector Graphics Programs

While every design software is different, we've collected some tips and tricks for exporting Bantam Tools Desktop Milling Machine Software-compatible SVG files from popular programs. If you need assistance with a specific file or are having trouble with another program, please contact us at support@bantamtools.com, and we'll be happy to help out!

Inkscape

Inkscape is a popular free vector graphics editor. It's open source and runs on Windows, Mac, and Linux operating systems. Inkscape uses SVG as its default file format, so Inkscape SVG files should open directly in the software.

Adobe Illustrator

Adobe Illustrator is a commercial vector graphics editor popular among professional designers. It's part of Adobe's Creative Cloud Suite and runs on Windows and Mac operating systems. It's easy to save Illustrator documents as SVG files. Follow these steps:

With your document open, click File > Save As.
In the Format drop-down box, select "SVG (svg)".
Give the file a name and click Save.
In the SVG Options window that appears, select the following options:

SVG Profiles: SVG 1.1
Type: Convert to outline

Click OK to save the file.

Sketch

Sketch is a popular vector-editing and design app for the Mac. From a Sketch document, it's simple to export individual items as SVG files. Follow these steps:

With your document open, click on the item, artboard, or items you'd like to export.
Expand the Export panel. If you don't already have export settings configured, it'll be labeled "Make Exportable."
In the Format drop-down box, select SVG. (If more than one set of export settings is shown, you can ignore or delete the additional rows.)
Click the Export button.
Give the file a name and click Save.

Have any questions? Don't hesitate to reach out at support@bantamtools.com. We're here to help! And if you mill some neat projects using SVG files, we'd love to see them! Send them our way or tag us on your social posts with #bantamtools.

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Use SVG Files to Mill Basic Parts Without Learning CAD and CAM

2018-09-25 | By Bantam Tools

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