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Parent Category: Big Blue Saw Blog
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Created: Wednesday, 11 January 2017 20:10
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Written by Julie Simancek
You may have noticed a new writing style here on our blog, so let me introduce myself. My name is Julie Simancek and I am the customer advocate for Big Blue Saw. I'm also a jeweler who specializes in non-traditional materials and a combat robot enthusiast who was a member of the Chaos Corps team from Battlebots Season 2. On a fairly regular basis I can be found fighting 1lb and 30lb robots at smaller competitions in the south for the team Near Chaos Robotics.
As the customer advocate I wear several hats throughout the day, but one of biggest parts of my day is answering emails about design files that won't upload to the website correctly. Sometimes those files have specific issues that I help customers out with. But recently we have seen an increase in file issues and questions that stem from a lack of easily searchable information on how file types and extensions impact making real objects with the waterjet and laser cutter.
So lets talk about file types and extensions so your next waterjet cut part can sail through the quoting process and get cut faster.
There are two types of images in common use, (1) vector and (2) bitmap/raster. I am going to show you both kinds of images and how to work with them to get to cleanly cut pretty waterjet cut and laser cut parts. Knowing what type of image you have and how it will be used can make a big difference between getting the part you need and getting a part that won’t function the way it is supposed to.
Bitmap and raster images are usually good for showing me what you want the finished part or project to look like. For example, if I were cutting out snowflake ornaments for a specific Christmas tree design, a JPEG image of the tree with the different snowflakes on it gives me a great idea about how they should function, and a rough idea of scale.
For the actual snowflakes themselves through, you would want me to use a vector based file like a DXF to cut them out with. Vector images are good for keeping sizes locked down and curves smooth.
Images that show me what your project should look like when completed:
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JPEGs
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Bitmaps
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Hand Drawn Images
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Assemblies from CAD programs
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PNGs (with embedded bitmaps)
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Bitmaps
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Anything you’ve scanned on a scanner
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Cell phone pics
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PDFs with bitmap images embedded or flattened PDFs.
Images that I can use or convert to cut parts with:
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DXF
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DWG
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EPS
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SVG
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AI
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STP
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STEP
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SLDPRT
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PDFs with vector images embedded
Raster images like bitmaps are made up of lots of tiny pixels. Think of them like the dots in a newspaper image or like a printed photograph. If you take a raster image and scale it up dramatically it becomes pixelated. The software that is scaling it up doesn’t have the information to fill in the details in between those dots to keep the image crisp and clean.
This is just like taking a photograph and photocopying every copy of a copy multiple times while playing with the scaling tool on the photocopier. Eventually the image starts to break down.
Ideally you will have an image that is a vector image. The reason why is that vector images keep all of the mathematical formulae that tells the software where all of the curves and lines are in the file. Every time you open a vector file, the software you are opening it with recalculates all of that math. Having the locations of the lines in your file locked in by that math means that different software programs can read and convert that file to different file extensions with minimal to no loss of resolution between programs. So you don’t have to use the same design software that I’m using to get your part to show up correctly.
Vector images also have one really convenient feature, they can be scaled up or down to any size without losing resolution. Since all of your drawing's features are described in mathematical terms, any software you use to change the the size will recalculate where to place the curves and how large they need to be every time you alter your file. The downside is that vector images can get really really large, particularly when they contain a lot of detail.
So on to an example. Let us say that you are new to CAD files, but you really want to make your niece a puzzle of the USA where all the states fit together. Learning CAD software is going slow and if you were to slog through drawing every state your niece would be 18 by the time you finished not 8. Not to fear, the internet can help you get the file you need. Just search “Map of the USA black and white vector file.”
Thanks to the internet search algorithms, the first 3 options look like solid leads on getting the state shapes you need.
Now you know that you don’t want state outlines that are recognisable, but not too detailed. Tiny details on parts smaller than 3” may be unnoticable on the part, but will run up cutting costs and may make tiny peninsulas on the pieces that are easy to break off. You also want an image that shows the states slightly separated. Our quoting and cutting software isn’t setup to do same line cutting, so you’ll want to make sure there is some space between the parts. Looks like the second search result had exactly what we need.
This website offers offers some great options for the file format. If you are going to alter Alaska, Hawaii, Delaware, and Maryland in Inkscape so they cut well, you want to download this file as an AI. Then you can open it in Inkscape, make your alterations, and then Save As a DXF. You may need to open it in LibreCAD and clean up some extra lines to get it to load, but luckily both Inkscape and LibreCAD are free. (Read our article on designing for Big Blue Saw using Inkscape, then take a look at a more advanced example.)
If you see exactly what you want in the file off the internet, and you can download it as a DXF or DWG format. Do that! DXFs are what the software and machines here read. So when you upload a DWG or a PNG file to our site, you can be assured that a program in the background is converting it to DXF for quoting, ordering, and cutting. Most of the time, that conversion goes smoothly, but sometimes parts get scaled wrong or endpoints become disconnected. Starting with a DXF can head some of those issues off at the pass.
So now you have your file, but learning Inkscape and altering it cut a great puzzle isn’t working out. Hey it happens. We do have a designer here that can alter your file to cut well that you can hire. Her fees for altering your file to a puzzle will be a lot lower than if you hired her to draw it up from scratch. Just send me your file and order particulars at info@bigbluesaw.com. I’ll get you a quote for her services and help you get to the ordering stage.
In the example above, I highlighted the EPS, PDF, and PNG formats all as viable ways to get the basic form of the puzzle downloaded. In my next articles I’m going to talk about those formats. They can be converted into DXF format for cutting, but there are some caveats to these kinds of files.
