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Written by Super User

Parent Category: Big Blue Saw Blog

Created: 18 January 2019

FreeCAD is 3D modeling and design software. It is free to use, open source , and runs on Windows, macOS, and Linux. FreeCAD supports importing common 3D file formats like STEP, IGES, and STL.

The latest stable release is version 0.17, released in April of 2018. But FreeCAD's developers have made many advances since then. Pre-release downloads of version 0.18 sport numerous updates, including features to make creating and exporting 2D drawings much easier.

You can download the release and latest pre-release versions of FreeCAD on the project's GitHub website.

Using FreeCAD to view and export STEP files

Let's take a quick look at how to use FreeCAD with Big Blue Saw, starting from a design formatted as a STEP file. The steps shown below were produced with a pre-release version of 0.18, from January 2019.

Let's suppose we have the STEP file with the part pictured above, and want to produce a 2D outline for use with Big Blue Saw's online quoting and ordering system.

After starting FreeCAD, go to the File menu and pick Open. You should select the STEP file to import.

FreeCAD will then show you your STEP file and allow you to zoom, pan, or rotate the view of the part.

Next, we need to switch to FreeCAD's TechDraw workbench in order to create a drawing. Choose "TechDraw" from the drop-down list of workbenches.

You'll notice that the toolbar and menu change to show the features needed for creating drawings. Click the "Insert new default Page" button to create a blank drawing.

FreeCAD will show the new drawing.

 Expand the Model tree on the left and you'll see a sub-menu item called "Template".

Click on Body001, the object representing the STEP file design, in the Model tree.

 And click the "Insert View in Page" button. A 2D view of the design will appear in the drawing.

Now we're ready to create a 2D file. Click the "Export a page to a DXF file" button on the toolbar. You'll see a dialog box that lets you enter a filename and the save location.

The file is then ready to use with Big Blue Saw's online quoting and ordering system to turn the design into a real part.

 

Here's the finished part waterjet cut from carbon fiber.

Are you a FreeCAD user? Let us know!

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Written by Julie Simancek

Parent Category: Big Blue Saw Blog

Created: 11 January 2019

Custom waterjet cut 3 inch span wrench for BattleBots team Hypothermia

 

When I’m cutting a set of parts for one of my projects, I often look around the shop for tools or tooling that I can add to the order that would upgrade the shop just a tiny bit better to make it easier to work in. One of my favorite adds to the low taper cut list is custom wrenches. The reason being is that one more part usually doesn’t increase the cost of cutting or shipping too much, and having a designated wrench for changing the lathe tooling that lives with the rest of the lathe tools keeps my wrench set from roaming around the shop in a unorganized jumble.

So let's design a wrench! First we need to identify where the working surfaces are on the recipient of our wrench are. For a hex headed bolt, the working surfaces are the faces that I’ve highlighted in pink below:

Notice that the force lines don’t extend to the convex corners. The reason for that is that there is less material on the convex corners than there is on the centers of the flat faces. If your wrench grabs the corners during use and applies the force there, they won’t hold up to much force before they strip out.

So let’s mock up a crescent wrench to match the hex bolt.

As you can see, we are only applying force to 4 of the 6 faces and if we were to cut the green wrench as shown, it would have to cut perfectly and the hex head would have to be forged perfectly to fit together. Since we are all working within a tolerance range lets add some ease into the places where the faces are interacting to make these work in real life. For starters, we are going to scale our example hex head up by 0.005”-0.01” larger than the actual bolt head. That will allow the crescent to slip onto the bolt without aligning it at the perfect angle.

In the image above, the dotted orange hexagon is the 1” height of my bolt. The black hexagon is 0.01” larger than the bolt head size. That extra room will make it so that my wrench will slip on the hex bolt easier and allow for that bolt to have some variation in size from the perfect CAD model. This is particularly important because the available hardware out there sometimes shifts during stamping or is heat hardened, and all of those factors can affect the finished size of the bolts.

Next we need to address where the wrench is going to touch the corners of the bolt head. As mentioned before, putting pressure on those corners is a fast way to strip a bolt. I hate pulling stripped hardware, so I’m going to add radii to the cutout that will keep the wrench from touching my bolt head.

Those 1/16” circles should keep the corners from getting dinged up nicely. Now to merge them with the larger hexagon. It’s starting to look like a wrench, but I need to adjust the depth that the bolt head slides into the spanner. The corners of the wrench I’ve highlighted below could slip during use and cause stripped corners.

So lets move our bolt head and hole a bit to the right.

Now let's extend the top and bottom parallel faces outward using the line tool to create where the mouth of the wrench will be.

And merge.

Now I just need to cut the green working face shape out of the blue outer wrench shape.

And now it is ready for cutting on the low taper waterjet. Why the low taper waterjet and not the regular one? Because taper in the cut will affect the performance of the wrench and possibly lead to having to dress the working faces. Which would be really difficult for the two faces that are closest to the handle. The low taper waterjet will get you a cut that is as close to 90 degrees through the thickness of the material as possible, leaving much less cleanup. Learn more about taper and low taper waterjet cutting in our FAQ article.

Having a few extra tools and parts in your file library to add to an order to spread out the costs of setup and cutting makes per part prices lower and helps you expand shop tools without a huge investment. There are also a few tools in my shop where replacement parts are no longer available or hard to find, so having a wrench made out of brass or HDPE that will fail before I strip out a specialty setting screw is also handy.

Another view of the Hypothermia wrench

 

Happy cutting!

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Written by Simon Arthur

Parent Category: Big Blue Saw Blog

Created: 10 January 2019

When Dennis Boring wanted to add twin turbochargers to his custom motorcycle, he needed a mounting bracket that would be durable and look as good as the rest of the bike. Dennis turned to Big Blue Saw for help in creating it.

He began by creating a 3D CAD model of the upgrades.

Below is the turbo bracket isolated from the rest of the model.

This was then exported to a 2D DXF file for Big Blue Saw to use.

Dennis also tested the fit of the design on the actual motorcycle using plywood parts he cut on his own laser cutter.

Satisfied with the fit, he ordered the pieces to be waterjet cut from 0.135 inch thick stainless steel 316 using our online quoting system.

The  pieces were fit together and TIG welded in place before final installation.

Here's what Dennis had to say about Big Blue Saw:

The first step was to fabricate the turbo support bracket from the pieces I had waterjet cut at Big Blue Saw which you can go check out at http://www.bigbluesaw.com/ .
They have you upload your DXF file(s) to their website, pick the material used, the thickness, and any further processing or finishing and then provide a detailed quote for the work. Nest your parts tight and fill in all the space you can for the best pricing. The workmanship is beyond compare! I recommend them 100% for any waterjet process needs.

If you want to install your own custom twin turbos, or are just interested in finding out more, Dennis's website is The Original Flapper Adapter and his contact information is available there.

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Written by Simon Arthur

Parent Category: Big Blue Saw Blog

Created: 03 January 2019

2019 is the International Year of the Periodic Table, and Big Blue Saw is ready to serve you with all the right elements. Big Blue Saw is starting off the year with discounts on custom parts from 3 of our most popular stock materials, made from some amazing atoms. We have both aluminum 6061 and stainless steel 304 on sale during the month of January.

 

 Monday, January 7-Wednesday, January 9: Save on 0.5 inch (½")  thick aluminum 6061

  Monday, January 14-Wednesday, January 16: Save on 0.12 inch  thick stainless steel 304

  Monday, January 21-Wednesday, January 23: 0.16 inch aluminum 6061

 

All orders placed online for the sale materials during the sale period will automatically receive a quantity discount. That means that when you order as little as one part, you get the same price as if you had ordered 10.

Questions and Answers about Big Blue Saw's Sales During Robot Building Season

• What is on sale?
  Custom parts from your designs made using 3 different stock materials. Each stock material is on sale during a different week. See the list above for material specifications and sale times. 
  
  Low-taper is not on sale.
• How much will I save?
  Orders as small as 1 part will automatically receive the quantity 10 discounted price. The dollar amount depends on the design and quantity ordered. 
• How can I order with the sale price?
  Just upload your design to our online quoting and ordering system, and check out through the website shopping cart. You will automatically receive the discount price when placing your order. No need to use coupon codes or other tricks.
• I don't have a design. How can I make one?
  Use your favorite CAD or vector image software. If you don't have this kind of software, check out our list of free or low-cost alternatives. Also, be sure to  read about how to format your CAD files for use with Big Blue Saw. 
• I didn't hear about your sale until just now and don't have time to get my design ready. When is your next sale?
  Sign up for our mailing list to get early notifications about the next sale.
• I have special requirements for shipping, secondary machining, or rush processing my order. Can I still get the sale price?
  To get the sale price, orders must be placed through the website. So typically we cannot accommodate special requests for sale parts.

More About the Sale Materials

Aluminum 6061, is our most popular material. Its primary component is, of course, aluminum, element 13. But it gains extra strength by being alloyed with its periodic table neighbors magnesium (element 12) and silicon (element 14).

Next is stainless steel 304. As the name suggests, it's mostly made of iron, element 26. But by blending iron with a healthy amount of chromium (24) and nickel (28), it becomes corrosion resistant stainless steel and able to stand up to harsh environments.

Let's Begin

Ready to order? Upload your design now to order waterjet cut parts online!