Today I begin my week #7 of Fablab Academy and in comparison to last week, this one is totalle different. This week is about Computer-Controlled Machining. So this means I have to design and make something big. In this week I will be learning how to use a new
machine, the Shop bot and the semi automatic router. I think of all the machines i've been waiting for the shop bot and getting to know it, i'm a little curious too about the semi automatic router. So let´s start with this week assignments and hope for the best.
This week assignmets are:
Group assignments:
Lab's safety training.
Test runout, alignment, fixturing, speeds, feeds, materials and toolpaths for your machine
Individual assignments:
Make (design+mill+assemble) something big (~meter-scale)
Extra credit: don't use fasteners or glue
Extra credit: include curved surfaces
What will I need for this week assignments:
ShopBot CNC
1/2 in plywood
SolidWorks or any design software you prefer.
Fusion 360
ShopBot 3 (software for the ShopBot)
Milling bits:
1/8" ball end mill
60° v-groove
1/4" flat end mill
ShopBot CNC
ShopBot CNC
A CNC (computer numeric control) tool is used in prototyping and full production for cutting, carving, machining and milling in a variety of materials including wood, mdf, plastics, foams and
aluminum. ShopBot Tools, like all CNC tools, move a cutter around a big table (X and Y axes) and move it up and down as well (Z axis) allowing it to make 3D movements and cut all sorts of
shapes. The cutter looks like a drill bit and is spun by a motor called a router or spindle.
It can create virtually any pattern or shape and will do it in materials such as wood, plastic, foam, aluminum and many composites. You
use the included software to design your parts on your personal computer, then, like a robot, the computer controls the cutter to precisely
cut your parts. Now, all the types of computer-driven tools that create things by cutting material away (such as CNCs or laser cutters) or
building up material in layers to create an object (3D printing) are called digital fabrication tools.
Unlike a drill bit, a router bit is designed to cut from the sides as well as the tip. By precisely moving the cutter through material, it can
create virtually any pattern or shape and will do it in materials such as wood, plastic, foam, aluminum and many composites.
Autodesk Fusion combines CAD, CAM, CAE, and PCB into a single, integrated cloud software platform. It includes all the tools that you
need to go from design to manufacturing, seamlessly.
With Autodesk Fusion, you'll be able to:
Explore design iterations with easy to use 3D modeling tools.
Produce high-quality CNC machined parts with integrated CAD/CAM.
Gain access to unified electronics design.
Test the performance of your designs with 3D simulation tools.
Explore manufacturing-ready outcomes with generative design.
Collaborate and manage your data seamlessly in the cloud.
This safety summary contains general safety warnings that should be understood during operation of this machine. Failure to observe these precautions could result in injury.
Learn and understand safe use of the machine. Do not allow untrained individuals to operate the machine without supervision. Be aware of the location of the Emergency Stop switches at all times.
Eye and ear protection MUST be worn by the machine operator as well as any bystanders or observers. Flying sawdust, material chips, and other debris can cause serious eye injury.
Wear closed-toe shoes at all times.
Make sure that material is properly secured before cutting and be aware of any small parts that may come loose after being cut. If a small part catches the edge of a spinning bit, it can be thrown forcefully in any direction, causing injury or damage.
Never place your hands on the rails of the ShopBot. Be aware that the machine may move unexpectedly in any direction, which can cause serious injury if your hands are in the path of movement.
Never wear gloves while operating the machine. As with any power tool, a glove can get caught in moving or spinning parts and pull your hand into the machinery.
Never leave a machine running and unattended. Understand that a spinning tool generates friction and heat, creating a risk of fire. This risk is minimized by using correct
chip load, using sharp bits, and by always double-checking your files before cutting. Be prepared to pause or stop the cut if something seems incorrect or unsafe.
Keep a working fire extinguisher within reach of the machine, for the reasons listed above.
Do not use cel phone while operating the ShopBot.
A2). Test runout, alignment, fixturing, speeds, feeds, materials and toolpaths for your machine
In this section, I'll show the measures, equipment I will use and how to change the milling bits. So let's begin:
So I dress up before I start my cutting assignments in the ShopBot. As you see I have the necessary security equipment as recommended in section A1:
Lab coat
safety gogles
safety earmuffs
No watch, bracelet or rings
No cel phone
The remote pendant in case of emergency.
Individual Assignments
A. Making a design
A1). Desig in solidworks
For this weekly assignments I have to design something big and then cut it in the ShopBot. I decided to make a coat rack. So lets begin with the design.
Some characteristics about the design:
I has to be big.
I'm desinging multiple parts and then assemble them.
I will try to avoid square edges.
And assemble the parts.
Here are som pictures of the desinging process:
The first two shows the rack.
In the next images it shows the base.
I made tow bases the small one has a 10 in. diameter and the big one 14 in. diameter
The idea of making two is for stability.
For the next part of the desing I made a rectangle that will be part of the cross that is goning to help the assemble process.
I made a cut in the middle for the assemble process
Finally the supports that will cross the rack.
I decide to make 7 of them.
And the assemble.
Individual Assignments
B. Setting the ShopBot
B1). Configuring the ShopBot with Fusion 360
In this part I'll show the previous configurations of the ShopBot using Fusion 360. First of all, you need to install Desktop Fusion 360.
Now lets start with the configuration:
Once you download Autodesk Fusion 360, you start the installation and open it.
Then click on Manufacture and then on the list Manufacture
Now click on Machine library
click on Local and on the plus sign to add a new option
click on Milling and define information of the ShopBot
In capabilities you have to uncheck the two options shown in the red rectangle
For the next step we go to: ShopBot library and download Shopbot OpenSBP library
After downloading the library, click on Post processing and the folder icon and select ShopBot tools / ShopBot Open SBP
In this third part I'll show the results of the calculations for the speed and feed values for the machining process. For these calculations, I'm using this web page: HSM advisor, which helps calcualte a free CNC
parameter calculator. For the end mill, I got the following parameters:
B4). Configuring the desing with Fusion 360
In this section I'll explain what I did before I start cutting my design. As I told you before it's very important to getting to know the machine, how it works, what can we do with it and of course the safety
measures/protocols in case of any emergency. In the video you can see the previous configurations of the ShoBot, lets begin:
I use solidworks for my design, I have to prepare the design to use it in Fusion 360.
I design several parts, so I made an assembly to gather all those pieces in one file.
In this part I have to make sure that all the parts are level (there shouldn't be any of the part on top/below of another part)
Make sure you group all the parts so that you make good use of the space, don't waste too much space (nesting).
Open Fusion and go to the new option, select Open.
In the screen I selected the file that has all the parts of my design.
You can see that all parts are group and I try to save space.
Next go to Manufacture then New setup, in this step you need to choose the machine, operation type you'll be doing. In my case ShopBot 9648 and milling.
Define the origin and my x and y axis.
Now, I go to the 2D contour button.
In this step i must:
Select the right milling bit (1/4 flat end mill).
In Tool section set the spindle speed to 12000 rpm.
In Geometry section choose the parts I want to cut and can give the cutting order.
In Clearence section define the bottom heigth, this means the depth of the cutting.
In Leads & transitions set the angle of the helix that leads into the cavity.
For the next step, click on 2D contour, simulate
Now, the Post Process
This step creates NC code for the setup.
Specify the machine and a file name.
Now, I define x,y,x axis and set origin using the ShopBot 3 software.
Save the file and if youre ready to cut.... CUT!
Here's a video of the ShoBot configuration
B5). Cutting time
This is the moment of truth.... lets start cutting the coat rack. But before, just one more test before I start cutting. So I simulate the cutting process in the air and verify everything was ok, I share the video. As
you can see in the video there were no problems.
Now, the moment of truth.... my final cutting in the ShopBot.. Here's a video that shows different moments during the cutting.
I decided to put a logo from the Faculty of Engineering, the final result has no fasteners and no glue, here´s the final result:
Problems during this week.
This was a very interesting week. But it's important to understand that "things happen" and its a way to learn about materials, machines, procedures and configurations.
During this week assignments, some problems came along. So let me tell you about them and what I did to solve them.
The x and y axis.
So, while I was configuring the the design in Fusion 360 I didn't notice that my axis were wrong. I notice about this when I made my first simulation on the ShopBot.
What did i do? First, I check the ShopBot and verify if there was something blocking part of the rails.
Then I verify milling bit.
Finally I notice the x and y axis were wrong, so I went back to fusion 360 and modify them.
You can seethe video of the problem during the simulation.
Another problem was the measures of the supports were off by a few millimeters.
What did I do? In this part I had to start reducing by 0.05 inches approximately
I think the ideal way to test the supports was to cut just the holes and start testing the supports. But I thouth about it to late, so I had to make measures changes several times.
You can see some pictures of the results I got by changing the measurements of the supports.
Final part
Files
In this part you can download the files that I use for this 7th week assignments.