Fab Academy 2017
Learn how to make ALMOST anything!

Computer Controlled Machining


 

For this week's assignment, It was required to

Make something Big!

 

So, What is a CNC?

The term “CNC” is a generic term which can be used to describe many types of device, this would include plotters, vinyl cutters, 3D printers, milling machines and others. CNC stands for Computer Numerically Controlled and basically means that the physical movements of the machine are controlled by instructions, such as co-ordinate positions that are generated using a computer.

The term “CNC Machine” is typically used to refer to a device which uses a rotating cutting tool which moves in 3 or more axes (X, Y and Z) to cut-out or carve parts in different types of materials. The information on these pages will focus on what are typically referred to as “CNC Routers” although it would be applicable to most CNC milling and engraving machines too.

Egypt is celebrating Mothers' day next week, and this task is the perfect opportunity to make my mum a handmade gift instead of buying her one! :)

Some interesting Stories to tell, when I first started working at Fab Lab, I was making small stuff like key chains and pen holders. And on one of the mothers' days, I bought her a gift out of wood and the first question she asked me was "Did you make this?". That made me happy actually, because seeing my mum embracing this making mindest and shifitng her thoughts from "How much it costs to buy?" to "How can I make it?" is an achievement that counts! :)

I got my first idea for this week's task from a funny story happened while I was brainstorming for ideas. I was having a chat with the school psychiatrist and we were laughing about having a sharing session, and she told me "Unfortunately, I don't have a chaise long, so you can stay and talk"; so I replied "Well, let's do it! :D " .

 

Generally, To prepare your file for machining, you need to do few steps:

1. Design using 2D and 3D tools.

2. Select your material.

3. Prepare your CAM file (g code file in whatever format your machine accepts).

4. Prepare your machine.

5. Cut.

 

Design using 2D and 3D tools:

I sketched the chaise long along with dimensions as shown in picture. It's a simple structure from both sides, connected with sheets inhereted as press-fit.

 
 

My second idea was the table, and this what I went for at the end. It had the same design concept as the chaise long with 2 main structures glued with press-fit sheets, shown in picture.

 

For CAM, I used VCarve Pro. The software is really amazing and easy to use. The full design of the table was implemented in 20 minutes. The wood plate that we usually use is 2440 x 1220 mm in dimensions.

Here How it looked.

   

Now, the file is ready for CAM operations!

I used VCarve Pro as I use the PRS alpha Shopbot. You can get your file ready in few steps:

1. Open new job, set its dimensions and the material thickness origin.

I used MDF wood of thickness 14 mm.

Creating New Job on VCarve Pro.

2. Import your DXF file as vectors:

Importing the file.

And Here how's the file appears

Imported file.

3. Preparing toolpaths:

Toolpaths are the main component! they are the paths which the machine actually implement. So, it's extremely important to understand types of toolpaths and which one is suitable fo your job.

In V Carve Pro, there are lots of types. And you can simply check them by choosing "Toolpaths" in main menu.

Important Note:

In your material settings, it's pereferable to add 2 mm to make sure that the cut is implemented well. You'll get that warning (In the below picture) but you can click Ok and proceed.

I used an End Mill 1/4" Down-cut to cut the border. You can check its specs in the picture below.

End Mill Specs and settings.

This will create the path for the machine and you can check it in 3D view.

End Mill path.

End Mill direction.

The Last thing you need to do is to download your toolpath for the machine.

 

Preparing Your machine:

The first of the machine is to set your origins; X, Y and Z.

On the Shopbot, When you open the controller, this is your control panel on which you do most of the work.

To Zero X and Y axis, click on XY button . This will enable the machine to start zeroing using proximity switches automatically whitout any intervention from you.

To Zero the Z axis, click then on Z Button . The machine will ask you to put the metal plate under the tool and then run the process.

Zeroing Z axis. Zeroing X & Y
 

And you're then ready to go!

Cutting the files:

Now that you're ready to go, load your part files with the logical sequence of engraving or cutting the interior and then cutting the outer edge. This will give your piece more stability and accuracy in the cut process.

Then Just Click "Cut", and Here you go.

Repeat those steps till you finish all your part files.

 
 
 
   

HERE WE GO!

   

Downloads:

1. V Carve file..

2. Shopbot toolpaths files..