Computer Controlled Machining

Make (design+mill+assemble) something big.

Demonstrate 2D design development for CNC production

Describe workflows for CNC production

Documented how you designed your object (something big)

Documented how you made your CAM-toolpath

Described problems and how you fixed them

Included original design files

Included a hero shot

Loaded a program and tested if your board works

Group assignment:

Complete your lab's safety training

Test runout, alignment, speeds, feeds, and toolpaths for your machine

Document your work to the group work page and reflect on your individual page what you learned

Link to the group assignment page.

Group Assignment

Choosing and measuring the material

I choose MDF 12mm for the assignment.

We measured the different materials the Lab has in stock. Most were 12mm.

Since I want to paint my shelf later, we choose MDF as its easiest to paint.

We carried the plate to the CNC

CAD and CAM in Fusion

Creating the test files in Fusion and preparing the toolpath:

Create some simple test models. One to test joints, a circle for runout, a rectangle for alignment.

Add dogbones with the dogbone add-in (explained below) or by hand.

Align them (make sure they are at least the diameter of the tool away from each other)

Go to the manufacture workspace

Create a new setup

First to set is the orientaton (select Z and Y option) and the origin (selected by hand, see pic)

Now adjust the stocksize. The material I'm using is 12mm thick. Hit ok for the setup

Select 2d contour as the toolpath

Select tool

If you need to make a new one, click the plus and this window will appear. Add the dimensions of your flute

Adjust the cutting data to your needs

Set this to 1

After you added the tool, select the edges to mill (make sure to select the bottom ones)

Set the bottom height offset to -0.2mm to fully cut through the material (make sure that there is a sacrifical layer of wood on your cnc that yo can cut into underneath)

Set the sideways compensation to right and the maximum roughing stepdown to about a fourth of the material thickness

If you hit ok now, it should look somewhat like this

You can simulate the toolpath now (Actions>Simulate)

No collision should occur. You might need to change your tool settings otherwise.

If you are happy with the path, you can hit post process

Select the post-processor of your cnc (usually needs to be downloaded first) and choose a location to save. Click Post.

Test results

Now that the models

Break the tabs to release the model

The result is rather bad, very jagged edges. This is because the tool is already quite old. For my actual shelf, I will use a sharper tool.

All cutouts

Sanding the edges to smooth them out

The cleaned models. Some edges weren't accessible with the sanding paper and some other parts broke off. The parts are very small and these problems wouldn't occur on a much larger scale

The joints fits together verywell. I did not create any offset for these. But the MDF is rather "soft" so I could easily hammer them in place. For future designs I'll add a small offset (about 0.075mm per side) just to be on the safe side.I will test this again before cutting my actual design.

The circles inner diameter is 20mm in Fusion and it's also 20mm in the cut part. So there is no runout in the tool. It's center and the spinning axis are aligned.

For the square the inner corners are rounded off. This was to be expected, as the tool diameter is 6mm. The angle is 90°, so no alignment issues with the machine

_{End of group assignment}

Design in Fusion360

I designed a chair, following this tutorial.

Starting with the plate to sit on. I placed it at this height using a construction plane.

Next up are the legs. I designed the left side first, already integrating the parts where I will stick it together.

Using construction planes and the mirror tool Icopy the right leg.

Adding the back plate :)

Forstability, I am adding these braces.

Front and back.

I still need to cut some pockets into the backplate and the sitting plate.

Lastly I am arranging the components on a plate that has the size of the wood I'll be using.

Adding dogbones

Now we I need to add dogbones to all my inner corners. This needs to be done, because the milling tool has a cylindrical shape and a certain diameter, therefore there cannot be any sharp inner corners in the design. I followed this tutorial to install a add-in for fusion which adds dogbones automatically. Follow this link: http://tapnair.github.io/Dogbone/ and install the add-in:

Download the add-in

Extract all the files and rename the folder to just "Dogbone". Ctrl+C the folder.

Head over to your AppData folder.

Open: Autodesk > Autodesk Fusion 360 > API > AddIns and then paste the Dogbone folder there

(Re-)Start Fusion. Head to Utilities and open Add-Ins. Click on the green plus to add a new one.

Select the Dogbone folder inside the master folder and add it

It will now appear in the list

Activate the checkmark and hit Run

Now, in the solid workspace, you will find this Dogbone tool

CAM Toolpath

Navigate to the Manufacture workspace. And create a new setup.

Apply all of the needed settings for the setup.

The first thing that will be cut are the pockets. So I am starting with 2D pocket.

These are the settings. Make sure you select all the pockets in you model.

Last two setting pages of 2D pockets.

Here you can see the toolpath which the machine will take. You see all of the pockets being milled.

I still need to do the edge cuts though. 2D contour is the optimal tool for this.

I am setting a 4mm flat end mill as the tooland select all the edges.

Here I am setting the Passes settings and so on.

Also here, you can see what the toolpath looks like.

Export this and go to your CNC.

Download my Fusion project file

Operating the big CNC

The mill in our lab is the elsign EasyWorker Master Pro 2513.

Before I started milling, I was given an instruction to the machine with an overview on all of the parts of the machine. Here we have the main part of the machine: the head that holds the milling tool.

The tool holder

valve for the high pressured air

The extraction station with the On/Off switch

The control station for the extraction pipes (This is there because there are multiple machines connected to the extraction, and to get the best pull to the extraction station, the ways to the other tools can be closed electricly)

And the vacuum bed control. A compressor creates the vacuum for the bed.

In order to operate the milling machine, we first loaded the bed with the material we wanted to mill. In my case this was a circa square sheet of wood with 12mm thickness. Under this sheed of wood was a sacrificial layer of MDF.

After loading the stock, it's time to prepare the CNC:

Start the PC.
Press the green start button after the program has started.
Start the machine after the program and stop the machine before closing the program to avoid information discrepancies.
Incorrect order of operation can lead to the mill crashing into the tool swapping station. The CNC lacks collision detection and could be damaged in such a scenario.

After completing these steps, we must zero the Gantry. For our CNC Mill, the zero point is located at the bottom right of the bed from the user's perspective while facing the control station. Consequently, we manually set the zero point using the control station's remote, adjusting its position incrementally until we are satisfied.

When zeroing the z-axis, the machine offers multiple automatic processes. Firstly, the machine can determine the length of the current tool automatically using a sensor located at the back. Secondly, the Gantry is equipped with a zeroing sensor similar to our Roland MDX-40. This step requires the assistance of two individuals. One person holds the zeroing sensor while the other initiates the process, keeping a finger on the escape button or the emergency stop in case any issues arise. The escape button serves as an immediate stop for the machine's operation.

Let's begin the milling process. Firstly, we ensured our safety by wearing earbuds and protective eye gear.
Next, we proceeded to open the high-pressure air valve.
Then, we started the vacuum bed with all neccessary vacuum zones active.
Following that, we activated all the necessary vacuum zones to start the vacuum bed.
Lastly, we initiated the exhaust system while confirming if the exhaust to the mill was either closed or open, considering that other connected machines might have been used.
Once these preparations were completed, we loaded the toolpath that was created in Fusion360. After carefully reviewing the projected job in the software, we commenced the milling process either by clicking the "start" button in the program

Process of milling the pockets.

Process of milling the edges.

-This is what it looked like after milling. There were no big complications while cutting.

Ahmed helped me break the tabs. I also sanded the edges a bit.

And lastlyI assembled the chair. I had to use a hammer to get everything together. But now that it fits it's so tight it's making the chair very stable. I have already stood on it and itdidn't wiggle.