Cable carrier and E-stop switches installation

I finally managed to install the cable carriers and the E-stop switches. The machine looks better and better now.

More wiring

I've received the cable carrier drag chain and emergency stop buttons on Friday. I need to install them on the machine

Cutting some foam

As the purpose of the CNC machine is to cut and carve foam, I did some testing, adapted some hot wire tools for the purpose and cut some foam I had lying around.

Cutting the logo of Aliptera

Using a hot wire tool:

Tried some 3D carving. The melted foam didn't have where to go so the bad result is expected.

The tool used:

Some more "Art"

Tools used to build the machine

It is time to talk about the tools used to build the machine.

• A drill press, bought specially for this purpose from Kijiji.
• A miter saw I borrowed from my friend Ion, Ion thank you for lending it to me, without it I would have a hard time cutting all those aluminum profiles!
• A bench grinder I made;
• A hand drill and various other hand tools.

Wiring and table fittment

Last weekend I didn't do too much: I cut the table out of birch plywood, it is not yet attached to the moving X axis frame;

I mounted the electronics and did some wiring.

I found some neat locations for the home position switches and wired them:

Building a base for the machine

I decided to build a wooden base for the machine.

First 3D real test

The 3D "pen" test

Building the X axis

As I'm gaining experience building this thing, It seems to go faster and easier,  maybe I'm seeing the finish?

Testing the Z and Y axes

They are working fine!

Z axis mechanical drive

This is the most complicated thing of the whole enchilada.

In order to move the whole beam up and down, it has two driving belts, one for each end of the beam, driven together by a shaft.
To counter balance the weight of the beam and Y mechanical axis, I choose to use constant force springs, instead of weights for the purpose of reducing the inertia.

The constant force springs are expensive, so for now I'm using a low-tech approach, bungee-cords.

Received printed idler gear

I have received the 3D printed idler gear today.

Thank you Alex for printing them for me! They look really nice.

Thank you Cristian for helping me modifying the source file so the model accepts 608Z ball bearings I already have.

Working on the belt tensioner:

Tool holder

Working on the tool holder. Lots of bearings!

Linux CNC RTOS errors

Something is wrong with the computer running the LinuxCNC. As I generate steps in software I need it to be fast. I'm getting errors in the real time kernel. Eventually I figured it out: The thermal paste on the heat-sink have dried out and provided inadequate cooling to the CPU.

Building the electronic board

The parts for the motor driver have arrived, I am assembling them.

Y axis trial

Posting pictures and video for the Y axis movement.

Z axis trial

Posting pictures and video for the Z axis movement.

Building the frame

I've cut the aluminium profiles and started to build the frame. Here are some pictures:

Electronics

Motor drivers: I ordered TB6600 motor drivers and I made a simple board to interface to the parallel port.

Schematics:

Layout:

I found an old computer and I installed LinuxCNC. It seems to be working fine.

Mechanical Movement

Motors:
Choice was between stepper motors and DC servo motors; I decided stepper motors would be easier to control. I ordered 3 stepper motors from AliExpress: link

I decided to use belts for converting rotational movement of the steppers to translational movement. They are faster, low noise, and cheaper than lead-screw used generally for this purpose. I found a nice site selling belts, gears and all kind of useful stuff: http://www.robotdigg.com/

Planning

The machine would have a fixed frame, as it offers more rigidity, having a table moving in X axis, a gantry moving on the Z axis and a tool holder moving on the gantry along the Y axis.

A rotating axis "A" axis could be added to rotate the tool or on the table, rotating the work-piece.

The frame:
After some research I decided to build the machine out of  "baltic birch" plywood. The sliding prismatic joint should be made by bearings on aluminium profiles. It should look something like this:


I found some discarded aluminium framing materials, I decided to make the frame out of that, as it confers more rigidity and more important it is not subjected to warping as the wood is and also I can use it as a basis for the prismatic joints as well.

Scope

While building prototypes of concept model lip wing aircraft, presented on aliptera.com website, I run into cutting by hand complex curved shapes for the wings and fuselage.

The work was tedious at least, the model didn't look very good and it took forever to make.

I reached the conclusion I need a CNC machine to do the complex shapes I want.

It needs to be able to cut foam in 3D, making complex shapes. For this I think a loop of nichrome wire of 1/4 -1/2 inch diameter would do nicely.  To ensure rigidity of the loop some thicker gauge wire should be used.

I would like to use it also for cutting/engraving aluminum, wood, plexiglass.

Size: As big as possible. 4 x 3 x 3 ft would be nice.