Week 07: Computer-Controlled Machining:



This week I have created a project for a table and chairs set. Also, I have created a name and logo for the set.

The design is inspired by a classic of historic chair design. I'm going to try to make my new design with compacted wood (OSB).

Week Journal:

2.- Teamwork

If you want to know the group assessment of this week, click on the image of SediCupCt.


With my first idea, I was going to work on the designs for a wooden bookcase with cardboard drawers, but when I started drawing the sketches I had a better idea.

I came up with trying to design a three-legged chair. The basic idea was to think of a triangular chair, but thinking better, with this shape, the chair would be a bit uncomfortable.

So I used a square shape and I remembered seeing that design. Searching on the Internet I found it. My inspiration is based on the 1963 "Steltman Chair" design by designer Gerrit Rietveld.

Due to its history, this chair was designed for the jeweler named Johannes Steltman and its use was intended to be a chair for choosing wedding rings. These chairs by designer Gerrit Rietveld can be found in the Rijksmuseum and in the Kroller-Muller museum.

From this starting point, I have redesigned my own model to be manufactured with an osb wood slat (625x2050) mm.

4.-Designing a chair:

To design the model, I have used Solidworks because I am more used to it.

I start by drawing the 2D sketches with all their measurements defined. This sketch is the one I am going to use for milling.

After drawing the sketch, I extrude according to the thickness of the wood I'm going to use.

I save this piece and do the same for the remaining pieces.

To verify that all the pieces fit together, I create an assembly.

I see the result of this model and think that it should round the corners. I modify the sketches using the rounding tool and get my second chair model.

Also, with this rounded model, I am going to apply the textures of the material that I am going to use for milling (OSB wood).

With all the parts modified, I redo the assembly.

The idea to join this design is to use wood glue or other joining elements. This model will be assembled with these components, but the next design, the table, will not use any of them.

**** This choice has been made because being a wood formed with compact woods, I have thought that using the dovetail to join could be weak.

With another type of wood, I would use the dovetail to join the parts and thus avoid the use of screws or glue.



In order to work the parts with the milling software, I am going to export the sketches in .dwg or vector .eps format.

To save them in dwg, I do it directly from Solidworks, to check that it is exported well I open it with e-drawing.

To go vector, I import the dwg into Illustrator and save in eps and svg.

5.-Making a table:

To make a complete set, I have designed a table to match the chairs.

The idea is that the four chairs placed around the table, seen from above, form a square, so it occurred to me to make a round table, to make the effect of a circle inscribed in a square.

Unlike chairs, the table has been designed to be assembled without glue or screws. It only joins with the grooves that have its parts.

His pieces would be the following:

The assembly of its parts designed in SolidWorks would be the following:


To see the effect of the whole set, I have created a render:

6.-Creating the code for the milling machine:

To operate the 3-axis milling machine, I am going to use Vectric's Aspire program.


The steps that I have followed to create the cnc file to mill the chair have been the next:

When opening the program, the first thing I do is set the dimensions of the wooden board.

Then I insert the vector file that I created earlier.

After importing the file, I have to create its contours with the command "create contour" and check that the vectors that form them are closed.

If the vectors are not joined, I have to use the check open vectors tool, and with this tool close them.

With the edit mode, I have to put some chamfers in the corners of the joining regions, so that the mill can fit well. If the chamfers are not fitted, due to the geometry of the mill, the corners will be rounded when turning 90 degrees during the milling process.

When all the contours are well adapted, I can start working with the milling operations.

In this case I am going to create a profiling path, with a depth of 16 mm so that it crosses the 15 mm thick board, I am going to configure the tool, which will be a 6mm mil and for wood.

In addition, I am going to indicate that I machine the lines on the outside and I am going to add some tabs in the trajectories to prevent the part from moving during milling (5mm length and 3mm thickness).

*** To make the tool start more smoothly, I'm going to indicate that it starts with a ramp approach.

Once all the parameters are configured, I name the operation and click on calculate.

At this moment I can simulate the toolpath to verify that the operation that I have configured is done correctly.

When verifying the operation, I save the file in “G code Arcs (mm) .tap” format.

*** WARNING: it is important to order the processes when milling. First you have to do the milling processes of the inner parts and at the end the cutting milling processes.

I save this file on the milling machine's pendrive.

7.-Milling the chair:

The parameters and the process to create the gcode of the chairs, without the same as with the table:

After generating the file with Aspire. I insert the pendrive into the router control knob and turn on the router.

The first thing I have to do is the HOME of the machine.

When I have made the home machine, I configure my work home on the corner of the wooden plank.

To do this I bring the mill close to the corner of the corresponding wooden plank, carefully, I make the x = 0 y = 0 and go down slowly to make the z = 0 (loosening the bur a little and tightening again).

* These steps are similar to doing HOME on the circuit mill.

Then I load the file with the code from the pendrive. When it is loaded, from the control I configure the working speed.

At this point, I turn on the puller and hit OK to begin milling the saddle.

8.-Milling the table:

Following the same sequence as with the chair, I have generated the file to mill the table and have launched the code to the milling machine.


With all the pieces milled, all that remains is to assemble the parts of each element.

Chair: wood glue, 12 screws and 6 brackets are required.

Table: nothing else is necessary.


10.-Alternative version:

While I was making the model, since I like to play board games with friends, I came up with a version of board games, which can also be attractive for workshops or activities with children.

This is a version based on Parcheesi:

Each chair painted in a color (like the players) and the round table has a modification to add some colored acrylic pieces.

The set’s logo born from the shape of the set seen from the top view

and the number 2-5-2 born from the chairs.

12.-Experience and conclusions of the week WEEK7:

I liked this week, because since I graduated from university, I have not used a milling machine of this size to do a project.

The topic of creating something great motivated me and I chose to do the set that I have talked about.

It seemed to me a creative week, in addition to the fact that the wood that I have used (OSB) I did not know, it has been a good discovery.

I also liked sharing this experience on Regional Review, because the results are so impressive. Also, some colleagues who shared their work got very cool.

“What went wrong”: Nothing relevant.

“What went well”: The milled parts assembled very well. I did not need to sand them or adapt them so that they could be assembled.

“What will you do differently next time”: I would try milling the acrylic pieces. I did not have time to do that test for the version of Parcheesi.


252-hec-fab table set model 1
252-hec-fab table set model Parcheesi